Decadal cooling in the Indian summer monsoon after 1997/1998 El Niño and its impact on the East Asian summer monsoon

2010 ◽  
Vol 37 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Kyung-Sook Yun ◽  
Kyung-Ja Ha ◽  
Bin Wang ◽  
Ruiqiang Ding
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
El Niño ◽  
East Asian Summer Monsoon ◽  
El Nino ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Asian Summer

scholarly journals Tropical volcanism enhanced the East Asian summer monsoon during the last millennium

2021 ◽  
Author(s):  
Fei Liu ◽  
Chaochao Gao ◽  
Jing Chai ◽  
Alan Robock ◽  
Bin Wang ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
El Niño ◽  
East Asian Summer Monsoon ◽  
Volcanic Eruption ◽  
El Nino ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Volcanic Eruptions ◽  
Last Millennium ◽  
Asian Summer

Abstract Extreme East Asian summer monsoon (EASM) rainfall frequently induces floods that pose threats to millions of people across East Asia. The intensified EASM rainfall has been generally attributed to internal modes of climate variability, while external volcanic forcing has been suggested to suppress the EASM. In contrast to the hydrological weakening theory of volcanic eruptions, we present convergent empirical and modeling evidence for significant intensification of EASM rainfall in response to strong tropical volcanic eruptions. Our paleoclimate proxy analyses show a significantly increased EASM in the first summer after large tropical eruptions from 1470 AD to the present. The multi-proxy ensemble mean demonstrates that the occurrence of an El Niño in the first boreal winter after a volcanic eruption is necessary for the enhanced EASM. The results from the last-millennium climate model simulations show that a volcano-induced El Niño and the associated warm pool air-sea interaction intensify EASM precipitation, overwhelming volcanic-induced moisture deficiency. This work offers a new perspective on the intertwined relationship between external forcing and internal variability in the complex climate system and potential flood disasters resulting from tropical volcanic eruption.

scholarly journals How Does the East Asian Summer Monsoon Behave in the Decaying Phase of El Niño during Different PDO Phases?

2014 ◽  
Vol 27 (7) ◽  
pp. 2682-2698 ◽  
Author(s):  
Juan Feng ◽  
Lin Wang ◽  
Wen Chen
Keyword(s):  
Summer Monsoon ◽  
El Niño ◽  
East Asian Summer Monsoon ◽  
El Nino ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
The Philippines ◽  
Central China ◽  
Rainfall Pattern ◽  
Asian Summer

Abstract Modulation of the Pacific decadal oscillation (PDO) on the behavior of the East Asian summer monsoon (EASM) in El Niño decaying years has been studied. When El Niño is in phase with the PDO (El Niño/high PDO), the low-level atmospheric anomalies are characterized by an anticyclone around the Philippines and a cyclone around Japan, inducing an anomalous tripolar rainfall pattern in China. In this case, the western Pacific subtropical high (WPSH) experiences a one-time slightly northward shift in July and then stays stationary from July to August. The corresponding anomalous tripolar rainfall pattern has weak subseasonal variations. When El Niño is out of phase with the PDO (El Niño/low PDO), however, the anomalous Philippines anticyclone has a much larger spatial domain, thereby causing an anomalous dipole rainfall pattern. Accordingly, WPSH experiences clearly two northward shifts. Therefore, the related dipole rainfall pattern has large subseasonal variations. One pronounced feature is that the positive rainfall anomalies shift northward from southern China in June to central China in July and finally to northern China in August. The different El Niño–EASM relationships are caused by the influences of PDO on the decaying speed of El Niño. During the high PDO phase, El Niño decays slowly and has a strong anchor in the north Indian Ocean warming, which is responsible for the anomalous EASM. Comparatively, during the low PDO phase, El Niño decays rapidly and La Niña develops in summer, which induces different EASM anomalies from that during the high PDO phase. Additionally, PDO changes El Niño behaviors mainly via modifying the background tropical winds.

scholarly journals Forced and internal modes of variability of the East Asian summer monsoon

2008 ◽  
Vol 4 (3) ◽  
pp. 645-666 ◽  
Author(s):  
J. Liu ◽  
B. Wang ◽  
J. Yang
Keyword(s):  
Summer Monsoon ◽  
El Niño ◽  
East Asian Summer Monsoon ◽  
North China ◽  
El Nino ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Internal Mode ◽  
Modes Of Variability ◽  
Asian Summer

Abstract. The modern instrumental record (1979–2006) is analyzed in an attempt to reveal the dynamical structure and origins of the major modes of interannual variability of East Asian summer monsoon (EASM) and to elucidate their fundamental differences with the major modes of seasonal variability. These differences are instrumental in understanding of the forced (say orbital) and internal (say interannual) modes of variability in EASM. We show that the leading mode of interannual variation, which accounts for about 39% of the total variance, is primarily associated with decaying phases of major El Nino, whereas the second mode, which accounts for 11.3% of the total variance, is associated with the developing phase of El Nino/La Nina. The EASM responds to ENSO in a nonlinear fashion with regard to the developing and decay phases of El Nino. The two modes are determined by El Nino/La Nina forcing and monsoon-warm ocean interaction, or essentially driven by internal feedback processes within the coupled climate system. For this internal mode, the intertropical convergence zone (ITCZ) and subtropical EASM precipitations exhibit an out-of-phase variations; further, the Meiyu in Yangtze River Valley is also out-of-phase with the precipitation in the central North China. In contrast, the slow and fast annual cycles forced by the solar radiation show an in-phase correlation between the ITCZ and subtropical EASM precipitation. Further, the seasonal march of precipitation displays a continental-scale northward advance of a rain band (that tilts in a southwest-northeastward direction) over the entire Indian and East Asian summer monsoon from mid-May toward the end of July. This uniformity in seasonal advance suggests that the position of the northern edge of the summer monsoon or the precipitation over the central North China may be an adequate measure of the monsoon intensity for the forced mode, while the intensity of the internal mode of EASM variability should measured by the intensity of Meiyu. Given the fact that the annual modes share the similar external forcing with orbital variability, the results presented here may help to understand the differences in the EASM variability on the interannual and orbital time scales.

Enhanced tropospheric biennial oscillation of the East Asian summer monsoon since the late-1970s

2021 ◽  
pp. 1-54
Author(s):  
Wen Chen ◽  
Kaiming Hu ◽  
Shangfeng Chen
Keyword(s):  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
El Nino ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Tropospheric Biennial Oscillation ◽  
Asian Summer ◽  
Biennial Oscillation

Abstract The tropospheric biennial oscillation (TBO) of East Asian summer monsoon (EASM) has major impacts on East Asian climate. Here it is shown that, since the late-1970s, the TBO signal of EASM has strengthened significantly. The EASM TBO in wind anomalies undergoes a transition from a cyclone over the western North Pacific (WNPC) in preceding summer to an anticyclone over the western North Pacific (WNPAC) in following summer, with the anomalies strengthening remarkably after the late-1970s. Correspondingly, the biennial component of precipitation anomalies in eastern China show different distributions. Both observational and numerical simulation analyses demonstrate that these changes are caused by the westward shift of El Niño warming and enhanced Indo-Pacific and Atlantic-Pacific coupling. The positive sea surface temperature (SST) anomalies associated with the TBO of EASM shift toward the central Pacific after the late-1970s, which favor the strengthening of the WNPC and cause a weakened EASM. In following summer, both the north Indian Ocean and tropical north Atlantic SST warming are closely coupled with El Niño since the late-1970s, which favor the strengthening of WNPAC and cause an intensified EASM. Together, these changes provide more favorable background state for the transition of circulation anomalies over the western North Pacific, giving rise to enhanced biennial variability in EASM in the late-1970s.

Stalagmite δ18O variations in southern India reveal divergent trends of Indian Summer Monsoon and East Asian Summer Monsoon during the last interglacial

2015 ◽  
Vol 371 ◽  
pp. 191-196 ◽  
Author(s):  
Narayana C. Allu ◽  
Manish Tiwari ◽  
Madhusudan G. Yadava ◽  
Nguyen Chi Dung ◽  
Chuan-Chou Shen ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Southern India ◽  
Last Interglacial ◽  
Asian Summer
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