scholarly journals Seasonal and interannual (ENSO) climate variabilities and trends in the South China Sea over the last three decades

2018 ◽  
Author(s):  
Violaine Piton ◽  
Thierry Delcroix
Keyword(s):  
South China Sea ◽  
El Niño ◽  
El Nino ◽  
The South ◽  
The North ◽  
Meridional Winds ◽  
El Niño Events ◽  
The Mean ◽  
Increasing Trends ◽  
El Nino Events

Abstract. We present a short overview of the long-term mean and variability of five Essential Climate Variables observed in the South China Sea over the last 3 decades, including sea surface temperature (SST), sea level anomaly (SLA), precipitation (P), surface wind and water discharge (WD) from the Mekong and Red Rivers. At the seasonal time scale, SST and SLAs increase in the summer (up to 4.2 °C and 14 cm, respectively), and P increases in the north. The summer zonal and meridional winds reverse and intensify (mostly over the ocean), and the WD shows positive anomalies. At the interannual time scale, each variable appears to be correlated with El Niño Southern Oscillation (ENSO) indices. Eastern Pacific El Niño events produce basin-wide SST warming (up to 1.4 °C) with a 6-month lag. The SLAs fall basin-wide (by up to 9 cm) during an El Niño event (all types), with a 3-month lag. The zonal and meridional winds strengthen (up to 4 m/s) in the north (weaken in the south) during all types of El Niño events, with a 3–5-month lag. A rainfall deficit of approximately 30 % of the mean occurs during all types of El Niño phases. The Mekong River WD is reduced by 1/3 of the mean 7–8 months after all types of El Niño events. We also show increasing trends of SST as high as 0.24 °C/decade and SLAs by 41 mm/decade. Increasing trends are observed for zonal wind, which is possibly linked to the phase of the Pacific Decadal Oscillation, and decreasing trends are observed for P in the north and both WD stations that were analyzed. The likely driving mechanisms and some of the relationships between all observed anomalies are discussed

Super instrumental El Niño events recorded by a Porites coral from the South China Sea

Coral Reefs ◽  
2018 ◽  
Vol 37 (1) ◽  
pp. 295-308 ◽  
Author(s):  
Xijie Wang ◽  
Wenfeng Deng ◽  
Xi Liu ◽  
Gangjian Wei ◽  
Xuefei Chen ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
El Niño ◽  
El Nino ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Porites Coral ◽  
El Niño Events ◽  
El Nino Events

The Contribution of Boreal Spring South Pacific Atmospheric Variability to El Niño Occurrence

2020 ◽  
Vol 33 (19) ◽  
pp. 8301-8313
Author(s):  
Qingye Min ◽  
Renhe Zhang
Keyword(s):  
El Niño ◽  
El Nino ◽  
South Pacific ◽  
Tropical Pacific ◽  
The South ◽  
Atmospheric Variability ◽  
Boreal Spring ◽  
El Niño Events ◽  
El Nino Events ◽  
The Tropical Pacific

AbstractDespite the fact that great efforts have been made to improve the prediction of El Niño events, it remains challenging because of limited understanding of El Niño and its precursors. This research focuses on the influence of South Pacific atmospheric variability on the development of the sea surface temperature anomaly (SSTA) in the tropical Pacific. It is found that as early as in the boreal spring of El Niño years, the sea level pressure anomaly (SLPA) shows a configuration characterized by two significant negative anomaly centers in the north and a positive anomaly center in the south between the subtropics and high latitudes in South Pacific. Such an anomalous SLPA pattern becomes stronger in the following late boreal spring and summer associated with the strengthening of westerly anomalies in the tropical Pacific, weakening the southeasterly trade winds and promoting the warming of tropical eastern Pacific, which is conducive to the development of El Niño events. It is demonstrated that the SLPA pattern in boreal spring revealed in this study is closely associated with boreal summer South Pacific Oscillation (SPO) and South Pacific meridional mode (SPMM). As a precursor in boreal spring, the prediction skill of the South Pacific SLPA in boreal spring for the SSTA in the eastern equatorial Pacific is better than that of the SPMM. This study is helpful to deepen our understanding of the contribution of South Pacific extratropical atmospheric variability to El Niño occurrence.

Coastal upwelling along the north coast of Papua New Guinea and El Niño events during 1981–2005

2010 ◽  
Vol 60 (5) ◽  
pp. 1255-1269 ◽  
Author(s):  
Takuya Hasegawa ◽  
Kentaro Ando ◽  
Keisuke Mizuno ◽  
Roger Lukas ◽  
Bunmei Taguchi ◽  
...  
Keyword(s):  
Papua New Guinea ◽  
El Niño ◽  
Coastal Upwelling ◽  
El Nino ◽  
New Guinea ◽  
North Coast ◽  
The North ◽  
El Niño Events ◽  
El Nino Events

The Late Fall Extratropical Response to ENSO: Sensitivity to Coupling and Convection in the Tropical West Pacific

2008 ◽  
Vol 21 (23) ◽  
pp. 6101-6118 ◽  
Author(s):  
Ileana Bladé ◽  
Matthew Newman ◽  
Michael A. Alexander ◽  
James D. Scott
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Indian Ocean ◽  
Surface Cooling ◽  
West Pacific ◽  
The North ◽  
Late Fall ◽  
El Niño Events ◽  
Sst Anomalies ◽  
El Nino Events

Abstract The extratropical response to El Niño in late fall departs considerably from the canonical El Niño signal. Observational analysis suggests that this response is modulated by anomalous forcing in the tropical west Pacific (TWP), so that a strong fall El Niño teleconnection is more likely when warm SST conditions and/or enhanced convection prevail in the TWP. While these TWP SST anomalies may arise from noise and/or long-term variability, they may also be generated by differences between El Niño events, through variations in the tropical “atmospheric bridge.” This bridge typically drives subsidence west of the date line and enhanced trade winds over the far TWP, which cool the ocean. In late fall, however, some relatively weaker and/or more eastward-shifted El Niño events produce a correspondingly weakened and displaced tropical bridge, which results in no surface cooling and enhanced convection in the TWP. Because the North Pacific circulation is very sensitive to forcing from the TWP at this time of year, the final outcome is a strong extratropical El Niño teleconnection. This hypothesis is partly supported by regionally coupled ensemble GCM simulations for the 1950–99 period, in which prescribed observed El Niño SST anomalies in the eastern/central equatorial Pacific and an oceanic mixed layer model elsewhere coexist, so that the TWP is allowed to interact with the El Niño atmospheric bridge. To separate the deterministic signal driven by TWP coupling from that associated with inter–El Niño differences and from the “noise” due to intrinsic TWP convection variability (not induced by local SST anomalies), a second large-ensemble (100) simulation of the 1997/98 El Niño event, with coupling limited to the TWP and tropical Indian Ocean, is carried out. Together, the model findings suggest that the extratropical El Niño teleconnection during late fall is very sensitive to convective forcing in the TWP and that coupling-induced warming in the TWP may enhance this El Niño teleconnection by promoting convection in this critical TWP region. A more general implication is that diagnostic studies using December–February (DJF) seasonal averages may obscure some important aspects of climate anomalies associated with forcing in the tropical Pacific.

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