Abstract
There exists a need to document details related to the spatiotemporal climatology of precipitation over the Arabian Peninsula (Arabia) based on a sound assessment. Areal precipitation was calculated for Arabia, subtropical Arabia (STA), and tropical Arabia (TA) using a weighting scheme to adjust for latitudinal changes in grid-cell areas and extract statistics that have geographical/spatial interpretation based on a quality-controlled spatially-distributed precipitation dataset (1980–2019). Areal annual precipitation mean over Arabia (STA/TA) is 88.61 mm (85.72/92.79). While boreal winter and spring seasons are the wet seasons over Arabia (29, 40%) and STA (36, 40%), boreal spring and summer are the wet seasons over TA (41, 25%). Only 25% of Arabia (STA/TA) receives more than 110.73 (108.48/113.73) mm of precipitation annually. Spatiotemporal trends were explored using the Mann–Kendall test, applied to trend free pre-whitened data, and the Theil-Sen estimator. Average areal precipitation over Arabia and STA is decreasing during the boreal winter and spring seasons at varying rates. On the other hand, boreal summer and fall precipitation is increasing over Arabia, STA, and TA with only that of TA summer being statistically significant. An elongated region extending from southwest to northeast has a statistically significant negative trend in annual, spring, and winter precipitation. The southern part of Arabia is dominated by positive trends in annual, summer, and fall precipitation with only isolated areas being statistically significant. The statistically significant decreasing trend in wet season precipitation over Arabia calls for more conservative water resource management strategies and bold adaptation measures.