Spring-summer Sea Ice Variations Of Antarctica And Its Relationship With Climate Factors

Sea ice is an important factor in the polar climate system. Sea ice is an interface between the ocean surface and the atmosphere, and it greatly inhibits solar radiation, kinetic energy and vapour exchange between the ocean and the atmosphere and changes the radiation budget and energy balance on the ocean surface. The South Pole and the North Pole are great cold sources located at both ends of the earth, with 99% of the earth’s glaciers and sea ice reserves and have profound impact on global climate change. In the past 30a, satellite data indicated that the Arctic sea ice cover showed a shrinking trend. So, people pay more attention on the Antarctic sea ice change. Antarctic sea ice is found in the transition zone between the Antarctic continent and sub-Antarctica, has an important influence on the ocean, atmosphere and climate environment of Antarctica. With the development of satellite remote sensing technology, especially the development of passive microwave remote sensing, it is possible to study the large scale and long time series of Antarctic sea ice.In this thesis, we select the SMMR, SSMI and SSMIS monthly mean sea ice concentration products from the NSIDC(National Snow and Ice Data Center) and MERRA albedo products from NASA(National Aeronautics and Space Administration) between 1982 and 2015 to study the Antarctic spring-summer sea ice variations. We also use the sea surface temperature data obtained from Earth System Research Laboratory of NOAA(the Ocean, Atmosphere and Geoscience Laboratory of National Ocean & Atmosphere Administration) and ERA-Interim surface net solar radiation data from ECMWF(European Centre for Medium-Range Weather Forecas) to study the relationship between sea ice variations and climatic factors.The results indicated that the three elements of the Antarctic spring-summer sea ice concentration, extent and albedo all showed fluctuated increasing trend, but the increase speed was different. Where the sea ice concentration increased at a rate of 0.549%/10yr (confidence level 84.37%); sea ice extent increased at a rate of 0.027X 106 km2/yr, the confidence level reached 99.97%; sea ice albedo increased at a rate of 1.106%/10yr (confidence level 99.91%). This indicated that the Antarctic sea ice indeed showed an increasing trend.For the single month of Antarctic spring-summer, sea ice concentration, extent and albedo all showed increasing trend. The sea ice concentration had the largest increase in February with a rate of 1.058%/10yr, and had the most gentle increase in January with a rate of 0.097%/lOyr. The sea ice extent decreased from November to the following February. The sea ice extent had the largest increase in January with a rate of 0.041 ×106km2/yr, and had the most gentle increase in February with a rate of 0.019×106km2/yr. Sea ice albedo had the largest increase in December with a rate of 1.557%/10yr, and had the most gentle increase in January with a rate of 0.621%/10yr.For the spatial distribution, we analyze the variations of Antarctic spring-summer sea ice from 1982 to 2015 and find that the spatial distribution of sea ice concentration and albedo has a high degree of consistency. Sea ice distributed around the Antarctic continent. The higher values were mainly found on the continental coast, Amundsen Sea and the Weddell Sea; in contrast, the lower values were found on the outer edge of the sea ice, the Ross Sea, part of Amundsen Sea and the Amery Ice Shelf. The higher sea ice concentration follow the higher sea ice albedo, the lower sea ice concentration follow the lower sea ice albedo.The change trend of climatic element was contrast with trend of sea ice change. Sea surface temperature and surface net solar radiations showed fluctuated decreasing trend. The sea surface temperature decreased at a rate of -0.032℃/10yr (confidence level 97.68%). The surface net solar radiations showed a lower decreased trend with a rate of -0.268 w/m2 /10yr, the confidence level is only 31.84%. The sea surface temperature was significantly negatively correlated with sea ice concentration, sea ice extent and sea ice albedo, both at a 99% significance level. The correlation coefficient between sea surface temperature and sea ice concentration was -0.581, the correlation coefficient was -0.502 with sea ice extent, and was -0.925 with sea ice albedo. The surface net solar radiations was also significantly negatively correlated with sea ice concentration, sea ice extent and sea ice albedo. The negative correlation coefficient between surface net solar radiation and sea ice concentration was highest and reached-0.560 at a 99% significance level. The correlation coefficient was -0.498 (significance level 99%) with sea ice albedo and next to sea ice concentration. The correlation coefficient with sea ice extent was lowest and only reached -0.318 (significance level 90%).The spatial distribution of sea surface temperature and surface net solar radiations also has a high degree of consistency. Spatial distribution is influenced by latitude. With the increase of latitude, sea surface temperature and the surface net solar radiations showed a decreasing distribution. The lower values were found in the Ross Sea, Weddell Sea, Amundsen Sea and Bellingshausen Sea. The higher values distribute with the decrease of latitude and were mainly found on the outer edge of the sea ice of the low latitude region.Spatially, the higher sea ice concentrations follow the higher sea ice albedos, lower sea surface temperature and surface net solar radiations patterns. The lower sea ice concentrations follow the lower sea ice albedos, higher sea surface temperature and surface net solar radiations patterns...