Assessment of aerosol-cloud-rainfall interactions in Northern Thailand

摘要

Biomass burning in the northern Thailand probably provides strong input of aerosols into the atmosphere, withpotential effects on cloud and rainfall, over an entire burning season. This research was focus on effect ofbiomass burning aerosols on clouds and rainfall using multiple regression analysis and AOT for indicatingaerosol concentrations from satellite MODIS (Terra / Aqua) and AERONET station since 2003-2012. Theresults indicated that average AOT of the Northern Thailand showed the highest value in pre-monsoon seasonespecially in March with 0.5 unit less and decreased in June to July. It corresponded with hotspot data weremostly occurring in pre-monsoon season. Furthermore, almost all of the aerosols that were found duringmonsoon season as the big particles, caused by salt spray combine with water vapor. In the other hand, almostall of the aerosols during pre-monsoon were the small particles which come from the black carbon caused bybiomass burning. There was high positive relationship with rainfall with cloud water content (CWC) and cloudfraction (CF), but it was found that were negative relationship with aerosol optical thickness (AOT) andhotspot (HP). There was moderate relationship between rainfall amount with AOT, cloud fraction (CF), cloudwater content (CWC) and hotspot (HP) in all provinces of the northern Thailand. It was noticed that in anyyear there were the high biomass burning aerosols which caused rain later than usual about 1-2 months.