关键词: 卫星热红外, 遥感, 火山监测, 长白山

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