Mineral dust aerosols in the NASA Goddard Institute for Space Sciences ModelE atmospheric general circulation model

Abstract

We describe an updated model of the dust aerosol cycle embedded within the NASA Goddard Institute for Space Studies ‘ModelE’ atmospheric general circulation model (AGCM). The model dust distribution is compared to observations ranging from aerosol optical thickness and surface concentration to deposition and size distribution. The agreement with observations is improved compared to previous distributions computed by either an older version of the GISS AGCM or an offline tracer transport model. The largest improvement is in dust transport over the Atlantic due to increased emission over the Sahara. This increase comes from subgrid wind fluctuations associated with dry convective eddies driven by intense summertime heating. Representation of ‘preferred sources’ of soil dust particles is also fundamental to the improvement. The observations suggest that deposition is too efficient in the model, partly due to AGCM rainfall errors.