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Numerical model simulation of the Saharan dust event of 6-11 March 2006 using the Regional Climate Model version 3 (RegCM3)

journal contribution
posted on 2023-06-07, 16:53 authored by Carolina Cavazos, Martin ToddMartin Todd, Kerstin Schepanski
The Sahara desert is the world's primary source of mineral dust aerosols and is known to be an important but poorly understood component of the climate system. Climate models which incorporate dust modules have the potential to improve our understanding of the climate impacts of dust. In this study, the performance of the Regional Climate Model version 3 (RegCM3) with an active dust scheme is evaluated, using a major dust event of 6¿11 March 2006 as a test case. To account for the distribution of preferential dust source regions, soil texture characteristics were modified in dust source regions identified from long-term SEVIRI satellite data. The dust event was associated with a pronounced cold outbreak of midlatitude air over the northern Sahara which produced anomalously strong northerly winds, which propagated from west to east over the Sahara during the study period. This resulted in dust mobilization from multiple dust sources across the domain. RegCM3 represents the space/time structure of near-surface meteorology well, although surface winds are underestimated in absolute terms. The experiment in which soils are modified provides a better representation of local dust sources and emission and resulting atmospheric optical thickness (AOT). In this experiment, model simulated dust flux exported from the Sahara to the Sahel and the tropical east Atlantic is estimated as 1.9 Tg d-1. The dust event had a profound impact on the surface solar radiation budget of ~-140 W m-2 per unit AOT (domain average). The shortwave radiative effect at the top of the atmosphere is~-10 W m-2 per unit AOT over the study domain. However, this is strongly dependent on surface albedo. The results also highlight how errors in model simulated circulation lead to errors in the position of the dust plume.

History

Publication status

  • Published

Journal

Journal of Geophysical Research

ISSN

0148-0227

Publisher

American Geophysical Union

Issue

D12

Volume

114

Pages

24.0

Department affiliated with

  • Geography Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

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