GACP Projects
Determination of Regional Aerosol Radiative Forcing from Remote Sensing Data and Model Simulations
Si-Chee Tsay, PI
Qiang Ji, Co-I
Abstract: Support is requested to study the direct radiative forcing in regions that are influenced by sulfate, dust, and biomass burning aerosols. We will focus on these three types of tropospheric aerosols, frequently observed over the Atlantic Basin and Asian Pacific, to develop an understanding of aerosol direct radiative forcing on a regional scale. Since tropospheric aerosols have a relatively short lifetime with large temporal and spatial variations, satellite observations consti-tute the most effective means to address and assess what radiative effects the deposition of aerosols may have upon these regions. In addition, radiative trans-fer modeling is required to bridge the angular and spectral gaps of satellite ob-servations, and surface remote sensing provides additional information content for comparisons that confirm quantitatively the usefulness of the integrated data.
The intent of this proposal is to support data analysis, model simulation, and collaboration with a group of scientists led by B. N. Holben of AERONET at NASA Goddard Space Flight Center. Specifically, the proposed objectives are:
- to extend the insights, to be learned from the EOS/AM1 MODIS meas-urements, to the re-analysis of collocated AVHRR and GOES data. Expe-rience gained from the analysis of MODIS Airborne Simulator data ac-quired during recent field campaigns proves the concept effective;
- to mobilize an existing suite of surface remote sensing instruments, in-cluding broadband radiometers, shadow-band radiometer, sunphotome-ter, micro-pulse lidar, and microwave radiometer, to collocate with satel-lite nadir overpass at targeted areas for enhancing the AERONET data base and providing data for intercomparisons; and
- to perform model simulations, based on our past work, of a very sophisti-cated column-radiation model which includes molecular scattering, gase-ous absorption, particulate extinction, and surface bidirectional reflection that produces accurate radiance fields and fluxes at any level and viewing geometry. This column-radiation model also utilizes a comprehensive physical/optical aerosol model which includes the relative humidity ef-fects and allows a variety of partitions of chemical component and mass.
With the aid of these models, we will fuse the space-borne and ground-based remote sensing data to conduct a detailed sensitivity study of aerosol radiative forcing and quantify the range of uncertainty. The results of this proposed study should greatly advance our ability to characterize the effects of regional aerosols on direct radiative forcing.
