CCM Validation Activity for SPARC


List of CCMVal Contributions

The table below gives an overview of CCMVal Collaborators and ongoing CCMVal work.
General questions can be directed to Veronika Eyring.
Please directly contact the CCM Collaborators for specific questions on a certain study.
Please see Guidelines  for CCMVal Collaborators for instructions how to become a formal "CCMVal Collaborator".

List of CCMVal Contributions: CCMVal-1
List of CCMVal Contributions: CCMVal-2: individual studies
List of CCMVal Contributions: CCMVal-2: SPARC CCMVal Report (names listed here and the model groups have access to CCMVal-2 PHASE0 data)
List of CCMVal Contributions: CCMVal-2: studies with sensitivity runs in support of WMO 2010
List of CCMVal Contributions: CCMVal-2: individual studies continued

The CCMVal data policy involves two phases plus an additional PHASE 0 for newly submitted data. The current status is as follows:
CCMVal Collaborator(s)
Date of Proposal
Data Request(s)
Veronika Eyring,
Neal Butchart,
Darryn Waugh
Assessment of 
trace species
and ozone in
CCM simulations
of the recent past

Simulations of the stratosphere from thirteen coupled chemistry-climate models (CCMs) are evaluated to provide guidance for the interpretation of ozone predictions made by the same CCMs. The focus of the evaluation is on how well the fields and processes that are important for determining the ozone distribution are represented in the simulations of the recent past. The core period of the evaluation is from 1980 to 1999 but long-term trends are compared for an extended period (1960-2004).

CCMVal 1st data request

WMO 2006 data request
Eyring et al., 2006
Veronika Eyring,
Darryn Waugh

Multi-model projections of stratospheric ozone in the 21st century

Multi-model simulations with nearly identical forcings from the current generation of coupled chemistry-climate models (CCMs) are used to project the evolution of ozone throughout the 21st century. While there is a wide spread in the predicted evolution of ozone, the CCMs agree in several important regards, so that general conclusions can be made and some confidence placed in their projections. 

01/01/2006 WMO 2006 data request Closed
Eyring et al., 2007
Neal Butchart, Irene Cionni, Veronika Eyring,
Darryn Waugh
Stratospheric Climate and Circulation Changes

The CCM simulations will be used to study stratospheric climate and circulation changes. The study will only use diagnostics from the underlying GCMs with the exception of the age-of-air tracer. Ozone will only appear if this is relevant to any discussion of changes in the radiative heating.  In contrast to previous comparisons of stratospheric climate predictions, the CCM simulations used here are all transient simulations and have almost identical experimental set-up and forcings.  The analyses will update or extend the few other published inter-comparisons of stratospheric predictions, including the heat fluxes temperature relationship as assessed in Austin et al. (2003), temperature changes discussed in Eyring et al. (2006) and the changes in tropical upwelling considered by Butchart et al. (2006). We will look at those aspects of stratospheric climate and circulation change which are robust, i.e. model independent. A more detailed analysis of temperature changes than in Eyring et al. (2006) will consider the seasonal and spatial distribution of the trends and separate secular trends from low frequency variability. The relative importance of the diabatic and adiabatic contributions to the temperature changes will be assessed.  A key question that will be addressed is how the Arctic polar vortex changes in the REF2/SCN2 simulations. Other key questions to be addressed are: what are the predicted changes in the Brewer-Dobson circulation and to what extent are these changes related to age of air changes in the different models. Also how do changes in tropical upwelling  relate to changes in polar down-welling.

01/10/2006 CCMVal Dynamics data request

Closed Butchart et al., in preparation, 2009
John Austin Solar Cycle Variations in Ozone and Temperature
Past CCM simulations of zonally averaged ozone and temperature will be examined for the presence of the 11-year solar cycle using linear regression against the 10.7 cm flux and other relevant variables. Previous simulations (e.g. Shindell et al., 1999; summary of model results in Soukharev and Hood, 2006), indicate that both 2- and 3-D models do not represent the correct vertical distribution of the ozone signal, especially in the tropics. Those models give an ozone response which is too low in the upper and lower stratosphere, and two high in the middle stratosphere, as a result of which the observed middle stratospheric minimum is not simulated. The temperature solar cycle is also not simulated accurately because of the radiative impact of ozone.  By contrast, the REF1 simulations of AMTRAC reveal the correct ozone vertical distribution in the tropics (Austin et al., 2006) and other REF1 simulations also produce similar results (personal communications, 2006). In AMTRAC control runs which contain a solar cycle, but fixed forcings agree with previous (poor) simulations in not reproducing the mid stratospheric ozone minimum solar response. In the proposal, all the relevant CCMval simulations will be examined, including some future runs, firstly to establish which simulations have the correct solar signal and which do not. This information will then be used to identify the degree to which different aspects of the forcings are able to simulate the ozone solar cycle, to include SSTs and the QBO, and whether the full solar cycle in UV forcing needs to be applied.  
15/10/2006 CCMVal 1st data request Closed Austin et al., 2008
Andrew Gettelman,
Thomas Birner
Vertical Temperature Structure of the Tropical Tropopause Layer (TTL) Climatological characteristics of the vertical temperature structure of the tropical tropopause layer (TTL) are studied from state-of-the-art GCMs. We will focus on two, the Canadian Middle  Atmosphere Model - CMAM, and the Whole Atmosphere Community Climate Model - WACCM, but extend the analysis to all available CCMs and compare to radiosonde observations.
The radiosonde analysis focuses on five tropical stations for the years 1998-2005, located in the West Pacific. Averaged profiles are constructed with respect to the cold point tropopause (i.e. the top of the TTL). This results in an extremely sharp cold point in mean temperature profiles and a very strong peak in thermal stratification just above the cold point. The strength of this peak is not significantly correlated to cold point temperature/height, stratification just below the cold point, or convective activity as estimated by CAPE. The base of the TTL shows up as a maximum in lapse rate, as well as a maximum in the frequency of occurence of dry superadiabatic lapse rates.
Given their rather coarse vertical resolution (~1 km around the cold point), CMAM and WACCM exhibit a remarkably realistic TTL, including a distinct cold point and base of the TTL, despite the crude representation of deep convection in these models. Deficiencies of these models emerge when looking at the variability of e.g. cold point temperature and lapse rates in the TTL.
15/10/2006 CCMVal 1st data request Closed Gettelman et al., 2009
Klairie Tourpali Past and Future
UV calculations

Surface UV irradiance is mainly affected by the total ozone amount (TOZ), clouds, aerosols and surface albedo. In order to assess the response of surface UV to model predicted total ozone changes, a radiative transfer model will be used with TOZ as main varying input. The analyses will be performed for clear skies for the past ozone changes as calculated by the CCMs as well as for their future predictions. In a second stage, the same analyses will be conducted with the inclusion of surface albedo in the radiative transfer modeling in addition to total ozone predictions. A comparison will be made for the past UV irradiance to available measurements in order to assess the magnitude and variability of the response.


Data needed: 2D monthly mean total ozone and surface albedo as a function of longitude and latitude

Closed Tourpali et al., 2009
Farah Khosrawi,
Rolf Müller
Separation of 
and Transport
Induced Ozone
Changes in the
We would like to compare monthly averages of N2O and O3 derived from CCM simulations with monthly averages of N2O and O3 derived from satellite observations. Using monthly averages of N2O and O3 helps to separate O3 variability due to latitudinal transport from photochemical changes. This method has been suggested by Proffitt et al. (2003). In their study Proffitt et al. (2003) seasonally averaged lower stratospheric distributions of N2O and O3 which were binned by potential temperature or altitude. The study by Proffitt et al. (2003), which was based on ER-2 data, was restricted to the lower stratosphere and the Northern Hemisphere. However, in the following studies by Khosrawi et (2004) and Khosrawi et al. (2006) the method of Proffitt et al. (2003) has been successfully applied to satellite data and extended to the upper stratosphere and Southern Hemisphere. Satellite data are particularly suitable for deriving monthly averages of N2O and O3 due to their high spatial and temporal resolution. Khosrawi et al. (2006) derived a 1-year climatology from ILAS/ILAS-II observations. Another 1-year climatology has been derived from Odin/SMR observations. Such climatologies can be derived also from CCM simulations and then compared to the climatologies derived from satellite observations. Thereby, differences in ozone dynamics and chemistry between the models and the observations can be made visible. Validation studies of this kind will complement those considering ozone profile observation at specific locations or ozone column measurements.
CCMVal 1st data request Ongoing
Nathan Gillett,
Lesley Gray,
Gareth Marshall
, Susan Solomon, David Thompson,
Adam Scaife

Implications of projected future changes in stratospheric ozone for tropospheric climate

We propose to examine the dynamical implications of future changes in stratospheric ozone for tropospheric climate, by prescribing a range of future ozone scenarios from CCMVal models in a coupled ocean-atmosphere GCM. We will start by comparing simulated ozone for 1980-2005 with observed ozone changes to validate these models. This work will build on the model intercomparison study of Eyring et al. (2006), but will be more focused on validation of the aspects of stratospheric ozone most important for surface climate, and will be aimed at identifying a quantitative metric of model-observation agreement in simulated ozone. This metric will then be used to identify a subset of models whose simulations of past ozone change are most realistic. We also propose to use detection and attribution methods (e.g. Mitchell et al., 2001) to objectively compare simulated and observed zonal mean stratospheric ozone changes, and to distinguish the component of ozone change associated with stratospheric chlorine change from a residual component related to changes in atmospheric dynamics. Having identified a subset of models with the most realistic simulations of past ozone changes, we will use their simulations of future ozone change to drive an ensemble of simulations of HadGEM1 over the 2000-2050 period. Our focus will be on dynamical changes in the troposphere, particularly changes in the Southern Annular Mode, and their implications for the climate of the Southern Hemisphere. 27/10/2006
CCMVal 1st data request Ongoing

Wolfgang Steinbrecht
Long-term ozone and temperature variations I plan to compare interannual and long-term ozone and temperature variations from the observational records (NDSC lidars and microwave radiometers, SAGE, HALOE, SBUV) with the CCMVal simulation results. Initially, the focus will be on the upper stratosphere. The goal would be to separate chlorine-related ozone changes from other variability.
CCMVal 1st data request Ongoing

Chiara Cagnazzo,
Elisa Manzini

Evaluation of the response of the stratosphere to ENSO events in CCMs

The role of variations in Sea Surface Temperatures (SSTs) associated with ENSO events on the Northern winter polar stratospheric circulation is a topic of current investigation, addressed with the analysis of observations, reanalysis and models. Results from these investigations indicate that ENSO events are associated with a polar warming of a few degrees in the lower stratosphere in late winter and early spring. Consequently, the polar vortex is weakened, and the warm ENSO influence emerges in the zonal-mean flow.  Here it is planned to extend the evaluation of the stratospheric response to ENSO events to the simulations with observed SSTs recently performed with Chemistry Climate Models.  The main aims are to identify the coherence in the responses across the models and  to understand the causes of the possible range of responses in terms of simulation designs and model biases. It is planned to construct composites of specified meteorological and chemical fields from time series of an ENSO index for cold, neutral and warm SST conditions, following Manzini et al (2006).

10/11/2006 CCMVal 1st data request
3D Monthly means for temperature and geopotential height
Closed Submitted
John Austin,
Piers Forster,
and the SPARC T-trends panel
Simulated versus 

temperature trends,
the impact on
In the process of analysing the past CCM simulations for a solar cycle in ozone and temperature (proposal by J. Austin et al.), a linear trend term will be included in the regression analysis. This proposal analyses that trend term for emperature over the period 1980 to the end of the simulations, and compares results with up to date observations from satellites and radiosondes (Randel et al., 2006). Latitudinal varying trends will be interpreted in terms of the known impacts of ozone for the individual models, described in Eyring et al., 2006. Calculations for the global average as a function of pressure reflect the performance of the model radiation scheme and will be compared with earlier calculations with a different suite of models by Shine et al.(2003). The water vapour and ozone fields will also be used to determine global timeseries of radiatively weighted forcings. The impact of the individual forcings will then be estimated by linearly regressing the temperatures against the forcings as a function of pressure.
10/11/2006 CCMVal 1st data request Ongoing
Signe Bech Andersen Comparison of observed and modeled trends in total column ozone The purpose of the study is to update work on observation versus model agreement with regard to ozone recovery (Andersen et al., 2006; Weatherhead and Andersen, 2006). The plan is to investigate if observed changes in ozone trends are in agreement with what is expected from model calculations. Latitudinal, altitudinal and seasonal features will be studied.
14/11/2006 CCMVal 1st data request
in particular ozone fields
Martyn Chipperfield,
Wenshou Tian
Comparison of NOy abundance, partitioning and trends in CCM runs
This study will investigate the NOy chemistry of the CCM runs. The yield of NOy produced from N2O will be compared (e.g. correlation plots) and differences related to photochemical parameters and possibly transport. The distribution of the main NOy reservoirs will be compared with climatological data (e.g. SPARC dataset). This will also show the impact of the models' (simple) denitrification schemes. The partitioning of species in the NOy family will be intercompared and, hopefully, tested by comparison with profile observations of most of the major NOy species (e.g. balloon profiles, ATMOS,.., - subject to issues of sampling the models). The impact of aerosols on NOy partitioning will be investigated by analysing runs through the Pinatubo period and afterwards. Finally, any long term trends in NOy species will be deduced and compared to that expected based on the N2O boundary condition.
15/11/2006 CCMVal 1st data request
Thilo Erbertseder,
Veronika Eyring
Hemispheric Ozone Variability Indices

Total column ozone is used to trace the dynamics of the lower and middle stratosphere which is governed by planetary waves. In order to analyse the planetary wave activity a Harmonic Analysis will be applied to global multi-year total ozone observations from e.g. TOMS (Total Ozone Monitoring Spectrometer (TOMS) and ERS-2/GOME (Global Ozone Monitoring Experiment) and corresponding total ozone fields from coupled chemistry-climate models (CCMs). It will be quantified to what extent the CCMs are able to reproduce the zonal and hemispheric planetary wave activity.
As diagnostic variables we apply the hemispheric ozone variability indices one and two (Erbertseder et al., 2006). They are defined as the hemispheric means of the amplitudes of the zonal waves number one and two, respectively, as traced by the total ozone field. The hemispheric ozone variability indices can be regarded as a simple and robust diagnostic to quantify model-observation differences concerning planetary wave activity. It allows a first-guess on how the dynamics is represented in a model simulation before applying costly and more specific diagnostics.

WMO 2006 data request Ongoing


Marion Marchand,
Slimane Bekki,
Philippe Keckhut,
Nicolas Yan


Variability and trends of the stratosphere in CCM
simulations and NDACC measurements
We are planning to estimate the contributions of different factors in the variability and long-term trend of the stratospheric chemical composition and dynamics. We will carry out multivariate regression analyses on long time series of observations and CCM simulations. The observational data will be taken from the international NDACC (Network for the Detection of Atmospheric Composition Changes) data series. The model-simulated data will be taken from the CCMVal REF1 numerical simulations. The aim is to check the consistency between observations and model simulations and identify the driving factors in the evolution of the stratosphere over several NDACC measurement sites. 16/02/2007

Markus Kunze,
Ulrike Langematz

CCM validation against measurements obtained during the SCOUT-O3 aircraft campaigns

During the European project SCOUT-O3 aircraft campaigns were carried out in Darwin (Nov/Dec 2005) and Ouagadougou (West Africa, Aug. 2006). We want to validate CCMs against the measurements obtained during these campaigns. As a direct validation is not possible, we want to analyse the inter-annual variability and the longitudinally differences in the CCMs. Emphasis of the analysis is on temperature, water vapour (measured with the instruments FISH and FLASH), ozone (FOZAN), methane (ALTO), carbon monoxide (CO_TDL), CFC-12, CFC-11, Halon 1211 (HAGAR), nitric oxide and total reactive nitrogen (SIOUX).

CCMVal  SCOUT-O3 aircraft data request


Susann Tegtmeier Persistence and photochemical decay of springtime total ozone anomalies in CCMs The CCM total ozone timeseries will be used to analyse the persistence and decay of springtime total ozone anomalies integrated over the entire extratropics, following the approach of Fioletov and Shepherd (GRL 2003, 2005). In the observations, interannual anomalies established through winter and spring persist with very high correlation coefficients through summer until early autumn in the quiescent summertime stratosphere, though decaying in amplitude as a result of photochemical relaxation.  In the same way, long-term ozone trends in the summer are slaved to the springtime trends. Following the analysis of Tegtmeier and Shepherd (ACP 2007) for the Canadian Middle Atmosphere Model, the model results will be compared to the observations to assess the summertime transport and photochemical decay in the models, and the extent to which the summertime long-term ozone trends reflect the winter/spring trends 24/03/2007
CCMVal 1st data request
in particular ozone fields

Seok-Woo Son, Darryn Waugh,
Lorenzo Polvani 
Tropopause in the 21st century
We will examine the global tropopause pressure in the 21st century with CCM outputs. The recent study (e.g., Santer et al. 2003) showed that the global tropopause pressure (height) is decreasing (rising) for last several decades. This trend, however, may not hold in the 21st century because of the rapid recovery of stratospheric ozone. In the proposed study, we will examine the effect of ozone recovery to the global tropopause pressure. The possible impact of a stronger Brewer-Dobson circulation in the future climate (e.g., Butchart et al. 2006) to the tropopause pressure will be also examined.

Son et al., 2009
Simone Tilmes, Ross Salawitch, Rolf Mueller, and Markus Rex Relationship between chemical ozone loss and the chlorine activation potential The relationship between chemical ozone loss and  the volume of air  exposed to PSC temperatures during the course of winter (VPSC) (Rex et  al., 2004, Tilmes et al., 2004) was proposed as a diagnostic to  indicate whether models reproduce  realistically the temperature  sensitivity of polar chemical ozone destruction. Further, Tilmes et  al., 2006, derived a more compact relationship between chemical ozone  loss and the PSC Formation Potential (PFP). PFP is a diagnostic that  includes information on the vortex temperature, vortex volume, VPSC,  and the lifetime of the vortex. We want compare these diagnostics and  the relationship between chemical ozone loss and PFP for the different  models. Chemical ozone loss of the CCMs will be derived using  tracer-tracer correlations. Differences between the model results and
the observed relationship will localize shortcomings of dynamical  and/or chemical processes in different models.

Run-Lie Shia Parameterization of cross tropopause exchange in Caltech/JPL 2-D CTM My proposed research objects include (1) Use the monthly zonal mean CCMVal model output of O3, N2O and other trace gases to study  stratosphere-troposphere exchange in order to improve the parameterization of cross tropopause exchange in Caltech/JPL 2-D CTM. (2) Use the temperature and zonal wind data to identify sudden stratospheric warming events and study their influence on the tracer-tracer correlation in high latitudes of the upper troposphere. 12/04/07


Jussi Kaurola, Alkis Bais, Gunther Seckmeyer

Past and future surface UV radiation levels

In the SCOUT-O3 project one task of Activity 4 (UV radiation) is to calculate past and future surface UV radiation levels based on the CCM model results of Activity 1 (Ozone, climate and UV predictions).  We hope that modellers in SCOUT-O3 Activity 1 make a swift response to this request.

CCMVal  SCOUT-O3 UV data request

Sebastian Mieruch,
Stefan Noël, Heinrich Bovensmann, John Burrows
Water vapour trends from GOME and SCIAMACHY satellite measurements
– Comparison with chemistry-climate model simulations

Global water vapour total column amounts have been retrieved from spectral data provided by the Global Ozone Monitoring Experiment GOME flying on ERS-2 which was launched in April 1995 and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY SCIAMACHY onboard ENVISAT launched in March 2002. For this purpose the Air Mass Corrected Differential Optical Absorption Spectroscopy AMC-DOAS approach is used. The combination of the data from both instruments, which requires special treatment at the interchange, provides us with a long-term global data set spanning already now more than 11 years with the possibility of extension up to 2020 by GOME-2 on Metop. Thus this data set is well suited for a trend analysis. Using linear and non-linear methods from time series analysis as well as standard statistics the trends of water vapour contents and their errors are calculated. Several factors affecting the trend such as the length of the time series, the magnitude of the variability of  the noise and the autocorrelation of the noise are investigated. Special emphasise lies on the calculation of the statistical significance of the observed trends which reveal local significant changes, decrease as well as increase, of water vapour concentrations distributed over the whole globe. The data set is suitable to test the ability of coupled chemistry-climate models (CCMs) to reproduce total column water vapour trends in the past. We plan to compare the trend analysis to results of the CCMVal simulations. 

CCMVal 1st data request
in particular water vapour fields

Michaela Hegglin,
Thomas Birner
Trends in water vapor and ozone in the UTLS Trends in water vapour and ozone in the UTLS will be investigated using tropopause-based diagnostics applied to the 150 year climate simulations of the Canadian Middle Atmosphere Model (CMAM). We intend to investigate the radiative feedback of changes in ozone and water vapour on the strength of the tropopause inversion layer [Birner, 2006; Randel et al., 2007] and to infer changes in stratosphere-troposphere exchange processes. The analysis will be extended to other CCMs within the CCMVal archive. 12/07/07
CCMVal 1st data request Ongoing
Susan Strahan,
Jessica Neu
Evaluation of transport characteristics in Chemistry-Climate
We are developing a set of transport diagnostics to be applied to chemistry-climate models. The diagnostics will be used to evaluate the ability of models to realistically represent stratospheric transport processes, especially those relevant to simulation of ozone. Both present day and future scenarios will be evaluated. The results of these evaluations will become part of the CCMVal/SPARC report (2009). 17/07/07
CCMVal 1st data request,
SPARC CCMVal Report data request
Eugene Cordero,
Veronika Eyring,
Sium Tesfai

A comparison of CCM and AOGCM simulations in the 20th and 21st century
We plan to investigate if systematic differences exist between climate simulations completed using CCMs versus AOGCMs. The study will initially focus on climatology and trends of temperature, wind and ozone in the 20th century, with a particular emphasis on the coupling between the stratosphere and the troposphere.  The 21st century simulations will also be evaluated to identify and understand differences between the different classes of models and their predictions for the future.  The questions we hope to address in this study include:  are CCMs better able to simulate the 20th and 21st century atmosphere compared to AOGCMs. 20/07/07
CCMVal 1st data request Ongoing

Vanessa Sherlock,
Brian Connor
Comparison of  N2O column and tropospheric VMR TCCON is a network of ground-based Fourier Transform spectrometers operating in the near infrared ( Retrievals of nitrous oxide (N2O) column densities have been performed from data from the Park Falls, Darwin and Lauder TCCON sites, and corresponding estimates of the mean tropospheric N2O volume mixing ratio have been derived. The purpose of this study is to compare the observed latitudinally-dependent seasonal variation in the N2O column and tropospheric VMR with that predicted by CCM models with a particular view to understanding of the influence of the stratosphere on the seasonal cycle of tropospheric N2O. 17/09/07
CCMVal 1st data request Ongoing

Björn-Martin Sinnhuber Correlation of mid-stratospheric ozone anomalies in autumn and total ozone in spring at high latitudes Recent observations have provided evidence that Arctic total ozone anomalies in spring are correlated with anomalies in mid-stratospheric ozone several months before during late summer and autumn (Kawa et al., ACP, 2005; Sinnhuber et al., ACP, 2006). We will analyse the available CCM output to investigate to what extent this correlation is reproduced by the
CCMVal 1st data request Ongoing

Darryn Waugh, Veronika Eyring

Performance Metrics of Stratospheric-Resolving
Chemistry-Climate Models
A quantitative evaluation of the ability of stratospheric-resolving CCMs to reproduce key process is performed using the data-based diagnostics and CCMs shown in Eyring et al. (2006). A single, simple metric is used to assign a quantitative score (“grade”) to each model-data comparison. The grades are used to assign relative weights to the CCMs' predictions of 21st century ozone.
Output from Eyring et al. (2006)
Waugh and Eyring, 2008
Hamish Struthers Dynamical containment of Antarctic ozone depletion
Bodeker et al. [2002] used the NIWA total column ozone assimilated data set and NCEP/NCAR reanalysis to show that even though the ozone hole size, as measured by the 220DU contour, has increased from 1980 to 2000 the dynamical vortex area as diagnosed by the meridional
impermeability has remained fixed. This implies the area of significant ozone loss has continued to fill the dynamical vortex over the last 20 years. In addition, the results suggest that in recent years the size of the ozone hole (as measured by the 220DU contour) has been constrained by the dynamical vortex rather than through the extent of chemical processing. Here, the analyses will be repeated using CCM output and the results will be compared with observations, focusing on whether CCMs capture the dynamical containment of ozone depletion as seen in the measurements.
22/01/08 SCOUT-O3 2nd data request Closed Struthers et al.
Birgit Hassler, Irene Cionni, Greg Bodeker
A vertically resolved, monthly mean, ozone database from 1850 to 2100 for constraining global climate model simulations A new global 3 dimensional (latitude, altitude, time) monthly mean ozone database is presented that spans 1850- 2100. The observational core of the database, from 1979-2006, is constructed from several solar occultation satellite-based instruments and ozonesondes, to provide ozone profiles from the surface to 70 km at high vertical resolution (1 km). The profiles were linearly scaled to ensure that they integrated to the monthly mean values provided by the NIWA combined total column ozone database (Bodeker et al.,  2005). A least squares regression model, incorporating basis functions for the main geophysical drivers of ozone variability (e.g. trend, QBO, solar cycle, volcanoes) was applied to the zonal mean data at each 2 degrees of latitude and then used to fill any missing data gaps. This was done by linearly interpolating between the regression model residuals and adding the filled residuals back to the regression model. To extend the measurements backward to 1964, a climatology of profiles was calculated from the core database from 1979-1983 and then scaled using a ground-based (Dobson and Brewer spectrophotometer) total column ozone database (Fioletov et al., 2002). In turn, the resultant profiles from 1964-1968 are averaged to provide a climatology which is repeated annually back to 1850. Ozone profiles from 2006-2100 were extracted from REF2 chemistry-climate model (CCM) runs made available through CCMVal (Eyring et al., 2007). The CCM output is scaled and spliced to the measurements at the end of 2006 to ensure a smooth transition. This database is expected to provide a best estimate of ozone fields suitable as input for Atmospheric-Ocean Global Circulation and Earth System Model simulations that do not include chemistry. 12/02/08 CCMVal 1st data request
in particular ozone fields

Dieter Peters Study of decadal changes in zonal asymmetries of CCMVal model experiments
The long-term evolution of stratospheric ozone depends not only on changes of many stratospheric constituents, but also on changes in the climate of the troposphere and stratosphere caused by natural variability and anthropogenic forcing. Planetary waves propagating from troposphere to stratosphere and related transport processes lead to quasi-stationary zonal asymmetries in stratospheric ozone and other trace species, which may alter during climate change. For exambles, a pronounced wave one structure in stratospheric ozone was found during the last four decades, based on analyses, assimilated ERA-40 data set and former satellites (Peters and Entzian, 1999; Knudsen and Andersen, 2001; Gabriel et al., 2007; Peters et al., 2008). Vice versa, the resulting zonal asymmetries in the stratosphere can effectively induce changes in the troposphere-stratosphere circulation system as shown by model sensitivity studies for the Northern Hemisphere by Kirchner et al. (2003) and Gabriel et al. (2007), as well as for the Southern Hemisphere by Crook et al. (2008). An assessment of the evolution of stratospheric ozone in state-of-the-art climate-chemistry model simulations provides some confidence in their predictions of future ozone recovery, but there are also strong differences between observed ozone fields and models as well as between the different models used in the assessments (e.g. Eyring, et al., 2006, 2007; Braesicke et al., 2007). Much of these differences are related to the deficiencies in describing planetary waves and related transport characteristics accurately, but a detailed assessment of the zonal asymmetries in stratospheric ozone and other trace species has not been done up to now. The main purpose of the proposed study is to investigate the decadal changes and intraseasonal variability of zonal asymmetries related to dynamical quantities, to stratospheric ozone, and to other trace species based on different CCMVal experiments. In the framework of the proposed study, the addressed structure problems will be examined in more detail.
CCMVal 1st data request Ongoing

Seok-Woo Son, Darryn Waugh,
Lorenzo Polvani
Impact of recovery of stratospheric ozone on tropospheric climate We will use output from the CCMs together with output from the AR4 climate models to examine the impact of changes in stratospheric ozone  during the 21st century on tropospheric climate.  Aspects to be examined include changes in  the structure and position  of the tropospheric jet and  of the Hadley Circulation.   06/04/08
CCMVal 1st data request Ongoing
Son et al., 2008
Sun Wong,
Andrew Dessler

Evaluation of Stratosphere-Troposphere Exchange (STE) by Deep Convection in
Chemistry-Climate Models
We propose to evaluate the ability of Chemistry-Climate Models to simulate the stratosphere-troposphere exchange by deep convection in both the tropics and extratropics. Measurements of H2O and CO by Aura Microwave Limb Sounder (MLS) has illustrated the importance of the MJO in regulating the transport of tropospheric H2O and CO into the stratosphere through the tropical tropopause layer. In particular, the transport of CO involves the interaction between the MJO and the seasonal cycle of surface biomass burning. Together with Cloud-Aerosol LIDAR Infrared Pathfinder Satellite Observations (CALIPSO), Aura MLS also demonstrated the importance of ice, which is lofted by deep convection, in moistening the extratropical overworld. To see if or how these deep convective STE are represented in the models, we will apply similar analyses that we have used on these measurements on the CCMVal model outputs of deep convection parameters and chemical species (including H2O, O3, and CO). We hope to assess the following issues: (i) how convection is organized in the tropics in the models, and how this is compared with observations; (ii) how convection in the models interacts with the seasonal cycle of surface emission to transport chemical species into the lower stratosphere, and how this will influence the simulated lower stratospheric chemistry; and (iii) whether transports of H2O into the lower stratosphere by extratropical deep convection are properly represented in the models, and how this will influence the climate forcing.
CCMVal 1st data request Ongoing

Chaim Garfinkel, Dennis  Hartmann The Different ENSO Teleconnections and Their Effects on the Stratospheric Polar Vortex Reanalysis data has been used to study the El-Nino Southern Oscillation (ENSO) signal in the troposphere and stratosphere during the late fall to mid-winter period. Typical warm ENSO events have extratropical tropospheric teleconnections that increase the wave-1, and reduce the wave-2 amplitude, as compared to cold ENSO. The decrease in wave-2 does not affect the polar vortex strength, but the increase in wave-1 does. The proximate cause of this modification in tropospheric wave forcing is a deepening of the wintertime Aleutian low via the Pacific-North America Pattern (PNA). During easterly Quasi-Biennial Oscillation (EQBO), warm ENSO does not show a PNA response; consequently, the polar vortex does not show a strong response to the different phases of ENSO.  The lack of a PNA response to warm ENSO under EQBO also explains the reduced response of the vortex to the different phases of QBO under WENSO. It is not clear whether the lack of a PNA response to warm ENSO in EQBO is a real physical phenomenon or a feature of the limited data record we have. To this end, and also to confirm our other results, we wish to study the CCM data. In particular, we wish to examine the consistency between the reanalysis and CCM data. 11/04/08 CCMVal Dynamics data request Ongoing

CCMVal-2: individual studies
Alexey Karpechko,  Nathan Gillett, Mark Baldwin Stratosphere-troposphere dynamical coupling in Chemistry-Climate Models We will assess ability of CCMs a) to simulate downward propagation of geopotential height anomalies on timescales of annular modes variability, and b) to simulate the past long-term changes in Antarctic troposphere circulation and their coupling to stratospheric trends. 26/05/08
CCMVal-2 Data request 2008

Thomas Reichler
Multivariate validation of CCMVal simulations
In this research, the CCMVal simulations will be compared against observations and against the simulations of the IPCC-AR4 model archive. The goal of this investigation is to understand and characterize the differences between stratosphere resolving models and conventional "low-top" models in terms of the simulated tropospheric and stratospheric climate. The proposed model diagnostics will cover many different aspects of climate, belonging to atmospheric circulation, hydroclimate, and radiative and non-radiative energy fluxes. Both, mean climate and climate variability will be examined, and the different results from each simulation will be combined into a single metric of model performance. The outcome of this activity will support the upcoming SPARC CCMVal Report, in particular chapter 8 ("Natural variability", lead by Manzini and Matthes) and chapter 10 ("Effect of the stratosphere on climate", lead by Baldwin and Gillett). 11/06/08
CCMVal-2 Data request 2008 Ongoing

37 Robert Kaspar,
Yuk Yung, Run-Lie Shia
Antarctic Ozone Hole: Comparison of data and model Recently, the ultraviolet absorption cross section of ClO dimer was remeasured.  The new value suggests that the rate of atmospheric ozone depletion due to CFCs is much lower than was previously thought.  In this project, CCM outputs will be compared to satellite images and in situ measurements of actual ozone densities.  Our goal is to determine the extent to which the current Antarctic ozone hole theory needs to be modified in order to be consistent with the absorption cross section parameter. 28/06/2008
CCMVal-2 Data request 2008 Ongoing

Claudia Timmreck,
Gera Stenchikov, Irene Fischer-Bruns
Atmospheric effects of large volcanic eruptions Major volcanic eruptions have a strong impact on stratospheric and tropospheric climate, chemical composition and the atmospheric circulation. Stratospheric sulfate aerosol particles from large volcanic eruptions produce significant transient cooling of the troposphere and warming of the lower stratosphere. The radiative impact of volcanic aerosols also produces a response that generally includes an anomalously positive phase of the Arctic Oscillation which is most pronounced in boreal winter.  The main atmospheric thermal and dynamical effects of volcanic eruptions persist for about two years after each eruption. We like to analyze the dynamical effects of the last three major volcanic eruptions (1963 Mt. Agung, 1982 El Chichon and 1991 Mt. Pinatubo) in the CCMVAL simulations. The work will continue work from Stenchikov et al. (2006) who evaluated the volcanic responses in the IPCC simulations. Although the IPCC models display generally the main features (stratospheric warming and tropospheric cooling) as can be seen in observations, they show a considerable range of different dynamic responses to high volcanic aerosols loading.  It is therefore interesting to investigate how the different chemistry climate models will respond to such a strong external forcing. The intended analyses will allow us to better evaluate the impact of high stratospheric aerosol loading (volcanic eruptions, geo-engineering) in chemistry climate models. This potentially could lead to improving chemistry climate model predictions for the extratropical latitudes of the Northern Hemisphere. 10/07/2008
CCMVal-2 Data request 2008 Ongoing

Michael Prather, Huisheng Bian,
Martyn Chipperfield,
Doug Kinnison
CCMVal Photocomp 2008
The calculation of photolysis (J) rates is a possible source of considerable difference between CCMs. Within the overall aims of CCMVal, and the forthcoming SPARC CCMVal Report, we are conducting an intercomparison of model photolysis rates. This will help identify, and reduce, model-model differences. All models are welcome to take part. To do this you will need to download a few data files, run your photolysis code and output the results in a standard format. See links at for more information. When you have results ready please create a directory with your model name under "/project_spaces/ccmval/PHOTOCOMP" and upload the data to this directory of the CCMVal Archive at BADC (see Guidelines for CCMVal Collaborators at Guidelines for CCMVal Collaborators for instructions how to become a formal "CCMVal Collaborator"). Once you have finished the transfer of your data, please notify Martyn Chipperfield by email. Results received by September 1, 2008 can be included in the first draft CCMVal Report. 15/07/2008
CCMVal Photocomp 2008 Ongoing

Roger Dargaville,
David Karoly

Impacts of stratospheric ozone variations on Southern Hemisphere and Australian climat

The project has three main sections:
1) to examine the model simulations to assess the range of impacts of stratospheric ozone depletion and recovery on Southern Australian climate i.e. SAM variations and resultant impacts on surface temperature and precipitation in the Southern Hemisphere and Australia.
2) use the CCMVal model output to evaluate the performance of a new Chemistry Climate Model based on the UK Met Office Unified Model coupled to the UK Chemistry and Aerosol Model under the Australian Community Climate and Earth Systems Simulator (ACCESS) framework, and
3) to aid in the testing and development of a simple statistical model using chorine loading and lower stratospheric temperature over Antarctica as predictors of Antarctic ozone variations to simulate the variations in the Antarctic ozone hole during 1979-2007 and recovery of the Antarctic ozone hole in the 21st century.
CCMVal-2 Data request 2008 Ongoing

Federico Fierli,
Elisa Palazzi, Ignacio Pisso
Behaviour of chemicals and tracers in the proximity of stratospheric dynamical barriers
We plan to evaluate the capability of current-state-of the art CCMs to reproduce the behaviour of chemicals and tracers in the proximity of stratospheric dynamical barriers. Dynamical barriers play a key role on the transport and concur in determining the distribution of chemical species in the upper troposphere and the stratosphere. Many studies have been conducted in the past to quantify the permeability of such barriers and their spatial and temporal variability. Nevertheless, the capability of CCMs to reproduce these barriers and their dynamics is, to our knowledge, still poorly known. The improved resolution of the new CCMs allows to better resolve the sharp horizontal and vertical gradients (see i.e. Palazzi et al., ACPD in preparation; Brühl, Pers. Comm.). We will use high-resolution in-situ measurements from past aircraft campaigns to evaluate the distributions of tracers across the polar vortex, the tropical tropopause and the sub-tropical barrier in the CCM simulations. The observations cover a relatively large temporal and spatial range (from 1992 to 2006, 8 tropical campaigns, 3 mid-latitude campaigns, 7 polar campaigns), allowing to evaluate CCMs in a wide range of dynamical conditions. We will assess whether CCMs can reproduce the dynamical structure of the different barriers and the chemical tracer fields across them. The methodology is twofold: (1) We will use dynamical diagnostics such as PV, potential temperature/equivalent latitude coordinates and tropopause height following coordinates to directly compare the observed and model-calculated distributions around the transport barriers and tracer-tracer correlations. (2) We will apply statistical diagnostics (see i.e. Sparling, Rev. Geophys., 2000) to compare the mean properties of tracers distributions.
27/08/2008 CCMVal-2 Data request 2008 Ongoing

Andrew Klekociuk, Andrew Pilgrim,
Gennady Milinevsky,
Simon Alexander
Long-term variability in stratospheric planetary wave activity: Comparison of CCMVal-2 model output and observations
Stratospheric planetary wave amplitudes will be evaluated from CCMVal daily fields. Statistics of wave activity on monthly, annual and longer timescales will be compared with observed variability derived from meteorological assimilations (UKMO, NCEP) and recent high resolution data sets (e.g. COSMIC GPS-RO). A focus will be on possible changes in planetary wave activity associated with the Antarctic Ozone Hole, and the observed long-term phase shift of the spring quasi-stationary wavenumber 1 in the Southern Hemisphere extra-tropical region.
27/08/2008 3D daily temperature, geopotential height, meridional wind and zonal wind  consistent with T3I daily data of the
CCMVal-2 Data request 2008
Andreas Engel,
Gabriele Stiller
Comparison of mean age and its long term evolution derived from models and observations

Possible changes of the Brewer-Dobson circulation should be reflected in changes in mean age. A faster circulation would result in lower mean ages and visa versa. Atmospheric observations of mean age tracers exist back to 1975, but the sampling is irregular and the data are sparse. The focus of this study would therefore be to subsample the models in order to provide the same resolution as the data. In this way possible issues in the mean age trend derived from the sampling should be eliminated and the robustness of the differences between observations and models will be investigated. The MIPAS instrument on board the Envisat satellite provides a data set of SF6 with global coverage, from which mean age can be determined. This data set is still rather short but allows to validate annual cycles and global distributions of mean age between model and observations. In addition to use CCMVal data for testing the representativity of our sampling, we propose to supply both data sets for validation purposes to the CCMVal community.

Either model fields of mean age for the dates of the observations or mean age of air from the models interpolated to our measurements locations (time, lat, lon, alt). Ongoing
Irene Cionni
Greg Bodeker
Veronika Eyring
Ted Shepherd
Darryn Waugh

Mutli-model mean ozone time series in support of CMIP5 simulations
SPARC is producing a new consensus observational stratospheric ozone database covering the 1979-2006 period, for CMIP5 . This database will be provided together with regression coefficients for EESC and various known natural forcings (volcanic aerosol, solar, ENSO, QBO). The EESC regression coefficients will be used to extrapolate that data back in time, and form an ozone time series backward to cover the entire time period 1850-2006 (Bodeker et al., 2008). While a similar procedure could be used to extrapolate into the future, coupled chemistry climate model (CCM) simulations (Eyring et al., 2007) indicate that future stratospheric ozone abundance is likely to be significantly affected by climate change, and it is not yet possible to estimate this contribution statistically from observations. Therefore, the SPARC CCMVal activity is proposing to provide a dataset for CMIP5 that extends the Tier 1 observational database into the future based on CCM simulations that include the effects of climate change as well as EESC changes. The formation of a consistent ozone database using observations for the past and CCMs for the future is a current research activity, and has not previously been done. We propose to construct a reference time series based on CCM simulations for 1979-2100 using exactly the same methodology as for the consensus observational data base; namely using a regression model to isolate the long-term changes, to produce an analogue to the Tier 1 database which would be based on the model simulations but scaled to be consistent with the consensus observational database during the overlap period (1979-2006). The regression model will then allow this data set to be projected out from 2100 to 2150. The above will first be done using existing CCMVal-1 model simulations, which cover the time period 1960-2100. These were based on the SRES A1B GHG scenario and the WMO (2003) Ab surface halogens scenario. Although this is not entirely consistent with the new RCPs, CCM simulations using the A1B and A2 GHG scenarios produce similar stratospheric ozone distributions. If the new SCN-B2a CCMVal-2 model simulations (Eyring et al., 2008) that are forced with GHGs consistent with the new RCPs are available in time, the procedure will be repeated using these simulations. The above CCM-based time series can then be combined with the observationally-based time series to form a database that will cover the entire time period 1850-2150. Both time series will be made available through the SPARC Data Center, and would provide stratospheric ozone boundary conditions suitable for long-term global climate model simulations such as the mandatory CMIP5 experiments 1.2 and 2.1-2.4. 18/09/08
CCMVal 1st data request
CCMVal-2 Data request 2008

Michael Sigmond Assessment of basic dynamics diagnostics In support of Chapter 4 (Dynamics) of the new SPARC CCMVal report, we will assess basic dynamics quantities for all CCMVal-2 models. The focus will be on zonal mean zonal wind, temperature, and its seasonal cycle. Plots for dynamical quantities like those in Eyring et al. (2006) will be produced in order to compare the models to observations and CCMVal-1 simulations. 08/10/2008 CCMVal-2 Data request 2008 Ongoing
Ole Kirner
Roland Ruhnke

Long term simulation with a new PSC-parameterization in EMAC

We have developed a new PSC parameterization based on the efficient growth and sedimentation algorithm of van den Broek et al. [2004] and Carslaw et al. [2002] for the CCM EMAC (ECHAM/MESSy Atmospheric Chemistry). With the new parameterization it is possible to calculate the growth of NAT particles leading to a more detailed description of the simulated PSCs. According to the radius, the NAT particles are divided in different size bins (currently 8 size bins with mean radii from 0.1 μm up to 18 μm) with individual sedimentation velocities leading to a more sophisticated denitrification in the model. We have performed with EMAC and the new PSC parameterization a first long term simulation with a horizontal resolution of T31 and 39 vertical layers from 1980 to 2050. The purpose of this study is to investigate the distribution and the frequency of PSCs as well as the denitrification and dehydration in different CCMs in comparison to satellite data (as e.g. MIPAS/ENVISAT). 08/10/2008
CCMVal-2 Data request 2008 Ongoing
CCMVal-2: SPARC CCMVal Report (names listed here and the model groups have access to CCMVal-2 PHASE0 data)
Veronika Eyring
Ted Shepherd
Darryn Waugh
Synthesis Chapter
The executive summary will be divided into overall key findings, key findings per chapter, and key findings for each of the participating models. The key findings per chapter in Part A will be based on the models’ ability to simulate core processes structured around five major topics (radiation, dynamics, transport, stratospheric chemistry & microphysics, and UTLS). The overall key findings will include a synthesis of the results presented in the five topics to provide a coherent assessment of the current generation of CCMs based on the CCMVal concept. It will also include a summary of the results presented in Part B. The processes that contribute most to uncertainty in current coupled chemistry-climate modeling will be defined and future challenges for model developments summarized. The key findings per model will summarize the performance of each of the participating models relative to the thresholds identified in the individual chapters. While the set of diagnostics applied as part of the SPARC CCMVal report will go beyond the set that has been applied to the CCMVal-1 models (Eyring et al., 2006), the synthesis will also include a comparison of CCMVal-1 versus CCMVal-2 models that will be restricted to the diagnostics of Eyring et al. (2006) and the performance metrics of Waugh and Eyring (2008) in order to perform a quantitative assessment of model improvements. Model improvements will be documented for individual models that participate in both rounds (CCMVal-1 and CCMVal-2), for newly participating CCMs in order to see how they perform against the CCMVal-1 model validation standard and for different generations of models (CCMVal-1 versus CCMVal-2). 16/10/2008
CCMVal-2 Data request 2008 Ongoing
Victor Fomichev
Piers Forster

Chapter 3: Radiation

16/10/2008 CCMVal-2 Data request 2008 Ongoing
Neal Butchart,
Andrew Charlton,
Irene Cionni,
Peter Haynes,
Kirsten Krüger,
Paul Newman,
Scott Osprey,
Judith Perlwitz,
Fabrizzio Sassi,
John Scinocca,
Michael Sigmond

Chapter 4 : Dynamics

Output from CCMVal-2 simulations will be used to assess and compare the abilities of CCMs to reproduce the climate, circulation and associated variability of the stratosphere. The assessment will be process based, i.e. the underlying dynamical processes occurring in the model stratospheres will be evaluated as well as the basic meteorological quantities such as winds and temperature. The effects of climate change and ozone recovery on the modelled dynamical quantities and processes will be analysed.
16/10/2008 CCMVal-2 Data request 2008 Ongoing
Jessica Neu, Susan Strahan,
Peter Braesicke,
Anne Douglass, Petra Huck,
Luke Oman,
Diane Pendlebury,
Susann Tegtmeier
Chapter 5: Transport
In this chapter we evaluate model representation of stratospheric transport processes using process-oriented diagnostics derived from observations. The suite of diagnostics chosen are intended to cover the essential processes controlling stratospheric trace gas distributions, from entry in the tropical lower stratospheric to exit through the extratropical 100 hPa surface. The processes diagnosed include tropical ascent rate, isolation of the tropics from the tropopause to 800K, and isolation of descent in the polar vortices. Some of the diagnostics are well-known, such as the phase and amplitude of the water vapor tape recorder, mean age of air at 20 km, tropical-midlatitude distinctiveness as seen by N2O probability distribution functions (PDFs). The model outputs required include monthly mean and instantaneous N2O, CH4, H2O, and temperature. We will analyze 10-20 years of model output to capture means and variability for present day and future scenarios. Each model participating in CCMVal-2 will be evaluated. The results of the evaluations will be reviewed to produce a description of transport and transport credibility for each model.
16/10/2008 CCMVal-2 Data request 2008 Ongoing
Martyn Chipperfield
Doug Kinnison
Huisheng Bian,
Christoph Brühl ,
Tim Canty,
Sandip Dhomse,
Lucien Froidevaux,
Lynn Harvey,
Rolf Müller,
Michael Prather ,
Cora Randall,
Ross Salawitch ,
Michelle Santee,
Simone Tilmes
Chapter 6: Stratospheric Chemistry & Microphysics
This chapter is focused on documenting and evaluating the stratospheric chemical and microphysical processes used in CCMs. The focus here will be to discuss how chemical formalisms affect model performance. Two benchmarks will be used: 1) A photolysis benchmark to evaluate the accuracy of the photolysis code used in CCMs (see SPARC website for details of how to participate); and 2) a fast chemistry benchmark to examine chemical partitioning compared to a reference photostationary state (PSS) box model. The PSS model will be constrained by the temperature and long-lived (reservoir) fields from each CCM REF0 simulation. The PSS model will act as a benchmark to intercompare the fast chemistry calculations in the CCMs. This chapter will also evaluate reservoir species abundances and long-lived distributions. Global comparisons will be made with satellite observations and climatologies from in-situ aircraft data. Annual cycles and long-term trends will also tested against ground-based data. Polar chemical process in CCMs will also be extensively evaluated (e.g., ozone loss, dehydration, denitrification, and chlorine activation processes). The comparisons will be primarily done with the REF0 and REF1 runs. Some additional checks of chemical fields from REF2 runs (e.g. consistency predicted stratospheric Bry, Cly, NOy trends) may be performed. 16/10/2008 CCMVal-2 Data request 2008 Ongoing
Andrew Gettelman,
Michaela Hegglin,
Markus Kunze,
Ulrike Langematz,
Laura Pan,
Seok-Woo Son,
Simone Tilmes,
David Plummer,
Lorenzo Polvani,
Mijeong Park,
Thomas Birner,
Peter Hoor,
Huikyo Lee,
Don Wuebbels
Chapter 7:
Upper Tropopsphere and Lower Stratosphere
CCMVal-2 CCMs will be analyzed to understand their representation of  the Upper Tropopsphere and Lower Stratosphere (UTLS). The analysis will  include both the tropics and the extra-tropics. Present day  simulations will be compared to observations.  This includes detailed  analysis of the Tropical Tropopause Layer (TTL) structure and  variability, including water vapor transport into the stratosphere and  TTL clouds. Tropical waves and dynamics will be analyzed.  Extratropical tracer-tracer correlations will be compared to satellite  chemistry observations and in-situ aircraft. Short lived species in  the TTL will be examined. In addition, long term historical and future  trends in critical parameters (such as the extent of the tropics, and  the tropopause) will be investigated. The work will form Chapter 7 of the SPARC CCMVal Report. 16/10/2008 CCMVal-2 Data request 2008 Ongoing
Elisa Manzini,
Katja Matthes,
Anne Douglass,
Natalia Calvo,
Lesley Gray,
Kuni Kodera,
Bill Randel,
Thomas Reichler, Claudia Timmreck,
Gera Stenchikov,
Shigeo Yoden,
Greg Bodeker,
Chiara Cagnazzo,
Irene Fischer-Bruns,
Junsu Kim,
Elisabeth Viktor,
Cristina Pena Ortiz
Chapter 8: Natural variability
This chapter will focus on natural variations of stratospheric ozone. Observations have demonstrated ozone variations on a number of spatial and temporal scales. Some of such variations may result from coherent natural forcing, such as the seasonal cycle, the 11-year solar cycle, the QBO and variations in transport associated with large-scale circulations. To quantify the impact of anthropogenic perturbations of the ozone layer, it is necessary to understand the underlying natural ozone variations. The goal of this Chapter is to evaluate how well the CCMs simulate natural stratospheric ozone variability based on current knowledge about links between natural forcing and ozone and especially with respect to their overall performance (done in part A). We will answer the following questions (1) If the models do simulate natural ozone variations do we understand the most important contributions and processes that determine it? (2) Can we trust a trend from a model that does not represent natural ozone variations? The evaluation includes the assessment of modeled ozone variations associated with the seasonal cycle, annular modes, the solar cycle, QBO, ENSO, and volcanos.
16/10/2008 CCMVal-2 Data request 2008 Ongoing
John Austin
John Scniocca
Hamish Struthers
David Plummer David Stephenson
Chapter 9: Long-term projections of stratospheric ozone
The chapter will focus on long-term changes (past and future) in ozone and ozone indices and on the cause of these changes (i.e. related to changes in chemistry, dynamics, radiation, transport and UTLS discussed in Part A chapters). For the REF1 and REF2 runs performed for the 2006 Ozone Assessment, this has been done by Eyring et al. (2006, 2007). Many other studies have also now been completed with these, although papers are in some cases still being prepared or have only just been submitted. These results will be summarized here, together with the additional CCMVal-2 simulations that have been completed to date which provide preliminary results for the 2010 Ozone Assessment.  Please note that the title is subject to change, the co-author list is not complete, and the required analysis has not yet been fully determined.
16/10/2008 CCMVal-2 Data request 2008 Ongoing
Mark Baldwin,
Nathan Gillett,
Eugene Cordero,
Ed Gerber,
Alexy Karpechko,
Paul Kushner,
Scott Osprey,
Judith Perlwitz,
Lorenzo Polvani,
Thomas Reichler,
John Scinocca,
Seok-Woo Son,
David Stevenson,
Dave Thompson, Klarie Tourpali
Chapter 10:
Effect of the stratosphere on climate
This chapter will investigate how stratospheric variability and change influence tropospheric climate. The chapter will include an assessment of the realism of the tropospheric climates of the CCMVal models, together with an assessment of their simulation of dynamical stratosphere-troposphere coupling, and these features will be compared with those of the CMIP3 models. The chapter will also consider the simulated effects of stratospheric changes on the troposphere, including an assessment of dynamical, radiative and chemical effects.
16/10/2008 CCMVal-2 Data request 2008 Ongoing

CCMVal-2: studies with sensitivity runs in support of WMO 2010
Veronika Eyring
Irene Cionni
Greg Bodeker
Doug Kinnison
Andrew Charlton
and CCMVal-2 model PIs
Effects of halogens and climate changes on stratospheric ozone through the 21st century

We will analyze projections of ozone from several sensitivity studies in addition to the CCMVal REF-B2 simulations to quantitatively disaggregate between the drivers of the projected ozone and to better assess uncertainties due to the chosen GHG scenarios. Specifically, we will disentangle the effects of changes in climate and ODSs on ozone and present a thorough analysis of the effects of increases in GHGs and climate change on ozone through the 21st century. This analysis will be relying strongly on the SCN-B2b (fixed halogens) and SCN-B2c (NCC) simulations. By comparing SCN-B2b with REF-B2, the impact of halogens can be identified and it can be assessed at what point in the future the halogen impact is undetectable, i.e. within climate variability (full ozone recovery). By comparing the sum of SCN-B2b and SCN-B2c (each relative to the 1960 baseline) with REF-B2, the nonlinearity of the responses will be assessed. With the analysis of SCN-B2c simulations we will also addresses the policy-relevant (if academic) question of what would be the impact of halogens on the atmosphere in the absence of climate change. Additional simulations with different GHG emission scenarios (SCN-B2a simulations) will then allow us to further extend that and to investigate the effects of different GHG emissions scenarios, and others, to provide a richer set of conclusions. SCN-B2e (enhanced bromine) is a sensitivity simulation that is consistent with REF-B2 with the exception that an additional source of stratospheric inorganic bromine (Bry) from very short-lived substances (VSLS) is included, in light of the fact that observations derived from the breakdown of long-lived organic source gases underestimate the Bry abundance in the stratosphere by about 5 ppt. Thus, all these sensitivity simulations are designed to augment, in various ways, the science that can be obtained from the reference simulations that will be analyzed as part of the SPARC CCMVal Report. This work will be done in support of Chapter 3 of the 2010 WMO/UNEP Ozone Assessment on ‘Future Ozone and its Impact on Surface UV’.

2nd CCMVal-2 Data request 2009 Closed
Eyring et al., ACPD, 2010

Eyring et al., GRL, submitted, 2010
Andrew Charlton-Perez et al
Quantifying uncertainty in projections of stratospheric ozone over the 21st century Uncertainty in projections of stratospheric ozone can come from a variety of different sources. Of these different sources, there are important contrasts to be drawn between uncertainty in future greenhouse gas scenarios, uncertainty which stems from the design of chemistry-climate models and uncertainty due to internal variability of the coupled chemistry-climate system. In this study we propose to apply a new technique, already used on the CMIP3 ensemble, to quantify the different sources of uncertainty in projections of stratospheric ozone. Uncertainty will be fractionally partioned between several different sources as a function of time, for different stratospheric regions and different stratospheric variables using the methodology of Hawkins and Sutton (BAMS, 2009). Quantification of the uncertainty in this way will help to determine the extent to which overall uncertainty in projections of stratospheric ozone can be narrowed through future developments of chemistry-climate models. In order to complete the analysis, a set of scenario simulations common to several different CCMs is necessary. We will analyze projections of ozone from several CCMVal-2 sensitivity simulations with GHG scenarios different than SRES A1B in addition to the CCMVal REF-B2 reference simulations.
2nd CCMVal-2 Data request 2009 Closed Charlton-Perez et al., ACPD, 2010
Nathan Gillett et al.
Attribution of stratospheric temperature and ozone changes using CCMVal simulations Detection and attribution methods have previously mainly been used to assess the causes of tropospheric climate changes, particularly to attribute the causes of surface temperature changes. These techniques rely on a regression of observed changes onto the simulated responses to individual forcings, with uncertainties estimated from simulated internal variability. To date assessments of the causes of observed stratospheric ozone and temperature change have relied mainly on qualitative comparisons of simulations and observations. Newly completed Ref B2b and Ref B2c simulations may allow a separation of the observed responses to ODS changes and greenhouse gas changes. We will apply a detection and attribution analysis to compare observed ozone changes including TOMS, and SBUV/SAGE datasets, with simulated ozone changes from CCMVal-2 Ref B2, B2b and B2c simulations. A similar analysis will be applied to assess the causes of changes in stratospheric temperature changes using MSU T4 and SSU temperatures, and temperature output from CCMVal-2 simulations.
2nd CCMVal-2 Data request 2009 Ongoing Gillett et al., ACPD, 2010
CCMVal-1 and CCMVal-2: individual studies continued
Margaret Hurwitz, Paul Newman and Feng Li
Assessment and consequences of the delayed break-up of the Antarctic polar vortex
Previous model comparison studies (e.g., Eyring et al., 2006) have found that the transition to easterlies at 60S is delayed, as compared with observations, in many CCMs.  This study will compare the seasonal cycle of 100hPa heat flux in various models, and assess Antarctic winds and the transition to easterlies as a function of heat flux to determine cases where models perform well or poorly.
06/11/2008 CCMVal 1st data request Ongoing

Olaf Morgenstern
Impact of ozone recovery on tropospheric and stratospheric climate
We plan to analyze the CCMVal data with respect to large-scale circulation responses to ozone depletion and recovery. We would like to identity how ozone depletion and recovery affects tropospheric and stratospheric climate.
CCMVal 1st data request Ongoing

Mike Previdi, Beate Liepert, Seok-woo Son, Lorenzo Polvani

Impact of ozone recovery on the global hydrological cycle
Using the CCMVal-2 simulations we plan to investigate the response of the global water cycle to predicted ozone recovery in the 21st century, and to compare these results with those obtained from the IPCC-AR4 climate simulations. Using the latter, Previdi & Liepert (2007, GRL) showed that the subtropical dry zone SDZ (i.e. the latitude where evaporation exceeds precipitation) is expected to extend poleward with increasing GHG concentrations, and that this expansion of the SDZ is partially connected to the extratropical tropospheric circulation. We plan to extend that study by analyzing the CCMVal-2 simulations, and determine the impact of ozone recovery. We will be looking at how changes in lower-stratospheric polar temperatures correlate with the annular modes and to the surface precipitation minus evaporation fields.
CCMVal-2 Data request 2008 Ongoing

Alexander Sen Gupta
Caroline C. Ummenhofer
Andrea Taschetto
Matthew H. Engaland
Variability and projections for Southern Hemisphere extra tropical circulation in comparison to the AR4 models Variability in the Southern Ocean is strongly determined by the overlying atmospheric forcing. As such, the Southern Ocean scientific community is concerned that atmospheric variability and the projected response to future changes may not be adequately represented in the current AR4 climate models. Detailed comparison of surface forcing between CCMVal and AR4 models are therefore of considerable interest. In particular, differences in the response of the Southern Annular Mode will be assessed.
CCMVal 1st data request Ongoing

Ulrike Langematz
Greg Bodeker, Petra Huck
Development of ozone in the pre1980 era We analyze the development of ozone in the pre1980 era in the CCMVal2 REF-B1 simulations. The work will follow a paper by Huck et al. (2009) in which the method and a first analysis of the CMAM CCM will be presented. In the follow-up study the focus will be on the consistency of the pre1980 behaviour of ozone in the whole suite of the CCMVal-2 CCMs. Understanding the differences in the evolution of ozone between 1960 and 1980 is necessary for understanding inter-CCM differences in the return of ozone to 1960 or 1980 levels. 25/02/09
CCMVal-2 Data request 2008 Ongoing

Paul Kushner,
Steven Hardiman, Christopher Fletcher, Judah Cohen
Investigating the role of snow and other land surface forcings in the  stratosphere-troposphere system In this project, we will investigate how variability in surface  parameters, in particular snow cover, can lead to hemisphere scale  tropospheric circulation anomalies via planetary wave forcing.  Previous work has shown that the stratosphere mediates many aspects of  the tropospheric circulation in this class of problems. Our project  will investigate the role of October snow cover in winter climate and  the role of spring-to-summer snow albedo feedback in summer climate.  We will analyze variability and trends in the CCMVal simulations with  reference to observations and the IPCC AR simulations. 25/02/09 CCMVal-2 Data request 2008 Ongoing

Dmitry Vyushin, Paul Kushner

Temporal power-law characteristics of the
stratosphere-troposphere circulation
Climate variations on timescales longer than a year are often  characterized by temporal scaling (“power-law”) behavior for which  spectral power builds up at low frequencies in contrast to red-noise behaviour for which spectral power saturates at low frequencies. In  this project we will analyze the spatial distribution of temporal  power-law exponents (“Hurst exponents”) for the global atmospheric circulation of the stratosphere and troposphere. This analysis is expected to provide insights into trend evaluation and evaluation of data homogeneity in observational products. We will analyze the CCMVal 
simulations with reference to previous work on observations and the CMIP3 simulations.
CCMVal-2 Data request 2008 Ongoing

Lei Wang, 
Paul Kushner
Stationary wave response to climate change in the stratosphere- troposphere system
In this project, we will analyze the stationary wave response to climate forcings in the CCMVal simulations using nonlinear stationary wave models. These models allow the stationary wave response to climate change to be decomposed into parts related to changes in zonally asymmetric forcings (such as the change to the diabatic heating distribution) and changes to the zonal mean basic state. Previous work has shown that the stationary wave response can contributes significantly to the stratospheric Brewer Dobson Circulation response. In situations where this is the case, this work will help elucidate the dynamics of the BDC response.
25/02/09 CCMVal-2 Data request 2008 (3D climatologies of meteorological and
diabatic heating fields  at different time periods)

Michaela Hegglin, Ted Shepherd Past and future stratospheric ozone flux into the troposphere The flux of stratospheric ozone into the troposphere is important for the radiative budget and the oxidizing capacity of the troposphere. We will perform a multi-model comparison of present day and future stratospheric ozone (and total reactive nitrogen) fluxes into the troposphere using a method similar to the one published by Tie and Hess (1997). 01/04/09
CCMVal-2 Data request 2008 Ongoing

Masakazu Taguchi Future changes in the stratosphere: wave activity
Possible future changes in the stratosphere, such as the Brewer-Dobson circulation, are considerably variable among models, as revealed by CCMVal simulations. Such model-to-model variability in the stratospheric circulation changes should be related to that in wave driving (EP flux) changes. It will be therefore useful to make an in-detail analysis on how and why activity of various waves changes in  the CCMVal simulations. 02/04/09 CCMVal 1st data request Ongoing

69 Joachim Urban,
Samuel Brohede,
Chris McLinden,
J. Jin,
F. Jegou,
F. Khosrawi,
S. Lossow
Comparison of Odin trace gas climatologies with chemistry-climate
models .
The Odin satellite carries two instruments:  Sub-Millimetre  Radiometer (SMR)  and  the  Optical  Spectrograph and Infra-Red Imager System (OSIRIS).  Between them global climatologies of O3, N2O, HNO3, NO2, H2O, CO, ClO, and BrO, spanning 2001-2009, have been compiled.  In addition, NOy and Bry datasets have been derived with the aid of photochemical modelling.  The goal of this work is a detailed comparison of these Odin climatologies with chemistry-climate models. 06/04/09
CCMVal 1st data request Ongoing
Charles McLandress Stationary and transient wave driving of the Brewer-Dobson
Using CCMVal-1 simulations from the Canadian Middle Atmosphere Model (CMAM), McLandress and Shepherd (2009) found that changes in both stationary (planetary) and transient (synoptic) wave drag account for a significant fraction of the acceleration of the Brewer-Dobson circulation under climate change. To determine the robustness of these results, a similar analysis will be applied to the models participating in CCMVal-2 using the REF-B2 simulations. 19/06/09
CCMVal-2 Data request 2008 Ongoing

Viktoria Mohr, Kirstin Krüger, and Markus Rex
TTL transport (Lagrangian study)
The CCM simulations will be used to study backward trajectories in the Tropical Tropopause Layer (TTL). These Lagrangian trajectories will be analysed to evaluate how well processes that regulate the transport of water vapour and very short lived substances (VSLS) from the troposphere into the stratosphere are represented by the CCMs. The understanding of water vapour is very relevant, as it is the most important greenhouse gas in the atmosphere. Stratospheric water vapour also changes the ozone distribution in the Stratosphere. Not only the understanding of the transport of water vapour, but also transport pathways of VSLS like Bromoform, from the surface to the stratosphere are significant for the ozone depletion in the stratosphere.
CCMVal 1st data request
and CCMVal-2 Data request 2008 as soon as CCMVal-2 mvoes to Phase 1

Gabriel Chiodo and R. Garcia-Herrera
The sensitivity of the coupled troposphere-stratosphere system to the solar cycle in future simulations
When modeling the solar cycle, it is important to incorporate the effects of ozone changes, and the spectral resolution of the solar forcing [Haigh, 1999]. Several authors demonstrated that the model results of the tropospheric response are very sensitive to the inclusion of interactive ozone chemistry [Rind et al., 2008; Haigh, 1997; Shindell et al., 1999], particularly for the summer hemisphere [Haigh,  1999].  Even though 11-year cycles have been reported in the summer Asian monsoon, the significance of the surface signals was low, regional and seasonally-dependent [Rind et al. 2008, Shindell et al. 1999]. Great effort has been provided to improve parameterization of photochemistry, but the simulated response in the middle and low stratospheric ozone concentration is unrealistic in many GCMs (e.g. in GISS-E, see Rind et al. [2008]). Furthermore, these modeling studies have not included a time-varying QBO, and ozone transport changes have been calculated non-interactively [Shindell et al., 1999; Rind et al. 2008]. In spite of these deficiencies, the observed solar-climate relationships seem to have been accurately reproduced in GCMs. Nevertheless, these simulations have been done to reproduce past climate, namely scenarios of important ozone losses, brought by human-induced stratospheric cooling [Shindell et al. 1998]. Hence, the importance of solar-induced ozone changes may have been low, but this may not hold true for present-date and future climate.  There is large body of modelling evidence supporting ozone recovery scenarios in the future [Eyring et al. 2007]. Stratospheric circulation changes, such as those reported by Garcia and Randel [2008] may alter meridional ozone distributions, and the modulation of the Hadley circulation in the equatorial troposphere. Accordingly, the sensitivity of the stratosphere to the solar cycle may be directly altered. Large heating rates could induce during solar maximum strong dynamical changes in the troposphere, with signatures in surface meteorological patterns. We plan to use currently existing CCMVal-1 simulations to address these issues. More specifically, we are interested in transient simulations, with inclusion of solar variability, consistent with SCN2 of CCMVal-1. Since the low-frequency variability of the solar activity is unknown, a constant 11-years cycle will was included in these simulations as natural external forcing. The structure of the solar signal will be investigated. Several diagnostics (EP-fluxes, meridional heat fluxes) will help us to assess circulation changes in both stratosphere and troposphere, and help identify propagation mechanisms. Furthermore, we will evaluate the solar influence on the modulation of the Brewer-Dobson circulation on the Hadley cells, which can provide a pathway for solar effects on tropical precipitation patterns in future climate.  We will include the multi-model ensemble REF2-SCN2 to our analysis, with special interest on those models which include internally generated and thus time-varying QBO.  Since the changes in ozone photochemistry and transports are calculated online, we believe that CCMVal coupled chemistry climate models will be a valuable tool for our work.
CCMVal 1st data request
and CCMVal-2 Data request 2008 as soon as CCMVal-2 mvoes to Phase 1

Steven Hardiman, Paul Kushner, Scott Osprey, Karen Smith
Investigating the link between Eurasian snow cover and stratospheric sudden warmings
We will investigate how anomalies in Eurasian snow cover lead to changes in planetary wave propagation that subsequently influence whether or not a stratospheric sudden warming will propagate into the troposphere. We will analyse how well this effect is captured in the CCMVal GCMs, and consider reasons why GCMs do / do not simulate it.
CCMVal-2 Data request 2008 Ongoing
Isla Simpson, Ted Shepherd Influence of SSTs on the variability and trends of the Southern hemisphere polar stratosphere CCMVal-2 simulations will be used to investigate to what extent the variability and trends of the Southern hemisphere polar stratosphere are influenced by sea surface temperatures (SSTs).  The ozone trends in the REF-B1 and REF-B2 simulations will be compared and if any differences are found there will be an attempt to relate this to differences in the SST forcing.  Furthermore, it will be investigated whether interannual variability in stratospheric dynamics and ozone is related to variability in the SSTs.
CCMVal-2 Data request 2008 Ongoing
Andrew Gettelman
Simulations of the evolution of the width of the tropical belt in Coupled Chemistry Climate Models (CCMs)

The width of the tropics will be examined in CCMs using a variety of different metrics of the general circulation and compared to observations. Changes to the structure of the Upper Troposphere and Lower Stratosphere (UTLS) in CCMs are examined to look at differences in how the tropopause and circulation, as well as clouds and precipitation are simulated to change.
CCMVal-2 Data request 2008 Ongoing
Eric Ray, Olaf Morganstern, Dan Smale, Eugene Rozanov, Michaela Hegglin, Gianni Pitari, Eva Mancini, Peter Braesicke, Neal Butchart, Steven Hardiman, Feng Li, Kiyotaka Shibata and David Plummer

Evidence for Stratospheric Circulation Changes Over the Past Three Decades From Multiple Measurement Sources
In this study we use a simple representation of the stratosphere, the tropical leaky pipe (TLP) model, to show possible stratospheric mean circulation and horizontal mixing changes that help elucidate reasons for the observed changes in stratospheric mean age estimates as well as total ozone.  Guided by circulation and mixing changes in several reanalyses datasets and an average of nine CCMs, the TLP model reveals a number of interesting results.  Comparisons of the mean circulation and mixing changes suggested by the measurements with those from average CCMVal-2 output reveal significant differences that may have important implications on the accurate simulation of future stratospheric climate.
CCMVal-2 Data request 2008 Ongoing
V. Grewe, S. Stähle, A. Gettleman
A statistical analysis of grading approaches

This study focuses on the evaluation of grading methodologies in a statistical framework.
the investigation is based on the data discussed in detail in Gettleman et al. (2010) (JGR special issue). Waugh and Eyring (2008) used a grading methodology, which did not include a detailed statistical analysis of the grading method. Possible shortcomings were shown in Grewe and Sausen (2009) in a theoretical framework, i.e. without using actual observations and model output.
Here we will apply statistical grading methodologies to observations and model output (Gettleman et al., 2010) based on the approach suggested by Grewe and Sausen (2009).
CCMVal-2 Data request 2008 Ongoing
Julie Jones, Olaf Morgenstern
A spatial and temporal evaluation of the SAM and southern hemisphere stratosphere-troposphere coupling in the CCMVal-2 simulations We shall assess the temporal behaviour of the Southern Hemisphere Annular mode (SAM) in the CCMVal-2 simulations.  The past simulated SAM shall be compared these to reconstructions (Jones et al. 2009) and observations, focussing particularly on whether the inability of the models to correctly simulation the austral Spring SAM behaviour found in AR4 simulations (Fogt et al. 2009) is also present in the CCMVal-2 simulations, and whether simulations with interactive ocean behave differently to those without. We shall also examine the seasonal spatial structure of the SAM (Kidston et al. 2009) in the simulations, comparing to reanalyses, and the spatial signal of the stratospheric SAM in the tropospheric climate, with a focus on New Zealand.  We shall also assess the vertical coherence between the stratosphere and the troposphere in the Southern Hemisphere extratropics as undertaken by Morgenstern et al. (2010) for the Northern Hemisphere. 15/04/2010
CCMVal-2 Data request 2008 Ongoing
Tiffany Shaw,
Judith Perlwitz, Nili Harnik
Seasonal cycle of the wave geometry and planetary wave reflection The CCMVal-2 simulations will be used to investigate the modeled seasonal cycle of the wave geometry and planetary wave reflection in both hemispheres. The wave geometry diagnostic separates the more commonly used index of refraction into vertical and meridional wave number contributions. Recent results show that an accurate representation of the seasonal cycle of the wave geometry is necessary for the proper representation of downward wave coupling between the stratosphere and troposphere. We will consider the wave geometry throughout the simulations and in particular how the wave geometry changes in the future. The modeled planetary wave reflection will be analyzed in detail using a cross-correlation analysis for those models which saved daily three-dimensional data.
CCMVal-2 Data request 2008 Ongoing
Yongyun Hu, Yan Xia, and Qiang Fu
Contribution of ozone radiative forcing to global warming in the 21st century

After ~ 20-year severe depletion from the late 1970s to late 1990s1, the ozone layer shows a stabilization or a weak increase in the past decade, consistent with the observed decline in ozone depleting substances (ODSs) that peaked in the middle 1990s2, 3. Since ODSs are also greenhouse gases, the reduction of ODSs under the 1987 Montreal Protocol serves to protect both the ozone layer and climate. Coupled chemistry-climate model (CCM) simulations, with projected stratospheric chlorine loading, predicted that stratospheric ozone will return to pre-1980 levels around 2050 and can even be above pre-1980 levels by 2100. An indirect O3 positive radiative forcing associated with the ozone increase is thus expected in the 21st century. Here we assess the contribution of ozone radiative forcing to global warming in the 21st century using simulation results from CCMs and the Intergovernmental Panel on Climate Change (IPCC) Forth Assessment Report (AR4) models.
21/05/2010 CCMVal 1st data request
and CCMVal-2 Data request 2008 as soon as CCMVal-2 moves to Phase 1

Didac Fortuny

Tropopause height as simulated by WACCM
We want to examine the changes in the tropopause height as simulated by WACCM. We want to compare the results obtained using the thermal definition of the tropopause with those obtained using the dynamical definition. We also want to study the relative contribution of the upper-tropospheric warming associated with increased greenhouse gases and the lower-stratospheric cooling associated with ozone depletion.
21/05/2010 CCMVal-2 Data request 2008

Kyong-Hwan Seo, Jung Ok, Sang-Dae Han

Evaluation of the annual cycle in surface air temperature The capability of producing the realistic annual cycle in surface air temperature and sea surface temperature in CCMVal (and CCMVal2) model runs will be compared to the observed using an EOF analysis. The observed second mode contains the warming trend after late 1970s, which will be also compared with a variety of reanalysis data and AR4 climate models. The pattern correlation and temporal anomaly correlation will be calculated. In addition, the fidelity in reproducing the two dominant tropical variability (ENSO and MJO) will be assessed. The MJO-ENSO relationship will be evaluated using EOF and regression analyses.  31/05/2010 CCMVal-2 Data request 2008
Monthly data: surface air temperature, SST, and SLP etc..
Daily data: OLR, SST, latent heat flux at surface, downwelling short radiation flux at surface, skin temperature, 1000-hPa, 850-hPa, 200-hPa winds, 3D specific humidity field, precipitation, etc

Matt Tully, Andrew Klekociuk Interannual Variability in Mid-latitude Southern Hemisphere Total Ozone

Observations of ozone over southern hemisphere (SH) mid-latitudes reveal the interannual variability relates somewhat differently to the various natural and anthropogenic cycles and forcings than is the case for the corresponding latitudes in the northern hemisphere, which have been better studied to date. In particular, the QBO plays a much greater role over much of the SH in winter and spring. We propose comparing model output with observations over SH mid-latitudes to assess how well the models capture the details of the observed variability.

17/06/10 CCMVal-2 Data request 2008

Andrew Gettelman
Simulations of the evolution of the width of the tropical belt in Coupled Chemistry Climate Models (CCMs)

The width of the tropics will be examined in CCMs using a variety of different metrics of the general circulation and compared to observations. Changes to the structure of the Upper Troposphere and Lower Stratosphere (UTLS) in CCMs are examined to look at differences in how the tropopause and circulation, as well as clouds and precipitation are simulated to change. The study will use REF-B1 and REF-B2 output from the CCMVal-2 experiments on the BADC archive.
CCMVal-2 Data request 2008


Markus Kunze, Peter Braesicke, Gabi Stiller, Ulrike Langematz

The role of the Asian summer monsoon in determining the composition of the lowermost stratosphere
Satellite observations have established the impact of the Asian Summer Monsoon on the composition of the upper troposphere and lower stratosphere (UTLS). For example a region of enhanced water vapour and decreased ozone is observed in the UTLS during the time of an established Monsoon anticyclone. Recent research highlighted the possibility of transport even deeper into the stratosphere. We will investigate how this observed evidence is represented in current chemistry-climate models by formulating relations between the dynamical structure of the anticyclone and the observed tracer anomalies. We will compare the models to each other and will confront individual models and a multi-model mean with the observational evidence.
CCMVal-2 Data request 2008

Maggie Hurwitz, Paul Newman, Luke Oman and Andrea Molod Stratospheric Temperature Response to El Niño events in the CCMVal-2 Models We have classified observed El Niño events as either “warm pool” or "cold tongue" events, based on the location of the largest positive SST anomalies in the equatorial Pacific Ocean.  Using various meteorological reanalyses, we found that the Antarctic stratosphere responds differently to these two types of El Niño events during the austral spring and summer seasons.  In this study, we will compare the observed stratospheric temperature response to El Niño with the modelled response, using output from the REF-B1 simulations.  In CCMs with an internally-generated QBO, we will examine the El Niño response with respect to the phase of the QBO. 18/06/10
CCMVal-2 Data request 2008
eddy heat flux and temperature (and possibly, ozone, winds and w*)

Chuanxi Liu and Yi Liu Impact of stratospheric processes and ENSO dynamics on the total column ozone over the Tibetan Plateau

As revealed in our previous studies (Liu et al., 2009, 2010), dynamical processes in both stratosphere (displacement of the polar vortex and the "low-ozone pockets" inside the Aleutian High) and upper troposphere and lower stratosphere (UTLS) (tropical convective heatings) contribute to extreme ozone minimum events over the Tibetan Plateau during winter. In the present research, impacts of the ENSO cycle and stratospheric disturbances on the Tibetan total column ozone will be examined using the CCMVal simulation data.The combined effects from both ENSO and Madden-Julian Oscillation will also be involved.
CCMVal-2 Data request 2008

B. Hassler, G.E. Bodeker, M. Dameris, D.E. Kinnison
Global patterns in halogen-induced changes in vertically resolved
stratospheric ozone
An accurate representation of the global distribution of stratospheric ozone and its temporal evolution is a prerequisite for making realistic predictions of the
future composition of the atmosphere and the climate on Earth. Although it is well known that zonal asymmetries in ozone distributions and trends exist, it was not possible so far to examine those in vertically resolved datasets on a global scale since no data set was sufficiently dense. For the study presented here, several satellite data sources and ozone soundings were combined to minimize the amount of missing data in a three dimensional (latitude, longitude, pressure) dataset of monthly mean ozone values from 1979 to 2006 with a resolution of 5° latitude × 60° longitude. However, this dataset is far from complete so that applications of traditional methods of determining ozone changes are not applicable. Therefore, a new approach was developed, a modification of the commonly used multiple, linear regression in which the explanatory variables are expanded in spherical harmonics to allow the description of spatial patterns in the fit coefficients, rather than calculating the fit coefficients of the explanatory variables for every grid point of the spatial grid separately. The expansion functions are fitted to the ozone values available for
each atmospheric level, and the complete global pattern is thereby defined by the fitted functions.
To evaluate the new approach with respect to its ability to reproduce spatial patterns and to generate reliable results in spite of numerous missing data, an
additional, gap-free monthly mean ozone dataset was calculated from a chemistry-climate model simulation with the same spatial and temporal characteristics as the observations. Results derived from the new, validated regression model applied to the observations show that zonal asymmetries in halogen-induced ozone changes are primarily present in polar regions and midlatitudes in winter and spring when planetary wave activity and the influence of the polar vortices are strongest. Comparisons with similar total column ozone
analyses show good agreements. In addition to the validation with chemistryclimate model output, this agreement suggests that the new method is capable to
allow, for the first time, a global estimation of vertically resolved, halogen-induced ozone changes.
CCMVal-2 Data request 2008

Mark Schoeberl
 Ozone profile changes
Climate change will alter the dynamics and thermodynamics of the stratosphere is a number of ways. As the stratosphere cools, water vapor dehydration events outside the tropics will become more severe (Antarctica) and we expect that as ozone photochemistry slows there will be changes in the vertical profile of ozone.  I plan to make a comparison between observations from Aura and the various models being used in CCMVal.
CCMVal-2 Data request 2008

Ryan Fogt and Judith Perlwitz
The sensitivity of the Amundsen / Bellingshausen Seas Low to ozone depletion and SSTs Participating
Recent studies show a marked warming along the western Antarctic Peninsula and West Antarctica.  The warming in these regions has been attributed to anthropogenic sources, and is in contrast to the rest of Antarctica which has remained stable or cooled slightly (albeit insignificantly) during the last 50 years. 
Analysis of the causality of this marked warming has pointed to oceanic influences and ice loss in the region.  However, these regions are also strongly influenced by the presence of the Amundsen / Bellingshausen Seas Low (ABSL), a semi-permanent pressure system sitting just offshore.  Our work will combine observations and model simulations to investigate the characteristic variability of the ABSL and the sensitivity of the regional Antarctic climate to these variations.  In particular to the CCMVal Projects, the project will detail the sensitivity of the ABSL to ozone depletion and various sea surface temperature configurations.  The use of CCM simulations will provide unique insight into how ozone depletion has influenced this regional feature, given their reliability in other large-scale Southern Hemisphere climate studies.  Further, it will provide a unique evaluation of the regional performance of the simulations contained within the CCMVal archive, and more so in a region of marked ongoing climate change.
18/10/2010 CCMVal-2 Data request 2008


Alkiviadis Bais, Kleareti Tourpali, A. Kazantzidis

Projections of UV radiation in the 21st century due to changes in ozone and clouds

Building on CCMVal-1 calculations of surface UV irradiance, the response of surface UV to model predicted total ozone changes and clouds is investigated in the course of the 21st century using a radiative transfer model.

CCMVal-2 Data request 2008

Celeste Johanson, Qiang Fu

Widening of the Hadely cell
Observations indicate a rapid widening of the Hadely cell over the past few decades.  This widening is not captured by the current GCMs in the IPCC AR4 archive.  One factor in this discrepancy may be that the IPCC AR4 models are not designed to simulate the effects of the stratosphere on climate change.  Here we investigate  Hadley cell variability in models with a more detailed representation of the stratosphere.  We will also compare the observed seasonality of trends in Hadley cell width to those in the CCMVal-2 models.  The initial focus will be on the austral spring season when the strong stratospheric cooling may have a significant impact on the boundary of the Southern Hemisphere Hadley cell branch.
18/01/2011 CCMVal-2 Data request 2008

Gang Chen
Stratospheric final warming events and downward influences
The stratosphere undergoes a final collapse of the polar vortex, appearing as a polar warming and the reversal of zonal winds from winter-time westerlies to summer-time easterlies, in the spring as solar heating in high latitudes increases. Unlike the sudden warming, the easterly zonal winds after the final warming do not return to westerly until
the final cooling takes place in the fall. The date on which the polar vortex breaks up, the so-called final warming onset time, varies from year to year. The interannual variability in the timing of the final warmings depends on the strength of planetary wave forcing, and it can have a large impact on the chemical depletion of stratospheric ozone. A late final warming is often associated with more ozone loss, because there is less ozone transport from the mid-latitudes and increased chemical destruction within the polar vortex. We will investigate the simulations of stratospheric final warming events in the CCMVal models, and the downward influences on the troposphere. The model simulations will be compared with reanalysis data, and the inter-model differences will be explained from
our previous theoretical work. Also, we will look into how much the delaying of stratospheric final warming dates in the Southern Hemisphere can contribute to the tropospheric wind trend, and how much the model bias in the onset date of final warming may affect the model simulated tropospheric wind trend.
CCMVal-2 Data request 2008

Darryn Waugh, Lei Wang
Southern Hemisphere High-latitude Temperature Trends

Significant stratospheric temperature trends have been observed in Southern Hemisphere (SH) high latitudes during the last three decades. These trends are characterized by a dipolar pattern whose phase varies among different months (with a large shift in phase between September and October). We will examine how well the CCMVal models reproduce these observed trends. We will also analyze scenario simulations forced by fixed GHG or ozone depleting substances to isolate the relative role of ozone depletion and increases in the Brewer Dobson circulation in causing these trends.
CCMVal-2 Data request 2008

Andrew Dessler
Contribution of stratospheric water trends to global warming According to the SPARC CCMVal report, stratospheric water vapor is expected to increase over the 21st century. I am interested in calculating the contribution of this trend in stratospheric water to global warming (and breaking out how much of the trend is due to the trend in methane versus the trend in the amount of water entering the stratosphere).
09/05/2011 CCMVal-2 Data request 2008

CCMVal-1 Publications:

Austin, J., K. Tourpali, E. Rozanov, H. Akiyoshi, S. Bekki, G. Bodeker, C. Brühl, N. Butchart, M. Chipperfield, M. Deushi, V. I. Fomichev, M. A. Giorgetta, L. Gray, K. Kodera, F. Lott, E. Manzini, D. Marsh, K. Matthes, T. Nagashima, K. Shibata, R. S. Stolarski, H. Struthers, and W. Tian, Coupled chemistry climate model simulations of the solar cycle in ozone and temperature, J. Geophys. Res., 113, D11306, 2008.

Eyring V., N.R.P. Harris, M. Rex, T.G. Shepherd, D.W. Fahey, G.T. Amanatidis, J. Austin, M.P. Chipperfield, M. Dameris, P.M. De F. Forster, A. Gettelman, H.F. Graf, T. Nagashima, P.A. Newman, S. Pawson, M.J. Prather, J.A. Pyle, R.J. Salawitch, B.D. Santer, and D.W. Waugh, A strategy for process-oriented validation of coupled chemistry-climate models. Bull. Am. Meteorol. Soc., 86, 1117–1133, 2005.

Eyring, V., N. Butchart, D. W. Waugh, H. Akiyoshi, J. Austin, S. Bekki, G. E. Bodeker, B. A. Boville, C. Brühl, M. P. Chipperfield, E. Cordero, M. Dameris, M. Deushi, V. E. Fioletov, S. M. Frith, R. R. Garcia, A. Gettelman, M. A. Giorgetta, V. Grewe, L. Jourdain, D. E. Kinnison, E. Mancini, E. Manzini, M. Marchand, D. R. Marsh, T. Nagashima, P. A. Newman, J. E. Nielsen, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, M. Schraner, T. G. Shepherd, K. Shibata, R. S. Stolarski, H. Struthers, W. Tian, and M. Yoshiki, Assessment of temperature, trace species and ozone in chemistry-climate model simulations of the recent past, J. Geophys. Res., 111, D22308, doi:10.1029/2006JD007327, 2006.

Eyring, V., D. W. Waugh, G. E. Bodeker, E. Cordero, H. Akiyoshi, J. Austin, S. R. Beagley, B. Boville, P. Braesicke, C. Brühl, N. Butchart, M. P. Chipperfield, M. Dameris, R. Deckert, M. Deushi, S. M. Frith, R. R. Garcia, A. Gettelman, M. Giorgetta, D. E. Kinnison, E. Mancini, E. Manzini, D. R. Marsh, S. Matthes, T. Nagashima, P. A. Newman, J. E. Nielsen, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, M. Schraner, J. F. Scinocca, K. Semeniuk, T. G. Shepherd, K. Shibata, B. Steil, R. Stolarski, W. Tian, and M. Yoshiki, Multimodel projections of stratospheric ozone in the 21st century, J. Geophys. Res., 112,  D16303, doi:10.1029/2006JD008332, 2007.

Gettelman, A., T. Birner, V. Eyring, H. Akiyoshi, S. Bekki, C. Brühl, M. Dameris, D. E. Kinnison, F. Lefevre, F. Lott, E. Mancini, G. Pitari, D. A. Plummer, E. Rozanov, K. Shibata, A. Stenke, H. Struthers, and W. Tian, The Tropical Tropopause Layer 1960–2100, Atmos. Chem. Phys., 9, 1621-1637, 2009.

Son, S.-W., L. M. Polvani, D. W. Waugh, H. Akiyoshi, R. Garcia, D. Kinnison, S. Pawson, E. Rozanov, T. G. Shepherd, and K. Shibata, The Impact of Stratospheric Ozone Recovery on the Southern Hemisphere Westerly Jet, Science, 320, DOI: 10.1126/science.1155939, 2008.

Son, S.-W., L. M. Polvani, D. W. Waugh, T. Birner, H. Akiyoshi, R. R. Garcia, A. Gettelman, D. A. Plummer, and E. Rozanov, Future tropopause trends as simulated by stratosphere-resolving
chemistry-climate models
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Tourpali, K., A. F. Bais, A. Kazantzidis, C. S. Zerefos, H. Akiyoshi, J. Austin, C. Brühl, N. Butchart, M. P. Chipperfield, M. Dameris, M. Deushi, V. Eyring, R. R. Garcia, M. A. Giorgetta, D. E. Kinnison, E. Mancini, E. Manzini, D. R. Marsh, T. Nagashima, G. Pitari, D. A. Plummer, E. Rozanov, J. F. Scinocca, K. Shibata, B. Steil, W. Tian and M. Yoshiki, Clear sky UV simulations in the 21st century based on Ozone and Temperature Projections from Chemistry-Climate Models, Atmos. Chem. Phys., 9, 1165-1172, 2009.

Waugh, D. W. and V. Eyring, Quantitative performance metrics for stratospheric-resolving chemistry-climate models, Atmos. Chem. Phys., 8, 5699-5713, 2008.

CCMVal-2 Publications (see details at

(1) SPARC CCMVal, SPARC CCMVal Report on the Evaluation of Chemistry-Climate Models, V. Eyring, T. G. Shepherd, D. W. Waugh (Eds.), SPARC Report No. 5, WCRP-X, WMO/TD-No. X,, 2010.

(2) JGR Special Issue (CHEMCLIM1-Modeling of chemistry and climate (Mc2) (Closed to New Submission December 31, 2009)

(3) follow up papers.

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Last modified:  9 June 2011

by Veronika Eyring