REPRESENTATION OF AEROSOL-CLOUD INTERACTIONS IN THE NASA GODDARD EARTH OBSERVING SYSTEM MODEL, VERSION 5 (GEOS-5)
Dr. Donifan Barahona, Climate and Radiation Studies, Global Modeling and Assimilation Office (GMAO), NASA Goddard Space Flight Center
April 27, 2015, 10:30 am, NASA Langley, Bldg 1250, Rm 116
Abstract:
Mounting evidence suggests that aerosols, both natural and anthropogenic, play a key role in many atmospheric processes. They act as precipitation forming agents, modify the radiative and thermal balance of the atmosphere, and alter the development of convection. Aerosol emissions impact the Earth’s climate directly by scattering and absorbing solar and thermal radiation and indirectly by modifying cloud properties. To account for the latter effects the modeling of the microphysical evolution of clouds must account explicitly for processes of ice nucleation and cloud droplet activation. In this seminar I will detail our current work to represent aerosol-cloud interactions (ACI) within the NASA GEOS-5 model, and its application to study aerosol indirect effects. Compared to the operational version of GEOS-5 the implementation of ACI leads to a more realistic representation of cloud properties, in better agreement with in situ and satellite data. Using the new implementation the aerosol indirect effect is analyzed in terms of sensitivities of different cloud and radiation quantities to aerosol abundance. The effect of ice nuclei on cloud formation is also discussed, with emphasis on the representation of ice nucleation in atmospheric models and its improvement using ultra-high resolution simulations.
Bio: Dr. Barahona’s bio may be viewed here.