Regional dust model performance during SAMUM 2006

Abstract

Traditionally there has been a lack of intensive measurements directly over dust sources for validating the accuracy of dust models. Utilizing the valuable and unprecedented SAMUM 2006 field campaign dust dataset in North Africa, we assess the performance and discuss the limitations of a state-of-the-art dust regional model to reproduce the complex dust patterns encountered during the campaign. The DREAM model operational forecast version during SAMUM 2006 (OPER) and an updated model, version (RESH) are run and compared. RESH reproduces the general Saharan dust pattern, whereas OPER shows limitations to quantitatively reproduce dust optical properties over sources and after long range transport simultaneously. Dust transport in RESH with enhanced number size bin distribution is proven to be more efficient and adequate. The modeled vertical extinction coefficient captures fairly well lidar observations. While particle number size distribution is consistently reproduced at surface level, we find significant underestimation in the middle troposphere for large particles. Occasionally, synoptic scale meteorology remains unsatisfactorily captured leading to errors in the location and intensity of dust emission and subsequent transport. Copyright 2009 by the American Geophysical Union.