Assessing the Shifting Roles of Timing, Extremes, and Intensity in Shaping Red Sea Rainfall Regimes
Abstract
The Red Sea is a broad trading ground for food, water, and energy, and it is spanned by hydrological opposites a surface water- and agriculture-driven Eastern Africa (EA), and a groundwater- and oil-driven Arabian Peninsula (AP). Natural water availability and sustainable use concern both sides, as the distribution of rainfall governs EAs agricultural strategy and reservoir operation, and it presents the only natural opportunity for aquifer recharge in the AP. To that end, we aim to understand how these rainfall regimes are shaped and changing over time across the Red Sea region (RSR) as a whole, and to delineate the roles played by extreme rainfall, various storm types (i.e., intensities), and their timing in characterizing those regimes. Using a 40-year (1981-2020), high-resolution (0.05) daily precipitation data set, we address the following questions over the RSR: (1) What are the relative contributions of light, moderate, and heavy rainfall to annual rainfall? (2) How do wet-season onset and duration vary across the region, and how do they compare to the timing of extreme storm events? (3) To what extent have these metrics undergone considerable change? We consider the central tendencies, variability, and linear trends in the importance of various rainfall intensities and wet-season timing relative to occurrences of extreme events. We also investigate brief case studies over selected catchments to demonstrate differences in these metrics across the region and to illustrate their interannual variability. Preliminary results show increasing contributions of modest rainfall to annual rainfall in place of heavier contributions. This suggests that a sharpened rainfall distribution in the future (made by heavier extremes) may not necessarily benefit surface water supply, as the storage of modest precipitation becomes progressively challenged by increasing evaporative demand.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H55G0814H