Simulation of present and future climate of Saudi Arabia using a regional climate model (PRECIS)

In this article, climate parameters (rainfall and temperature) are simulated for Saudi Arabia by downscaling the European Centre for Medium-Range Weather Forecasts (ECMWF) 40-year reanalysis (ERA40) and the European Community - Hamburg Atmospheric Model (ECHAM5) data using the UK Met Office Regional Climate Model PRECIS (Providing REgional Climates for Impacts Studies). Simulations are performed for a present climate of 30years (1971-2000) using ERA40 and ECHAM5, and future climate is predicted for a period of 50years (2021-2070) using ECHAM5 A1B emissions scenario. The results show that the spatial distribution of the present-day rainfall and temperature simulated by PRECIS are consistent with the observed dataset. In addition, their annual cycle and interannual variability are reasonably well reproduced. The dry precipitation and warm temperature biases exhibited in the driving fields (compared with the observations) are reduced because of the improvements in specific humidity and in the wind field within the PRECIS simulations compared with the driving fields. The projection using the calibrated national average temperature exhibits a positive trend in mean temperature of around 0.65 degrees C per decade. For rainfall projection, the results show that the coastal areas along the central parts of the Red Sea and the south-southwestern areas of Saudi Arabia may experience more extreme rainfall events, whereas the northern and central parts of the country may undergo a drying trend. (c) 2013 The Authors. International Journal of Climatology published by John Wiley & Sons Ltd on behalf of the Royal Meteorological Society.