资源环境科技发展态势分析平台

Little information is available about the synoptic weather patterns and physical factors contributing to the formation and intensity of heat waves (HWs) in Saudi Arabia. The research objectives were to identify the synoptic situations that are related to HW occurrence, to match different HW aspects (frequency and intensity) related to different circulation types, and to examine the possible links/associations between HW days and the sea surface temperature (SST) anomalies of closely associated water bodies (i.e., Mediterranean Sea, Black Sea, Caspian Sea, Arabian Gulf, Arabian Sea, and Red Sea).

Using a time-sensitive approach, a HW was defined as a period of at least two consecutive days with a daily maximum temperature equal or higher than the 90th percentile of the monthly maximum and with a daily minimum temperature equal or higher than the 85th percentile of the monthly minimum for the decade in question. Using reanalysis data for 1985-2014, three weather/circulation types were identified using Ward's method for cluster determination. Together, weather types 1 and 3 induced 57.5% of HW days and connected with negative anomalies in sea level pressure with lower heights and warmer temperatures at the 850 hPa level. Weather type 2 induced 42.5% of HW days and was related to positive anomalies at all heights. Intensification of Indian Summer Monsoon Trough and Arabian heat lows were key atmospheric features related to weather types 1 and 3. Anomalies of SSTs of the Red Sea, Arabian Gulf, Caspian Sea, Black Sea, and Mediterranean Sea displayed positive values for both weather types 1 and 3. SSTs anomalies seem to be a more important factor for intensity of a HW day. HWs in Saudi Arabia tend to occur during regional warming due to atmospheric circulation conditions and SST teleconnections.