The impact of aerosol optical depth impacts on rainfall in two different monsoon periods over Madurai, India

Abstract

Aerosols influence the formation and the life cycle of clouds to a significant extent. A wide range of measurements shows that anthropogenic aerosols often alter clouds and their optical properties. The present investigation has revealed the impacts of aerosol optical depth on rainfall for two different monsoon periods (2008-2009), and also estimated trend of aerosol optical depth from 2001 to 2009 over Madurai, India, by using MODIS and TRMM datasets. Annual averages of aerosol optical depth for 2001-2009 varied from 0.23 ± 0.12 to 0.39 ± 0.19. AOD was high in monsoon season, and it was low during winter. Maximum rainfall was recorded during the post-monsoon season, and aerosol optical depth had a significant positive correlation (0.94) with rainfall; during 2008, and a negative one (-0.61) in 2009. The cloud parameters, such as COD and CER, were positively correlated with rainfall during the 2008 post-monsoon season, while they were negatively correlated during the 2009 post-monsoon season. The results of Mann Kendal trend analysis show that there was no significant trend in aerosol optical depth during the study period. © Taiwan Association for Aerosol Research.