基于MODIS SWIR数据的干旱区草地地上生物量反演及时空变化研究

An Approach for Monitoring the Aboveground Biomass of Grassland in Arid Areas based on MODIS SWIR Bands

基于古浪县MODIS遥感资料和地面实测样方数据,筛选出干旱区草地地上生物量的敏感指数,构建了该区草地地上生物量反演模型,并对2000~2014年试验区草地产量的时空动态进行了分析。结果表明:基于NDTI指数的草地地上生物量反演模型预测精度较高,可用于大范围干旱区草地地上生物量的快速监测。2000~2014年古浪县生长季最大草地地上生物量空间分布差异明显,由南向北生物量逐渐降低。15a间温性草原化荒漠和温性荒漠地上生物量呈极显著增加趋势。各草地类型生物量峰值出现在7~8月份,不同草地类型间存在差异。研究结果可为干旱区草地资源和生态环境的动态监测和评价提供科学基础。

In this study,the sensitive index of grassland aboveground biomass in arid areas was selected by using ground measured samples data and MODIS remote sensing data in Gulang County, then a aboveground biomass inversion model was established and its accuracy was assessed.On that basis, the spatiotemporal dynamics of grassland aboveground biomass were analyzed in test area frm 2010 to 2014.The results indicated that the prediction accuracy of inversion model based on NDTI was higher, and could be used as a fast monitoring technique for grassland biomass in arid areas in a wide range.The spatial distribu- tion of maximum aboveground biomass of grassland during growing seasons was significant difference in Gulang County from 2000 to 2014, the biomass gradually reduce from the south to the north. The aboveground biomass of temperate steppe desert and temperate desert was increased significantly in last 15 years.The peak of aboveground biomass for different grassland types appeared in July or August.This study can provide a scientific basis for the dynamic monitoring and evaluation of grassland resources and eco- logical environment in arid areas.