| The mass balance and ice volume change of Antarctic ice sheet are of great significance for global change research. In polar area, minor changes in atmospheric temperature will raise the snow humidity of large areas, and the water will infiltrate into the bottom of ice to accelerate the disintegration and movement of ice sheet. Therefore, to detect the surface melting and melt distribution of the Antarctic ice sheet is essential for the study of global climate change.Antarctic’s special geographical location and climatic conditions make inability of the general sensors. But microwave remote sensing which has much advantage, such as all-weather and all-day remote sensing capability, can obtain more information on polar surface. Microwave remote sensing data are very sensitive on the melting information, and passive microwave data have already accumulated more than 30 years, providing the best data for the long time series of Antarctic melting monitoring. Study using 1978-2008years’data of passive microwave remote sensing (SSM / I and SMMR data), by researching and application of the Antarctic ice sheet surface melting continuity detection technology, and analysis of a long sequence melting image, got the real-time melting trend, to advanced the global change research.Study uses the microwave radiation characteristics of snow and ice, explored the passive microwave remote sensing principle of melting snow in-depth. And under the brightness temperature several of different frequency and polarization microwave bands, selected the most suitable band and polarization combinations for melt detection. By a simple comparison of several major international melting detection models, choose the cross-polarization ratio model (XPGR) for this study. The study combined with brightness temperature data in the Antarctic, corrected the melting threshold, and finally got the Antarctic melting images of 1978-2008. Antarctic automatic weather station data and the Antarctic average temperature on the edge of the site records are used to the simple ground verification.After the analysis of a long time sires of brightness temperature changes and the melting area of situation, study found that the edge of the Antarctic continent, the Antarctic Peninsula and the ice shelves are in a increased melting of state, especially in Amery ice shelf and Ross ice shelf. Most significantly, the brightness temperature curve has more pronounced upward trend in these area. Interior area’s brightness temperature did not change significantly, showing a good stability.To the melting situation curves, most melting region was at the edge. And there is a strong seasonal changes, in general, melt onset date began at the end of November, and melt end date occurred in March of next year. The melt range reached a peak in January. The average daily melting area in was about 1.8×105km2, but in January 2003, it has already reached 3.6×105km2, before and after comparison, the melt range was as much as doubled, showing that melting speed is very fast. And in 1978-1979, other month’s melting range except summer is close to 0. But after 1994, some areas have one all year round melt state, which indicated disintegration has occurred. Changes of melting range have demonstrated the increased melting in Antarctica, and it is a good response factor of the climate warming trend. |
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