冬小麦遥感冠层温度监测土壤含水量的试验研究

Canopy temperature monitoring soil water content based on field experiment of winter wheat

在冬小麦主要生育期(2002年4月初到5月底),对不灌溉的冬小麦测定了冠层温度、地温、气温以及土壤含水量,计算了冠气温差且分析了冠层温度和冠气温差与不同土层厚度的土壤含水量相关关系。结果表明:14∶00的冠层温度能较好地反映20cm土层的土壤含水量变化,但与其它各土层相关性有较大的波动性;14∶00的冠气温差能较好地反映40cm以上土层的土壤含水量变化,二者的相关性很高,在20cm、40cm土层,两者相关系数R2分别为0 98866、0 99389,这为用区域遥感数据反演主要生育期冬小麦的冠气温差进而监测区域40cm土壤含水量提供了实验性的依据;拔节期和灌浆期,用14∶00冠气温差来拟合各土壤层的土壤含水量有较高的精度,从而为用区域遥感数据监测区域土壤含水量提供了经验性的模型。

In the growth stage of winter wheat (from April to May in 2002), the canopy temperature, air temperature, volumetric soil water content were measured for the non-irrigation winter wheat. Beside, the canopy temperature, canopy-air temperature difference and volumetric soil water content are analyzed in this paper. The results indicate that the canopy temperature at (14∶00 )can reflect soil water content of the soil layen in 20?cm deep, but relativity in other soil levels has bigger fluctuation; the change of the volumetric soil water content in the depth 40?cm can be preferably reflected by the changes of canopy-air temperature difference at (14∶00),the relational coefficients are 0.988?66(20?cm),0.993?89(40?cm), respectively which indicate that it can used as the base for monitoring regional soil water content through the retrieval regional canopy temperature; And during jointing stage and grain filling stage, the higher precision by canopy-air temperature difference simulating volumetric soil water content can be used as an empirical model for monitoring regional volumetric soil water content.