Recent studies have suggested that the Saharan air layer (SAL) may have negative impact on tropical cyclone intensity development. Specifically, the SAL may alter the dynamics, microphysics and thermodynamics of tropical systems (e.g., Dunion and Velden, 2004), may cool the sea surface temperature (e.g., Lau and Kim, 2007), may suppress deep convection (e.g., Wong and Dessler, 2005), and may alter the radiation balance of the atmosphere (e.g., Slingo, et al, 2006). On the PIRATA/AEROSE-III expedition, organized by NOAA/AMOL, scientists from Howard University measured optical properties of dust associated with the SAL over the eastern and central tropical North Atlantic Ocean off-shore of the African continent during May 2007 using sunphotometers and other radiometers. For some of the dust events sampled by sensors on board the Ronald H. Brown, concurrent observation of vertical profiles of back scattered aerosol extension were made by NASA's CALIPSO satellite.

This study presents preliminary analysis of surface radiative forcing and atmospheric heating associated with a major dust outflow event from May 13-15. The analysis may shed light on the role of dust on the thermodynamics of the SAL and its impact on SST.