12th Conference on Atmospheric Chemistry


Global data from space: The contributions satellites make to aerosol measurement (Invited Speaker)

Ralph Kahn, NASA/GSFC, Greenbelt, MD

The MISR, MODIS, OMI, and POLDER instruments have demonstrated many new space-based passive aerosol remote-sensing capabilities. These include aerosol optical depth (AOD) over land to about 0.05 or 20% of the AOD, better-constrained results over dark water, and even some ability to measure AOD of smoke over cloud decks and dust over bright desert surfaces. Particle size distributions in three-to-five bins are produced under good, but not necessarily ideal, viewing conditions, spherical vs. non-spherical particle shapes are identified, and particle single-scattering albedo is constrained into two–to-four bins over water and some land. In many cases, aerosol source plume and elevated absorbing aerosol layer heights can be derived from stereo imaging, and the space-based CALIPSO lidar can operate for years, profiling aerosols far downwind of sources. This is immense progress over previous satellite instruments, which were not designed for aerosol studies, and produced only limited AOD information, and nothing quantitative about aerosol microphysical properties.

But even the current particle microphysical data from space are largely qualitative, and the accuracy of AOD and aerosol type retrievals varies considerably with conditions. So the satellite data must be used in a context that includes more precise but less extensive sub-orbital measurements, and together, these must be integrated into numerical models to address some of the leading climate and air quality questions. This talk will summarize current efforts to develop satellite aerosol data sets that can be used for modeling applications, with emphasis on wildfire smoke source characteristics, desert dust transports, and aerosol air mass type mapping.

Recorded presentation

Session 4, The Use of Remote Sensing and Surface Measurements for Air Quality Modeling - I
Wednesday, 20 January 2010, 1:30 PM-2:30 PM, B315

Next paper

Browse or search entire meeting

AMS Home Page