基于多种植被指数的土壤含水量估算方法

Soil Moisture Estimation Model based on Multiple Vegetation Index

快速且准确估算土壤含水量已成为农林业水资源监测的热点问题,应用植被指数估算土壤含水量的方法已得到广泛认可和应用。以便携式光谱仪测定的高光谱数据为基础计算得到8种植被指数,通过灰色关联分析法(GRA)对八种植被指数和基于红外热像仪测定的冠层温度进行分析与筛选,选取与土壤含水量具有较高相关性的指标进行多元线性回归分析,构建基于多种植被指数的土壤含水量估算模型(SMBMVI),并做模型精度分析。精度评价结果表明:模型拟合度较高,达到极显著水平(p<0.000),土壤含水量估算值与实测值具有较高相关性,r为0.636 1,RMSE为2.149 9。该方法引入多种植被指数,采用非接触式的测量方法估算小尺度研究对象的土壤含水量,能够作为遥感反演和直接测定土壤含水量的一种有效替代方法。模型的建立可以快速、准确的估算土壤含水量,为农林业水资源监测管理提供理论与技术参考。

Estimating soil moisture conveniently and exactly is a hot issues in water resource monitoring among agriculture and forestry.Estimating soil moisture based on vegetation index has been recognized and applied widely.8 vegetation indexes were figured out based on the hyper-spectral data measured by portable spectrometer.The higher correlation indexes among 8 vegeta-tion indexes and surface vegetation temperature were selected by Gray Relative Analysis method （GRA）.Then,these selected indexes were analyzed using Multiple Linear Regression to establish soil moisture estimation model based on multiple vegetation indexes,and the model accuracy was evaluated.The accuracy evaluation indicated that the fitting was satisfied and the signifi-cance was 0. 000 （P〈0. 001）.High correlation was turned out between estimated and measured soil moisture with R2 reached 0. 636 1 and RMSE 2. 149 9.This method introduced multiple vegetation indexes into soil water content estimating over micro scale by non-contact measuring method using portable spectrometer.The exact estimation could be an appropriate replacement for remote sensing inversion and direct measurement.The model could estimate soil moisture quickly and accurately,and provide theory and technology reference for water resource management in agriculture and forestry.