Spatio-Temporal Variability Analysing And Information System Building Of Polar Sea Ice

The polar sea ice as a huge cold source, with a high albedo, is a key factor affecting the global atmospheric circulation and climate change. There are obvious differences between Arctic and Antarctic sea ice for annual and seasonal variation due to their different geographical environment. Therefore, it is significant to investigate the spatio-temporal variability of polar sea ice and its correlation with environmental elements, which is good for Chinese polar expedition and global climate change prediction.The daily sea ice data from 1979 to 2015 investigated in this paper were about the Antarctic and Arctic area. The average value calculation, the concentration gradation color matching, the sea ice extent extraction and so on were processed by employing the IDL programming, then the sea ice concentration and sea ice extent parameter were obtained. According to the obtained sea ice concentration data, the characteristic of spatio-temporal variability of polar sea ice concentration was analyzed quantificationally. The annual and seasonal variability of sea ice extent were analyzed by using linear regression analysis method. Moreover, according to the data about daily sea surface temperature and air temperature from 1989 to 2015, the correlation relationship and hysteresis among Arctic sea ice extent, sea surface temperature and air temperature were studied by using linear and nonlinear correlation analysis method. The sea surface temperature and air temperature data obtained from the ship-based observations were used to analyze the factors affecting sea surface temperature and air temperature for sea ice edge line by employing mapping analysis method, taking the Chukchi More as an example. Finally, based on the sea ice concentration and sea ice extent data, the polar sea ice monitor system was built by using WebGIS technology. The main results and conclusions are as follows:(1) Arctic sea ice extent decreases with an amplitude about 52500 km2 annually from 1979 to 2015. Moreover, the fastest decline occur in summer, while the slowest decrease appear in winter. The sea ice extent annual minimum is decline faster than the maximum. Most of Arctic sea ice concentration is in 91-100% interval, which decline the fastest. In addition, Arctic sea ice extent shows a relatively stable seasonal variation, which has the same thawing and freezing period. During the summer, sea ice possesses some characteristics, such as fast thawing and sudden freezing. The Arctic sea ice thaws quickly in August, and freeze fast in October. The Arctic sea ice mainly freezes and thaws in the various marginal seas, including Bering sea, Okhotsk, Beaufort Sea, Chukchi Sea, East Siberian Sea, Laptev Sea, Kara Sea, Barents Sea, Hudson B. and Baffin Bay.(2) Antarctic sea ice extent increases slowly with about 22800 km2 annually increment from 1979 to 2015. Moreover, the fastest increase occur in May, while the slowest increase appear in November. Antarctic sea ice change most significant in high concentration interval. Most of Antarctic sea ice concentration is in 81-90% interval. In addition, Antarctic sea ice extent shows a relatively stable seasonal variation, which has 5 months thawing period and 7 months freezing period. Antarctic sea ice possesses some characteristics, such as fast thawing and slowest freezing.(3) From 1989 to 2015, a remarkable correlation relationship among Arctic annual average sea ice extent, sea surface temperature and air temperature was observed. The correlation coefficients R between sea ice extent and sea surface temperature, sea surface temperature and air temperature, sea ice extent and air temperature are 0.9010,0.8622 and 0.9511, respectively. However, the seasonal changes of Arctic sea ice extent lags behind that of sea surface temperature and air temperature with 17 days and 47-48 days, respectively. Uniformly, the seasonal changes of Antarctic sea ice extent lags behind that of sea surface temperature with 12 days.(4) The polar sea ice monitor system was constructed for the first time. The system can improve the efficiency of sea ice analysis and sea ice report, analyze the daily variation trend of sea ice and provide the sea ice service for China’s polar expedition ship when sailing in the polar ice.