Observations of enhanced aerosol longwave radiative forcing over an urban environment
Title | Observations of enhanced aerosol longwave radiative forcing over an urban environment |
Publication Type | Journal Article |
Year of Publication | 2008 |
Authors | Panicker, AS, Pandithurai, G, Safai, PD, Kewat, S |
Journal | Geophysical Research Letters |
Volume | 35 |
Issue | 4 |
Pagination | L04817 |
Date Published | FEB |
ISSN | 0094-8276 |
Abstract | Collocated measurements of sun/ sky radiance, aerosol chemical composition and radiative fluxes have been utilized to estimate longwave aerosol radiative forcing over Pune, an Indian urban site during dry winter [Dec2004 to Feb2005] by two methods. Hybrid method which uses observed downwelling and modeled upwelling longwave fluxes for different aerosol loadings yielded a surface forcing of 9.4 Wm(-2). Model approach includes utilization of skyradiometer derived spectral aerosol optical properties in the visible and near infra-red wavelengths, modeled aerosol properties in 1.2-40 mu m using observed soot and chemical composition data, MODIS water vapor and TOMS column ozone in a radiative transfer model. Estimates from model method showed longwave enhancement of 6.5 and 8.2Wm(-2) at the surface with tropical model atmosphere and temporally varying profiles of temperature and humidity, respectively. Study reveals that about 25% of the aerosol shortwave cooling is being compensated by increase in longwave radiation due to aerosol absorption. |
DOI | 10.1029/2007GL032879 |
Type of Journal (Indian or Foreign) | Foreign |
Impact Factor (IF) | 3.505 |