Aerosol black carbon radiative forcing at an industrial city in northern India

• Published in: Geophysical research letters Vol. 32; no. 8; pp. L08802 - n/a
• Main Authors: Tripathi, S. N., Dey, Sagnik, Tare, V., Satheesh, S. K.
• Format: Journal Article
• Language: English
• Published: American Geophysical Union 01.04.2005; Blackwell Publishing Ltd
• Subjects: Aerosols; Aerosols and particles; Atmospheres; Atmospheric Composition and Structure; Atmospheric heating; Atmospheric Processes; Atmospherics; Biogeosciences; Boundary layer; Carbon; Climate; Diurnal variations; Geophysics; Global Change; Pollution; Radiative forcing; Radiative processes; Regional climate change; Scattering; Surface chemistry; Surface cooling; Tungsten; urban and regional; urban, regional and global; India, Uttar Pradesh, Unnao Dist., Kanpur
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2005GL022515

During a comprehensive aerosol field campaign as part of ISRO‐GBP, extensive measurements of aerosol black carbon were made during December 2004, for the first time, at Kanpur, an urban continental location in northern India. BC diurnal variation is associated with changes in boundary layer mixing and anthropogenic activities. BC concentration in Kanpur is comparable to those measured in other mega cities of India but much higher than in similar locations of Europe, USA and Asia. High BC concentration is found both in absolute terms (6–20 μg m−3) and mass fraction (∼10%) yielding very low single scattering albedo (0.76). The estimated surface forcing is as high as −62 ± 23 W m−2 and top of the atmosphere (TOA) forcing is +9 ± 3 W m−2, which means the atmospheric absorption is +71 W m−2. The short wave atmospheric absorption translates to a lower atmospheric heating of ∼1.8°K/day. Large surface cooling and lower atmospheric heating may have impacts to regional climate.