Abstract: The paper first summarizes the advances in detection of volcano activity using satellite thermal infrared remote sensing and discusses the feasibility and means to monitor the thermal anomaly caused by volcano activities through satellite thermal infrared remote sensing technology. Then, some applied methods are put forward to remove the influences of geological environments and meteorological variation on earth surface thermal infrared radiation for extracting volcanic thermal anomaly. These methods include getting rid of the influences of ground environment factors, such as terrain, vegetation and rock types by establishing brightness temperature variation models of volcanic region and eliminating the influences of weather by difference calculation of brightness temperature between volcanic region and adjacent contrast region. Finally, the paper gives a study case of Changbai Mountains volcano. By using NOAA AVHRR data of the three years of 1999, 2003 and 2004, the authors analyzed and interpreted the thermal infrared brightness temperature images of Changbai mountain volcano region, and calculated the annual variations of brightness temperature of Changbai Mountains Tianchi Lake and adjacent contrast region. The result shows that the spatial distribution of brightness temperature in Changbai mountains volcano area is mainly controlled by hypsography and physiognomy, and presents a “tundish” shape. From Tianchi Lake to its peripheral places, the brightness temperature increases gradually, but the Tianchi Lake is a clear hot spot in cold background. The temporal variation of brightness temperature in this region is mainly influenced by seasons and presents seasonally changeable characteristics. The comparison analyses of annual variations of brightness temperature between Tianchi Lake and contrast region reveal that the brightness temperature of Tianchi Lake in 2003 and 2004 increased markedly with a magnitude about 2K compared with that in 1999. We suppose this elevated temperature is likely to be a reflection of increasing activity of Tianchi volcano in recent years. Furthermore, this result is consistent with that obtained by Changbai Mountains Tianchi Volcano Observatory in the past 4 years. These indicate that the satellite thermal infrared remote sensing is a feasible and effective measure for detecting volcano activity, and its application in detection of volcano activity deserves more detailed research.

Key words: satellite thermal infrared, remote sensing, volcano detection, Changbai Mountains

摘要： 介绍了卫星热红外遥感在国内外火山监测研究中的应用现状,结合热红外遥感在地震中的应用成果,对利用卫星热红外遥感监测火山活动的可行性及方法进行了探讨,提出通过火山区热红外亮温旬变、月变和年变模型扣除地形地貌、岩性、植被等地表环境因素的影响,通过火山区和邻近参照区红外亮温差值运算扣除气象因素影响的火山活动性热红外异常提取方法。并以长白山火山为例,利用1999、2003和2004年的NOAA卫星影像资料,对长白山火山及周围地区的热红外影像特征进行了分析解译,对长白山火山区与外围参照区的红外亮温年变差异进行了统计分析。结果表明:1)长白山火山区的红外亮温分布特征在空间上主要受地形控制,总体表现为以天池为中心,向外围逐渐升高的漏斗状,天池则是低温背景上的明显高温标记。在时间上,长白山火山区红外亮温的演变过程主要受季节变化的影响,具有明显的夏高冬低年变特征。2)相对于1999年,2003和2004年长白山火山区均显示出明显的升温趋势,升温幅度可达2K左右。我们认为这可能是近年来天池火山活动性逐年增强的反映。这也意味着利用卫星热红外遥感监测火山活动性将是行之有效的新途径,也是值得深入研究的课题。

关键词: 卫星热红外, 遥感, 火山监测, 长白山