Effects of Strong East Asian Cold Surges on Improving the Air Quality over Mainland China
نویسندگان
چکیده
A strong East Asian cold surge (SEACS) is one of the most distinct extreme weather events that can promote an improvement in local air quality. Combining East Asian atmospheric circulation with the air pollution index (API) datasets of 47 major cities throughout mainland China in 11 winter half-years (November–March) during 2001/2002–2011/2012, we investigated the influence of 39 SEACSs in conjunction with air pollution episodes on air quality over mainland China. The results showed that SEACS can cause considerable improvement in air quality and a remarkable decrease in the API over mainland China in up to 4 days after the SEACS outbreak day. The removal efficiency of air pollutants by SEACSs was greater than 30% in north central China, eastern southwest China, and southeast China. The occurrence date of the lowest value of the local API (indicating the best local air quality) can be observed as late day by day from northwest to southeast over mainland China after the SEACS outbreak, indicating a process of gradual improvement in Chinese air quality after the SEACS outbreak. When clean cold air originating from Siberia moves southward into coastal areas of southeastern China, the increase in sea level pressure, the drop in temperature and the enhancement in the northerly wind also tend to progress gradually from north to south over SEACS-affected East Asia. Thus, the “early in the north and late in the south” feature of air quality improvement by SEACSs over mainland China results from the southward movement of cold air masses from high to low latitudes after cold surge outbreaks.
منابع مشابه
Dynamical influence of the Tibetan Plateau on the winter monsoon over southeastern Asia
[1] Previous studies have shown (1) that the Tibetan Plateau produces a significant fraction of the two components of the Equatorial Mountain Torque (EMT) in winter, (2) that these torques are in part related to the East Asian cold surges, and (3) that the cold surges affect the convection over the maritime continent. We show here that these relations are strong enough for the convection over t...
متن کاملA Study on the Establishment of ECFA between Mainland of China and Taiwan
As the chances of a successful conclusion to the Doha Round of trade liberalization under the WTO become increasingly problematic, so the pace of negotiating local free trade agreements (FTAs) is increasing. According to the WTO report, countries in the Asia-Pacific region are âconsolidating their drive towards regionalism at an accelerated paceâ. After the trade agreements between China an...
متن کاملA Revisit of the Tropical-midlatitude Interaction in East Asia Caused by Cold Surges
A short-wave train emanating from the Southeast Asian tropics which links interannual variations of the winter climate systems in both East Asia and North America was identified recently. This shortwave train may affect the activity of cold-surge disturbances over the eastern seaboard of East Asia, and the northwestern Pacific. The interaction between cold surges and the planetary-scale winter ...
متن کاملDownstream modulation of North Pacific atmospheric river activity by East Asian cold surges
[1] An East Asian cold surge (EACS) is characterized by rapid advancement of a polar airmass toward the east coast of the Eurasian continent in boreal winter. Over the east coast of Asia, extratropical cyclogenesis and the amplitudes of atmospheric disturbances ranging from synoptic to subseasonal timescales are immediately enhanced as the cold air approaches. This study investigates for the fi...
متن کاملEast Asian winter monsoon: results from eight AMIP models
This study evaluates simulations of the East Asian winter monsoon in eight GCMs that participated in the Atmospheric Model Intercomparison Project (AMIP). In addition to validating the mean state of the winter monsoon, the cold surge and its transient properties, which includes the frequency, intensity, preferred propagation tracks, and the evolution patterns of the surges, are examined. GCM si...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2016