CCM Validation Activity for SPARC (CCMVal) |
|
No |
CCMVal
Collaborator(s) |
Title |
Abstract |
Date of
Proposal |
Data
Request(s) |
Status |
References |
|
CCMVal-1 |
||||||||
1 |
Veronika
Eyring, Neal Butchart, Darryn Waugh |
Assessment of
|
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). |
01/01/2006 |
CCMVal
1st data request WMO 2006 data request |
Closed |
Eyring
et al., 2006 |
|
2 |
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 |
|
3 |
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 |
|
4 |
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 |
|
5 |
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 |
|
6 |
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. |
15/10/2006 |
Data
needed: 2D monthly mean total ozone and
surface
albedo as a function of longitude and latitude |
Closed | Tourpali
et al., 2009 |
|
7 |
Farah Khosrawi, |
Separation of
|
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. |
25/10/2006 |
CCMVal 1st data request | Ongoing | ||
8 |
Nathan Gillett, |
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 |
||
9 |
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. |
09/11/2006 |
CCMVal 1st data request | Ongoing |
||
10 |
Chiara Cagnazzo, |
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 plus 3D Monthly means for temperature and geopotential height |
Closed | Submitted |
|
11 |
John
Austin, Piers Forster, and the SPARC T-trends panel |
Simulated versus
|
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 | ||
12 |
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 |
Ongoing | ||
13 |
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 |
Ongoing | ||
14 |
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. |
29/01/2007 |
WMO 2006 data request | Ongoing |
||
15 |
Marion
Marchand, |
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 |
Ongoing | |||
16 |
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 |
16/03/2007 |
CCMVal
SCOUT-O3 aircraft data request |
Ongoing |
||
17 |
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 |
Ongoing |
||
18 |
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. |
26/03/07 |
|
Closed |
Son et al., 2009 |
|
19 |
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. |
12/04/07 |
Ongoing | |||
20 |
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 |
Ongoing |
|||
21 |
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. |
02/05/07 |
CCMVal
SCOUT-O3 UV data request |
Ongoing |
||
22 |
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. |
12/06/07 |
CCMVal
1st data request in particular water vapour fields |
Ongoing |
||
23 |
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 | ||
24 |
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 |
Ongoing | ||
25 |
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 |
||
26 |
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 (www.tccon.caltech.edu). 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 |
||
27 |
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 CCMs. |
25/09/07 |
CCMVal 1st data request | Ongoing |
||
28 |
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. |
15/01/08 |
Output from Eyring et al. (2006) |
Closed |
Waugh
and Eyring, 2008 |
|
29 |
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. |
|
30 |
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 |
Ongoing |
||
31 |
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. |
13/03/08 |
CCMVal 1st data request | Ongoing |
||
32 |
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 |
|
33 |
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. |
06/04/08 |
CCMVal 1st data request | Ongoing |
||
34 |
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 | ||||||||
35 |
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 |
Ongoing |
||
36 |
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 |
||
38 |
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 |
10/07/2008 |
CCMVal-2 Data request 2008 | Ongoing |
||
39 |
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 http://homepages.see.leeds.ac.uk/~lecmc/ccmvalj/ 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 |
||
40 |
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 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. |
05/08/2008 |
CCMVal-2 Data request 2008 | Ongoing |
||
41 |
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 |
||
42 |
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 |
Ongoing | ||
43 |
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. |
18/08/09 |
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 | ||
44 |
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 |
18/09/08 |
CCMVal
1st data request and CCMVal-2 Data request 2008 |
Ongoing |
||
45 |
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 | ||
46 |
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) |
||||||||
47 |
Veronika
Eyring Ted Shepherd Darryn Waugh |
SPARC CCMVal Report 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 | ||
48 |
Victor Fomichev Piers Forster |
SPARC CCMVal Report |
16/10/2008 | CCMVal-2 Data request 2008 | Ongoing | |||
49 |
Neal
Butchart, Andrew Charlton, Irene Cionni, Peter Haynes, Kirsten Krüger, Paul Newman, Scott Osprey, Judith Perlwitz, Fabrizzio Sassi, John Scinocca, Michael Sigmond |
SPARC CCMVal Report |
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 | ||
50 |
Jessica Neu, Susan
Strahan, Peter Braesicke, Anne Douglass, Petra Huck, Luke Oman, Diane Pendlebury, Susann Tegtmeier |
SPARC CCMVal Report 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 | ||
51 |
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 |
SPARC CCMVal Report 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 | ||
52 |
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 |
SPARC CCMVal Report 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 | ||
53 |
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 |
SPARC CCMVal Report 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 | ||
54 |
John
Austin John Scniocca Hamish Struthers David Plummer David Stephenson |
SPARC CCMVal Report 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 | ||
55 |
Mark Baldwin, |
SPARC CCMVal Report 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 | ||||||||
56 |
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’. |
25/07/09 |
2nd CCMVal-2 Data request 2009 | Closed |
Eyring
et al., ACPD, 2010 Eyring et al., GRL, submitted, 2010 |
|
57 |
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. |
02/02/10 |
2nd CCMVal-2 Data request 2009 | Closed | Charlton-Perez
et al., ACPD, 2010 |
|
58 |
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. |
02/02/10 |
2nd CCMVal-2 Data request 2009 | Ongoing | Gillett et al., ACPD, 2010 |
|
CCMVal-1 and CCMVal-2: individual studies continued | ||||||||
59 |
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 |
||
60 |
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. |
21/01/2009 |
CCMVal 1st data request | Ongoing |
||
61 |
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.
|
03/02/2009 |
CCMVal-2 Data request 2008 | Ongoing |
||
62 |
Alexander Sen Gupta
|
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. |
19/02/2009 |
CCMVal 1st data request | Ongoing |
||
63 |
Ulrike Langematz
|
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 |
||
64 |
Paul Kushner,
|
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 |
||
65 |
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. |
25/02/09 |
CCMVal-2 Data request 2008 | Ongoing |
||
66 |
Lei Wang, |
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) |
Ongoing |
||
67 |
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 |
||
68 |
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 | ||
70 |
Charles McLandress | Stationary
and transient wave driving of the Brewer-Dobson circulation |
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 |
||
71 |
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. |
25/07/09 |
CCMVal
1st data request and CCMVal-2 Data request 2008 as soon as CCMVal-2 mvoes to Phase 1 |
Ongoing |
||
72 |
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. |
25/07/09 |
CCMVal
1st data request and CCMVal-2 Data request 2008 as soon as CCMVal-2 mvoes to Phase 1 |
Ongoing |
||
73 |
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. |
04/11/2009 |
CCMVal-2 Data request 2008 | Ongoing | ||
74 |
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. |
12/01/2010 |
CCMVal-2 Data request 2008 | Ongoing | ||
74 |
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. |
18/01/2010 |
CCMVal-2 Data request 2008 | Ongoing | ||
76 |
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. |
11/03/10 |
CCMVal-2 Data request 2008 | Ongoing | ||
77 |
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). |
25/03/10 |
CCMVal-2 Data request 2008 | Ongoing | ||
78 |
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 |
15/04/2010 |
CCMVal-2 Data request 2008 | Ongoing | ||
79 |
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. |
21/05/2010 |
CCMVal-2 Data request 2008 | Ongoing | ||
80 |
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 |
|||
81 |
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 |
|||
82 |
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 |
|||
83 |
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 | |||
84 |
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. |
17/06/10 |
CCMVal-2 Data request 2008 | |||
85 |
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. |
18/06/10 |
CCMVal-2 Data request 2008 | |||
86 |
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*) |
|||
87 |
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. |
20/08/2010 |
CCMVal-2 Data request 2008 | |||
88 |
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. |
20/08/2010 |
CCMVal-2 Data request 2008 | |||
89 |
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. |
22/09/2010 |
CCMVal-2 Data request 2008 | |||
90 |
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 | |||
91 |
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. |
07/12/2010 |
CCMVal-2 Data request 2008 | |||
92 |
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 | |||
93 |
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. |
21/02/2011 |
CCMVal-2 Data request 2008 | |||
94 |
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. |
09/05/2011 |
CCMVal-2 Data request 2008 | |||
95 |
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 |
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 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, 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 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- Waugh, D. W. and V. Eyring, Quantitative
performance metrics for stratospheric-resolving chemistry-climate
models, Atmos. Chem. Phys.,
8, 5699-5713, 2008.
|
(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, http://www.atmosp.physics.utoronto.ca/SPARC, 2010. (2) JGR Special Issue (CHEMCLIM1-Modeling of
chemistry and climate (Mc2) (Closed to New Submission December 31, 2009)
(3) follow up papers.
|
Austin, Soukharev and Hood (2006), ACPD,
in preparation. Andersen, S. B. , E. C. Weatherhead, A. Stevermer, J. Austin, C. Brühl, E. L. Fleming, J. de Grandpre, V. Grewe, I. Isaksen, G. Pitari, R. W. Portmann, B. Rognerud, J. E. Rosenfield, S. Smyshlayev, T. Nagashima, G. J. M. Velders, D. K. Weisenstein, J. Xia, Comparison of recent modeled and observed trends in stratospheric total column ozone, J. Geophys. Res., 111, D02303, 10.1029/2005JD006091, 2006. Bodeker, G.E., H. Shiona, and H. Eskes,
Indicators
of Antarctic ozone depletion, Atmospheric Chemistry and Physics,
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2603-2615, 2005.
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P., et al., 2007, A model intercomparison analysing the link between
ozone and geopotential height anomalies in January, Atmos. Chem. Phys.
Discuss., 7, 15409–15451. Butchart, N. et al.
(2006), Simulations of anthropogenic change in the strength of
the
Brewer-Dobson circulation, J. Climate,
doi:10.1007/s00382-006-0162-4. Crook,
J. A., N. P. Gillett, and S. P. E. Keeley, 2008, Sensitivity of
Southern Hemisphere climate to zonal asymmetry in ozone, Geophys. Res.
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T.,
Eyring, V., Bittner, M., Dameris, M., Grewe, V.: Hemispheric
ozone
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indices derived from satellite observations and comparison to a coupled
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from ground-based and satellite measurements: 1964–2000, Journal of
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A., D. Peters, I. Kirchner, and H.-F. Graf, 2007, Effect of zonally
asymmetric ozone on stratospheric temperature and planetary wave
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I., and D. Peters, 2003, Modelling the wintertime response to upper
tropospheric and lower stratospheric ozone anomalies over the North
Atlantic and Europe, Annales Geophysicae, 21, 2107-2118. Khosrawi et
al. (2004): Monthly averaged ozone and nitrous oxide from the Improved
Limb
Atmospheric Spectrometer (ILAS) in the Northern and Southern Hemisphere
polar
regions, Khosrawi et al. (2006): Monthly averages of nitrous oxide and ozone for the Northern and Southern Hemisphere high latitudes: A 1-year climatology derived from ILAS/ILAS-II observations, Knudsen, B. M., and S. B. Andersen, Longitudinal
variation in
springtime ozone trends, Nature, 413, 699-700, 2001 Manzini, E., M.A. Giorgetta, M.
Esch, L. Kornblueh and McLandress, C.,
and T. G. Shepherd, 2009, Simulated anthropogenic changes in the
Brewer-Dobson circulation, including its extension to high latitudes,
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D., and G. Entzian, 1999, Longitude-dependent decadal changes of total
ozone in boreal winter months during 1979-92, J. Climate, 12, 1038-1048 Proffitt et al. (2003): Seasonally averaged ozone and nitrous oxide in the Northern Hemisphere lower stratosphere, J. Geophys. Res., 108(D3), 4110, doi:10.1029/2002JD002657. Randel et al., In preparation, JGR, 2006. Shindell et al. (1999), Science,
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Ozone Layer, Nature, 441, 39-45, doi:10.1038/nature04746,
2006. |
Last modified: 9 June 2011 |
|
by Veronika
Eyring |