Intraseasonal variability of western North Pacific subtropical high based on the El Niño influence and its relationship with East Asian summer monsoon

2012 ◽  
Vol 48 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Sae-Rim Yeo ◽  
Jong-Ghap Jhun ◽  
WonMoo Kim
Keyword(s):  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
El Nino ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Intraseasonal Variability ◽  
Subtropical High ◽  
Asian Summer

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.

Spring Arctic Oscillation-East Asian summer monsoon connection through circulation changes over the western North Pacific

2011 ◽  
Vol 37 (11-12) ◽  
pp. 2199-2216 ◽  
Author(s):  
Dao-Yi Gong ◽  
Jing Yang ◽  
Seong-Joong Kim ◽  
Yongqi Gao ◽  
Dong Guo ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
Arctic Oscillation ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Asian Summer ◽  
Circulation Changes

Deficiencies and possibilities for long-lead coupled climate prediction of the Western North Pacific-East Asian summer monsoon

2010 ◽  
Vol 36 (5-6) ◽  
pp. 1173-1188 ◽  
Author(s):  
Sun-Seon Lee ◽  
June-Yi Lee ◽  
Kyung-Ja Ha ◽  
Bin Wang ◽  
Jae Kyung E. Schemm
Keyword(s):  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Climate Prediction ◽  
Asian Summer

scholarly journals Role of tropical cyclones over the western North Pacific in the East Asian summer monsoon system

2019 ◽  
Vol 3 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Xian Chen ◽  
◽  
Zhong Zhong ◽  
YiJia Hu ◽  
Shi Zhong ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Monsoon System ◽  
Asian Summer

Different Enhancement of the East Asian Summer Monsoon under Global Warming and Interglacial Epochs Simulated by CMIP6 Models: Role of the Subtropical High

2020 ◽  
Vol 33 (22) ◽  
pp. 9721-9733
Author(s):  
Chao He ◽  
Wen Zhou
Keyword(s):  
Global Warming ◽  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Subtropical High ◽  
The Tibetan Plateau ◽  
Southerly Wind ◽  
Asian Summer

AbstractSoutherly wind in the lower troposphere is an essential feature of East Asian summer monsoon (EASM) circulation, which is reported to be enhanced under global warming scenarios and interglacial epochs. Based on an analysis of an ensemble of CMIP6 models, this study shows that the magnitude of intensification of the EASM circulation is much smaller under global warming scenarios than during interglacial epochs. Distinct changes in the western North Pacific subtropical high (WNPSH) are responsible for the different responses of the EASM circulation. The WNPSH is substantially enhanced during interglacial epochs, which acts to strengthen the southerly wind associated with the EASM on the western flank of the WNPSH. However, the change in the WNPSH is insignificant and cannot strengthen the EASM under global warming scenarios, and the weakly enhanced EASM circulation may be a direct response to intensified heating over the Tibetan Plateau. The land–ocean thermal contrast explains the different responses of the WNPSH. During interglacial epochs, the summertime surface warming over the subtropical North Pacific is much weaker than over Eurasia due to the large thermal inertia of the ocean to increased insolation, and the WNPSH is intensified as a response to the suppressed latent heating over the subtropical North Pacific. The fast response of the WNPSH to abrupt quadrupling of CO2 without sufficient ocean warming is an analog to the interglacial epochs, but it is offset by the effect of slow oceanic warming, resulting in an insignificant change of the WNPSH under global warming scenarios.

scholarly journals Coupling Modes of Climatological Intraseasonal Oscillation in the East Asian Summer Monsoon

2016 ◽  
Vol 29 (17) ◽  
pp. 6363-6382 ◽  
Author(s):  
Zehao Song ◽  
Congwen Zhu ◽  
Jingzhi Su ◽  
Boqi Liu
Keyword(s):  
East Asia ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
Diabatic Heating ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Intraseasonal Oscillation ◽  
Rainfall Anomaly ◽  
Asian Summer

Abstract The present study used harmonic and multivariate empirical orthogonal function (MV-EOF) analyses to identify the existence of climatological intraseasonal oscillation (CISO) in the diabatic heating, precipitation, and circulation of the East Asian summer monsoon (EASM). The strongest CISO signals are found in the north of the western North Pacific, possibly because of the horizontal gradient of diabatic heating induced by the seasonal land–sea thermal contrast. Further, the phase relationship between the diabatic heating components maintains the EASM CISO. The first two coupling modes of EASM CISO in the circulation are robust during May through August, with a period of 40–80 days, and exhibit phase locking to the stepwise establishment of the EASM, which reveals the coaction of the Mongolian cyclone (MC) around Lake Baikal at 850 hPa, the western North Pacific subtropical high (WNPSH) at 500 hPa, and the South Asian high (SAH) over the Tibetan Plateau (TP) at 200 hPa. The first mode shows that the jointly enhanced MC, WNPSH, and SAH correspond to a tripole rainfall anomaly with strong mei-yu and baiu fronts over East Asia. The second mode, however, indicates the eastward and northwestward propagation of MC and WNPSH, respectively, with suppressed SAH, as well as a dipole rainfall anomaly over East Asia. Both the observations and numerical simulation verify the importance of daily diabatic heating and SST in maintaining the CISO modes over the WNP, where the condensation heating related to atmospheric forcing determines the local intraseasonal air–sea interaction.

scholarly journals Interannual Seesaw between the Somali and the Australian Cross-Equatorial Flows and its Connection to the East Asian Summer Monsoon

2014 ◽  
Vol 27 (11) ◽  
pp. 3966-3981 ◽  
Author(s):  
Chen Li ◽  
Shuanglin Li
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Yellow River ◽  
Southern Oscillation ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Significant Negative Correlation ◽  
Subtropical High ◽  
Yellow River Valley ◽  
Asian Summer

Abstract The correlations among the summer, low-level, cross-equatorial flows (CEFs) over the Indian–west Pacific Ocean region on the interannual time scale are investigated by using both the NCEP–NCAR reanalysis and 40-yr ECMWF Re-Analysis (ERA-40) datasets. A significant negative correlation (seesaw) has been illustrated between the Somali CEF and the three CEFs north of Australia (the South China Sea, Celebes Sea, and New Guinea; they are referred to in combination as the Australian CEF). A seesaw index is thus defined with a higher (lower) value representing an intensified (weakened) Somali CEF but a weakened (intensified) Australian CEF. The connection of the seesaw with the East Asian summer monsoon (EASM) is then investigated. The results suggest that an enhanced seesaw corresponds to an intensified EASM with more rainfall in north China, the Yellow River valley, and the upper reach of the Yangtze River. The seesaw reflects the opposite covariability between the two atmospheric action centers in the Southern Hemisphere, Mascarene subtropical high, and Australian subtropical high. Whether the seesaw–EASM connection is influenced by El Niño–Southern Oscillation (ENSO) or the Indian Ocean SST dipole mode (IOD) is analyzed. The results remain unchanged when the ENSO- or IOD-related signals are excluded, although ENSO exerts a significant influence. This implies an additional predictability for the EASM from the CEF seesaw.

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