Constraining and Characterizing the Size of Atmospheric Rivers: A Perspective Independent From the Detection Algorithm

Journal Article · 18 August 2021 · Journal of Geophysical Research: Atmospheres

DOI: https://doi.org/10.1029/2020JD033746 · OSTI ID:1814044

Inda‐Díaz, H. A.  ^[1]; O'Brien, T. A.  ^[2]; Zhou, Y.  ^[3]; Collins, W. D.  ^[4]

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1. Lawrence Berkeley National Laboratory Berkeley CA USA, University of California Davis Davis CA USA
2. Lawrence Berkeley National Laboratory Berkeley CA USA, Indiana University Bloomington Bloomington IN USA
3. Lawrence Berkeley National Laboratory Berkeley CA USA
4. Lawrence Berkeley National Laboratory Berkeley CA USA, University of California Berkeley Berkeley CA USA

Abstract Atmospheric rivers (AR) are large and narrow filaments of poleward horizontal water vapor transport. Because of its direct relationship with horizontal vapor transport, extreme precipitation, and overall AR impacts over land, the AR size is an important characteristic that needs to be better understood. Current AR detection and tracking algorithms have resulted in large uncertainty in estimating AR sizes, with areas varying over several orders of magnitude among different detection methods. We develop and implement five independent size estimation methods to characterize the size of ARs that make landfall over the west coast of North America in the 1980–2017 period and reduce the range of size estimation from ARTMIP. ARs that originate in the Northwest Pacific (WP) (100°−180°E) have larger sizes and are more zonally oriented than those from the Northeast Pacific (EP) (180°−240°E). ARs become smaller through their life cycle, mainly due to reductions in their width. They also become more meridionally oriented toward the end of their life cycle. Overall, the size estimation methods proposed in this study provide a range of AR areas (between 7 × 10 ¹¹ and 10 ¹³  m ² ), that is, several orders of magnitude narrower than current methods estimation. This methodology can provide statistical constraints in size and geometry for the AR detection and tracking algorithms, and an objective insight for future studies about AR size changes under different climate scenarios.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1814044
• Journal Information: Journal of Geophysical Research: Atmospheres, Journal Name: Journal of Geophysical Research: Atmospheres Journal Issue: 16 Vol. 126; ISSN 2169-897X
• Publisher: American Geophysical Union (AGU)Copyright Statement
• Country of Publication: United States
• Language: English