A Climatology of Saharan Dust Measurements Observed by CALIPSO, MODIS, and OMI in Support of the TC4 Field Experiment

During summer months, elevated layers of Saharan dust form off the western African coast and are frequently carried across the North Atlantic Ocean into the extreme western Caribbean region by predominate easterly flow. For more than a decade, satellites have observed this pattern of dust transport. Somewhat strikingly, however, is the absence of enhanced aerosol observations in the region immediately across the Isthmus of Panama and lower Central America in the adjacent waters of the Pacific Ocean. One of the goals of the Tropical Composition, Clouds, and Climate Coupling Experiment (TC4) field mission is to better understand the cause of this observed gradient in dust properties and help answer questions on how dust may be scavenged by precipitation from tropical convection, how they may be lofted to the upper troposphere, or how transport may be blocked by coastal mountain ranges and diverted along the coast. This poster will a present an aerosol climatology compiled for the summer of 2007 using measurements from CALIPSO, MODIS, and OMI - members of the A-Train satellite constellation. CALIPSO provides profile observations of aerosols and clouds with a two-wavelength polarization-sensitive lidar. MODIS and OMI provide aerosol observations over broader geographical regions at visible and in the near UV region, respectively. Together these datasets provide complementary information on Saharan dust that can provide a broad context for interpreting the aircraft measurements acquired during TC4. Preliminary comparisons on spatial homogeneity and typing with aircraft lidar and in situ aerosol observations will also be presented.