基于混合像元分解的海坛岛植被覆盖度因子研究

摘要

在USLE/RUSLE中，降雨侵蚀力与地表植被覆盖度因子具有季节变化特征．本研究考虑到两者的时空耦合性，采用基于混合像元分解的计算方法，得到了海坛岛不同月份的地表植被覆盖度因子Ci值（第i月的地表植被覆盖度因子值）和不同地类的年植被覆盖度因子C值，为岛内土壤侵蚀预报和水保工作提供参考．对第i月的地表NDVI i 值与年C/C i 值进行分析，发现它们呈现较好的线性关系，用SPSS软件进行回归分析得到两组线性回归参数．年C值与11月份的地表NDVI拟合程度最好， NDVI i 与C i 值的拟合程度好于年C值与NDVI i ．最后得到海坛岛通用的C i 值估算模型C i＝1.007-1.119· NDVI i ，该模型的决定系数达到0.8，可用于计算岛内各月份的Ci 值．%Rainfall erosivity and vegetation coverage factor of USLE/RUSLE vary over seasons .Con-sidering the coupling of time-space of the 2 factors, liner model of mixed pixel decomposition was ap-plied in this study to calculate the monthly vegetation coverage factor Ci and annual C value on Haitan Island.Meanwhile, annual C/Ci value with NDVIi were found to have good liner relation , and tow lists of linear regression coefficients for C /Ci value with NDVIi were calculated by SPSS software .An-nual C value was best fitted with NDVI of November, and the goodness of fit between NDVIi and Ci was better than that between NDVIi and Annual C.Eventually, an universal model for calculating Ci was established which can be presented as Ci =1.007-1.119· NDVIi, determination coefficient of which is 0.8 and can be used to calculate the Ci value for Haitan Island .