scholarly journals Different Influences of Southeastern Indian Ocean and Western Indian Ocean SST Anomalies on Eastern China Rainfall during the Decaying Summer of the 2015/16 Extreme El Niño

2020 ◽  
Vol 33 (13) ◽  
pp. 5427-5443
Author(s):  
Jiepeng Chen ◽  
Jin-Yi Yu ◽  
Xin Wang ◽  
Tao Lian
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Eastern China ◽  
Surface Wind ◽  
Tropical Indian Ocean ◽  
Northern China ◽  
Ocean Warming ◽  
Indian Ocean Warming ◽  
Extreme El Niño

ABSTRACTPrevious studies linked the increase of the middle and low reaches of the Yangtze River (MLRYR) rainfall to tropical Indian Ocean warming during extreme El Niños’ (e.g., 1982/83 and 1997/98 extreme El Niños) decaying summer. This study finds the linkage to be different for the recent 2015/16 extreme El Niño’s decaying summer, during which the above-normal rainfalls over MLRYR and northern China are respectively linked to southeastern Indian Ocean warming and western tropical Indian Ocean cooling in sea surface temperatures (SSTs). The southeastern Indian Ocean warming helps to maintain the El Niño–induced anomalous lower-level anticyclone over the western North Pacific Ocean and southern China, which enhances moisture transport to increase rainfall over MLRYR. The western tropical Indian Ocean cooling first enhances the rainfall over central-northern India through a regional atmospheric circulation, the latent heating of which further excites a midlatitude Asian teleconnection pattern (part of circumglobal teleconnection) that results in an above-normal rainfall over northern China. The western tropical Indian Ocean cooling during the 2015/16 extreme El Niño is contributed by the increased upward latent heat flux anomalies associated with enhanced surface wind speeds, opposite to the earlier two extreme El Niños.

Indo-Pacific climate during the decaying phase of the 2015/16 El Niño: role of southeast tropical Indian Ocean warming

2017 ◽  
Vol 50 (11-12) ◽  
pp. 4707-4719 ◽  
Author(s):  
Zesheng Chen ◽  
Yan Du ◽  
Zhiping Wen ◽  
Renguang Wu ◽  
Chunzai Wang
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Tropical Indian Ocean ◽  
Ocean Warming ◽  
Indian Ocean Warming

The Extreme El Niño Events Suppressing the Intraseasonal Variability in the Eastern Tropical Indian Ocean

2020 ◽  
Vol 50 (8) ◽  
pp. 2359-2372
Author(s):  
Gengxin Chen ◽  
Dongxiao Wang ◽  
Weiqing Han ◽  
Ming Feng ◽  
Fan Wang ◽  
...  
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Intraseasonal Variability ◽  
Tropical Indian Ocean ◽  
Ocean Dynamics ◽  
El Niño Events ◽  
Extreme El Niño ◽  
El Nino Events

AbstractIn the eastern tropical Indian Ocean, intraseasonal variability (ISV) affects the regional oceanography and marine ecosystems. Mooring and satellite observations documented two periods of unusually weak ISV during the past two decades, associated with suppressed baroclinic instability of the South Equatorial Current. Regression analysis and model simulations suggest that the exceptionally weak ISVs were caused primarily by the extreme El Niño events and modulated to a lesser extent by the Indian Ocean dipole. Additional observations confirm that the circulation balance in the Indo-Pacific Ocean was disrupted during the extreme El Niño events, impacting the Indonesian Throughflow Indian Ocean dynamics. This research provides substantial evidence for large-scale modes modulating ISV and the abnormal Indo-Pacific dynamical connection during extreme climate modes.

Indian Ocean warming during peak El Niño cools surrounding land masses

2017 ◽  
Vol 51 (5-6) ◽  
pp. 2097-2112 ◽  
Author(s):  
N. Herold ◽  
A. Santoso
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Ocean Warming ◽  
Indian Ocean Warming

Evolution of South Tropical Indian Ocean Warming and the Climatic Impacts Following Strong El Niño Events

2019 ◽  
Vol 32 (21) ◽  
pp. 7329-7347 ◽  
Author(s):  
Zesheng Chen ◽  
Yan Du ◽  
Zhiping Wen ◽  
Renguang Wu ◽  
Shang-Ping Xie
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Surface Wind ◽  
Tropical Indian Ocean ◽  
Early Summer ◽  
Kelvin Waves ◽  
Boreal Summer ◽  
Western Boundary ◽  
The Mean

Abstract The south tropical Indian Ocean (TIO) warms following a strong El Niño, affecting Indo-Pacific climate in early boreal summer. While much attention has been given to the southwest TIO where the mean thermocline is shallow, this study focuses on the subsequent warming in the southeast TIO, where the mean sea surface temperature (SST) is high and deep convection is strong in early summer. The southeast TIO warming induces an anomalous meridional circulation with descending (ascending) motion over the northeast (southeast) TIO. It further anchors a “C-shaped” surface wind anomaly pattern with easterlies (westerlies) in the northeast (southeast) TIO, causing a persistent northeast TIO warming via wind–evaporation–SST feedback. The southeast TIO warming lags the southwest TIO warming by about one season. Ocean wave dynamics play a key role in linking the southwest and southeast TIO warming. South of the equator, the El Niño–forced oceanic Rossby waves, which contribute to the southwest TIO warming, are reflected as eastward-propagating oceanic Kelvin waves along the equator on the western boundary. The Kelvin waves subsequently depress the thermocline and develop the southeast TIO warming.

Remote forcing of Indian Ocean warming on Northwest Pacific during El Niño decaying years: a FOAM model approach

2013 ◽  
Vol 31 (6) ◽  
pp. 1375-1383 ◽  
Author(s):  
Haibo Hu ◽  
Xiaoyuan Hong ◽  
Yuan Zhang ◽  
Xiuqun Yang ◽  
Wei Liu ◽  
...  
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Ocean Warming ◽  
Northwest Pacific ◽  
Remote Forcing ◽  
Foam Model ◽  
Indian Ocean Warming ◽  
Model Approach

Why Was the Indian Ocean Dipole Weak in the Context of the Extreme El Niño in 2015?

2017 ◽  
Vol 30 (12) ◽  
pp. 4755-4761 ◽  
Author(s):  
Lin Liu ◽  
Guang Yang ◽  
Xia Zhao ◽  
Lin Feng ◽  
Guoqing Han ◽  
...  
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
Indian Ocean Dipole ◽  
El Nino ◽  
Tropical Indian Ocean ◽  
Tropical Pacific ◽  
Boreal Summer ◽  
El Niño Modoki ◽  
The Indian Ocean ◽  
Extreme El Niño

The Indian Ocean witnessed a weak positive Indian Ocean dipole (IOD) event from the boreal summer to autumn in 2015, while an extreme El Niño occurred over the tropical Pacific. This was different from the case in 1997/98, when an extreme El Niño and the strongest IOD took place simultaneously. The analysis here suggests that the unique sea surface temperature anomaly (SSTA) pattern of El Niño in 2015 might have contributed to the weak IOD that year. El Niño in 2015 had a complex SSTA pattern, with positive warming over the central and eastern tropical Pacific. Such a combination of the classic El Niño (also known as cold-tongue El Niño) and the recently identified central Pacific El Niño (also known as El Niño Modoki II) had opposite remote influences on the tropical Indian Ocean. The classic El Niño reduced the strength of the Walker circulation over the tropical Indian Ocean, but this was offset by El Niño Modoki II. This study points out that the IOD can be strongly modulated by combined El Niño types in some circumstances, as in 2015.

scholarly journals Historic Yangtze flooding of 2020 tied to extreme Indian Ocean conditions

2021 ◽  
Vol 118 (12) ◽  
pp. e2022255118
Author(s):  
Zhen-Qiang Zhou ◽  
Shang-Ping Xie ◽  
Renhe Zhang
Keyword(s):  
Indian Ocean ◽  
East Asia ◽  
El Niño ◽  
El Nino ◽  
Summer Rainfall ◽  
Ocean Warming ◽  
Northwest Pacific ◽  
Indian Ocean Warming ◽  
Yangtze Basin ◽  
The Indian Ocean

Heavy monsoon rainfall ravaged a large swath of East Asia in summer 2020. Severe flooding of the Yangtze River displaced millions of residents in the midst of a historic public health crisis. This extreme rainy season was not anticipated from El Niño conditions. Using observations and model experiments, we show that the record strong Indian Ocean Dipole event in 2019 is an important contributor to the extreme Yangtze flooding of 2020. This Indian Ocean mode and a weak El Niño in the Pacific excite downwelling oceanic Rossby waves that propagate slowly westward south of the equator. At a mooring in the Southwest Indian Ocean, the thermocline deepens by a record 70 m in late 2019. The deepened thermocline helps sustain the Indian Ocean warming through the 2020 summer. The Indian Ocean warming forces an anomalous anticyclone in the lower troposphere over the Indo-Northwest Pacific region and intensifies the upper-level westerly jet over East Asia, leading to heavy summer rainfall in the Yangtze Basin. These coupled ocean-atmosphere processes beyond the equatorial Pacific provide predictability. Indeed, dynamic models initialized with observed ocean state predicted the heavy summer rainfall in the Yangtze Basin as early as April 2020.

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