Enhanced layer of black carbon in a north Indian industrial city

Abstract

During a comprehensive aerosol field campaign as part of Indian Space Research Organization Geosphere Biosphere Programme (ISRO-GBP), aircraft measurements of vertical profiles of aerosol black carbon (BC) were made during winter, for the first time, at Kanpur (80°20'E and 26°26'N), an urban industrial location in Northern India. Two vertical profiling from the same day (morning and afternoon) of BC showed that BC decreases with height up to ~600 m and then increases up to 900 m before becoming more or less constant with height. Potential temperature profile, derived from concurrent measurements of temperature, shows a stable layer at the same altitude where BC shows increased concentration. This vertical structure of boundary layer was further confirmed by separate temperature and relative humidity profiles obtained from balloonsondes during December. The increased BC at ~900 m suggests the presence of enhanced BC layer, which will have significant implications to BC radiative forcing and modifying cloud properties.