Fourth Symposium on Lidar Atmospheric Applications


African Dust and Smoke Influences on Radiative Effects in the Tropical Atlantic Using CERES and CALIOP Data

John E. Yorks, SSAI/NASA GSFC, Greenbelt, MD; and M. J. McGill, S. Rodier, M. Vaughan, Y. Hu, and D. L. Hlavka

The effects of aerosols on solar and terrestrial radiation have been studied in the past using combinations of satellite data, atmospheric imagers, and surface observations. However, these data are unable to accurately differentiate aerosol layer height and type. The launch of the CALIPSO satellite in April 2006 allows the science community to explore aerosol-cloud interactions through parameters such as cloud and aerosol layer height, optical depth and depolarization ratio. During the month of July, clouds over the Tropical Atlantic Ocean can be affected by Saharan dust events and biomass burning from southern Africa. The influence of African dust and smoke aerosols on cloud radiative properties over the Tropical Atlantic Ocean are analyzed for the month of July for three years (2006-2008) using collocated data collected by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Clouds and the Earth's Radiant Energy System (CERES) instruments on the CALISPO and Aqua satellites. On average, profiles with clouds below 5 km have a daytime instantaneous shortwave (SW) radiative flux of 271.6 W/m2 and profiles with cirrus clouds have a SW radiative flux of 208.0 W/m2. When dust and smoke aerosols are present in profiles with clouds below 5 km, the SW radiative flux decreased to 209.3 W/m2 and 243.0 W/m2, respectively. These effects are likely due to the aerosol layer location, with changes in cloud microphysics contributing as well. These cloud-aerosol interactions have a significant impact on the radiation budget in the Tropical Atlantic because of the spatial and temporal extent of desert dust and smoke from biomass burning in the atmosphere.

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Session 8, Satelite Studies and Lidar Observations - I
Thursday, 15 January 2009, 8:30 AM-9:45 AM, Room 122A

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