热惯量法在干旱遥感监测中的应用研究

Use of thermal inertia approach in the monitoring of drought by remote wensing

利用NOAA/AVHRR资料计算了真实热惯量、表观热惯量、NOAA/AVHRR通道4亮温差与土壤水分之间的关系模型,并讨论了陕西特殊地形、地面植被覆盖对表观热惯量与土壤水分之间关系的影响。结果表明:在实际的干旱遥感监测服务中,可以使用表观热惯量与土壤相对湿度建立的模型来监测地面旱情。考虑地形、植被和土壤类型因素时,下垫面越均一,表观热惯量与土壤相对湿度的相关性越好,但植被覆盖对地表温度差的影响需要进一步的研究。

Thermal inertia approach is the major method to use remote sensing data to monitor drought and has produced positive effects in its use in north China. Shaanxi province straddles over three climatic zones from south to north and has complicated landforms. The paper uses NOAA/AVHRR data to calculate real thermal inertia, apparent thermal inertia and brightness-temperature difference on NOAA/AVHRR channel 4, and then deduce their relation models with relative soil moisture as well as discuss the effects of the landforms and vegetation coverage of Shaanxi province on the relation between apparent thermal inertia and soil moisture. The results reveal that the model depending on apparent thermal inertia and relative soil humidity can be used to monitor drought in the monitoring services by remote sensing. Considering a landform, vegetation and soil types, the correlativity between apparent thermal inertia and relative soil humidity become better as the underlying surface become more uniformed, but the effects of vegetation coverage on temperature on ground surface need be further studied.