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Dynamical Mechanisms Underlying the 2022/23 California Flooding: Analysis With A Stationary Wave ModelIn late December 2022 and the first half of January 2023, much of California experienced an unprecedented series of atmospheric rivers that produced heavy rains and near-record flooding. Previous work shows that a chain of dynamical events contributed to the extreme precipitation, including the development of a Rossby wave (as a result of forcing linked to the MJO) that emerged from the Indian Ocean in mid-December, and the subsequent development of a persistent positive Pacific North American (PNA) pattern that ultimately directed moisture onto the US West Coast starting in late December. Here, we use a stationary wave model (SWM) to further elucidate the dynamical and thermodynamical processes that drove the aforementioned chain of events. The results reveal the following: 1) The mid-December Rossby wave was likely induced by vorticity stretching and advection in the middle East linked indirectly to the MJO, 2) The initial development of the PNA in late December was triggered by transient and stretching sources of vorticity in the Pacific that were themselves induced by the aforementioned Rossby wave, and 3) The PNA was maintained through mid-January in part by diabatic heating west of Hawaii that was associated with anomalous precipitation influenced by the PNA circulation anomalies, thus representing a feedback on the PNA. One key finding from the SWM analysis is the limited direct role of tropical heating for inducing any of the dynamical mechanisms related to the California extreme event.
Document ID
20240001395
Acquisition Source
Goddard Space Flight Center
Document Type
Poster
Authors
Anthony M. DeAngelis
(Science Systems and Applications (United States) Lanham, Maryland, United States)
Siegfried D. Schubert
(Science Systems and Applications (United States) Lanham, Maryland, United States)
Yehui Chang
(Morgan State University Baltimore, Maryland, United States)
Young-Kwon Lim
(University of Maryland, Baltimore County Baltimore, Maryland, United States)
Natalie P. Thomas
(Universities Space Research Association Columbia, Maryland, United States)
Randal D. Koster
(Goddard Space Flight Center Greenbelt, Maryland, United States)
Michael G. Bosilovich
(Goddard Space Flight Center Greenbelt, Maryland, United States)
Andrea M. Molod
(Goddard Space Flight Center Greenbelt, Maryland, United States)
Allison Collow ORCID
(University of Maryland, Baltimore County Baltimore, Maryland, United States)
Amin Dezfuli
(University of Maryland, Baltimore County Baltimore, Maryland, United States)
Date Acquired
January 31, 2024
Subject Category
Earth Resources and Remote Sensing
Meeting Information
Meeting: 104th American Meteorological Society (AMS) Annual Meeting
Location: Baltimore, MD
Country: US
Start Date: January 28, 2024
End Date: February 1, 2024
Sponsors: American Meteorological Society
Funding Number(s)
CONTRACT_GRANT: NNG17HP01C
CONTRACT_GRANT: 80NSSC22M0001
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.
Technical Review
NASA Peer Committee
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