多光谱遥感的地温反演及岛状冻土区分割方法研究
Multi-spectral remote sensing based land surface temperature retrieval and isolated permafrost zone segmentation
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摘要: 受全球气候变化影响,国内东北高纬度冻土地区多年冻土退化显著,冻土融化过程中水分相态变化对土体的力学指标产生严重影响,导致多条高速公路路域滑坡、路基不均匀沉陷等地质灾害频发.为了研究岛状冻土区域分布规律,以北安至黑河高速公路K153-K183路域为研究区,分别选择覆盖范围2009年3、5、9月3景Landsat 7 ETM+影像数据,运用辐射传输方程法对研究区进行红外地表温度反演,得到研究区对应日期时刻地表温度图,分析了地温与NDVI、DEM的相关性.对反演的结果采用自然间断点分级法进行图层分类,通过对研究区地表温变分析和人工解译,获得对应时刻区域内的低温区分布图,对低温区进行相交运算,得到研究区2009年冻土分布图,经与北安至黑河高速公路冻土勘察结果比对,具有较好的一致性.Abstract: Affected by global climate change, the permafrost in northeast high latitude permafrost area of our country was degraded significantly, and the water phase change seriously affected the mechanical indexes of soil during the thawing process of frozen soil. Due to the permafrost melting of high latitude permafrost regions in China in recent years, a plurality of freeway roadbed has landslide, and uneven subsidence and other geological disasters had repeated in the northern part of Heilongjiang Province. In order to study the island permafrost distribution, choosing the K153-K183 Road area from Bei'an to Heihe expressway as the study area, the 3 Landsat 7 ETM+ image data converging the study area was choosen respectively on March, May, September in 2009. The surface temperature map of the corresponding date was obtained and the relationship between ground temperature and NDVI, DEM was analyzed through the retrieval of the infrared surface temperature in the study area using the radiation transfer equation method. Then the map layer of the inversion results was classified using natural breakpoint classification. The distribution map of the low temperature area of the corresponding moment was obtained through the analysis and the artificial interpretation of the surface temperature change of the study area. Frozen soil distribution map was obtained in the study area in 2009 on the intersection operation of the low temperature zone. It had a good consistency comparing with the expressway permafrost investigation results from Bei'an to Heihe.