Satellite imagery, a base line for glacier variation study on James Ross Island, Antarctica
Satellite imagery, a base line for glacier variation study on James Ross Island, Antarctica
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卫星图像，南极洲詹姆斯罗斯岛冰川变化研究的基线
作者：
P. Skvarca;H. Rott;T. Nagler
利用连续可见光和雷达卫星图像记录了南极半岛詹姆斯罗斯岛（JRI; 64° S，58° W）39个出口冰川的变化。监测时间间隔为17.4年，从1975年底一直到1993年初。该研究基于协同使用不同的传感器来监测冰川变化。数字增强的大地卫星TM图像还可以确定罗斯湾内的接地冰和浮冰之间的边界，并探测冰的褶皱，从而改进了对JRI面积范围的测量。除冰川边界外，经分析的ERS-1合成孔径雷达图像还提供了关于冰雪形态特征的信息。卫星数据显示，自1975年以来，冰川总体退缩，导致JRI上的冰川总面积明显减少。在测量的39个冰川中，有33个冰川在1975年至1993年期间退缩，其中15个冰川的退缩与冰川的大小相比是显著的。这与过去20年中南极半岛记录的明显的大气变暖趋势是一致的。因此，JRI上的冰川面积分析为检测未来变化提供了一条基线。
Sequential visible and radar satellite imagery is used to document the fluctuations of 39 outlet glaciers on James Ross Island (JRI; 64° S, 58° W), Antarctic Peninsula. The monitoring time interval of 17.4 years extends from late 1975 until early 1993. The study is based on synergistic use of different sensors for monitoring glacier variations. The digitally enhanced Landsat TM images also allowed definition of boundaries between grounded and floating ice within Röhss Bay and detection of ice rumples, resulting in an improved measurement of the areal extent of JRI. In addition to glacier boundaries, the analyzed ERS-1 SAR images provide information on morphological properties of snow and ice. The satellite data show a general glacier retreat since 1975, resulting in clear decrease of overall glacier area on JRI. Of 39 glaciers measured, 33 glaciers retreated in the period 1975–93, 15 of which showed significant retreat in comparison to glacier size. This is in accordance with the pronounced atmospheric-warming trend recorded during the last two decades on the Antarctic Peninsula. The analysis of glacier areas on JRI thus provides a base line for detection of future changes.