Status Reports

Scientific achievements during the 1st year:

During the first year of PHOENICS project progress was made in all workpackages of the projects, data compilation, process parameterization and global model development.

Observational aerosol data have been compiled for validation and/or initialization of the process and global model in use in the project.

NO3 and associated water have been calculated on a global scale by the off line model TM3 (off-line global model) coupled with the thermodynamic equilibrium model EQSAM.

A parameterization of SOA formation from anthropogenic and naturally emitted VOC has been developed. This parameterization has been tested the TM3 model that has been used to calculate the global SOA distributions. Major uncertainties associated to the SOA computations have been identified and evaluated.

A mixture of 4 lumped organic aerosol components determined by model calculations has been proved to nicely reproduce the observed hygroscopicity of urban and polluted-rural organic aerosol.

A detailed cloud parcel model has been extended to internal and/or external aerosol mixtures of ammonium sulfate, ammonium bisulfate, dicarboxylic acids, and insoluble matter. The impact of dust and organics on the sulfate aerosol has been investigated. A first simplified parameterization of cloud processing of aerosol has been tested that requires as input the updraft velocity, the temperature, and the aerosol size and chemical characteristics at the cloud base.

The dry deposition parameterisation of aerosols has been modified to account for the size distribution simulated by the aerosol dynamic model rather than using the previous assumption of only accounting for two characteristic aerosol size distributions, one continental and the other marine. Replacement of these assumed size distributions with the actual distributions computed within the dynamic aerosol module M7 has improved consistency. The improvement of accuracy of the dry deposition computations remains to be evaluated.

Ongoing coupling of the WRF - Weather Research and Forecast - cloud resolving model with the M7 will provide a unique tool for testing aerosol scavenging parameterizations for use in the A-GCMs. Good progress has been made on this coupling although the wet scavenging parameterization work had a slow start. Evaluation of the water cycle in the models is also in progress using satellite data on water vapor and aerosols.

Significant progress has been made on the development of the global 2 way nested zoom model TM5 (off-line global model issued from TM3) that has been already applied to study the declining emissions of anthropogenic trace gases. The model is now ready to include aerosol formation and removal processes (implementation of appropriate routines has started). The model is expected to provide an excellent tool to test resolution dependency of aerosol formation as well as well as to calculate accurate budgets for aerosol formation over Europe.

Data on aerosol optical properties in the shortwave and longwave spectrum have been collected and methodologies to compute efficiently aerosol optical properties from model outputs have been reviewed.

The AERONET network data on optical depth, Angström-parameter, water-vapor, optical depth, refractive indices, size-distribution (22 bins) presenting a large year-to-year variability are compared with model results. Comparison between model and observations has to be restricted to the same years since multiyear averages may not apply to a particular year. MODIS data have been retrieved on 10x10 km2 (local), 100x100 km2 (standard satellite data-sets) and 300x300 km2 (global model) scales and have been compared to ground based data. Differences reflect the extent of pollution of the site. Comparison between MODIS and AERONET data allows selection of representative sites and provides information on the extent of local pollution.

ECHAM5 has been extended by the new aerosol module M7 that covers the nucleation of new sulphate particles, the condensation of sulphate on pre-existing particles, coagulation, the transfer of particles from insoluble to soluble modes, and the thermodynamic equilibrium with the water vapour phase. It considers all major aerosol components except nitrate and secondary organic aerosol that will be soon incorporated. Careful validation of the ECHAM/M7 model is underway.

The development of the alternative A-GCM is well on its way. The modal structure of the aerosol description has been implemented in the LMDzT-INCA module including all important aerosol components (dust, sea salt, black carbon, particulate organic matter, and sulphate). The INCA module (Interaction of Chemistry and Aerosols) allows computing e.g. the formation of sulphate with dynamically calculated oxidant precursor concentrations. The inclusion of the M7 aerosol dynamics code is planned in 2003.

For the purposes of the PHOENICS project, the LMDz and ECHAM5 models will also run with the same emission inventories.

The systematic approach to determine the direct effect of the mixed and size-resolved aerosol considering all its major components is progressing according to the Description of Work. Although the first climate effect calculations are not yet undertaken in the frame of the project, results on the distribution of the aerosols and its validation are emerging. Both A-GCMs are operational now and the M7 aerosol module already coupled with ECHAM5 is providing the first mixed aerosol chemical size-distribution results. Further improvement is foreseeing during the second year by the incorporation of the updated / improved parameterization of nitrate and organic aerosol and associated water and dry deposition and scavenging and cloud processing of the aerosols. The first aerosol climate effect calculations within PHOENICS will be also performed during the second year.