The Role of Atmospheric Rivers Moisture Origin in the Seasonality of Extreme Precipitation in the Eastern United States

• Published in: Journal of hydrometeorology
• Main Authors: Aljoda, Ali, Dhakal, Nirajan
• Format: Journal Article
• Language: English
• Published: 27.08.2024
• ISSN: 1525-755X; 1525-7541
• DOI: 10.1175/JHM-D-23-0210.1

Abstract Regional patterns of the seasonal weather and atmospheric moisture origins can impact the seasonal activities of extreme precipitation in the eastern United States (eUS). At many locations, tracks of atmospheric moisture can have different influence on timing of extreme precipitation based on the moisture origin source. In this study we evaluate the contribution of Atmospheric Rivers (ARs), and their moisture origin sources to the distribution and seasonal effectivity of annual maximum precipitation (AMP) across the eUS during 1950–2021. Our results suggest that AR is a dominant mechanism of AMP in the eUS as they contribute to 75% (31,438 out of 41,976) of total AMP events recorded between 1950–2021. The seasonal analysis based on circular density approach shows that spring, summer and fall seasons display strong signals of seasonality of AMP-AR events. The spatial patterns of AMP associated with the four major moisture sources (the Pacific Ocean, the Atlantic Ocean, the combined source of Caribbean Sea and Gulf of Mexico, and the local source of moisture) reinforce the key role ARs play in transporting water vapor to eUS from both oceanic and inland originated moisture. The results additionally highlight the importance of moisture sub-sources (major sources sub-regions) in modulating the seasonality of extreme precipitation in the eUS.