Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling
One of the primary meteorological causes of the winter precipitation deficits and droughts in California (CA) is anomalous developments and maintenance of upper-tropospheric ridges over the northeastern Pacific. In order to understand and find the key factors controlling the winter precipitation var...
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ftmdpi:oai:mdpi.com:/2073-4433/9/11/455/ 2023-08-20T04:08:32+02:00 Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling Boksoon Myoung Sang-Wook Yeh Jinwon Kim Menas C. Kafatos agris 2018-11-19 application/pdf https://doi.org/10.3390/atmos9110455 EN eng Multidisciplinary Digital Publishing Institute Meteorology https://dx.doi.org/10.3390/atmos9110455 https://creativecommons.org/licenses/by/4.0/ Atmosphere; Volume 9; Issue 11; Pages: 455 precipitation variability drought California sea surface temperature gradient western tropical Pacific EOF analysis estimation model decadal change Text 2018 ftmdpi https://doi.org/10.3390/atmos9110455 2023-07-31T21:51:04Z One of the primary meteorological causes of the winter precipitation deficits and droughts in California (CA) is anomalous developments and maintenance of upper-tropospheric ridges over the northeastern Pacific. In order to understand and find the key factors controlling the winter precipitation variability in CA, the present study examines two dominant atmospheric modes of the 500 hPa geopotential height in the Northern Hemisphere using an Empirical Orthogonal Function (EOF) and their associated large-scale circulation patterns for the last 41 winters (1974/75–2014/15). Explaining 17.5% of variability, the second mode (EOF2) shows strong anti-cyclonic circulations in the North Pacific and cyclonic circulations in the eastern USA and mid-latitude North Atlantic, similar to the atmospheric circulation observed in the 2013/14 drought of CA. EOF2 is tightly and significantly correlated with CA winter precipitation. EOF2 is associated with warm western‒cool eastern tropical Pacific, resembling a mirror image of canonical El Niño events. In particular, it is found that, since the mid-1990s, sea surface temperatures (SSTs) in the western tropical Pacific have been more tightly correlated with EOF2 and with the variability of CA precipitation. A diagnostic regression model based on the west‒east SST difference in the tropical Pacific developed for two recent decades (1994/95–2014/15) has been found to capture the slow-moving interannual variability of the CA winter precipitation (about 50%). The regression model performs well, especially for the central and northern CA precipitation, where the impacts of El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on precipitation are indecisive. Our results emphasize the significant role of the western tropical Pacific SST forcing in the recent past, and in turn on CA droughts and potentially other precipitation extremes. Text North Atlantic MDPI Open Access Publishing Pacific Atmosphere 9 11 455 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
precipitation variability drought California sea surface temperature gradient western tropical Pacific EOF analysis estimation model decadal change |
spellingShingle |
precipitation variability drought California sea surface temperature gradient western tropical Pacific EOF analysis estimation model decadal change Boksoon Myoung Sang-Wook Yeh Jinwon Kim Menas C. Kafatos Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling |
topic_facet |
precipitation variability drought California sea surface temperature gradient western tropical Pacific EOF analysis estimation model decadal change |
description |
One of the primary meteorological causes of the winter precipitation deficits and droughts in California (CA) is anomalous developments and maintenance of upper-tropospheric ridges over the northeastern Pacific. In order to understand and find the key factors controlling the winter precipitation variability in CA, the present study examines two dominant atmospheric modes of the 500 hPa geopotential height in the Northern Hemisphere using an Empirical Orthogonal Function (EOF) and their associated large-scale circulation patterns for the last 41 winters (1974/75–2014/15). Explaining 17.5% of variability, the second mode (EOF2) shows strong anti-cyclonic circulations in the North Pacific and cyclonic circulations in the eastern USA and mid-latitude North Atlantic, similar to the atmospheric circulation observed in the 2013/14 drought of CA. EOF2 is tightly and significantly correlated with CA winter precipitation. EOF2 is associated with warm western‒cool eastern tropical Pacific, resembling a mirror image of canonical El Niño events. In particular, it is found that, since the mid-1990s, sea surface temperatures (SSTs) in the western tropical Pacific have been more tightly correlated with EOF2 and with the variability of CA precipitation. A diagnostic regression model based on the west‒east SST difference in the tropical Pacific developed for two recent decades (1994/95–2014/15) has been found to capture the slow-moving interannual variability of the CA winter precipitation (about 50%). The regression model performs well, especially for the central and northern CA precipitation, where the impacts of El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on precipitation are indecisive. Our results emphasize the significant role of the western tropical Pacific SST forcing in the recent past, and in turn on CA droughts and potentially other precipitation extremes. |
format |
Text |
author |
Boksoon Myoung Sang-Wook Yeh Jinwon Kim Menas C. Kafatos |
author_facet |
Boksoon Myoung Sang-Wook Yeh Jinwon Kim Menas C. Kafatos |
author_sort |
Boksoon Myoung |
title |
Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling |
title_short |
Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling |
title_full |
Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling |
title_fullStr |
Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling |
title_full_unstemmed |
Impacts of Pacific SSTs on Atmospheric Circulations Leading to California Winter Precipitation Variability: A Diagnostic Modeling |
title_sort |
impacts of pacific ssts on atmospheric circulations leading to california winter precipitation variability: a diagnostic modeling |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2018 |
url |
https://doi.org/10.3390/atmos9110455 |
op_coverage |
agris |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Atmosphere; Volume 9; Issue 11; Pages: 455 |
op_relation |
Meteorology https://dx.doi.org/10.3390/atmos9110455 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/atmos9110455 |
container_title |
Atmosphere |
container_volume |
9 |
container_issue |
11 |
container_start_page |
455 |
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1774720849085988864 |