Influence of African Atmospheric Rivers on Precipitation and Snowmelt in the Near East's Highlands

Abstract

Atmospheric rivers (ARs) are important components of the global water cycle as they are responsible for over 90% of the poleward moisture transport at midlatitudes (Zhu & Newell, 1998). Estimations indicate that a typical AR over the North Pacific could carry much more water than some of the world's largest rivers (e.g., Ralph & Dettinger, 2011; Ralph et al., 2017). Three to five ARs are present in each hemisphere at any moment (Zhu & Newell, 1998), and they mostly prevail over the extratropical oceans, where they gain vast amounts of water vapor, and primarily make landfall on the western coasts of the midlatitude continents as a result of westerly flow (Guan & Waliser, 2015). In this respect, the mountainous western coasts of North Abstract Atmospheric rivers (ARs) traveling thousands of kilometers over arid North Africa could interact with the highlands of the Near East (NE), and thus affect the region's hydrometeorology and water resources. Here, we use a state-of-the-art AR tracking database, and reanalysis and observational datasets to investigate the climatology (1979-2017) and influences of these ARs in snowmelt season (March-April). The Red Sea and northeast Africa are found to be the major source regions of these ARs, which are typically associated with the eastern Mediterranean trough positioned over the Balkan Peninsula and a blocking anticyclone over the NE-Caspian region, triggering southwesterly air flow toward the NE's highlands. Approximately 8% of the ARs are relatively strong (integrated water vapor transport >∼275 kg m −1 s −1). AR days exhibit enhanced precipitation over the crescent-shaped orography of the NE region. Mean AR days indicate wetter (up to + 2 mm day −1) and warmer (up to + 1.5°C) conditions than all-day climatology. On AR days, while snowpack tends to decrease (up to 30%) in the Zagros Mountains, it can show decreases or increases in the Taurus Mountains depending largely on elevation. A further analysis with the observations and reanalysis indicates that extreme ARs coinciding with large scale sensible heat transport can significantly increase the daily discharges. These results suggest that ARs can have notable impacts on the hydrometeorology and water resources of the region, particularly of lowland Mesopotamia, a region that is famous with great floods in the ancient narratives. Plain Language Summary Atmospheric rivers (ARs) are important components of the global water cycle as they are responsible for over 90% of the poleward moisture transport at middle to high latitudes. ARs mostly prevail over the oceans and primarily landfall on the western coasts of the midlatitude continents as a result of westerly flow of the midlatitudes. Apart from the large ocean basins, certain ARs can develop and propagate over continents, which has received less scientific attention. In this respect, this study aims to show how overland African ARs developing in the snowmelt season can influence the Near East's highlands, which are essential for satisfying the water need of lowland areas of M...

A Dusty Atmospheric River Brings Floods to the Middle East

“…Another finding in our analysis was the important contribution of ARs to rapid snowmelt over the Zagros Mountains, consistent with the recent work by Bozkurt et al. (2021).…”

“…For example, the global AR catalog compiled by Waliser (2015, 2019) was able to identify the atmospheric river presented in the current study. in our analysis was the important contribution of ARs to rapid snowmelt over the Zagros Mountains, consistent with the recent work by Bozkurt et al (2021).…”

“…The characteristics of this AR, including its interaction with mountains, are quite similar to the ARs analyzed in Bozkurt et al. (2021).…”

“…The impacts of ARs on coastal regions like the western U.S. and Europe have been extensively studied (e.g., Collow et al., 2020; Lavers & Villarini, 2015; Ralph et al., 2006; Ramos et al., 2016). However, their role in extreme precipitation and rapid snowmelt leading to heavy floods over the Middle East has only recently received attention (Akbary et al., 2019; Bozkurt et al., 2021; de Vries et al., 2013; Dezfuli, 2020; Esfandiari & Lashkari, 2020; Massoud et al., 2020; Tubi et al., 2017). That limited body of research has attempted to shed light on the mechanisms of the ARs or statistical characteristics of their future changes.…”

A Multi‐Inventory Ensemble Analysis of the Effects of Atmospheric Rivers on Precipitation and Streamflow in the Namgang‐Dam Basin in Korea

“…Because ARs occur mostly in the warm conveyor belt of extratropical cyclones (ETCs) (Guo et al., 2020; Zhang et al., 2019), ARs are expected to affect not only WNA and WEU but also other regions during the seasons of strong ETC activities. Progresses in objective identification of ARs using gridded atmospheric data have facilitated analyzing ARs and their hydrological impacts in regions around the world other than WNA and WEU (Blamey et al., 2018; Bozkurt et al., 2021; Esfandiari & Lashkari, 2020; Gorodetskaya et al., 2014; Kamae, Mei, & Xie, et al., 2017; Kamae, Mei, Xie, Naoi, & Ueda, 2017; Kim et al., 2021; Mahoney et al., 2016; Moore et al., 2012; Massoud et al., 2020; Mundhenk et al., 2016; Park et al., 2021a; Ramos et al., 2015, 2018; Sharma & Déry, 2020b; Stohl et al., 2008; Viale et al., 2018; Ye et al., 2020). For East Asia (EA), previous studies (Kamae, Mei, Xie, Naoi, & Ueda, 2017; Kim et al., 2021; Park et al., 2021a) related the seasonal cycle of the AR frequency to the seasonal variations of the large‐scale circulation and related ETC activities around Korea and EA as ETC activities over EA substantially increase in spring and early summer, the period of the northward march of the EA monsoon rainfall, then rapidly decrease from July to August (Kang et al., 2018; Kang & Son, 2021).…”