Impact of Dust Radiative Forcing upon Climate - Mineral Dust: A Key Player in the Earth System - page 332

Fig. 13.5 ( Left ) Anomalous surface air temperature ıT S and ( right ) moist static energy ıh S
(divided by C p ) in response to the forcing in Fig. 13.1 . Extreme values of the color scale may
vary among panels
regions of large aerosol forcing, including the Sahel (Fig. 13.5 b, c). This cooling is
attributed to the increase of Sahel precipitation with particle absorption (Fig. 13.7 )
and not the increasing magnitude of the surface forcing and dimming of the surface.
As precipitation increases, the surface becomes more humid. The contribution of
increasing humidity to ıh S (not shown) exceeds the increase of ıh S required by
F T , so that the near-surface air must cool (Fig. 13.5 b, c). Similar compensation of
surface temperature and humidity where dust increases precipitation is seen in the
experiments of Miller et al. ( 2004b ), as well as the simple model of Miller and Tegen
( 1999 ).
Coupling of surface air temperature to the TOA forcing is seen in the ESM
experiments of Miller and Tegen ( 1998 ). In this model, the dust concentration is
largest over the Arabian Sea during NH summer, due to the confluence of plumes