The impact of SST-forced and unforced teleconnections on 2015/16 El Niño winter precipitation over the western United States
The factors impacting western U.S. winter precipitation during the 2015/16 El Niño are investigated using the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) data, and simulations with the Goddard Earth Observing System version 5 (GEOS-5) atmospheric general circu...
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ftpubmed:oai:pubmedcentral.nih.gov:6121706 2023-05-15T15:11:17+02:00 The impact of SST-forced and unforced teleconnections on 2015/16 El Niño winter precipitation over the western United States Lim, Young-Kwon Schubert, Siegfried D. Chang, Yehui Molod, Andrea M. Pawson, Steven 2018-06-29 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121706/ http://www.ncbi.nlm.nih.gov/pubmed/30197468 https://doi.org/10.1175/JCLI-D-17-0218.1 en eng http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121706/ http://www.ncbi.nlm.nih.gov/pubmed/30197468 http://dx.doi.org/10.1175/JCLI-D-17-0218.1 Article Text 2018 ftpubmed https://doi.org/10.1175/JCLI-D-17-0218.1 2019-08-04T00:16:50Z The factors impacting western U.S. winter precipitation during the 2015/16 El Niño are investigated using the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) data, and simulations with the Goddard Earth Observing System version 5 (GEOS-5) atmospheric general circulation model forced with specified sea surface temperatures (SSTs). Results reveal that the simulated response to the tropical Pacific SST associated with the 2015/16 El Niño was to produce wetter than normal conditions over much of the west coast including California – a result at odds with the negative precipitation anomalies observed over much of the Southwestern U.S. It is shown that two factors acted to partly counter the canonical ENSO response in that region. First, a potentially predictable but modest response to the unusually strong and persistent warm SST in the northeastern Pacific decreased precipitation in the Southwestern U.S. by increasing sea level pressure, driving anticyclonic circulation and atmospheric descent, and reducing moisture transport into that region. Second, large-scale unforced (by SST) components of atmospheric variability (consisting of the leading modes of unpredictable intra-ensemble variability) resembling the positive phase of the North Atlantic Oscillation and Arctic Oscillation are found to be an important contributor to the drying over the western U.S. While a statistical reconstruction of the precipitation from our simulations that account for internal atmospheric variability does much to close the gap between the ensemble mean and observed precipitation in the Southwestern U.S., some differences remain, indicating that model error is also playing a role. Text Arctic North Atlantic North Atlantic oscillation PubMed Central (PMC) Arctic Merra ENVELOPE(12.615,12.615,65.816,65.816) Pacific Journal of Climate 31 15 5825 5844 |
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Article Lim, Young-Kwon Schubert, Siegfried D. Chang, Yehui Molod, Andrea M. Pawson, Steven The impact of SST-forced and unforced teleconnections on 2015/16 El Niño winter precipitation over the western United States |
topic_facet |
Article |
description |
The factors impacting western U.S. winter precipitation during the 2015/16 El Niño are investigated using the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) data, and simulations with the Goddard Earth Observing System version 5 (GEOS-5) atmospheric general circulation model forced with specified sea surface temperatures (SSTs). Results reveal that the simulated response to the tropical Pacific SST associated with the 2015/16 El Niño was to produce wetter than normal conditions over much of the west coast including California – a result at odds with the negative precipitation anomalies observed over much of the Southwestern U.S. It is shown that two factors acted to partly counter the canonical ENSO response in that region. First, a potentially predictable but modest response to the unusually strong and persistent warm SST in the northeastern Pacific decreased precipitation in the Southwestern U.S. by increasing sea level pressure, driving anticyclonic circulation and atmospheric descent, and reducing moisture transport into that region. Second, large-scale unforced (by SST) components of atmospheric variability (consisting of the leading modes of unpredictable intra-ensemble variability) resembling the positive phase of the North Atlantic Oscillation and Arctic Oscillation are found to be an important contributor to the drying over the western U.S. While a statistical reconstruction of the precipitation from our simulations that account for internal atmospheric variability does much to close the gap between the ensemble mean and observed precipitation in the Southwestern U.S., some differences remain, indicating that model error is also playing a role. |
format |
Text |
author |
Lim, Young-Kwon Schubert, Siegfried D. Chang, Yehui Molod, Andrea M. Pawson, Steven |
author_facet |
Lim, Young-Kwon Schubert, Siegfried D. Chang, Yehui Molod, Andrea M. Pawson, Steven |
author_sort |
Lim, Young-Kwon |
title |
The impact of SST-forced and unforced teleconnections on 2015/16 El Niño winter precipitation over the western United States |
title_short |
The impact of SST-forced and unforced teleconnections on 2015/16 El Niño winter precipitation over the western United States |
title_full |
The impact of SST-forced and unforced teleconnections on 2015/16 El Niño winter precipitation over the western United States |
title_fullStr |
The impact of SST-forced and unforced teleconnections on 2015/16 El Niño winter precipitation over the western United States |
title_full_unstemmed |
The impact of SST-forced and unforced teleconnections on 2015/16 El Niño winter precipitation over the western United States |
title_sort |
impact of sst-forced and unforced teleconnections on 2015/16 el niño winter precipitation over the western united states |
publishDate |
2018 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121706/ http://www.ncbi.nlm.nih.gov/pubmed/30197468 https://doi.org/10.1175/JCLI-D-17-0218.1 |
long_lat |
ENVELOPE(12.615,12.615,65.816,65.816) |
geographic |
Arctic Merra Pacific |
geographic_facet |
Arctic Merra Pacific |
genre |
Arctic North Atlantic North Atlantic oscillation |
genre_facet |
Arctic North Atlantic North Atlantic oscillation |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121706/ http://www.ncbi.nlm.nih.gov/pubmed/30197468 http://dx.doi.org/10.1175/JCLI-D-17-0218.1 |
op_doi |
https://doi.org/10.1175/JCLI-D-17-0218.1 |
container_title |
Journal of Climate |
container_volume |
31 |
container_issue |
15 |
container_start_page |
5825 |
op_container_end_page |
5844 |
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1766342170452688896 |