Spatiotemporal assessment of dust loading over the United Arab Emirates

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ABSTRACTEvaluation of the spatiotemporal distribution of dust loading over the UAE is a great challenge because of its dependence on many climatic parameters and surface features. Indeed, the region has the world's largest confluences of natural and anthropogenic dust emissions. Those being the case, ground‐based and remotely sensed data are used conjointly to characterize the dust loading at both local and large scales. The ground‐based measurements comprise AERONET aerosol optical properties measurements represented by the aerosol optical thickness (AOT870) and Angstrom component (α500/870) collected at high temporal resolution between 2004 and 2007 over several stations. The remotely sensed data consists of diffuse horizontal irradiance (DHI) estimated from retrieved MSG/SEVRI images using Helioclim‐III (CEP: Centre for Energy and Processes, MINES ParisTech) or Artificial Neural Network (ReCREMA: Research Center for Renewable Energy Mapping and Assessment, MASDAR Institute) from 2004 to 2010 over the same locations. On correlating the monthly average DHI estimates to the monthly AOT870 measurements, higher correlation was found with the ReCREMA products rather compared to the Helioclim‐III products. Therefore, the monthly AOT870 and α500/870 values have been retrieved from the available DHI estimates over the United Arab Emirates (UAE). The resulting maps offer a clear guide to patterns of the monthly dust severity variability. Temporally, the dust loading occur mainly during the March–May/June–August (MAM/JJA) period where the obtained monthly AOT870 and Angstrom component (α500/870) can both reach an approximate value of ∼0.6. Spatially, the dust loading over the region follow the climatic parameters with almost homogeneous distribution expected between May and July where AOT870 and α500/870 exhibit high large‐scale spatial variability. On the basis of the European Centre for Medium‐Range Weather Forecasts (ECMWF) and ground‐based wind speed and direction data, the dust blows mainly from the southwest/southeast and the northeast sides.