A135-06
Direct Aerosol Radiative Effect Above Clouds in the Southeast Atlantic from Airborne Measurement

Friday, 11 December 2020: 19:20
Virtual
Samuel E LeBlanc1, Sebastian Schmidt2, Sabrina Cochrane3, Hong Chen4, Jens Redemann5, Connor J. Flynn5, Kristina Pistone6, Michal Segal-Rosenhaimer6, Meloe S Kacenelenbogen6, Yohei Shinozuka7, Stephen P Broccardo8 and Marc Mallet9, (1)NASA Ames Research Center, Bay Area Environmental Research Insitute, Moffett Field, CA, United States, (2)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (3)University of Colorado at Boulder, ATOC, Boulder, CO, United States, (4)Laboratory for Atmospheric and Space Physics, Boulder, United States, (5)University of Oklahoma, School of Meteorology, Norman, OK, United States, (6)NASA Ames Research Center, Moffett Field, CA, United States, (7)Bay Area Environmental Research Institute Sonoma, Sonoma, CA, United States, (8)Universities Space Research Association San Jose, Moffett Field, CA, United States, (9)CNRM / Meteo-France, Toulouse, France
Recorded Presentation
Abstract:
When aerosol overlie bright clouds, their radiative impact on the incident light can be either positive or negative. To better constrain this quantity, we have measured biomass burning aerosols over stratocumulus clouds and their properties during field campaigns spanning 3 years in the southeast Atlantic as part of the ObseRvations of CLouds above Aerosols and their intEractionS (ORACLES). Using solar direct beam irradiance and spectral hemispheric irradiance gathered by the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) and Solar Spectral Flux Radiometers (SSFR), we derive the change in shortwave radiant energy due to the absorption and scattering of these aerosols.

We present computed diurnally averaged radiative effect, using direct measurements along with a newly developed parameterization, and a comparison to similarly derived quantities using a regional model. In addition to the aerosol optical depth (AOD), one of the main regulating factors in this region is the impact of underlying clouds to the albedo influencing the lofted aerosol layer. The confluence of regional aerosol and cloud properties result in a local maximum of the direct radiative effect between 18°S and 14°S for September 2016, which is at a more southern latitude than the measured maximum above cloud AOD.

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