Assessment of the Climate Vulnerabilities of the Arabian Peninsula

The Arabian Peninsula (AP), like many places around the world, is apparently witnessing the impacts (amount, patterns, and frequency of precipitation) of global warming. Precipitation over the AP is largely controlled by two main wind regimes, the winter (October to March) northerlies or northwesterlies, hereafter referred to as westerlies, and the summer (April to September) monsoonal wind regimes. The global monthly Climate Prediction Centers (CPC) Merged Analysis of Precipitation (CMAP) data (spatial resolution: 2.5° × 2.5°; temporal resolution: monthly; operational period: January 1979 to November 2011) was used to investigate the nature and magnitude of precipitation variations over the AP throughout 1979 - 2010. Trends in CMAP-derived precipitation patterns were examined over the winter and summer seasons throughout Periods I (1979-1995) and II (1996-2010). Reversals in precipitation patterns were observed in Periods I and II, where areas witnessing an increase in precipitation in Period I showed a decrease in precipitation throughout Period II, and vice versa for the remaining areas. Our findings suggest: (1) an increase in precipitation during Period I over the southeastern and southwestern coastal areas of AP (e.g., Muscat, Sanaa, and Jeddah) that is probably related to the intensification of the monsoons at the expense of the westerlies, (2) an increase in precipitation during Period II over the northwestern and southeastern of AP (e.g., northwestern Saudi Arabia, Empty Quarter, western and southwestern Oman, and eastern Yemen) is here attributed to intensification of the westerlies, and 3) the general similarity of annual trend patterns to the summer trend (Period I) and to winter trend (Period II) suggest that the annual trends are largely controlled by monsoonal wind regimes in Period I and by the westerlies in Period II. Outputs (i.e., precipitation) of climatic models (CCSM4.0) over the AP are being extracted (for upcoming 100 years) , downscaled, and correlated with Period II precipitation trends to investigate whether the observed precipitation trends in Period II mark the onset of global warming-related climate change.