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

Abstract

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.

Distinct impact of tropical SSTs on summer North Pacific high and western North Pacific subtropical high

“…On the other hand, for the W–IO (C–WP) years, the IO warming (WP cooling) persists until the following summer. On the basis of the longer period of 1950–2007, Ding and Li [] have also reported the significant ENSO‐related IO warming and WP cooling. These results correspond strongly to the evolutionary change in IO, WP, and EP SSTs displayed in Figure .…”

A decomposition of ENSO’s impacts on the northern winter stratosphere: competing effect of SST forcing in the tropical Indian Ocean

“…Following the occurrence of warm/cold ENSO (El Niño/La Niña) events in the tropical eastern Pacific, the tropical Indian Ocean and the tropical Atlantic also becomes warmer/colder. Many previous studies have proved the significant lead/lag correlations between the SST anomalies in the tropical eastern Pacific in winter and those in the tropical Indian Ocean (e.g., Cadet 1985;Tourre and White 1995;Lanzante 1996;Nicholson 1997;Klein et al 1999;Murtugudde and Busalacchi 1999;Yu and Rienecker 1999;Ding and Li 2012) and the tropical Atlantic (e.g., Weare et al 1976;Covey and Hastenrath 1978;Curtis and Hastenrath 1995;Lanzante 1996;Enfield and Mayer 1997;Nicholson 1997;Klein et al 1999;Alexander et al 2002) throughout the winter and subsequent spring. Some studies also related these SST responses in the tropical Indian Ocean and Atlantic Ocean to the zonally homogeneous atmospheric warming/cooling responses in the tropical troposphere to warm/cold ENSO (e.g., Newell and Weare 1976;Angell and Korshover 1978;Angell 1981;Pan and Oort 1983;Reid et al 1989).…”

Tendencies, variability and persistence of sea surface temperature anomalies

“…ENSO SSTA variance is smallest in boreal summer and largest in winter 6 . In turn, ENSO state influences SSTA persistence in the Indian Ocean, where SSTA variability is comparatively small 7 . Between the Indian Ocean and central Pacific, SSTA variability in the seas around Indonesia and the western Pacific is smaller than in the central and eastern Pacific where ENSO-related amplitudes are largest.…”