South Pacific influence on the termination of El Ni(n)over-tildeo in 2014

作者：Imada Yukiko^*; Tatebe Hiroaki; Watanabe Masahiro; Ishii Masayoshi; Kimoto Masahide

来源：Scientific Reports, 2016, 6(1): 30341.

DOI：10.1038/srep30341

The El Nino/Southern Oscillation (ENSO) is the dominant mode of climate variability affecting worldwide extreme weather events; therefore, improving ENSO prediction is an important issue. In this regard, a peculiar time evolution of ENSO in 2014 posed a challenge to the climate science community. Despite the observance of several precursors for a strong El Nino to develop during the summer and autumn, cold sea surface temperature (SST) anomalies appeared unexpectedly to the south of the equatorial cold tongue, which prevented development of an El Nino event in the late summer. Several hypotheses have been raised to explain the unmaterialized El Nino in 2014, but complete understanding of processes responsible for terminating this event has not yet been obtained. Here we show, using observations and extended seasonal prediction experiments with a climate model, that cold off-equatorial subsurface water in the South Pacific Ocean penetrated into the equatorial region along the slanted isopycnal surface via the mean advection, and it prevented the El Nino evolution in 2014. The negative subsurface temperature anomalies in the off-equatorial South Pacific Ocean were persistent throughout the last decade, and additional numerical simulations indicated that they contributed to the suppression of El Nino events during the 2000s.

• 出版日期2016-7-28
• 单位中国气象科学研究院