利用多源遥感数据识别波弗特海冰间水道

Detection of Sea Ice Lead in Beaufort Sea Based on Multisensory Remote Sensing Images

  • 摘要: 采用MODIS可见光反射率、热红外亮温和RadarSat-2双极化后向散射等多源数据,通过建立决策树综合判断来识别波弗特海域冬季的冰间水道及其内部冰型,并进行精度评价。研究发现,MODIS热红外只能粗略提取冰间水道轮廓;而高分辨率的RadarSat-2影像可以提供更多海冰类型信息,但是不同冰型的后向散射信号有重叠,影响水道提取的精度。研究结合多源数据建立决策树,综合极化后向散射和表面温度等参数来判断海冰类型,从而识别不同发育阶段的冰间水道。该方法的识别精度优于单变量方法。高分辨率Sentinel-2光学影像验证了不同阶段冰间水道的顺序分布。多源数据的应用有助于更准确地计算水道区域的海-气热通量和产冰量,同时为船只导航提供更详细的冰情信息。

     

    Abstract: Based on multisensory data, including sptical and thermal images from MODIS, and dual-polarization SAR image from RadarSat-2, sea ice in Beaufort Sea is classified, sea ice leads are identified and accuracy of the result is also evaluated. Experiment shows that thermal images from MODIS is only useful in extracting lead area with coarse resolution, while the high-resolution SAR image could provide more information on sea ice type in lead. However, overlay of signals from different ice type largely reduces the overall accuracy from supervised classification of RadarSat-2 image. Therefore, decision tree is established to incorporate multisensory data. Characteristics of different ice types and leads is analyzed and utilized in decision tree to detect ice leads in different stages of development. Validation shows that overall accuracy of the result from decision tree is 14.8% higher than that from supervised classification. The sequential structure composed of various development stages of ice leads is confirmed in Sentinel-2 images. The result might facilitate accurate calculation of heat flux and ice production, as well as ship navigation with detail ice type in lead

     

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