Forthcoming Articles http://www.gyqx.ac.cn EN-US http://www.gyqx.ac.cn/EN/current.shtml http://www.gyqx.ac.cn 5 Since the 21st century, due to global warming, the Arctic near-surface temperature increases rapidly, the warming rate can reach more than twice the global average rate, known as the "Arctic amplification" (AA) phenomenon. This paper discusses the causes of the Arctic amplification effect from three aspects: first, in the Arctic climate feedback, the decrease of sea ice leads to the increase of open sea surface, the absorption of solar radiation increases, the sea-air interaction is enhanced, and the sea ice melts further. This is positive feedback. Second, due to the low absolute temperature in the Arctic, according to Planck's radiation law, Planck feedback is negative in the Arctic, but it promotes the Arctic amplification effect. Third, more open sea and higher temperature increase the humidity and the number of clouds in the Arctic. Due to the greenhouse effect of water vapor, the lower wave radiation increases, and it promotes the near-surface layer heating. Water vapor and cloud feedback on the Arctic warming contribution has significant seasonality, mainly occurring in winter. The increase of temperature thickens the atmospheric column. The change of the upper-pressure gradient causes the change of zonal wind, the zonal component decreases and the meridional component increases, forms the ridge, through which the lower latitude region can exchange heat and water vapor with the Arctic. The Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) have also been confirmed related to Arctic warming. The Atlantic Meridional Overturning Circulation (AMOC) anomaly was once thought to be the driver of Arctic warming. Recent studies suggest it is more likely to be the result of Arctic warming. The Arctic amplification influences mid-latitude and even global climates by affecting atmospheric circulation. Warming in the Arctic strengthens the Siberian High, the growth of the duration of the Siberian High and its expansion into East Asia result in enhanced cold advection in the coastal areas of East Asia and adjacent seas in winter, affecting the East Asian Winter Wind System(EAWM) and promoting the flow of cold air to East Asia. It will result in severe winter cold in East Asia, forming a "warm Arctic-cold Eurasian" pattern. In addition, Arctic warming leads to cold events in eastern North America, corresponding to the 250hPa anomalous elevation field, forming low troughs. Winter climate waves can be formed by those low troughs and high ridges over the northeastern Pacific Ocean or Greenland. It is believed that Arctic warming and sea ice loss can affect the mid-latitudes through two mechanisms: first, Arctic warming changes the zonal wind by affecting the pressure field, then increases the blocking event. However, the research shows that the effect of this mechanism on the mid-latitude is not significant. Second, it affects the atmospheric circulation of the northern hemisphere through trophic-stratospheric coupling, but this mechanism is still controversial. However, due to flaws in research methods and uncertainty in the data, the factors affecting the Arctic amplification effect are still controversial. For example, many studies believe that ice and snow albedo feedback is the core factor driving the “Arctic amplification” phenomenon, and other factors indirectly affect the Arctic amplification through sea ice and snow melting. Some studies have shown that even without considering the role of sea ice, the Arctic amplification phenomenon is still significant. Therefore, it is particularly important to improve research methods and the quality and accuracy of data. Finally, the existing problems are put forward.]]> Based on daily gauge station datum, monthly reanalysis datasets from NCEP/NCAR and monthly SST data from Hadley Center in UK (HadISST), The climatic characteristics of freezing days and their causes have been studied on. It is found that there are 69 stations (85.2%) of longest persistent days in the single freezing processes and 63 stations (77.8%) of total winter freezing days occurred in 1976, 1983 and 2007, Weining's 66d (1976) and 39d (2007) being the longest events respectively. The main mode of winter freezing days in Guizhou which the center is in central showed a consistent distribution in the whole region with a variance of 65.04%. When the winter freezing days in Guizhou were abnormally large, the abnormally active Ural Mountain blocking high pressure and the abnormally strong East Asian Trough were conducive to the formation of stable meridional circulation in East Asia. while the low value system in Central Asia guided the cold air in front of the blocking high and the Mongolian cold high southward, formed a shallow abnormal cold pad in the lower troposphere of Guizhou and its north. At the same time, the warm and humid air flow in the middle and lower troposphere from the Bay of Bengal and the South China Sea crawled and uplifted along the edge of the cold air pile near the Yunnan-Guizhou Quasi-Stationary Front under the action of the abnormal circulation circle, and formed an unstable vertical stratification anomaly of warm up and cold down in the middle and lower troposphere over Guizhou, resulting in the formation of winter freezing in Guizhou. In addition, the wave disturbance energy propagation from North Atlantic and low latitude tropical played an important role in the formation and maintenance of the blocking situation in the middle and high latitudes and the anomaly of the low trough system in Eurasia. When the freezing days were abnormal less, the situation is opposite. Finally, there is a closely relationship between the winter freezing days anomaly in Guizhou with the La Niña event in the equatorial Middle East Pacific and the SST anomaly in the North Pacific, Indian Ocean, and South China Sea.

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