|This project is funded by the European Commission through the Environment and Climate Programme.|
The investigation will cover two scale regimes: the corridor cross-section with multiple plumes as resulting from dense air traffic at plume ages of several minutes to hours, and the scale of the flight corridor within the region of the North Atlantic at time scales of several hours to days.
In particular, the project investigates the following questions:
|Task 1:||"Measurements": Performance of in situ measurements within and near to the flight corridor extending over the whole corridor scale|
|Task 1.1:||Improve and complete instruments to be used onboard the Falcon|
|Task 1.2:||Performance of a Falcon measurement campaign including weather forecasts for the campaign planning|
|Task 1.3:||Measurements with a B747 of NO, NO2, O3, and H2O along the North Atlantic route and coordination with MOZAIC measurements|
|Task 1.4:||Set-up of data bank|
|Task 2:||"Modelling": Analysis and interpretation of the previous and the additional measurements in correlation with the actual emissions, meteorology and background air chemistry conditions during the measurement periods.|
|Task 2.1:||Refinement of models|
|Task 2.2:||Analysis of the horizontal and vertical trace gas distributions|
|Task 2.3:||Quantification of the relative contributions from surface emissions relative to air traffic emissions|
|Task 2.4:||Determination of the frequency and area sizes of regions with ice supersaturation|
|Task 2.5:||Analysis of interaction between multiple plumes|
|Task 2.6:||Analysis of ozone chemistry, mainly in upper troposphere and also in lower stratosphere for measured situations|
The measurements and the data analysis will be performed in coordination with the the NASA research program SONEX. SONEX is the abbreviation of :q.SASS (Subsonic Aircraft Assessment) Ozone and NOx Experiment.:eq. The Office of Aeronautics of NASA in Washington issued a NASA Research Announcement :q.Atmospheric Effects of Aviation/Subsonic Assessment:eq. in July 3, 1996. The SONEX experiment is planned to take place in August and September 1997. During SONEX, it is planned to perform extensive measurements with an instrumented DC-8 aircraft within the North Atlantic air traffic region.
The Falcon flights will be conducted within a three weeks campaign. The Falcon will be equipped with new engines at that time which enables a flight duration and range of 5 hours and 3000 km, respectively, and an increased maximum cruise altitude of about 13 km. The B747 flights will be performed within a period of two months 1997 covering also the Falcon campaign period.
The POLINAT-2 measurements will be performed in temporal overlap with the SONEX experiment. The activities to be coordinated with SONEX enclose:
In cooperation with the Brookhaven National Laboratory (BNL, Dr. Russel Dietz) and as possible part of SONEX, preparations are being made to release a tracer from the DC-8 and to measure the tracer on board the Falcon in order to make sure that both aircraft were measuring the same air masses. This option might require to reduce part of the particle measurement systems for some of the FALCON flights. If this option cannot be realized, the identification of airmasses must be made with trajectory computations and analysis of all other measured air constituents.
:tabref refid=techn page=no. lists the species which will be measured on board the Falcon during the present project together with the instrumental techniques used for the aircraft-based measurements.
|NO, NO2, NOy||Chemiluminescence|
|H2O||Frost point hygrometer|
|HNO3, HNO2, SO2, H2SO4,||Mass spectrometry Acetone, HCN|
|Particulates||CN-counter, Electrostatic aerosol classifier|
|Wind, Temperature, pressure||Standard meteorological instrumentation PositionINS and GPS navigation system Table 1. Experimental techniques used for the POLINAT-2 Falcon|
Subsequently the status of the instruments and the planned improvements are described briefly.
NO, NO2: Existing with present detection limits for NO/NO2 measurements, 50/70 pptv and 5/10 pptv in 1 s and 60 s, respectively. The detection limit of the NO and NO2 instruments will be lowered by a factor of about 5 for the POLINAT-2 measurements.
NOy: An instrument to measure the sum of reactive nitrogen oxides (NOy ~ NO + NO2 + NO3 + HNO2 + HNO3 + N2O5 + ClONO2 + aerosol nitrate + .. ) will be added to the POLINAT instrument package. NOy species are reduced to NO by reduction on the heated surface of a gold catalysator using CO as a reducing gas and measured with an additional NO detector. The expected detection limit is 100 pptv in 1s.
Basic meteorological parameters: Existing.
AAMAS will measure HNO2, HNO3, SO2, H2SO4, HCN, and Acetone. The measurements will be made by a novel greatly improved aircraft-borne IMR-MS (Ion-Molecule Reaction Mass Spectrometer) instrument (AAMAS 2 = Automatic Aircraft-borne Mass Spectrometer 2). Optionally HO2 and OH may also become detectable. Here the detection method (IMR-MS with titration with SO2 and NO) is still under development and the number of racks required may limit its usage.
Water vapour frost-point hygrometer: Existing.
MASS (Mobile Aerosol Sampling System): existing. The MASS is provided in an upgraded form, to allow ice crystal sampling, aerosol volatility characterization, continuous concentration measurement at fixed particle size, higher efficiency total concentration measurement at high altitude, and impactor sampling of aerosols of larger size.
The project will include one major field campaign in 1997 with 40 flight hours. The base of the aircraft operations will be the airport of Shannon in Ireland or Tenerife. A local operation centre will be installed in Shannon or Tenerife during the campaign. The flight pattern will include long range flights between Tenerife, Shannon and Iceland or Norway. The cruising altitudes will be either below or above the local tropopause. The flight pattern will also include shorter legs at the maximum cruising altitude of the Falcon (about 13 km) at the end of the flights for measurements above the flight levels used by most of the commercial air traffic. The flight planning will start 24 hours ahead of the take-off time based on ECMWF forecasts, as provided by KNMI, and informations on the air traffic routes across the North Atlantic fixed for the next day by NATS in Prestwick. In addition forecasted 3-day backward-trajectories for air parcels ending at positions along the planned Falcon track will also be available for experiment planning.
Beside the data measured with the Falcon, also data of the North Atlantic air traffic for the campaign period will be collected for post campaign data analysis and interpretation.
For this purpose, the ETH will perform NO, NO2, O3, and water vapour measurements along the North-Atlantic route, using a Swissair B-747 Combi as measuring platform with the following instrumental set-up:
An instrument rack will be located in the freight compartment of Swissair B-747 Combi, including instruments for the measurements of NO, NO2 and O3. NO is measured based on chemiluminescence, NO2 is measured using a photolysis converter. The detection limits and its associated time constants are: NO: 50 ppt in 3 s; NO2: 65 ppt in 3 s. O3 is measured by UV-absorption, the detection limit and associated time constants are 0.5 ppb in 4 s. The water vapour will be measured by a dew point mirror with automatic cleaning mechanism. Resolution is 0.1 K, accuracy 0.25 K, the time constant depends on absolute humidity, a typical value is 10 s. Meteorological data will be computed from INS data and data collected by aircraft-integrated sensors. The secondary (i.e., computed) quantities include temperature and the three- dimensional wind vector with a time resolution of 2 seconds or better. (Note: Due to legal restrictions, the primary data from aircraft-integrated sensors cannot be made available.)
Attempts will be made to use so-called 'large eddy correlation techniques' to estimate vertical fluxes of the various constituents; an exact measurement, however, will not be possible with the available instrumentation due to too long time constants.
All measurements will be completely automated, a data download and re-calibration of the system is envisaged after each flight.
The entire instrumentation will be mounted on the airplane during a period of 2 months covering the field campaign of POLINAT-2 in 1997.
We plan to exchange the flight planning data with related projects for coincident measurements. The coordination will be organized by LMD.
The models used comprise the scales of individual plumes, multiple plumes, the North Atlantic and the global scale. Global and regional chemical transport models (CTM) will be applied which use the actual weather analysis data from numerical weather prediction (NWP) models, as provided e.g. by ECMWF. The same data will be used to compute trajectories of the air masses reaching or leaving the measured flight paths. Along these trajectories, various plume models are used to compute the lateral and vertical turbulent dispersion, the chemical transformations and aerosol formation.
Table 2 collects the models to be applied in POLINAT-2.
|UiO||3d, global, CTM (chemical transport model)||8x10°, 9 layers up to 10 hPa||2.2, 2.3, 2.6||Isaksen, UiO|
|CTMK||3d, global, CTM||4° x 5°, 15 levels up to 30hPa||1.2, 2.2, 2.3, 2.6||Kelder, KNMI|
|STOCHEM||3d, global, Lagrangian CTM||10x10°, 20000 Lagrangian particles||2.6||Johnson, UK Met. Office|
|ECHAM||3d, global, GCM||T21||2.3||Sausen, DLR|
|HIRLAM||3d regional NWP (numerical weather prediction)||50km x 50 km cells, 16 levels up to 25 hPa||1.2, 2.2, 2.3, 2.4, 2.5||Kelder, KNMI|
|HIRLAM - CTM||3d, North Atlantic, CTM||10 layers up to 100 hPa, 50-100 km grid||2.1, 2.2, 2.3, 2.6||Hov, UiB|
|PLUME, PUFF and TRAJECTORY MODELS|
|FLOW3D||3d flow field and dilution in jet plume||1 m to 1 km||2.5||Ford, Hayman, AEA|
|AEA||Plume chemistry with aerosols and hydrocarbons||2d, along trajectory of FLOW3D||2.5||Ford, Hayman, AEA|
|KTM||Trajectory model||trajectories based on ECMWF analysis||1.2, 2.2, 2.3, 2.5, 2.6||Kelder, KNMI|
|GAUSS||3d Gaussian plume model with LES (Large-Eddy Simulation) diffusivities||analytical solution, domain of 500 km x 500 km x 5 km||2.5||Schumann, Konopka, DLR|
|NILU||puff-model with gas and aerosol chemistry along long-range trajectory||1d, trajectory model||2.5, 2.6||Stordal, NILU Table 2. Models used for POLINAT-2.|
The questions will be investigated by analyzing the measurements in comparison to the weather conditions, background concentrations, and by model analysis.
The nature of air masses will be identified based on the relative magnitude of various measured tracer concentrations by DLR, MPI, LMD, ETH and UMR. Apart from trajectory analysis, KNMI will use backward time-integrations of the CTMK-model to decide on the origin of air masses in the past (up to five days). Three-dimensional model simulations with analysed wind fields and run for emission data bases including surface and aircraft emissions will be used (by UiB, KNMI, UiO, DLR, AEA-UKMetOff.) to determine the relative contribution from various emission sources. The change in sulphate chemistry during these transports will be addressed through simulations with the CTMK model (KNMI) and by means of box models along trajectories (NILU). By means of ECHAM runs transporting tracers with and without subgrid-scale model contributions, DLR will determine the relative importance of synoptic scale motions compared to subgrid scale convective motions.
Regions with ice supersaturation will be identified based on the measurements with the LMD water vapour frost point hygrometer, which offers the necessary accuracy for such measurements. The limitation of POLINAT in this task is the relatively small number of measurements, resulting in possibly a pure statistics. However, it can be checked how far the measured data compare with the weather analysis (it appears that these are sometimes better than previously thought) and with the data obtained on the B747 or within other projects. As far as possible with the given ressources, satellite data will be used to check for regions with persistent contrails and to investigate the frequency and size of regions which are conditioned for persistent contrails.
This objective will be addressed by identification of measured concentration peaks of exhaust species (DLR, MPI, LMD, UMR), identification of the source aircraft (DLR), backward trajectory analysis (KNMI), modelling of air parcel mixing and chemistry along the trajectory with aircraft sources (NILU), modelling and analysis of aerosol formation (AEA) and comparison with measured particle spectra (UMR). The modelling of the species in the plumes will describe the chemical reactions, diffusion, and the interactions between different plumes that cross each other. This will give a more realistic description of the chemical composition in the plumes when they reach the grid size of the global models (50-150 km).
For the weather conditions corresponding to the measurement campaigns, chemical transport models will be applied for analysis of ozone production rates and resultant ambient concentrations at global scales (UiO, KNMI, AEA-UKMetOffice) and regional scales (KNMI, UiB) for specific time periods using 3-d CTM coupled to limited area numerical weather prediction models. Moreover, models will be applied to analyse the ozone production rates and resultant concentrations along trajectories (NILU).
Special emphasis will be put on the calculation of the relationship between the local chemical production (or loss) rate of ozone and the local concentration of nitrogen oxides. Another topic to be addressed in the calculations will be to evaluate the competition between chemical and physical processes in the upper troposphere which determine the fate of the precursors (in particular NOx) and the formation of ozone and products of NOx (PAN, HO2NO2).
|M0||01/96||Start of the POLINAT-2 project|
|M1||07/96||Workshop with presentations of analysis results based on previous measurements|
|M2||07/97||Workshop with presentations of analysis results based on previous measurements and detailed planning of the experiment|
|M3||07/97||Refined instruments ready for flight|
|M4||10/97||End of measurement campaign, data available as quicklooks|
|M5||12/97||All measurement data in POLINAT database|
|M6||12/97||Set-up of input data for final model runs|
|M7||01/98||Drafts for final report by the partners|
|M9||04/98||Delivery of final report Table 3. Milestones|
|Coordinator:||DLR: Deutsche Forschungsanstalt für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany|
|Contractors:||MPG/MPI: Max-Planck-Institut für Kernphysik (Bereich Atmosphärenphysik), Heidelberg, Germany|
|KNMI: Koninklijk Nederlands Meteorologisch Instituut, AE de Bilt, the Netherlands|
|CNRS/LMD: Laboratoire de Meteorologie du CNRS, Ecole Polytechnique, Palaiseau, France|
|NILU: Norsk institutt for luftforskning, Lillestrom, Norway|
|AEA: National Environmental Technology Centre, AEA Technology, Culham, United Kingdom|
|ETH: Eidgenössische Technische Hochschule, Atmosphärenphysik, Zürich, Switzerland|
|Associated Contractors:||UiB: University of Bergen, Institute of Geophysics, Norway|
|UiO University of Oslo, Department of Geophysics, Norway|
|in collaboration with|
|UMR: University of Missouri-Rolla, Laboratory for Cloud and Aerosol Sciences, Rolla, MO, USA|
|MetOff: UK Meteorological Office, Bracknell, United Kingdom|
A list of main scientific contact partners is included. For each task, one group has the prime responsibility, see Table 4. Table 5 shows how the partners share in the work.
|Coordinator||Task 1||Task 2|
|DLR, Prof. Dr. U. Schumann||DLR, Dr. H. Schlager||KNMI, Dr. H. Kelder|
|UMR||AEA Table 4. Scientific project structure|
|2.6||+||+||+||X||+||+||Table 5. Workshare (X: responsible group, +: participant)|
Each group will provide data and other information, participate in meetings and workshops, as required, and provide the necessary reports to the coordinator on request.
All data will be collected in the already existing POLINAT-data bank, organized by DLR.
The results will be published as soon as possible, preferably in reviewed journals. The final project report will document the work performed, list the results obtained, and summarize the conclusions drawn.
Subsequently, the role of individual partners is described:
|1.1||Improvement and completion of the POLINAT instrumentation: The detection limit of the NO and NO2 instruments will be lowered by a factor of five. This is helpful for the background NOx measurements outside the polluted North Atlantic corridor region. In addition, a NOy detector will be added to the POLINAT instrument package to cover also the sum of the reactive nitrogen species.|
|1.2:||Performance of a measurement campaign in 1997: DLR will organize the
field campaign in 1997 with 40 flight hours. The base of the aircraft operations
will be Shannon in Ireland or Tenerife. A local operation centre will be
installed during the campaign.
DLR will also organize all coordination activities as required to coordinate the SONEX experiment with the POLINAT activities.
In particular, DLR negotiates with the Brookhaven National Laboratory (Dr. Russel Dietz) to seek for possible tracer release and analysis facilities.
|1.4:||Set-up of data bank: DLR has set-up the data bank for POLINAT-1 and will organize the data collection for POLINAT-2.|
|2.1:||Refinement of models: DLR will contribute the emissions data base for the air traffic in the North Atlantic, refine plume models to analyse the mixing in the plumes, and provide the global circulation model ECHAM for transport analysis.|
|2.2:||Analysis of the horizontal and vertical trace gas distributions: DLR will analyse the measured data in relation to model analysis|
|2.3:||Quantification of relative contributions from surface emissions relative to air traffic emissions: The global climate circulation model ECHAM is applied to analyse the relative importance of subgrid scale compared to synoptic scale vertical transport contributions.|
|2.4:||As far as possible with the given ressources, satellite data (NOAA AVHRR) will be analysed for contrail formation to investigate the relation between humidity and contrails.|
|2.5:||Analysis of multiple plumes: We compute the expected concentrations using a simple plume model.|
The following trace gases are to be measured by AAMAS 2:
The MPI takes over a share of 30 KECU of the Falcon operation costs.
KNMI will perform weather forecasting and post-campaign meteorological analysis in the planned measurement campaign. The KNMI trajectory model will be used for qualifying the transport of aircraft and other anthropogenic emissions, and its use will be extended to domain-filling trajectories.
A regional version of the CTMK model embedded in the global version will be used for chemistry-transport studies of the measurement episodes.
KNMI will provide the trajectory information as required for coordination of the DC-8 and Falcon flights during the coordinated POLINAT-2-SONEX experiments.
LMD carries a share of the Falcon operation costs (30 KECU).
In particular, NILU will contribute with an expanding plume and chemistry model to the POLINAT-2 project, with emphasis on multiple plume calculations. Measurements of several chemical species, e.g. NOx, HNO3 and O3 and turbulence data available from POLINAT-1 and -2 will be used in order to give a more realistic description of both the chemical composition of the background atmosphere and the meteorological conditions in the model. Both tropospheric and stratospheric chemistry will be included.
AEA will contribute to the analysis tasks, in particular by modelling the aerosol formation in the exhaust plume of aircraft. In collaboration with UK Met. Office (C. Johnson), global model analysis will be contributed to task 2.5.
At the end of POLINAT-1 it is expected that a model of the generation and evolution of an exhaust aerosol will have been established. A certain amount of model validation using data from the two experimental campaigns will have been completed. In the light of this comparison, it will undoubtedly be necessary to develop some aspects of the model to improve the correspondence with reality, as explained for task 2.1.
Having developed an aerosol/chemistry plume model, it will be put to use in interpreting new data obtained in the experimental campaigns planned under POLINAT-2, and in taking a closer look at some aspects of POLINAT-1 data. In addition, it would be valuable to make use of aerosol and chemistry data taken by the same instrumentation on board the DLR Falcon on behalf of other programmes (for example the German national programme to study aircraft emissions).
The global model STOCHEM will be used by UK Met. Office to assess the relative contribution of convective transport of boundary layer pollution compare to that arising from the emissions of subsonic aircraft, and to apply the model to investigate the large scale effects of the current air corridors on the background atmosphere. As a subsidiary, but important, objective, the validation of the model through its ability to reproduce the temporal and spatial behaviour of trace constituents in the atmosphere.
The system without the water vapour instrument is prepared for measurements on routine flights before this project starts. The complete installation will be mounted on a Swissair airliner, and the measurements will be performed during the campaign of POLINAT-2.
Particle measurements will include total concentration, size distribution, hydration information, and morphology. In this proposed POLINAT campaign the gaps in the measurement matrix from the initial POLINAT campaign will be filled in, and the particle - gas phase species correlations observed in the initial POLINAT campaign will be explored. The MASS will be upgraded to allow ice crystal sampling, aerosol volatility characterization, continuous concentration measurement at fixed particle size, higher efficiency total concentration measurement at high altitude, and impactor sampling of aerosols of larger size.
The participation of the University of Missouri-Rolla group includes no funding from the CEC. UMR, as an American institute, did participate in POLINAT-1 with funding by various sources including the Univ. of Missouri and NASA.
The instruments and analysis tools remain in the property of each group and will be used for follow-on projects by them.
Press releases will be provided at proper times to inform the public on major interim findings and the final result.
Any publication using data from various groups will include co-authors from all those groups. The principal author will be listed first; the ordering of the other authors depends on the relative contributions, as decided by the principal author. No publication is permitted without the written agreement of each input providing group, under control of the project coordinator.
The POLINAT data-set will be made available for free or for a modest copy charge one year after the project terminates. It can be made available to other groups earlier under special agreements if there is a mutual interest in such an exchange, and if all partners agree.
The data exchange between POLINAT-2 and SONEX partners will be organized between the POLINAT-2 and SONEX coordinators as far as required for optimal use of the measurements results of both groups and such that the rights of the individual groups creating the data are satisfied.
Table 6 gives the expected time plan.
|1.2 Falcon campaign||
|1.3 B747 measurements||
|1.4 Data bank||
|2.1 Model preparations||
|2.2 Concentration fields||
|2.3 Surface contributions||
|2.4 Ice supersaturation||
|2.5 Multiple plumes||
|2.6 Ozone chemistry||
POLINAT-2 will also gain form the experience obtained within AERONOX (1991-1994, CEC Contract EV5V-CT91-0044), follow-on projects suggested there, and related national programmes, e.g., in the Netherlands, France, Germany, and USA.
The partners of POLINAT-2 are willing to coordinate their activities with related projects for optimization of mutual benefits.
Moreover, as stated before, POLINAT-2 will be performed in coordination with the the research program SONEX, the "SASS (Subsonic Aircraft Assessment) Ozone and NOx Experiment.", funded by the Office of Aeronautics of NASA in Washington, DC, USA.
Main scientific contact person for each participant:
Dr. Ulrich Schumann
Institut für Physik der Atmosphäre
Tel. (49) 8153-28-2510, 2500, 2520
Fax. (49) 8153-28-1841
Priv.-Doz. Dr. Frank Arnold
Max-Planck-Institut für Kernphysik
Fax: 06221-516 324
Tel: 06221-516 467 (229, Sekretariat)
Dr. Joelle Ovarlez
Laboratoire de Meteorologie Dynamique
F-91128 Palaiseau Cedex
Tel: 0033-1 69 33 48 00
Fax: 0033-1 69 33 30 05
Dr. Hennie Kelder
Koninklijk Nederlands Meteorologisch Instituut
NL-3730 AE de Bilt
Fax: 0031 30 2 210407
Tel: 0031 30 2 206472
Dr. Garry D. Hayman
National Environm. Techn. Centre
Abingdon, Oxon. OX14 2DB
Tel 0044 1235 463108
Fax 0044 1235 463005
Dr. Frode Stordal
Norsk institutt for luftforskning
P.O. Box 64
Tel: +47 63 898 175
Fax: 0047 63 89 80 50
Dr. I.S.A. Isaksen
University of Oslo
PB 1022 Blindern
Tel.: +47 22 85 58 22
Fax: +47 22 85 52 69
Dr. Oystein Hov
Norsk institutt for luftforskning
P.O. Box 64
Tel: +47 63 898 000
Fax: 0047 63 898 050
Dr. Philip D. Whitefield
University of Missouri-Rolla
Cloud and Aerosol Sciences Lab.
Rolla, MO 65401
Dr. J. Staehelin, ETH,
Eidgenössische Technische Hochschule,
Institute for Atmospheric Science,
fax: 0041 1 633 10 58
Tel: 0041 1 633 27 48