Possible causes for the persistence barrier of SSTA in the South China Sea and the vicinity of Indonesia

2012

Journal of Climate

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This study confirms a weak spring persistence barrier (SPB) of sea surface temperature anomalies (SSTAs) in the western tropical Indian Ocean (WIO), a strong fall persistence barrier (FPB) in the South China Sea (SCS), and the strongest winter persistence barrier (WPB) in the southeastern tropical Indian Ocean (SEIO). During El Niñ o events, a less abrupt sign reversal of SSTAs occurs in the WIO during spring, an abrupt reversal occurs in the SCS during fall, and the most abrupt reversal occurs in the SEIO during winter. The sign reversal of SSTA implies a rapid decrease in SSTA persistence, which is favorable for the occurrence of a persistence barrier. The present results indicate that a more abrupt reversal of SSTA sign generally corresponds to a more prominent persistence barrier. El Niñ o-induced changes in atmospheric circulation result in reduced evaporation and suppressed convection. This in turn leads to the warming over much of the TIO basin, which is an important mechanism for the abrupt switch in SSTA, from negative to positive, in the northern SCS and SEIO. The seasonal cycle of the prevailing surface winds has a strong influence on the timing of the persistence barriers in the TIO.The Indian Ocean dipole (IOD) alone can cause a weak WPB in the SEIO. El Niñ o events co-occurring with positive IOD further strengthen the SEIO WPB. The SEIO WPB appears to be more strongly influenced by ENSO than by the IOD. In contrast, the WIO SPB and the SCS FPB are relatively independent of the IOD.

Section: Mechanisms Of Barrier Developmentsupporting

confidence: 91%

Influences of ENSO Teleconnection on the Persistence of Sea Surface Temperature in the Tropical Indian Ocean

2012

Journal of Climate

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“…Similar to the phenomenon of autocorrelations of the tropical central–eastern Pacific SSTA, which show a rapid decrease in the boreal spring, Wajsowicz () reported that autocorrelations of the southeastern tropical Indian Ocean SSTA show a rapid decline in the boreal winter, resulting in a winter persistence barrier (WPB). Zhao and Li () also showed a similar persistence barrier of SSTA in the South China Sea and the vicinity of Indonesia around the southeastern tropical Indian Ocean. The WPB in the southeastern tropical Indian Ocean is associated with strong seasonal phase locking of the IOD.…”

Section: Seasonal Mean Predictability Limit Of Monthly Sstmentioning

confidence: 69%

Temporal–spatial distribution of the predictability limit of monthly sea surface temperature in the global oceans

Intl Journal of Climatology

2012

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ABSTRACT:To examine atmospheric and oceanic predictability based on nonlinear error growth dynamics, the authors introduced recently a new method using the nonlinear local Lyapunov exponent (NLLE). In this study, the NLLE method is employed to investigate the temporal-spatial distribution of the limit of sea surface temperature (SST) predictability, based on reanalysis monthly SST data. The results show that the annual mean limit of SST predictability is the greatest in the tropical central-eastern Pacific (>8 months). Relatively high values were also obtained for the tropical Indian and Atlantic Oceans (5-8 months). In the northern and southern mid-high latitude oceans, the limit of SST predictability is less than 6 months, with a minimum value of only 2-3 months. The limit of SST predictability in different oceanic regions shows significant seasonal variations, related to the persistence barriers that occur during particular seasons. In addition to the well-known spring persistence barrier (SPB) in the tropical central-eastern Pacific, persistence barriers also occur in other ocean areas during seasons other than spring. A winter persistence barrier (WPB) exists in the southeastern tropical Indian Ocean and the northern tropical Atlantic. In the North Pacific and North Atlantic, a persistence barrier exists around July-September. These seasonal persistence barriers cause a relatively low limit of SST predictability when predictions are made across the season in which the barriers occur. In contrast, when predictions are made initiated from the season with a persistence barrier, the SST errors show rapid initial growth but slow growth in the following seasons, resulting in a relatively high limit in predictability. Analyses also indicate that the possibility of really eliminating the effects of persistence barriers on SST errors by improving ocean-atmosphere coupled general circulation models (CGCMs) or the data assimilation procedure is very low.

“…Chen et al (2007) reported a fall persistence barrier (FPB) of the SSTA in the South China Sea (SCS), which is well recognized during the developing phase of strong ENSO cases but becomes vague in weak ENSO and non-ENSO cases. Zhao and Li (2009) showed that the persistence barrier of SSTA exists not only in the SCS but also in the vicinity of Indonesia. The SCS barrier occurs around October and November, while the barrier in the Indonesia region occurs around November and December.…”

Section: Introductionmentioning

confidence: 98%

Winter Persistence Barrier of Sea Surface Temperature in the Northern Tropical Atlantic Associated with ENSO

2011

Journal of Climate

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This study investigates the persistence characteristics of the sea surface temperature anomaly (SSTA) in the northern tropical Atlantic (NTA). It is found that a persistence barrier exists around December and January. This winter persistence barrier (WPB) is prominent during the mature phase of strong ENSO events but becomes indistinct during weak ENSO and normal (non-ENSO) events. During strong El Niñ o events, the NTA SSTA shows a reversal in sign and a rapid warming during December and January. It is possible that this SSTA sign reversal reduces the persistence, leading to the occurrence of the NTA WPB. The present analyses indicate a dynamic relationship among the Pacific ENSO, the NTA SSTA, and the NTA WPB on a quasibiennial time scale: a strong El Niñ o event is usually preceded by a strong La Niñ a event, which leads to a sign reversal of the NTA SSTA in winter as a delayed response to ENSO, finally resulting in the NTA WPB. Analyses also suggest that the NTA WPB is affected by the North Atlantic Oscillation (NAO). The NAO enhances the persistence of the NTA SSTA during winter, tending to weaken the NTA WPB.