Impact of Ural blocking on sub-seasonal Siberian cold anomalies modulated by the winter East Asian trough

2021 ◽  
Author(s):  
Yuanyuan Song ◽  
Dehai Luo ◽  
Fei Zheng ◽  
Yao Yao
Keyword(s):  
East Asian ◽  
East Asian Trough

Rapid response of the East Asian trough to Tibetan Plateau snow cover

2020 ◽  
Vol 41 (1) ◽  
pp. 251-261 ◽  
Author(s):  
Wenkai Li ◽  
Bo Qiu ◽  
Weidong Guo ◽  
Pang‐chi Hsu
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
East Asian ◽  
Rapid Response ◽  
East Asian Trough ◽  
Tibetan Plateau Snow Cover

scholarly journals Further inquiry into the interaction between the winter North Pacific storm track and the East Asian trough

2020 ◽  
Vol 55 (3-4) ◽  
pp. 471-483
Author(s):  
Minghao Yang ◽  
Chongyin Li ◽  
Yanke Tan ◽  
Xin Li ◽  
Xiong Chen ◽  
...  
Keyword(s):  
North Pacific ◽  
East Asian ◽  
Storm Track ◽  
East Asian Trough ◽  
North Pacific Storm Track

scholarly journals Intraseasonal Variation of the Strength of the East Asian Trough and Its Climatic Impacts in Boreal Winter

2016 ◽  
Vol 29 (7) ◽  
pp. 2557-2577 ◽  
Author(s):  
Lei Song ◽  
Lin Wang ◽  
Wen Chen ◽  
Yang Zhang
Keyword(s):  
East Asia ◽  
East Asian ◽  
Quantitative Description ◽  
Storm Track ◽  
Northern Eurasia ◽  
Boreal Winter ◽  
Near Surface ◽  
East Asian Trough ◽  
Climatic Impacts

Abstract The East Asian trough (EAT) is a distinct component of the boreal winter circulation whose strength corresponds to the amplitude of the Northern Hemispheric stationary waves. In this study, the mechanism and climatic impacts of the intraseasonal variations of the EAT’s strength are investigated through composite analysis and dynamical diagnostics. The significant roles played by the low-frequency Rossby wave (RW) and synoptic transient eddy (TE) are revealed. Before the peaks of strong EAT events, an upper-tropospheric RW train propagates across northern Eurasia and interacts with preexisting surface cold anomalies over central Siberia. This pattern intensifies the Siberian high and causes RW convergence toward the EAT, leading to 30% of the EAT’s amplification directly via the RW-induced feedback forcing. Meanwhile, RW weakens the background baroclinicity and reduces TE activities near the entrance region of the North Pacific storm track. The TE-induced feedback forcing leads to another 30% of the EAT’s amplification. The evolution and dynamical processes of the weak EAT events generally resemble those of the strong events with opposite signs. These results are consistent with the knowledge on the mechanism of the strong and weak EAT events regarding the role of RWs with additional quantitative description and provide new insights regarding the role of TEs. Variations of the EAT’s strength exert significant climatic impacts on East Asia and its downstream region. Near-surface air temperature is below (above) normal over East Asia during the growth and peak stages of the strong (weak) EAT events and above (below) normal over North America afterward.

scholarly journals Activity Characteristics of the East Asian Trough in CMIP5 Models

Atmosphere ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. 67 ◽  
Author(s):  
Xiong Chen ◽  
Xing Liu ◽  
Xin Li ◽  
Mingyang Liu ◽  
Minghao Yang
Keyword(s):  
East Asian ◽  
Cmip5 Models ◽  
East Asian Trough

Meridional displacement of the East Asian trough and its response to the ENSO forcing

2016 ◽  
Vol 48 (1-2) ◽  
pp. 335-352 ◽  
Author(s):  
Marco Y.-T. Leung ◽  
Hoffman H. N. Cheung ◽  
Wen Zhou
Keyword(s):  
East Asian ◽  
East Asian Trough ◽  
Meridional Displacement

The impact of large-scale circulation on daily fine particulate matter (PM2.5) in major populated regions of China during winter 

2021 ◽  
Author(s):  
Zixuan Jia ◽  
Ruth Doherty ◽  
Carlos Ordóñez ◽  
Chaofan Li ◽  
Oliver Wild
Keyword(s):  
Particulate Matter ◽  
Relative Humidity ◽  
Large Scale ◽  
Southern China ◽  
East Asian ◽  
River Delta ◽  
Large Scale Circulation ◽  
East Asian Trough ◽  
Siberian High ◽  
Pollution Episodes

<p>With rapid economic growth and urbanization, air pollution episodes with high levels of particulate matter (PM<sub>2.5</sub>) have become common in China. While emissions of pollutant precursors are important, meteorology also plays a major role in pollution episodes, especially in winter. We examine the influence of the dominant large-scale circulation and the key regional meteorological features on PM<sub>2.5</sub> over three major regions of China: Beijing–Tianjin–Hebei (BTH), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD). The East Asian winter monsoon (EAWM) is primarily studied, including some of its main large-scale components such as the East Asian trough and the Siberian high, as it influences PM<sub>2.5 </sub>differently in different parts of China. In the BTH region, the shallow East Asian trough curbs the invasion of northerly cold and dry air from the Siberian high which induces high relative humidity and heavy pollution, possibly via relative humidity-promoted aerosol formation and growth. A weak southerly wind in Eastern and Southern China associated with a weakened Siberian high suppresses horizontal dispersion, contributing to pollution accumulation over YRD. In addition, the El Niño-Southern Oscillation (ENSO) as the dominant mode of global ocean-atmosphere interaction has a substantial modulation on precipitation over southern China. In the PRD, weak southerly winds and precipitation deficits over southern China are conducive to atmospheric pollution possibly via reduced wet deposition. Furthermore, we construct new circulation-based indices based on the dominant large-scale circulation: a 500 hPa geopotential height-based index for BTH, a sea level pressure-based index for YRD and an 850 hPa meridional wind-based index for PRD. These three indices can effectively distinguish different levels of pollution over BTH, YRD and PRD, respectively. We also show how additional regional meteorological variables can improve the prediction of regional PM<sub>2.5</sub> concentrations for these three regions. These results are beneficial to understanding and forecasting the occurrence of severely polluted days for BTH, YRD and PRD from a large-scale perspective.</p>

scholarly journals Processes for Occurrence of Strong Cold Events over Eastern China

2017 ◽  
Vol 30 (22) ◽  
pp. 9247-9266 ◽  
Author(s):  
Lei Song ◽  
Renguang Wu
Keyword(s):  
North Atlantic ◽  
High Latitude ◽  
Wave Train ◽  
East Asian ◽  
Eastern China ◽  
Cold Air ◽  
East Asian Trough ◽  
Siberian High ◽  
Cold Events ◽  
Upper Level

A strong cold event hit eastern China around 24 January 2016 with surface air temperature reaching more than 10°C below the climatological mean in most regions of eastern China south of 40°N. A total of 37 strong cold events similar to the January 2016 event with temperature anomalies over eastern China exceeding −5°C have been identified during the winters from 1979/80 to 2015/16. A comparative analysis of events with surface temperature anomalies of the same intensity but limited to north of 40°N indicates that the southward invasion of cold air to eastern China south of 40°N is related to two factors. One is the latitudinal location of the upper-level wave train, the surface Siberian high, and the midtropospheric East Asian trough over the mid- to high-latitude Eurasian continent. The other is a subtropical upper-level wave train emanating from the midlatitude North Atlantic. The emergence of the subtropical wave train is related to the positive phase of the North Atlantic Oscillation (NAO). When the mid- to high-latitude wave train is located too far northward and the subtropical wave train induces an anomalous midtropospheric high over southern China, the East Asian trough does not extend southwestward and the Siberian high does not expand southeastward. In such a case, the cold air mainly affects northeastern China and northern Japan.

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