Spatial heterogeneity in near surface aerosol characteristics across the Brahmaputra valley Binita Pathak1, Arup Borgohain2, Pradip Kumar Bhuyan1,∗, Shyam Sundar Kundu2, S Sudhakar2, Mukunda M Gogoi3 and Toshihiko Takemura4 1Centre for Atmospheric Studies, Dibrugarh University, Dibrugarh 786 004, India. 2North–East Space Application Centre, Umiam, Shillong, Meghalaya 793 103, India. 3Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695 022, India. 4Research Institute for Applied Mechanics, Kyushu University 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan. ∗Corresponding author. e-mail:
[email protected] In order to examine the spatial variability of the aerosol characteristics across the Brahmaputra valley, a land campaign was conducted during late winter (February 3–March 2) 2011. Measurements of parti- culate matter (PM, PM10,PM2.5) and black carbon (BC) concentrations were made onboard an interior redesigned vehicle. The length of the campaign trail stretched about 700 km, covering the longitude belt of 89.97◦–95.55◦E and latitude belt of 26.1◦–27.6◦N, comprising 13 measurement locations. The valley is divided into three sectors longitudinally: western sector (R1: 89.97◦–91.75◦E), middle sector (R2: 92.5◦– 94.01◦E) and eastern sector (R3: 94.63◦–95.55◦E). Spatial heterogeneity in aerosol distribution has been observed with higher PM10 and PM2.5 concentrations at the western and middle sectors compared to the eastern sector. The locations in the western sector are found to be rich in BC compared to the other two sectors and there is a gradual decrease in BC concentrations from west to east of the Brahmaputra valley.