利用U-Net的格陵兰冰盖冰面湖提取和面积变化分析

Extraction and Area Change Analysis of Supraglacial Lakes in Greenland Ice Sheet Using U-Net Model

  • 摘要: 冰面湖作为冰盖质量损失、海平面上升、气候变化等全球变化问题的指示器,对研究全球气候变化背景下冰盖的稳定性有着重要的作用。利用深度学习中的语义分割模型U-Net实现了不同情形下Landsat卫星影像中冰面湖的提取,并与多种方法进行了比较,发现U-Net冰面湖提取方法在性能和效率上表现最佳。提取2000—2020年北极格陵兰岛Sermeq Avannarleq冰川附近的冰面湖,并分析冰面湖面积的季节变化和年际变化。结果表明,该区域的冰面湖面积在每年5月—9月呈现先增后减的变化趋势,5月中旬开始增加,7月中下旬达到峰值,9月基本消亡;该区域的冰面湖面积在2000—2020年呈现增加的趋势,表明该区域冰盖融化量逐渐增加。

     

    Abstract:
    Objectives As a sensitive indicator of global changes such as ice sheet mass loss, sea level rise and climate change, supraglacial lakes play an important role in the study of ice sheet stability.
    Methods U-Net is a semantic segmentation model, which extracts supraglacial lakes from Landsat satellite images in different situations.
    Results The extraction of supraglacial lakes by U-Net possesses the optimal performance and efficiency. And the supraglacial lakes near the Sermeq Avannarleq Glacier in Greenland ice sheet are extracted from 2000 to 2020, and the seasonal and interannual variations of the area are analyzed.
    Conclusions The area of supraglacial lakes starts to increase in mid-May, reaches the peak in the mid-late-July, and almost disappears in September in a year. For the long time series change, the area of supraglacial lakes in this region shows an increasing trend from 2000 to 2020, indicating that the amount of ice sheet melting is gradually increasing.

     

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