Simulated and projected relationship between the East Asian winter monsoon and winter Arctic Oscillation in CMIP5 models

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.

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Pacific multi-decadal oscillation modulates the effect of Arctic oscillation and El Niño southern oscillation on the East Asian winter monsoon

International Journal of Climatology ◽

10.1002/joc.5461 ◽

2018 ◽

Vol 38 (6) ◽

pp. 2808-2818 ◽

Cited By ~ 5

Author(s):

Dong Chen ◽

Huijun Wang ◽

Jianqi Sun ◽

Ya Gao

Keyword(s):

El Niño ◽

Arctic Oscillation ◽

East Asian Winter Monsoon ◽

El Nino ◽

Southern Oscillation ◽

East Asian ◽

Winter Monsoon ◽

El Niño Southern Oscillation ◽

El Nino Southern Oscillation ◽

Asian Winter Monsoon

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

Journal of Climate ◽

10.1175/jcli-d-18-0136.1 ◽

2018 ◽

Vol 31 (21) ◽

pp. 9001-9014 ◽

Cited By ~ 5

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.

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On the Strengthened Relationship between the East Asian Winter Monsoon and Arctic Oscillation: A Comparison of 1950–70 and 1983–2012

Journal of Climate ◽

10.1175/jcli-d-13-00335.1 ◽

2014 ◽

Vol 27 (13) ◽

pp. 5075-5091 ◽

Cited By ~ 41

Author(s):

Fei Li ◽

Huijun Wang ◽

Yongqi Gao

Keyword(s):

Arctic Oscillation ◽

East Asian Winter Monsoon ◽

East Asian ◽

Winter Monsoon ◽

Arctic Sea Ice ◽

Northern Eurasia ◽

Tropical Region ◽

Horizontal Structure ◽

Near Surface ◽

Asian Winter Monsoon

In this paper, the authors use NCEP reanalysis and 40-yr ECMWF Re-Analysis (ERA-40) data to document the strengthened relationship between the East Asian winter monsoon (EAWM) and winter Arctic Oscillation (AO) on the interannual time scale with a comparison of 1950–70 and 1983–2012. Their connection was statistically insignificant during 1950–70, whereas it was statistically significant during 1983–2012. The latter significant connection might be attributed to the East Asian jet stream (EAJS) upstream extension: the EAJS signal is relatively confined to the western North Pacific before the 1970s, whereas it extends westward toward East Asia after the 1980s. This upstream extension leads to the rearrangement of eastward-propagating Rossby waves with a much wider horizontal structure, thereby bonding the EAWM and the AO. Furthermore, the authors present observational evidence and model simulations demonstrating that the reduction of autumn Arctic sea ice cover (ASIC) is responsible for the strengthened EAWM–AO relationship after the 1980s by producing the EAJS upstream extension. After the 1980s, a strong anticyclonic anomaly over the polar ocean and anomalous easterly advection over northern Eurasia are generated by the near-surface heating over the Barents–Kara (B–K) Seas caused by the reduction of ASIC. This further induces cold anomalies over northern Eurasia, altering the meridional temperature gradient between the midlatitude and tropical region and consequently leading to westward penetration of the EAJS.

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The Climatology and Interannual Variability of the East Asian Winter Monsoon in CMIP5 Models

Journal of Climate ◽

10.1175/jcli-d-13-00039.1 ◽

2014 ◽

Vol 27 (4) ◽

pp. 1659-1678 ◽

Cited By ~ 63

Author(s):

Hainan Gong ◽

Lin Wang ◽

Wen Chen ◽

Renguang Wu ◽

Ke Wei ◽

...

Keyword(s):

East Asia ◽

Interannual Variability ◽

Large Scale ◽

East Asian Winter Monsoon ◽

East Asian ◽

Winter Monsoon ◽

Cmip5 Models ◽

Northwestern Pacific ◽

Cold Bias ◽

Asian Winter Monsoon

Abstract In this paper the model outputs from the Coupled Model Intercomparison Project (CMIP) phase 5 (CMIP5) are used to examine the climatology and interannual variability of the East Asian winter monsoon (EAWM). The multimodel ensemble (MME) is able to reproduce reasonably well the circulation features of the EAWM. The simulated surface air temperature still suffers from a cold bias over East Asia, but this bias is reduced compared with CMIP phase 3 models. The intermodel spread is relatively small for the large-scale circulations, but is large for the lower-tropospheric meridional wind and precipitation along the East Asian coast. The interannual variability of the EAWM-related circulations can be captured by most of the models. A general bias is that the simulated variability is slightly weaker than in the observations. Based on a selected dynamic EAWM index, the patterns of the EAWM-related anomalies are well reproduced in MME although the simulated anomalies are slightly weaker than the observations. One general bias is that the northeasterly anomalies over East Asia cannot be captured to the south of 30°N. This bias may arise both from the inadequacies of the EAWM index and from the ability of models to capture the EAWM-related tropical–extratropical interactions. The ENSO–EAWM relationship is then evaluated and about half of the models can successfully capture the observed ENSO–EAWM relationship, including the significant negative correlation between Niño-3.4 and EAWM indices and the anomalous anticyclone (or cyclone) over the northwestern Pacific. The success of these models is attributed to the reasonable simulation of both ENSO’s spatial structure and its strength of interannual variability.

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