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Using Bias-Corrected GCM Data to Study the Climatology of the Arabian Gulf Region

Water resources are particularly vulnerable to population growth and economic development in water-scarce regions, such as the Arabian Gulf region. Therefore, it is necessary to improve our understanding of the precipitation distribution, especially in a changing climate, for optimal water resources management in the region.

Several studies using global and regional climate models have indicated a decreasing trend of precipitation amount in the arid and semiarid areas. This led Dr. Lulin Xue, a third cycle awardee of the UAE Rain Enhancement Program (UAEREP) and the Chief Scientist at Hua Xin Chuang Zhi Science and Technology LLC, to work on a project to better understand the future climate changes in the Arabian Gulf Region (AGR).

The study uses the Weather Research and Forecasting (WRF) supported by bias-corrected Global Climate Model (GCM) data to model the climatology of the AGR, and to investigate the potential changes under the future scenario of a global warming environment.

In the study, the regional climate of the AGR is modeled using a set of simulations based on WRF model, including a 30-year benchmark simulation driven by reanalysis data, and two bias-corrected Community Earth System Model (CESM)-driven WRF simulations for retrospective and future periods that both include 10-year convection-permitting nested simulations.

The study used rain gauge datasets from six major airports in the UAE to evaluate the daily precipitation from the bias-corrected CESM-driven retrospective simulation. Changes in near-surface temperature, precipitation, and ambient conditions were determined using the outputs from the convection-permitting WRF simulations for the retrospective and future periods.

Results show that precipitation is expected to increase over the Arabian Gulf, but decreases over most of the continental area, particularly over the mountainous areas of the AGR. Interestingly, the wet index decreases in most areas of the AGR except the Arabian Gulf and eastern Al Hajar Mountains. The future changes in precipitation are found to be governed by both the thermodynamics and dynamics.The thermodynamic impact, which is controlled by the warming and moistening, results in more precipitation over ocean but not over land. The dynamic impact, which is controlled by the changes in large-scale circulation, results in decrease in precipitation over mountain areas in the AGR.

The simulations presented in this study provide a unique dataset to study the regional climate of the Arabian Gulf region. Future studies may include a better understanding of the changes in precipitation efficiency, the extreme events, the hydrological cycle, and the relative contributions of thermodynamic impacts and dynamic impacts on the changes in the precipitation climatology.

For more, see the following link:

https://journals.ametsoc.org/jcli/article/33/18/7787/353235/Convection-Permitting-Regional-Climate-Simulations