scholarly journals Revisiting the Northern Mode of East Asian Winter Monsoon Variation and Its Response to Global Warming

2018 ◽  
Vol 31 (21) ◽  
pp. 9001-9014 ◽  
Author(s):  
Hainan Gong ◽  
Lin Wang ◽  
Wen Zhou ◽  
Wen Chen ◽  
Renguang Wu ◽  
...  
Keyword(s):  
Global Warming ◽  
Radiative Forcing ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Coupled Model ◽  
Surface Air Temperature ◽  
Winter Monsoon ◽  
Cmip5 Models ◽  
Boreal Winter ◽  
Asian Winter Monsoon

This study revisits the northern mode of East Asian winter monsoon (EAWM) variation and investigates its response to global warming based on the ERA dataset and outputs from phase 5 of the Coupled Model Intercomparison Project (CMIP5) models. Results show that the observed variation in East Asian surface air temperature (EAT) is tightly coupled with sea level pressure variation in the expanded Siberian high (SH) region during boreal winter. The first singular value decomposition (SVD) mode of the EAT and SH explains 95% of the squared covariance in observations from 1961 to 2005, which actually represents the northern mode of EAWM variation. Meanwhile, the first SVD mode of the EAT and SH is verified to be equivalent to the first empirical orthogonal function mode (EOF1) of the EAT and SH, respectively. Since the leading mode of the temperature variation is significantly influenced by radiative forcing in a rapidly warming climate, for reliable projection of long-term changes in the northern mode of the EAWM, we further employ the EOF1 mode of the SH to represent the northern mode of EAWM variation. The models can well reproduce this coupling between the EAT and SH in historical simulations. Meanwhile, a robust weakening of the northern mode of the EAWM is found in the RCP4.5 scenario, and with stronger warming in the RCP8.5 scenario, the weakening of the EAWM is more pronounced. It is found that the weakening of the northern mode of the EAWM can contribute 6.7% and 9.4% of the warming trend in northern East Asian temperature under the RCP4.5 and RCP8.5 scenarios, respectively.

scholarly journals Quantifying the contribution of anthropogenic influence to the East Asian winter monsoon in 1960–2012

2019 ◽  
Vol 19 (15) ◽  
pp. 9903-9911
Author(s):  
Xin Hao ◽  
Shengping He ◽  
Huijun Wang ◽  
Tingting Han
Keyword(s):  
Air Temperature ◽  
General Circulation ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Surface Air Temperature ◽  
Circulation Model ◽  
Winter Monsoon ◽  
Anthropogenic Influence ◽  
Anthropogenic Forcing ◽  
Asian Winter Monsoon

Abstract. The East Asian winter monsoon (EAWM) is greatly influenced by many factors that can be classified as anthropogenic forcing and natural forcing. Here we explore the contribution of anthropogenic influence to the change in the EAWM over the past decades. Under all forcings observed during 1960–2013 (All-Hist run), the atmospheric general circulation model is able to reproduce the climatology and variability of the EAWM-related surface air temperature and 500 hPa geopotential height and shows a statistically significant decreasing EAWM intensity with a trend coefficient of ∼-0.04 yr−1, which is close to the observed trend. By contrast, the simulation, which is driven by the same forcing as the All-Hist run but with the anthropogenic contribution to them removed, shows no decreasing trend in the EAWM intensity. By comparing the simulations under two different forcing scenarios, we further reveal that the responses of the EAWM to the anthropogenic forcing include a rise of 0.6∘ in surface air temperature over East Asia as well as weakening of the East Asian trough, which may result from the poleward expansion and intensification of the East Asian jet forced by the change in temperature gradient in the troposphere. Additionally, compared with the simulation without anthropogenic forcing, the frequency of strong (weak) EAWM occurrence is reduced (increased) by 45 % (from 0 to 10/7). These results indicate that the weakening of the EAWM during 1960–2013 may be mainly attributed to the anthropogenic influence.

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

2020 ◽  
Author(s):  
Zixuan Jia ◽  
Massimo Bollasina ◽  
Chaofan Li ◽  
Ruth Doherty ◽  
Oliver Wild
Keyword(s):  
Global Warming ◽  
East Asian Winter Monsoon ◽  
Southern Oscillation ◽  
East Asian ◽  
Winter Monsoon ◽  
Pacific Region ◽  
Anthropogenic Aerosols ◽  
Asian Winter Monsoon ◽  
Asian Pacific Region ◽  
Asian Pacific

<p>The East Asian winter monsoon (EAWM) is a prominent feature of the northern hemisphere atmospheric circulation during boreal winter, which has a large influence on weather and climate of the Asian-Pacific region. At interannual time scales, the strength of the EAWM is strongly influenced by the El Niño-Southern Oscillation (ENSO), while the ENSO-EAWM relationship displays pronounced interdecadal variations associated with changes in the ENSO teleconnection pathways to East Asia. Using future transient simulations from the Max Planck Institute-Grand Ensemble (MPI-GE), changes in the ENSO-EAWM relationship are examined at various global warming levels during the 21<sup>st</sup>-century. Results indicate that this relationship will enhance from present-day to +1.5°C, and then weaken until +3°C, strongly impacted by changes in anthropogenic forcing with internal variability playing a negligible role. The ENSO-EAWM relationship is strongly related to the background mean state of both the EAWM and ENSO under global warming. Both the climatological EAWM strength and the ENSO-related anomalies across the Asian-Pacific region contribute to changes in the ENSO-EAWM relationship. Furthermore, anthropogenic aerosols are also found to play a major role in influencing the ENSO-EAWM relationship under moderate warming (up to 1.5°C).</p>

Different Impacts of the East Asian Winter Monsoon on the Surface Air Temperature in North America during ENSO and Neutral ENSO Years

2020 ◽  
Vol 33 (24) ◽  
pp. 10671-10690
Author(s):  
Tianjiao Ma ◽  
Wen Chen ◽  
Hans-F. Graf ◽  
Shuoyi Ding ◽  
Peiqiang Xu ◽  
...  
Keyword(s):  
Wave Packet ◽  
North Pacific ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Surface Air Temperature ◽  
Winter Monsoon ◽  
Asian Winter Monsoon ◽  
The North ◽  
The North Pacific ◽  
Central North Pacific

AbstractThe present study investigates different impacts of the East Asian winter monsoon (EAWM) on surface air temperature (Ts) in North America (NA) during ENSO and neutral ENSO episodes. In neutral ENSO years, the EAWM shows a direct impact on the Ts anomalies in NA on an interannual time scale. Two Rossby wave packets appear over the Eurasian–western Pacific (upstream) and North Pacific–NA (downstream) regions associated with a strong EAWM. Further analysis suggests that the downstream wave packet is caused by reflection of the upstream wave packet over the subtropical western Pacific and amplified over the North Pacific. Also, the East Asian subtropical westerly jet stream (EAJS) is intensified in the central and downstream region over the central North Pacific. Hence, increased barotropic kinetic energy conversion and the interaction between transient eddies and the EAJS tend to maintain the circulation anomaly over the North Pacific. Therefore, a strong EAWM tends to result in warm Ts anomalies in northwestern NA via the downstream wave packet emanating from the central North Pacific toward NA. A weak EAWM tends to induce cold Ts anomalies in western-central NA with a smaller magnitude. However, in ENSO years, an anomalous EAJS is mainly confined over East Asia and does not extend into the central North Pacific. The results confirm that the EAWM has an indirect impact on the Ts anomalies in NA via a modulation of the tropical convection anomalies associated with ENSO. Our results indicate that, for seasonal prediction of Ts anomalies in NA, the influence of the EAWM should be taken into account. It produces different responses in neutral ENSO and in ENSO years.

scholarly journals Biases and Improvements of the ENSO- East Asian Winter Monsoon Teleconnection in CMIP5 and CMIP6 Models

2021 ◽  
Author(s):  
Wenping Jiang ◽  
Hainan Gong ◽  
Ping Huang ◽  
Lin Wang ◽  
Gang Huang ◽  
...  
Keyword(s):  
East Asian Winter Monsoon ◽  
Southern Oscillation ◽  
East Asian ◽  
Winter Monsoon ◽  
Western Pacific ◽  
Cmip5 Models ◽  
Northwest Pacific ◽  
Cold Tongue ◽  
Asian Winter Monsoon ◽  
Mean State

Abstract The influence of El Niño–Southern Oscillation (ENSO) on the East Asian winter monsoon (EAWM) is investigated based on the outputs of phase 6 of the Coupled Model Intercomparison Project (CMIP6) models and compared to that in phase 5 (CMIP5). Results show that the CMIP6 models generally reproduce the ENSO-EAWM teleconnection more realistically than the CMIP5 models, although they still somewhat underestimate the ENSO-EAWM teleconnection than observed. Based on the inter-model spread of ENSO-EAWM teleconnection simulated in the CMIP5/CMIP6 models, we reveal that the commonly underestimated ENSO-EAWM teleconnection among the models can be traced back to the excessive cold tongue bias in the equatorial western Pacific. A model with a stronger climatological cold tongue favors generating a more westward extension of the ENSO-related SST anomaly pattern, which in turn forces an anomalous cyclonic circulation over the Northwest Pacific (NWP). It offsets the anticyclonic anomalies in the NWP triggered by the warm ENSO-related SST anomalies in the tropical Indian Ocean and the central-eastern Pacific and weakens the ENSO-EAWM teleconnection. Compared with the CMIP5 models, CMIP6 models better simulate SST mean state and the resultant ENSO-EAWM teleconnection. The present results suggest that substantial efforts should be made to reduce the bias in the mean-state SST for further improving the simulation and projection of the East Asian-western Pacific winter climate.

Sign in / Sign up

Export Citation Format

Share Document