716 Investigating the Role of Aerosols and Clouds on the Radiation Budget in Niamey, Niger Allison Marquardt Collow and Mark Miller Department of Environmental Sciences, Rutgers University, New Brunswick, NJ Goals -Simulate the radiative impact of measured aerosols and clouds on the radiation budget in the atmospheric column over the West African Sahel (Niamey, Niger) -Investigate the role clouds and aerosols on the heating rate profile individually and when combined Data and Methods -Aerosol properties derived from observations made by a Multifilter Rotating Shadowband Radiometer (MFRSR) -Cloud properties measured using a 95 GHz vertically pointing cloud radar, micropulse lidar, and laser cielometer -The radiation budget was modeled every 5 seconds using the shortwave (SW) version of the Rapid Radiative Transfer Model (RRTM) for the entire month of August 2006 (a) Aerosol Heating Effect (a) (b) (b) Cloud Heating Effect (c) (d) Figure 1: Diurnal cycle of aerosol optical depth at 500, 615, 674, and 870 nm for the 2006 wet season in Niamey, Niger Figure 4: Individual heating components(a) Diurnal heating rate profile with clouds and aerosols minus clouds, (b) Diurnal heating rate profile with clouds and aerosols minus aerosols Conclusions -Aerosols are present in the wet season and must be included in radiation transfer calculations. -Clouds and aerosols can result in an increase in radiative heating of ~5°K per day in the lower and upper troposphere. -The combined heating from clouds and aerosols is larger than the heating from the individual components, but smaller than when the components are added separately. -The radiative heating rates in this region are a result of an inseparable radiative feedback between clouds and aerosols. Acknowledgements Allison Marquardt Collow and Mark Miller are supported by DOE Award DE-FG02-08ER64531. (e) (f) Figure 3: RRTM calculations for August 2006 with clouds and aerosols present (a) Diurnal profile of downward SW radiation in Wm-2, (b) diurnal profile of upward SW radiation in Wm-2, (c) diurnal profile of downward direct SW radiation in Wm-2, (d) diurnal profile of downward diffuse SW radiation in Wm-2, (e) diurnal profile of net SW radiation in Wm-2, (f) diurnal profile of heating rate in °K per day Figure 2: Monthly average RRTM calculated and observed radiative flux divergences for August 2006 (a) clear sky, (b) Cloudy sky (c) Aerosols present, (d) Clouds and aerosols present