Influence of increased greenhouse gases and sulphate aerosols concentration upon diurnal temperature range over Africa at the end of the 20th century

Abstract

In order to investigate the diurnal temperature range response under enhanced greenhouse gases and sulphate aerosols concentrations over Africa, two ensembles of 19 integrations are conducted using the ARPEGE climate model. The ensembles are forced with the same observed changes in sea surface temperature and sea-ice extents but differ in terms of the anthropogenic direct effect included. When accounting for the additional anthropogenic effect due to the direct radiative forcing, diurnal temperature range significantly decreases during the last two decades of the 20th century over Africa. Over North and Southern Africa, this decrease is related to a significant increase of minimum temperatures mainly due to the additional greenhouse effect. Over West Africa, an increase of cloud albedo causes the daily maximum temperature to decrease resulting in a weakening of the diurnal temperature range. Simulated diurnal temperature ranee is then compared to the observed one to assess confidence in the results. Copyright 2006 by the American Geophysical Union.