Automatic detection, classification, and long‐term investigation of temporal–spatial changes of atmospheric rivers in the Middle East.

Most water vapour in various subtropical regions is transported by atmospheric rivers (ARs). It is crucial to study this phenomenon, especially in regions more vulnerable to climate change due to population growth and aridity. The study's primary purpose was to detect ARs in the Middle East. According to expectations, ARs were classified based on strength and temporal–spatial distribution and their changes were examined to characterize the risks of the phenomenon. The results showed that ARs had significantly increased over the past 50 years (1971–2020). The most positive increase was related to weak ARs (Cat 1) in the last two decades and exceptional events (Cat 5) in the last decade. The results also indicated the role of terrain in limiting the path of the AR axis and multiple sources of moisture in their strongest form. The occurrence of hazardous events (Cat 4 and 5) was estimated at up to 22% of all ARs in the Middle East, with the highest frequency in the last three decades. It was also found that events with a maximum IVT of >1,000 kg·m−1·s−1 occurred 10 times during the last half of the last century. Also, an AR with a maximum IVT of 1,102 kg·m−1·s−1 occurred once in the region. The temporal distribution of these extreme events showed that they could occur at any time, depending on the conditions of AR formation. However, extreme events mainly occurred in March. [ABSTRACT FROM AUTHOR]