The Impact Of Sea Ice Changes In The Arctic On Winter Temperatures In China

Under the global warming background, the Arctic climate system occurred more significant than in other parts of the country, as the cold source of the global climate, changes in the Arctic climate and environment directly or indirectly affects global scale atmospheric circulation, ocean circulation and climate variability. Sea ice is the Arctic climate change indicator and criterion, the changes in the size and distribution of is one of an important manifestation of climate change in the Arctic, will also impact the global climate change through a variety of physical mechanism. China is located in the northern hemisphere high latitude region, all the year round by from the impact of cold polar air.Study the relationship between Arctic sea ice and winter temperatures in China,not only able to explore the impact mechanism of the winter temperature in China, but also has some guiding significance for the prediction of winter air temperature in China.In this paper, the reorganization of the National Climate Center, China Meteorological Administration,160 stations nationwide form January 1951 to February 2015 monthly temperature data,analysis of almost 64 years winter air temperature in China in the interannual and decadal on the occasion of the spatial and temporal characteristics of; Arctic sea ice set provided by the British atmospheric data center(BADC) HadISST Sic data intensive degree 1 x 1 degree grid point data(time is from March 1979 to February 2014), analysis of the spatial and temporal variations of the Arctic sea ice; Using the NCEP / NCAR reanalysis data provide spatial resolution is 2.5 x 2.5 degrees of sea-level pressure data, 850 hPa and 500 hPa of geopotential height field data, u,v data and SST data(time is from 1979 to 2014), to approach the mechanism of effects of Arctic sea ice variations of winter temperature in China.The main conclusions of this paper are as follows:(1) The combination of seasonal sea ice concentration distribution can also be found, Arctic sea ice area and extent has obvious seasonal variation. The change of sea ice in the Arctic is the largest in autumn(especially in September), and the change in spring(especially in March) is the smallest. According to the main modal analysis of sea ice in different seasons, changes in the sea ice in the Arctic has obvious geographical distribution, the main changes area lies in the Greenland Sea, the sea of Okhotsk, the Bering Sea, the Barents Sea, the Labrador Sea and Davis sea area.(2) The analysis of winter temperature change of 1951-2014 years showed that the winter temperature in China has significant interannual and decadal variation features.Before the middle period of the eighties of the 20 th century,China winter is cold period, in the late 1980 s after a warm period. Winter temperatures of the first of EOF mode of the distribution patterns suggest that winter temperatures in China with good consistency, that is consistent with the global warming or cooling; the second of EOF mode shows that the North-South reverse variation characteristics of winter temperature in China, namely when the heating in northern China, southern China is cooling stage. Variation of air temperature in winter districts as REOF, the first space mode State of focus is the abnormal condition of the temperature in the middle and lower reaches of the Yangtze River and Southern China.The second mode reflects the temperature anomalies of the main areas in the southwest part of the region.(3) It can be seen the relations between the changes in the Arctic sea ice and winter temperatures China, By Synthesis of China's winter temperature anomalies when the sea ice more or less: from the whole, there is positive correlation between the Arctic sea ice changes with the winter air temperature in China, that when the Arctic sea ice ones, most of China's winter high temperatures, and significant area is located in the Northeast, but with winter temperatures of the southwest was negative correlation, the Southwest partial winter temperatures low.(4) Changes in Arctic sea ice caused by abnormal atmospheric circulation thereby affecting the Chinese winter temperatures by the influence of atmospheric circulation factors such as sea level pressure, height and wind fields. When autumn and winter sea ice ones, cold high pressure Eurasia region weakened low pressure on the ocean is correspondingly weak, the pressure difference between land and sea is reduced, especially the formation of a significant negative EUP in 500 hpa potential height field teleconnections, this time the East Asian winter monsoon is weakening phase, and Eurasia high latitudes prevailing westerly winds, high temperatures at this time of winter Chinese; on the contrary, when the autumn and winter sea ice less than normal, China's low winter temperatures.(5) East Asian winter monsoon strength of the affected land-sea thermal contrast zonal, which is mainly influenced by the Siberian high and the Aleutian low. When over Eurasia Siberian high intensity strengthening, the North Pacific Aleutian also is low in strengthening phase, the pressure difference between the land and sea along strengthen, resulting in enhanced East Asian winter monsoon also stage. Autumn and winter sea ice concentration degrees too much led to Arctic temperatures appear negative anomaly, which strengthened the atmospheric thermal gradient between Arctic and the Eurasian region in High-Latitude, also enhance the Eurasian wind circulation. Fall's ice concentration degree of sustained high and winter negative SST anomaly resulting in the winter Siberia high Weaken and strengthen the Eurasian continent in middle and high latitude westerly, Strengthening of westerly winds hinder cold air from the high latitudes to the south broke out, resulting in China's winter air temperature on the high side; Autumn sea ice concentration is low, the situation is the opposite.