Precipitation response to La Nina and global warming in the Indo-Pacific
Article
Article Title | Precipitation response to La Nina and global warming in the Indo-Pacific |
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ERA Journal ID | 1962 |
Article Category | Article |
Authors | Chung, Christine T. Y. (Author) and Power, Scott B. (Author) |
Journal Title | Climate Dynamics |
Journal Citation | 43 (12), pp. 3293-3307 |
Number of Pages | 15 |
Year | 2014 |
Publisher | Springer |
Place of Publication | New York, United States |
ISSN | 0930-7575 |
1432-0894 | |
Digital Object Identifier (DOI) | https://doi.org/10.1007/s00382-014-2105-9 |
Web Address (URL) | https://link.springer.com/article/10.1007/s00382-014-2105-9 |
Abstract | Recent studies have highlighted the nonlinear rainfall response to El Niño sea surface temperature (SST) events in the Indo-Pacific region and how this response might change over coming decades. Here we investigate the response to La Niña SST anomalies with and without global warming by performing idealised SST-forced experiments with an atmospheric general circulation model. The La Niña SST anomaly is multiplied by a factor 1≤α≤4 and added to climatological SSTs. Similar experiments using El Niño SST anomalies were previously performed, in which large nonlinearities in the precipitation response were evident. We find that: (i) Under current climatic conditions, as α increases, the precipitation responds in three ways: the intertropical convergence zone (ITCZ) dries and moves poleward, the maximum precipitation along the equator moves west, and the South Pacific convergence zone (SPCZ) narrows, intensifies, and elongates. For weak (α=1) La Niña events, the precipitation anomalies approximately mirror those from the El Niño events along the ITCZ and SPCZ, though there are some marked differences in the central-eastern Pacific. For stronger La Niña events (α>1), precipitation responds nonlinearly to SST anomalies, though the nonlinearities are smaller and differ spatially from the nonlinearities in the El Niño runs. (ii) The addition of a global warming SST pattern increases rainfall in the western Pacific and SPCZ, enhances the narrowing of the SPCZ, and increases the nonlinear response in the western Pacific. However, large La Niña events reduce the impact of global warming along the central-eastern equatorial Pacific as the global warming and La Niña SST anomalies have opposite signs in that region. (iii) The response to La Niña SST anomalies is driven primarily by changes in the atmospheric circulation, whereas the response to the global warming SST pattern is mainly driven by increases in atmospheric moisture. (iv) Large changes in La Niña-driven rainfall anomalies can occur in response to global warming, even if the La Nina SST anomalies relative to the warmer background state are completely unchanged. |
Keywords | climate change; climate variability; El Nino Southern Oscillation; global warming |
ANZSRC Field of Research 2020 | 370202. Climatology |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Australian Bureau of Meteorology |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q66y4/precipitation-response-to-la-nina-and-global-warming-in-the-indo-pacific
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