Recorded presentationJ2.5
Effects of Aerosols on Shallow Marine Clouds in Bay of Bengal
Matthew Igel, North Carolina State Univ., Raleigh, NC; and N. Meskhidze, A. Aiyyer, and L. Remer
With seasonal dust storms, considerable amounts of secondary organic aerosols (SOA) of biogenic origin and sharply rising anthropogenic emissions, the Indo-Gangetic Plain (IGP) is characterized by large concentrations of chemically complex aerosols that may serve as cloud condensation nuclei (CCN). The IGP encompasses most of northern and eastern India, the populous parts of Pakistan, and virtually all of Bangladesh. Though many studies have focused on aerosols emanating from this region, few have examined the direct and indirect climatic effects of these aerosols, particularly once the aerosol laden air masses leave the Indian subcontinent and enter the Bay of Bengal (BoB). BoB appears to be the ultimate destination of a considerable number of particles that can significantly modify properties of shallow marine clouds in this region. MODerate resolution Imaging Spectroradiometers (MODIS) aboard the Terra and Aqua platforms have been used in this study to quantify the effects of aerosols emanating from the IGP on shallow marine clouds in BoB. Particular attention has been given to pre- and post-monsoon seasons, when clouds should be more susceptible to increased CCN concentration. Results of our study show a consistent, sizable increase in MODIS retrieved aerosol optical depth (AOD) over BoB that is in good agreement with the increase observed by the AERONET (AErosol RObotic NETwork) station at Kanpur over which the aerosols travel en route to BoB. The effects of increased aerosol concentration on cloud effective radii and cloud optical thickness over the BoB are discussed. Potential long-term climatic effects for the case of continued/ increased pollutant emissions are also proposed. Recorded presentation
Joint Session 2, Measurements and Modeling of Aerosols and Clouds-II
Tuesday, 22 January 2008, 3:30 PM-5:30 PM, 220
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