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The double-peaked El Niño and its physical processes

Citation

Shin, N-Y and Kug, J-S and McCormack, FS and Holbrook, NJ, The double-peaked El Nino and its physical processes, Journal of Climate, 34, (4) pp. 1291-1303. ISSN 0894-8755 (2021) [Refereed Article]


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DOI: doi:10.1175/JCLI-D-20-0402.1

Abstract

Recently, El Niño diversity has been paid much attention because of its different global impacts. However, most studies have focused on a single warm peak in sea surface temperature anomalies (SSTAs), either in the central Pacific or the eastern Pacific Ocean. Here, we demonstrate from observational analyses that several recent El Niño events show double warm peaks in SSTA—called "double-peaked (DP) El Niño"—that have only been observed since 2000. The DP El Niño has two warm centers, which grow concurrently but separately, in both the central and eastern Pacific. In general, the atmospheric and oceanic patterns of the DP El Niño are similar to those of the warm-pool (WP) El Niño from the development phase, such that the central Pacific peak is developed by the zonal advective feedback and reduced wind speed anomalies. However, a distinctive difference exists in the eastern Pacific where the DP El Niño has a second SSTA peak. In addition, the DP El Niño shows more distinctive anomalous precipitation along the Pacific intertropical convergence zone (ITCZ) when compared with the WP El Niño. We demonstrate that the peculiar precipitation anomalies along the Pacific ITCZ play a critical role in enhancing the equatorial westerly wind stress anomalies, which help to develop the eastern SSTA peak by deepening the thermocline in the eastern Pacific.

Item Details

Item Type:Refereed Article
Keywords:double peaked El Niño, physical processes, ocean dynamics; El Niño, air–sea interaction, heat budgets/fluxes
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Natural hazards
Objective Field:Climatological hazards (e.g. extreme temperatures, drought and wildfires)
UTAS Author:Holbrook, NJ (Professor Neil Holbrook)
ID Code:142799
Year Published:2021
Deposited By:Oceans and Cryosphere
Deposited On:2021-02-11
Last Modified:2021-02-11
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