Examination of the aerosol first indirect effect during the 2003 Aerosol Intensive Operational Period (AIOP) at the Southern Great Plain (SGP)

HR: 1340h
AN: B33B-1025 [Abstracts]
TI: Examination of the aerosol first indirect effect during the 2003 Aerosol Intensive Operational Period (AIOP) at the Southern Great Plain (SGP)
AU: * Guo, H
EM: hguo@umich.edu
AF: Huan Guo, The department of Atmospheric, Oceanic and Space Sciences, the Univ. of Michigan, Ann Arbor, MI 48105
AU: Penner, J E
EM: penner@umich.edu
AF: Huan Guo, The department of Atmospheric, Oceanic and Space Sciences, the Univ. of Michigan, Ann Arbor, MI 48105
AU: Herzog, M
EM: Michael.Herzog@noaa.gov
AF: Michael Herzog, GFDL/NOAA, Princeton Univ., Princeton, NJ 08542
AB: Anthropogenic aerosols are effective Cloud Condensation Nuclei (CCN). The increased aerosol amount and number concentration will result in the higher cloud droplet number concentration. In case of the given cloud water content, higher cloud droplet number concentration implies smaller cloud droplets, that is, the so-called first aerosol indirect effect. However, the estimation of the aerosol indirect effect is highly uncertain. IPCC (2001) summarizes results that estimated the aerosol forcing ranging from 0 to -4.8W/m². Therefore, it is very important to investigate and understand the impact of the aerosol on the cloud optical, micro-physical and macro-physical properties. The Active Tracer High-resolution Atmospheric Model (ATHAM) is used as a Cloud Resolving Model (CRM) to examine the effect of aerosols on clouds. A CRM is a relatively high-resolution atmospheric model, which can at least crudely resolve cloud convection, and simulate clouds over a large domain that can represent ensemble cloud systems as well. During the 2003 Aerosol Intensive Operational Period (AIOP) at the Southern Great Plain (SGP), measurements of aerosol mass, aerosol size distribution, and cloud condensation nuclei (CCN) were available, which offers a good opportunity to examine the aerosol indirect effect, that is, the impact of the aerosols on the cloud droplet sizes, cloud albedo, and cloud morphology. The simulated results from ATHAM will be compared with the observations to evaluate the performance of the model. sensitivity tests will also be conducted to examine aerosol-cloud interactions.
DE: 3311 Clouds and aerosols
SC: Biogeosciences [B]
MN: Fall Meeting 2005