从卫星红外亮温与大地热流的关系看地震前的热红外异常

A perspective to thermal infrared anomalies before earthquakes from the relationship between satellite infrared brightness temperature and terrestrial heat flow

一些强地震前地表可产生热异常是人们比较一致的认识,但能否用卫星遥感技术观测到地下热异常则存在很大的分歧.本文试图通过分析热红外亮温与大地热流值的关系,探讨利用卫星遥感技术观测地震热异常的可能性及其存在的一些问题.研究结果表明:(1)在绝大多数情况下,亮温随大地热流值的升高而升高,升高的速率平均为0.057℃/mW·m^(-2).如果地震引起的大地热流异常为100 mW·m^(-2),则有可能产生卫星红外平均亮温约5.7℃的异常.(2)不同地区亮温随大地热流值变化速率不同,即使地震前出现了卫星热红外亮温异常,但不同地区表现也是不同的.(3)在一些地区一些季节,亮温与大地热流值关系不明显,可能是亮温数据受气象因素干扰所致.这说明地震前的热红外亮温异常是复杂的,甚至有时是难于观测到的.

It is often accepted that thermal anomalies on the earth surface can occur before some major earthquakes. But it is very controversial whether such thermal anomalies can be observed by satellite remote sensing technology. We attempt to explore the possibility and problems on the observation of thermal anomalies before earthquakes using satellite remote sensing data by analyzing the relationship between thermal infrared brightness temperature and terrestrial heat flow. The result shows that in most cases, brightness temperature increases with the growing terrestrial heat flow at an average rate 0. 057℃/mW·m^-2. If the terrestrial heat flow anomaly resulted from an earthquake is 100 mW·m^-2, there would be a satellite thermal infrared anomaly about 5. 7℃. In different regions, the brightness temperature changes with the terrestrial heat flow at varied rates. Even if satellite thermal infrared anomalies occur before earthquakes, they will have differing expressions. For some regions and seasons, the relationship between brightness temperature and terrestrial heat flow is not obvious, because the brightness temperature data is very likely disturbed by meteorological factors. That implies that the thermal infrared brightness temperature anomalies associated with earthquakes are actually very complicated and cannot be observed sometimes.