The purpose of the Goddard's Aerosol Assimilation System (GAAS) is to combine the advances in remote sensing of atmospheric aerosols, aerosol modeling and data assimilation methodology to produce high spatial and temporal resolution 3D aerosol fields, and to assess the impact of these fields on climate modeling and more generally on atmospheric climate assimilation. This proposal focus on the introduction of CALIPSO aerosol observations, combined with aerosol measurements from MODIS on both TERRA and AQUA satellites. Concurrent assimilation of OMI observations is being pursued on a pending proposal. The ultimate goal of this effort is to develop an A-Train aerosol data assimilation system with the eventual addition of PARASOL observations. Specifically, we propose:
- To develop a 1D variational scheme which utilizes CALIPSO attenuated backscatter at the satellite footprint, producing aerosol mass profiles for each species as well as aerosol extinction at the model's vertical grid. The GAAS background fields entering these calculations will have the benefit of MODIS, and at a later stage, of OMI aerosol measurements. Careful consideration of observational and background bias will be an integral part of this initial development.
- To assimilate the 1D-Var retrievals produced in (1) by means of an analysis splitting technique, consistently utilizing the average kernel for proper definition of observation operators. Particular attention will be paid to the modeling of background error covariances required to properly handle the spread of information provided by the extremely narrow CALIPSO swaths. The resulting assimilated fields constrained by MODIS/CALIPSO/OMI will be made available to the CALIPSO team to further improve their aerosol retrieval problem.
- To investigate the impact of the CALIPSO constrained aerosol fields on the climate simulations/assimilations produced with the GMAO's GEOS-5 Atmospheric General Circulation Model (AGCM). In particular, it is anticipated that CALIPSO observations will be of great utility for refining the planetary boundary layer (PBL) parameterization in the GEOS-5 Atmospheric General Circulation Model.
n every stage of this development, extensive use of AERONET/MPLNET and other ground base systems will be used for validation of our algorithms.
