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dc.contributor.authorHoell, A.
dc.contributor.authorFunk, C.
dc.contributor.authorZinke, Jens
dc.contributor.authorHarrison, L.
dc.date.accessioned2017-04-28T13:58:03Z
dc.date.available2017-04-28T13:58:03Z
dc.date.created2017-04-28T09:06:05Z
dc.date.issued2017
dc.identifier.citationHoell, A. and Funk, C. and Zinke, J. and Harrison, L. 2017. Modulation of the Southern Africa precipitation response to the El Niño Southern Oscillation by the subtropical Indian Ocean Dipole. Climate Dynamics. 48 (7-8): pp. 2529-2540.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/52224
dc.identifier.doi10.1007/s00382-016-3220-6
dc.description.abstract

The climate of Southern Africa, defined as the land area bound by the region 15°S–35°S; 12.5°E–42.5°E, during the December–March rainy season is driven by Indo-Pacific sea surface temperature (SST) anomalies associated with the El Niño Southern Oscillation (ENSO) and the Subtropical Indian Ocean Dipole (SIOD). The observed December–March 1979–2014 Southern Africa precipitation during the four ENSO and SIOD phase combinations suggests that the phase of the SIOD can disrupt or enhance the Southern Africa precipitation response to ENSO. Here, we use a large ensemble of model simulations driven by global SST and ENSO-only SST to test whether the SIOD modifies the relationship between Southern Africa precipitation and ENSO. Since ENSO-based precipitation forecasts are used extensively over Southern Africa, an improved understanding of how other modes of SST variability modulate the regional response to ENSO is important. ENSO, in the absence of the SIOD, forces an equivalent barotropic Rossby wave over Southern Africa that modifies the regional mid-tropospheric vertical motions and precipitation anomalies. El Niño (La Niña) is related with high (low) pressure over Southern Africa that produces anomalous mid-tropospheric descent (ascent) and decreases (increases) in precipitation relative to average. When the SIOD and ENSO are in opposite phases, the SIOD compliments the ENSO-related atmospheric response over Southern Africa by strengthening the regional equivalent barotropic Rossby wave, anomalous mid-tropospheric vertical motions and anomalous precipitation. By contrast, when the SIOD and ENSO are in the same phase, the SIOD disrupts the ENSO-related atmospheric response over Southern Africa by weakening the regional equivalent barotropic Rossby wave, anomalous mid-tropospheric vertical motions and anomalous precipitation.

dc.publisherSpringer
dc.titleModulation of the Southern Africa precipitation response to the El Niño Southern Oscillation by the subtropical Indian Ocean Dipole
dc.typeJournal Article
dcterms.source.volume48
dcterms.source.number7-8
dcterms.source.startPage2529
dcterms.source.endPage2540
dcterms.source.issn0930-7575
dcterms.source.titleClimate Dynamics
curtin.departmentDepartment of Environment and Agriculture
curtin.accessStatusFulltext not available


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