基于HJ-HSI数据的伊犁绢蒿荒漠草地生物量估测

以地面实测数据为依据,通过获取其同步HJ-HSI影像光谱反射率,筛选出光谱变量、波段变量,对不同利用状态的退化伊犁绢蒿(Seriphidium transiliense)荒漠草地(围栏封育区N,围栏外重度退化区W_1,围栏外中度退化区W_2)的地上生物量进行估测。结果表明,1)各季节不同利用状态伊犁绢蒿荒漠草地群落HJ-HSI光谱反射率不同,春季为W_2NW_1,夏季为W_2W_1N,秋季为W_1W_2N;2)HJ-HSI可以实现对伊犁绢蒿荒漠草地地上生物量的估测,估测模型因群落类型和季节不同而存在差异。春、夏、秋3个季节的估测模型,N分别由DVI、NDVI、620.225-627.895nm反射率平均值所构建,W_1分别由近红外波段(Rn)、656.305nm和776.8199nm反射率归一化值、MSAVI构建,W_2分别由652.09和732.01nm反射率归一化值、红外波段(Rr)、584.52-598.295nm反射率平均值构建。

Estimation of biomass based on HJ-HSI data in Seriphidium transiliense desert grassland

The aboveground biomass of degraded Seriphidium transiliense desert grassland areas under differ-ent utilisations (N:fenced area,W1:unfenced and heavily degraded area,and W2:unfenced and moderately degraded area)were estimated using spectral variables and band variables selected from the spectral reflectance of a HJ-HSI satellite image taken in the same period.The results showed that:1)The spectral reflectance of the grassland communities differed among plots during different seasons,and their reflectance was ordered as W2〉 N 〉 W1 in spring,W2〉 W1〉 N in summer,and W1〉 W2〉 N in autumn;2)HJ-HSI can be used to estimate the aboveground biomass of this kind of grassland,and the results of the estimation models vary a-mong different community types and seasons.The estimates obtained by the models for the spring,summer, and autumn were as follows:DVI,NDVI,620.225-627.895 nm reflectance average construction in plot N;Rn,656.305 and 776.8199 nm reflectance normalised values,MSAVI construction in W1;652.09 and 732.01 nm reflectance normalised values,Rr,584.52-598.295 nm average construction in plot W2 .