MODIS多波段数据对南极海冰变化的监测研究
Monitoring of Antarctic Sea Ice Based on the Multichannel MODIS Data
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摘要: 以归一化雪被指数法为基础根据南极的环境特点提出了MODIS影像的0．86m与1．24m的新波段组合方法分别实现了晴空与薄云下的海冰提取大幅度地提高了南极海冰监测的效率与分辨率 结合AMSR－E微波数据进行了海冰变化研究得到2002 2010年的全南极海冰范围与净冰面积都在2月份达到最小值均值分别为3．17×106 km2与2．42×106 km2 都在9月份达到最大值均值分别为18．40×106 km2与16．60×106 km2 而全南极海冰的年际变化可分为三个阶段从2002 2004年海冰基本持平2005 2007年海冰减少2008 2010年海冰重新增长这与南极海冰20a长周期的推断相符合但9年间的全南极海冰无明显的趋势性变化Abstract: In consideration of the Antarctic special environmenta new sea－ice extraction method of usin g the 0．86m and 1．24m wave bands of MODIS is proposedbased on the Normalize Difference Snow Index NDSI．It can extract the sea ice under the clear sky and thin cloud condition res pectivelywhich lar gel y improve the efficienc y and spatial resolution of Antarctic sea－ice monitoring．The new method is used to obtain the monthly sea ice images in the whole Antarctica of recent years．Thencombining the AMSR－E datathe change monitoring of Antarctic sea ice is executed．It indi cates thatfrom 2002to 2010both the Antarctic sea－ice extent and sea－ice area reach the minimums in Februarywith the averages are 3．17×106 km2 and 2．42×106 km2 res pectivel y．And the maximums appear in September with the averages are 18．40×106 km2 and 16．60×106 km2．The inter annual change of Antarctic sea ice can be divided to three periodsthe flat period of the year from 2002to 2004the reduced period of 2005to 2007and the increased period of 2008to 2010．It verifies the 20years cycle of Antarctic sea ice in the inter annual change．The change trend of the whole Antarctic sea ice is not obvious in the recent nine years．
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