Analysis of extreme summer temperatures in Saudi Arabia and the association with large-scale atmospheric circulation

Abstract

Extreme temperature events (ETEs) over Saudi Arabia have been receiving special attention in recent decades due to their impacts on water resources, the energy sector, human health, and crop yields. In this study, maximum temperature (Tmax) data for the summer season (June-Aug) obtained from 27 meteorological stations in Saudi Arabia have been analyzed for the period 1981–2017. Frequency analysis revealed that stations located in the Central, Northern, and Coastal regions have a relatively higher number of summer ETEs. A composite analysis has been performed to assess the association between global circulations and ETEs in Saudi Arabia using global reanalysis data. It is found that the summer ETEs in Saudi Arabia are associated with a mid-latitude circumglobal wave-like (CGT) pattern. The upper-level circulations associated with the ETEs in various regions of Saudi Arabia display a weak (e.g., Coastal region) to well-developed (e.g., Central region) CGT wave pattern in the mid-latitudes. The upper level anomalous high (low) pressure over Eurasia (Central Asia) coupled with the surface anomalous low (high) pressure anomalies assists the hot dry air from desert regions that favour the occurrence of ETEs in different regions of Saudi Arabia. A lead-lag relationship between 200 hPa geopotential height and ETEs in the Central region of Saudi Arabia reveals a strong association between mid-latitude circulation and ETEs. Moreover, an inverse relationship between Tmax over Saudi Arabia and the El-Niño Southern Oscillation (ENSO) is found. The ENSO modulates the regional Tmax anomalies over Saudi Arabia through the upper-level mid-latitude circulation.