基于不同植被指数TVDI和VSWI模型的焉耆盆地土壤湿度反演

Retrieval of soil moisture in Yanqi Basin based on TVDI and VSWI models with different vegetation indices

以新疆焉耆盆地为研究区域,基于Landsat 8 OLI数据计算归一化植被指数(NDVI)、增强型植被指数(EVI)、改进的修正土壤调整植被指数(MSAVI)、土壤调整植被指数(SAVI)以及地表温度(Ts)等,建立温度植被干旱指数(TVDI)模型和植被供水指数(VSWI)模型反演新疆焉耆盆地的土壤湿度,比较不同土壤湿度反演模型对研究区的适应性,进一步分析焉耆盆地土壤湿度的空间分布特征。结果表明,构建NDVI-Ts、MSAVI-Ts、SAVI-Ts、EVI-Ts空间特征,其散点符合三角形的关系,R^(2)均0.83以上;利用不同植被指数NDVI、MSAVI、SAVI、EVI计算出的TVDI、VSWI与土壤相对湿度0~10 cm RSM数据呈现负相关关系,两种模型具有较高的一致性,利用MSAVI指数反演的TVDI、VSWI决定系数最高,R^(2)分别为0.296、0.235;焉耆盆地湿度总体上以半干旱(0.6<TVDI、VSWI<0.8)为主,以干旱(TVDI、VSWI>0.8)为辅;土壤湿度空间格局,焉耆盆地中部出现正常现象,东南部和东北部出现干旱现象。TVDI、VSWI模型可以实现对焉耆盆地土壤湿度反演,为焉耆盆地水资源与生态环境研究提供较好的参考信息。

This article take the Yanqi Basin in Xinjiang as an example,in this paper Landsat 8 OLI data was used to calculate the normalized vegetation index(NDVI),enhanced vegetation index(EVI),modified soil adjusted vegetation index(MSAVI),soil adjusted vegetation index(SAVI)and land surface temperature(Ts),establishes TVDI model and VSWI model were applied to retrieve the soil moisture of Yanqi Basin,compared to the adaptability of different soil moisture retrieval models and the spatial distribution characteristics of soil moisture in Yanqi Basin were further analyzed.The results show that establishing the spatial characteristics of NDVITs,MSAVI-Ts,SAVI-Ts and EVI-Ts and the scatter points of NDVI-Ts,MSAVI-Ts,SAVI-Ts and EVI-Ts conform to the relationship of triangles with R2 above 0.83;TVDI and VSWI were calculated by NDVI,MSAVI,SAVI and EVI have negative correlation with RSM data of 0~10 cm soil relative humidity,and the two models showed high consistency.TVDI and VSWI retrieved by MSAVI have the highest correlation,R^(2)=0.296,R^(2)=0.235,respectively;The Yanqi Basin was mainly featured with semi-arid(0.6<TVDI,VSWI<0.8)and arid characteristics(TVDI,VSWI>0.8);The spatial pattern of soil moisture:Normal phenomena appear in the middle of the Yanqi Basin,and arid areas mainly distributed in the southeast and northeast.TVDI and VSWI models are applicable for the inversion of soil moisture in the Yanqi Basin and the research results provide better reference information for the study of water resources and ecological environment in Yanqi Basin.