冬小麦冠气温差及根层土壤含水量的频谱分析

Spectral analysis of temperature differences between winter wheat canopy and air and son water content in root zone

本文用频谱分析的理论和方法，对冬小麦冠气温差和根层土壤含水量进行了分析．分析表明，作物冠气温差在田间一个方向为平稳随机过程，且有某种周期变化的特征．通过信号检测发现，作物冠气温差可用５个频率的周期函数表示，并得知，作物冠气温差与根层土壤含水量之间存在某种相关关系，根层土壤含水量可用作物冠气温差的线性滤波函数描述．

Temperature differences beteewn winter wheat canopy and air as well as soil water content in root zone were measured in a test field in an area of 4-hectare.By using spectral analysis and signal detection,temperature differences between canopy and air is found to behave randomly in one direction of the field,whereas the distrbution in the other direction can be described as a superposition of five cyclic functions. Co-spectral analysis yielded 0.7 coherence at certain frequencies between temperature differences and soil water content.The soil water content in root zone can be simulated by a linear filter model of temperature differences between canopy and air.