Northeast India (NEI) is located within the boundary of the great Himalayas in the north and the Bay of Bengal (BoB) in the southwest, experiences the mixed influence of the westerly dust advection from the Indian desert, anthropogenic aerosols from the highly polluted Indo-Gangetic Plains (IGP) and marine aerosols from BoB. The present study deals with the estimation and characterization of aerosol radiative forcing over a semi-continental site Tripura, which is a strategic location in the western part of NEI having close proximity to the Outflow of the IGP. Continuous long term measurements of aerosol black carbon (BC) mass concentrations and columnar aerosol optical depth (AOD) are used for the estimation of aerosol radiative forcing in each monthly time scale. The study revealed that the surface forcing due to aerosols was higher during both winter and pre-monsoon seasons, having comparable values of 32 W/m(2) and 33.45 W/m(2) respectively. The atmospheric forcing was also higher during these months due to increased columnar aerosol loadings (higher AOD similar to 0.71) shared by abundant BC concentrations (SSA similar to 0.7); while atmospheric forcing decreased in monsoon due to reduced magnitude of BC (SSA similar to 0.94 in July) as well as columnar AOD. The top of the atmosphere (TOA) forcing is positive in pre-monsoon and monsoon months with the highest positive value of 3.78 W/m(2) in June 2012. The results are discussed in light of seasonal source impact and transport pathways from adjacent regions. (C) 2016 Elsevier B.V. All rights reserved.

来源平台：SCIENCE OF THE TOTAL ENVIRONMENT