Contribution of extreme daily precipitation to total rainfall over the Arabian Peninsula

This study examines the relative contribution of extreme daily precipitation events (RR > 99th percentile) to accumulated rainfall over the Arabian Peninsula in current and future climates. Both gridded observations and model simulation data are analyzed. Observations reveal that the extreme daily precipitation events contribute nearly 40% (70%) to the accumulated amount of rainfall in the wet (dry) regions of the Peninsula for the period 1970-1999. The regional climate model simulations show a large overestimation of the annual mean rainfall in the present climate. However, the model data also depicts almost an enhanced contribution of extreme daily precipitation events to the accumulated rainfall over the Peninsula. In agreement with observations, the simulated extreme precipitation events show a small (large) contribution to total rainfall in the wet (dry) regions. The relative contribution of extreme daily precipitation events to total rainfall increases over the southern and central parts of the Peninsula in case of the future climate. We also found an increase in the accumulated amount of simulated precipitation associated with extreme events in the future climate when compared to the reference period. This indicates that extreme events are likely to become more intense over the Peninsula in the future. The results indicate an increase in daily precipitation intensities over the Arabian Peninsula in the future. The results presented in this study highlight that a better understanding of extreme precipitation events and their regional distribution over the Arabian Peninsula currently and in the future is essential for judicious socio-economic planning for the region.