Simulation of aerosol deposition flux over the Arabian Peninsula with CHIMERE-2017: Sensitivity to different dry deposition schemes

Abstract

Abstract The performance of aerosol dry deposition schemes of the regionally adapted chemistry transport model CHIMERE2017 (version 2017r4) is evaluated. The model is simulated over the domain of Arabian Peninsula for a period of one year starting from November 2016 to October 2017 using two different dry deposition schemes, ( Wesely, 1989 ) and ( Zhang et al., 2001 ). The daily accumulations of the simulated total aerosol deposition fluxes are compared with the corresponding measurements carried out by means of a dust deposition gauge in Abu Dhabi, United Arab Emirates. The monthly mean aerosol deposition flux at the measurement site during the study period is 0.0112 kg m−2 month−1, which is in agreement with observations from other locations in the Middle East and North Africa. The simulated deposition flux over the Arabian Peninsula shows large spatiotemporal variability peaking in the south in summer and in the eastern and northeastern parts of the peninsula in spring. By contrast, winter and autumn are characterized by comparatively low deposition levels on the entire peninsula. Dry deposition is found to be the most effective removal mechanism of atmospheric aerosols in the region with several orders of magnitude higher flux levels than its wet counterpart. The results indicate that the size-resolved deposition scheme of Zhang et al., 2001 is the most suitable one on the Arabian Peninsula. The simulated yearly accumulated total deposition fluxes on the inlands and coastal regions of the peninsula are respectively in the range 0.1–0.5 kg m−2 year−1 and 0.01–0.1 kg m−2 year−1.