Assessment of Past Precipitation Extreme Events Over the Qassim Region in Saudi Arabia

Abstract

Extreme precipitation events can pose catastrophic stress to humankind and the environment. Therefore, it is crucial to characterize past extreme events in many infrastructure designs, operations, and management. This study analyzes such events over a very arid part of Saudi Arabia, the Qassim region. Also, the current work analyzes the features and temporal trends in historical precipitation patterns in terms of their intensity and occurrence. The observed daily precipitation data (PCP) were collected from two climate stations in Buraidah and Ar Rass cities between 1990 and 2019. The number of relatively heavy precipitation days of more than 10 mm per day (R10) was investigated. Also, the annual maximum precipitation (Max PCP) and total precipitation (Total PCP) were analyzed. Further, trend analysis was performed utilizing the nonparametric Mann–Kendall trend test at a 5% significance level, along with Sen’s slope, for estimating the magnitude of the monotonic trend in the latter variables. Results show that out of all the rainy days in the region (on average, only 12–17 wet-days a year), around 20% come with more than 10 mm of rainfall annually. In addition, results also indicate slight changes in the precipitation occurrence patterns over the Qassim region throughout the reference period, shown in slight decreases in the count of wet (PCP ≥ 0.1 mm) and R10 in Buraidah. In contrast, Ar Rass shows slight increases in these indices. The MK test results, however, show no significant trend in annual maximum precipitation or total precipitation at the two stations for the study period.