Salimi, S; Helali, J; Lotfi, M; Momenzadeh, H; Hosseini, SA; Oskuei, EA; Izadi, A; Yarmoradi, Z; Bakhshi, I (2020). Investigating the origin and pathways of atmospheric rivers in the world. THEORETICAL AND APPLIED CLIMATOLOGY, 142(2-Jan), 165-175.

Atmospheric rivers (ARs) play an important role in the water cycle and destructive phenomena such as floods and storms. Thus, here the origin, structure, and pathway of ARs in the world were investigated considering the importance of the issue. To this end, the daily wind vector and jet stream data of the ERA-Interim were obtained with 0.25 degrees x 0.25 degrees spatial resolution for 1995-2019. Satellite images of Moderate Resolution Imaging Spectroradiometer (MODIS), Global Precipitation Measurement (GPM), and Geostationary Operational Environmental Satellite (GEOS) Water Vapor were used to examine the amount of precipitation caused by ARs. Also, graphical images were produced to study the origin, pathway, and expansion of ARs. The results indicated that jet streams play a major role in the genesis, direction, and pathway of ARs. Also, high-pressure (low-pressure) centers have a substantial role in the expansion (destination) of ARs. Regions such as west of the USA, west of southern headland of South America, northwest of Europe, the path of northeast Saudi Arabia to northeast Iran, Australia, and the distance between Japan and the east coast of Russia were the most affected regions of precipitation due to ARs. According to the results, there were seven major sources of ARs in the world, of which the most important one was located in southeast Asia. Regarding monthly distribution, January, September, and October had the highest occurrence of ARs. There was a minor difference in the number of ARs in two hemispheres. Only in the southern hemisphere did the ARs have a longer longitude. Investigating the number of occurrences of ARs indicated that in the highest state, three to four ARs were observed in the world simultaneously. Also, more than 90% of the ARs moved through the oceans.