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

Cavazos, Carolina, Todd, Martin C. and Schepanski, Kerstin (2009) Numerical model simulation of the Saharan dust event of 6–11 March 2006 using the Regional Climate Model version 3 (RegCM3). Open Access Journal of Geophysical Research: Atmospheres, 114 (D12). D12109. DOI 10.1029/2008JD011078.

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Abstract

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 similar to-140 W m(-2) per unit AOT (domain average). The shortwave radiative effect at the top of the atmosphere is similar to-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.

Document Type: Article
Keywords: Meteorology; MINERAL DUST; AEROSOL PROPERTIES; OPTICAL-PROPERTIES; RADIATIVE IMPACT; DESERT DUST; TROPOSPHERIC AEROSOLS; EXPERIMENT SHADE; SOURCE AREAS; CLOUDS; SENSITIVITY
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1029/2008JD011078
ISSN: 2169-8996
Date Deposited: 10 Jan 2012 08:51
Last Modified: 16 Jan 2018 09:04
URI: http://oceanrep.geomar.de/id/eprint/13336

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