scholarly journals Change in Relationship between the East Asian Winter Monsoon and the East Asian Jet Stream during the 1998–99 Regime Shift

2019 ◽  
Vol 32 (18) ◽  
pp. 6163-6175 ◽  
Author(s):  
Se-Yong Song ◽  
Sang-Wook Yeh ◽  
Jae-Heung Park
Keyword(s):  
East Asian Winter Monsoon ◽  
East Asian ◽  
Hadley Circulation ◽  
Winter Monsoon ◽  
Jet Stream ◽  
Decadal Change ◽  
Reanalysis Dataset ◽  
Asian Winter Monsoon ◽  
East Asian Jet Stream ◽  
The Relationship

Abstract A composite analysis was conducted on the reanalysis dataset for 1979–2016, along with an idealized model experiment to show that the relationship between the East Asian jet stream (EAJS) and the East Asian winter monsoon (EAWM) is nonstationary. The relationship between EAWM and the EAJS weakened during the late 1990s. This decadal change in the EAJS–EAWM relationship was mainly due to a change in the secondary circulation across the EAJS between two contrasting periods, induced by the northward shift of the EAJS. A possible mechanism associated with the decadal change in meridional displacement of the EAJS is proposed. The enhanced convective activity in the western tropical Pacific after the late 1990s results in stronger Hadley circulation that could have contributed to the northward displacement of the Hadley circulation boundary latitude. Subsequently, this leads to the northward shift of the EAJS. Therefore, it is necessary to define a new EAJS index to account for the EAWM variability based on the change in the oceanic and atmospheric mean state across the late 1990s.

Roles of Intraseasonal Disturbances and Diabatic Heating in the East Asian Jet Stream Variabilities Associated with the East Asian Winter Monsoon

2018 ◽  
Vol 31 (7) ◽  
pp. 2871-2887 ◽  
Author(s):  
Nagio Hirota ◽  
Mai Ohta ◽  
Yousuke Yamashita ◽  
Masaaki Takahashi
Keyword(s):  
Diabatic Heating ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Low Frequency ◽  
Winter Monsoon ◽  
Jet Stream ◽  
Mean Flow ◽  
Asian Winter Monsoon ◽  
Frequency Components ◽  
East Asian Jet Stream

This study evaluates the relative importance of diabatic heating and intraseasonal disturbances with regard to the variabilities of the East Asian jet stream (EAJS) associated with the East Asian winter monsoon (EAWM). First, strong and weak monsoon years are selected based on the EAWM index of Jhun and Lee, which is highly correlated with the monsoon northerlies between the Eurasian continent and the Pacific. The EAJS is stronger and narrower in strong monsoon years and weaker and wider in weak monsoon years. Model experiments were performed to investigate the atmospheric response to the diabatic heating and the eddy–mean flow feedback from the intraseasonal disturbances. The diabatic heating is closely related to the convective activities. The intraseasonal disturbances include high-frequency components with periods of 3–10 days and low-frequency components with periods of 10–90 days. The model results indicate that the diabatic heating plays a major role maintaining the stronger and weaker EAJS in the strong and weak monsoon years, respectively, whereas the impacts of the eddy feedback are relatively small.

Interdecadal change in the relationship between the winter North Pacific storm track and the East Asian winter monsoon

2021 ◽  
pp. 1-57
Author(s):  
Minghao Yang ◽  
Chongyin Li ◽  
Xin Li ◽  
Yanke Tan ◽  
Xiong Chen ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
North Pacific ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Storm Track ◽  
Winter Monsoon ◽  
Interdecadal Change ◽  
Asian Winter Monsoon ◽  
The Relationship ◽  
North Pacific Storm Track

AbstractBased on the daily NCEP reanalysis, the present study investigates the interdecadal change in the relationship between the winter North Pacific storm track (WNPST) and the East Asian winter monsoon (EAWM), and evaluates the WNPST-EAWM relationship in 17 CMIP6 models. The results show that the out-of-phase WNPST-EAWM relationship underwent an interdecadal change in the mid-1980s. The WNPST-EAWM relationship became less significant during P2 (1990-2015). The atmospheric circulation anomaly related to the EAWM during P1 (1955-1980) is more robust than that during P2. The interdecadal weakening WNPST-EAWM relationship may be attributed to the interdecadal damping WNPST-EAWM interaction. The EAWM-related anomalous baroclinic energy conversion and moisture effect, including meridional and vertical eddy moisture fluxes, contribute to the significant attenuation of the WNPST during P1. The transient eddy-induced dynamic forcing and thermal forcing anomalies, as well as the barotropic process represented by the local Eliassen-Palm flux divergence associated with WNPST, can also significantly manipulate the upper-tropospheric jet during P1. However, the atmospheric circulation and interaction between the WNPST and EAWM during P2 are not as significant as those during P1. The effect of ENSO on the WNPST is significantly different before and after the mid-1980s. After the mid-1980s, the WNPST shows the characteristic of moving equatorward during El Niño events. It seems that ENSO takes over the WNPST from the EAWM after the mid-1980s. In addition, except for BCC-ESM1, CanESM5 and SAM0-UNICON, most of the CMIP6 models cannot reproduce the significant out-of-phase WNPST-EAWM relationship.

Interdecadal variability of the relationship between the East Asian winter monsoon and ENSO

2007 ◽  
Vol 98 (3-4) ◽  
pp. 283-293 ◽  
Author(s):  
W. Zhou ◽  
X. Wang ◽  
T. J. Zhou ◽  
C. Li ◽  
J. C. L. Chan
Keyword(s):  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Interdecadal Variability ◽  
Asian Winter Monsoon ◽  
The Relationship

scholarly journals Changes in the relationship between ENSO and the East Asian winter monsoon under global warming

2020 ◽  
Author(s):  
Zixuan Jia ◽  
Massimo A. Bollasina ◽  
Chaofan Li ◽  
Ruth Doherty ◽  
Oliver Wild
Keyword(s):  
Global Warming ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Asian Winter Monsoon ◽  
The Relationship

Interdecadal Weakening of the East Asian Winter Monsoon in the Mid-1980s: The Roles of External Forcings

2018 ◽  
Vol 31 (21) ◽  
pp. 8985-9000 ◽  
Author(s):  
Jiapeng Miao ◽  
Tao Wang ◽  
Huijun Wang ◽  
Yali Zhu ◽  
Jianqi Sun
Keyword(s):  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Monsoon Circulation ◽  
Jet Stream ◽  
Anthropogenic Aerosols ◽  
Coupled Models ◽  
East Asian Trough ◽  
Asian Winter Monsoon ◽  
External Forcings

Observations show that the East Asian winter monsoon (EAWM) experienced an interdecadal weakening in the mid-1980s. This is evident for all members of the EAWM system (i.e., East Asian trough, upper-tropospheric jet stream, and lower-tropospheric monsoon circulation). Here, we investigate the relative contributions of natural (volcanic aerosols and solar variability) and anthropogenic [greenhouse gases (GHGs) and anthropogenic aerosols] forcings to this interdecadal weakening using multiple coupled models within phase 5 of the Coupled Model Intercomparison Project (CMIP5). The results indicate that in the midtroposphere, the increased GHG concentrations play an important role in weakening the East Asian trough (EAT) by increasing the sea surface temperatures (SSTs) over the North Pacific. In the upper troposphere, natural external forcings contribute to the observed weakening of the meridional shear of the East Asian jet stream (EAJS) by regulating the meridional temperature gradient (MTG) over the East Asian region. In the lower troposphere, both anthropogenic and natural forcings can weaken the Siberian high during this period. Overall, based on the present analysis of the CMIP5 output, GHGs and natural forcings play key roles in shaping the observed interdecadal weakening of the EAWM during the mid-1980s. Additionally, contributions from internal variability cannot be neglected and require further investigation.

Reexamining the relationship of La Niña and the East Asian Winter Monsoon

2019 ◽  
Vol 53 (1-2) ◽  
pp. 779-791 ◽  
Author(s):  
Peng Zhang ◽  
Zhiwei Wu ◽  
Jianping Li
Keyword(s):  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
La Niña ◽  
Asian Winter Monsoon ◽  
La Nina ◽  
Relationship Of ◽  
The Relationship

scholarly journals Sedimentary Dynamics of the Central South Yellow Sea Revealing the Relation Between East Asian Summer and Winter Monsoon Over the Past 6000 years

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenzhe Lyu ◽  
Tengfei Fu ◽  
Zhangxi Hu ◽  
Ying Zhong Tang ◽  
Guangquan Chen ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
East Asian Winter Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Asian Winter Monsoon ◽  
Asian Summer ◽  
Sedimentary Dynamics ◽  
The Relationship

The mud areas of East Asian marginal seas record considerable information about regional environmental evolution. However, debate continues regarding the relative importance of the major factors in regional sedimentary dynamics, i.e., the East Asian summer monsoon, East Asian winter monsoon, and oceanic circulation. In this study, we investigated the characteristics of grain size from a gravity core obtained in the South Yellow Sea to reveal changes in sedimentary dynamics since 6,000 years BP, and to elucidate the relationship between the East Asian summer monsoon and the East Asian winter monsoon. We found that the mean grain size was in the range of 6.9–7.8 Φ, the sediment was poorly sorted within a small range (1.2, 1.5), and the M values from 4.7 to 6.7 μm and most of the C values from 24 to 65 μm suggested pelagic suspension transport. Results indicated that the intensity of both the East Asian summer monsoon and the East Asian winter monsoon showed a fluctuating trend of decrease after approximately 6,000 years BP, and that the relationship between them was generally anticorrelated. Based on these results, we suggest that positive correlation between the East Asian summer monsoon and the East Asian winter monsoon usually results in the fall or establishment of ancient dynasties in the Central Plains of China and that negative correlation between them is controlled by strong solar radiation. Weakening of solar radiation diminishes its control of the intensity of (and thus the correlation between) the East Asian summer monsoon and the East Asian winter monsoon, at which time the North Atlantic Oscillation plays a modulating role.

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