Open AccessObservations of diurnal and spatial variability of radiative forcing by equatorial deep convective clouds
Author(s) -
Nowicki Sophie M. J.,
Merchant Christopher J.
Publication year - 2004
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003jd004176
Subject(s) - forcing (mathematics) , radiative forcing , radiative transfer , cloud forcing , environmental science , noon , atmospheric sciences , diurnal cycle , climatology , convection , geology , physics , meteorology , climate change , oceanography , quantum mechanics
From geostationary satellite observations of equatorial Africa and the equatorial east Atlantic during May and June 2000 we explore the radiative forcing by deep convective cloud systems in these regions. Deep convective clouds (DCCs) are associated with a mean radiative forcing relative to non–deep convective areas of −39 W m −2 over the Atlantic Ocean and of +13 W m −2 over equatorial Africa (±10 W m −2 in both cases). We show that over land the timing of the daily cycle of convection relative to the daily cycle in solar illumination and surface temperature significantly affects the mean radiative forcing by DCCs. Displacement of the daily cycle of DCC coverage by 2 hours changes their overall radiative effect by ∼10 W m −2 , with implications for the simulation of the radiative balance in this region. The timing of the minimum DCC cover over land, close to noon local time, means that the mean radiative forcing is nearly maximized.