Spatial distribution of the Southeast Asian smoke plume over the Indian Ocean and its radiative heating in the atmosphere during the major fire event of 2006

Abstract

Smoke plumes originating from vegetation fires engulf Southeast Asia and East Equatorial Indian Ocean (EEIO) during October‐November period in almost all the El Niño years. For the first time, observations of the vertical profiles of aerosol extinction coefficient using the Cloud Aerosol Lidar Pathfinder Satellite Observation (CALIPSO), along with the spatial distribution of aerosol optical depth (AOD) derived from NOAA‐18‐AVHRR provided an opportunity to study the 3‐dimensional structure of the plume that spread over an area of ∼1 million km2 (0.5<AOD<1.2) during October‐November 2006. The plume was confined to altitude <3.0 km with an accumulation around 0.6–2.0 km. The shortwave aerosol direct heating of the atmosphere by this plume was >32 Wm−2 over a wide area and the mean aerosol radiative heating rate in the atmosphere estimated over Singapore is 1.2 K/day between 0.6–2 km. This led to an increase in the lower tropospheric stability in this location.