Regional climate model (RegCM3)‎ sensitivity to the domain size selection : application over the southwest Asia

Abstract EN

he iiiipact of the domain size selection on simulated precipil;i(ion using the third version of the International Center for Theoiciical Physics (ICTP) Regional Climate Model (RegCM3), over the SiMiih west /Asian region is the primary aim of this study.

To do this: ;i ', oral simulations have been performed using 3-different domaiiiN (v\'ith different number of grid-bo.xes), and fixing the other paranieicrs.

The first (large ~ 32x10*’ km") model domain, Dl, with numlxM ofgrid points 176 x 142 and extended from 0.88"E to 79.57°H and Irum 5.63"S to 49.90°N with, Tlic sccond (the medium -20x10^ km" i iiiodel domain, D2, with number of grid points 96 x 96 and extendi'.i Irom 20.87°E to 63.58°E and from latitude 4.69° to 42.78°N and I lie ihird (small ~l 7.5x I O’’ km") model domain, D3, with number of grid points 88 x 88 which extended from 29.ll49°to 67.3309° E and fioiii 5.62° to 40.1 1°N.

To evaluate the model performance; the daily, iIk' monthly, the seasonal and the annual simulated rainfall from the three domains runs have been tested with the corresponding field from ihi global daily l“xr Tropical Precipitation Measuring Mission ( I'RMM; dataset for one year period (2002) over Saudi Arabia as a candid;ile country of the region.

The results show that; the RegCM model is capable of capturing the structure of the localized total precipitaiion with good intensities, especially over the south-western zones ol Saudi Arabia,, the small the domain size, the more precipitaiion produced, tlie model with the small domain is suitable for stud>ing the spatial and temporal variability of the annual, seasonal, as well as monthly precipitation and the model with the