Letters to Nature

Nature 395, 367-370 (24 September 1998) | doi:10.1038/26456; Received 16 April 1997; Accepted 3 July 1998

Quantification of dust-forced heating of the lower troposphere

P. Alpert1, Y. J. Kaufman2, Y. Shay-El1, D. Tanre3, A. da Silva4, S. Schubert4 & J. H. Joseph1

  1. Department of Geophysics and Planetary Sciences, Tel-Aviv University, Israel 69978
  2. Climate and Radiation Branch, Code 913, NASA/GSFC, Greenbelt, Maryland 20771, USA
  3. Laboratoire d'Optique Atmosphérique, Bât. P5, UST de Lille, 59655 Villeneuve d'Ascq Cedex, France
  4. Data Assimilation Office, Code 910.3, NASA/GSFC, Greenbelt, Maryland 20771, USA

Correspondence to: P. Alpert1 Correspondence should be addressed to P.A. (e-mail: Email: pinhas@cyclone.tau.ac.il).

Aerosols may affect climate through the absorption and scattering of solar radiation and, in the case of large dust particles, by interacting with thermal radiation1, 2, 3. But whether atmospheric temperature responds significantly to such forcing has not been determined; feedback mechanisms could increase or decrease the effects of the aerosol forcing. Here we present an indirect measure of the tropospheric temperature response by explaining the 'errors' in the NASA/Goddard model/data-assimilation system. These errors, which provide information about physical processes missing from the predictive model, have monthly mean patterns that bear a striking similarity to observed patterns of dust over the eastern tropical North Atlantic Ocean. This similarity, together with the high correlations between latitudinal location of inferred maximum atmospheric heating rates and that of the number of dusty days, suggests that dust aerosols are an important source of inaccuracies in numerical weather-prediction models in this region. For the average dust event, dust is estimated to heat the lower atmosphere (1.5–3.5 km altitude) by approx0.2 K per day. At about 30 dusty days per year, the presence of the dust leads to a regional heating rate of approx6 K per year.