Double blanket effect caused by two layers of black carbon aerosols escalates warming in the Brahmaputra River Valley

Abstract

First ever 3-day aircraft observations of vertical profiles of Black Carbon (BC) were obtained during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) conducted on 30th August, 4 th and 6th September 2009 over Guwahati (26°11′N, 91°44′E), the largest metropolitan city in the Brahmaputra River Valley (BRV) region. The results revealed that apart from the surface/near surface loading of BC due to anthropogenic processes causing a heating of 2 K/day, the large-scale Walker and Hadley atmospheric circulations associated with the Indian summer monsoon help in the formation of a second layer of black carbon in the upper atmosphere, which generates an upper atmospheric heating of, ∼2 K/day. Lofting of BC aerosols by these large-scale circulating atmospheric cells to the upper atmosphere (4-6 Km) could also be the reason for extreme climate change scenarios that are being witnessed in the BRV region.