Cloud-System Resolving Model for Arabian Peninsula Winter Rainfall

The Arabian Peninsula (AP) is a water-scarce region. The spatial and temporal distribution of rainfall is thus crucial for the administrators to manage various socio-economic sectors such as agriculture, industrial development and water resources of the region. Because of the scarcity of the data in the AP, a high-resolution model is needed for realistic representation of the rainfall distribution. However, the uncertainties in current climate models are mainly related to the representation of clouds, moist convection, and complex topography. Reducing the grid spacing down to few kilometers is thus an attractive approach (Cloud-System Resolving Model; CRM) to simulate clouds formation and precipitation development over the desert areas. This CRM approach reduces some parameterization uncertainties and increases the role of specifics in the microphysical properties. In this work, we implement a CRM for the period 2006-2016 to simulate clouds formation and precipitation development over the AP. CRM is driven by ERA-Interim reanalysis with horizontal resolutions of 2 km over an extended AP domain (1800 km x 1800 km). Validation is conducted against surface data suggests that the simulated rainfall with the CRM is in better agreement with the observed rainfall compared to convective parametrized model. The assessment of precipitation statistics reveals that the CRM approach adequately represent the diurnal cycles of precipitation over the AP. We will present these findings and further discuss the dominant precipitation-causing mechanisms over the AP. The outcome of this work is important for the implementation of a high-resolution numerical models for the prediction of the AP winter rainfall on seasonal and sub-seasonal scales.