基于温度植被特征空间的夏季重庆土壤干湿状况与土地利用关系研究

干旱是影响社会发展和农业生产的重要因素，土壤干湿状况则是监测干旱的重要指标之一，用温度植被特征空间来反映区域土壤的干湿状况具有一定的指示意义。本文以重庆市作为研究区，以2006年重庆特大旱灾年为例，选择了与土壤墒情数据获取时间相同且云量较少的7幅MODIS产品，建立了温度植被指数特征空间。首先，利用土壤墒情站点的实测结果分析比较两种植被指数（NDVI，EVI）构建的温度植被干旱指数（TVDI）在反映土壤干湿状况时的差异；然后利用2006年MODIS重庆土地利用覆被数据，分析重庆市丘陵山地区地表含水状况的空间差异，进而结合该区的主要土地利用类型，探讨各种土地覆被类型的土壤干湿状况。研究表明，TVDI能够有效的反映土壤湿度的时空差异，是一种有效的实时监测土壤干湿状况的手段，且用EVI构建的TVDIE比NDVI构建的TVDIN更适合用于监测重庆市夏季干旱；林地和草地的TVDI分级分布的较为均匀，涵养水源的能力较强，疏林地次之，耕地最弱；植被覆盖十分有助于涵养水源抵抗旱情，土壤湿度与土地利用方式之间存在一定的相关性。

Relationship between summer soil moisture status and land use type based on characteristics of surface temperature /vegetation index space,in Chongqing

In this paper,Chongqing was chosen as the study area and the study period was 2006.The characteristics of surface temperature /vegetation index spaces were built with the soil moisture data and less cloud cover MODIS products which were acquired at the same time.The Temperature Vegetation Dryness Index （TVDI） was built by two kinds of vegetation index （NDVI,EVI） and named TVDI N,TVDI E separately.Firstly,the difference of two kinds of TVDI reflected the soil moisture status was analyzed with soil moisture site data.Then,using the land-use cover data of MODIS,the spatial diversity of the surface soil water conditions of hilly and mountainous areas in Chongqing was analyzed.Finally,combined with the main land use types of the study area,the soil moisture status of each land cover type was explored.The results show that,TVDI can effectively reflect the spatial and temporal differences in soil moisture and is an effective means which can monitor the soil moisture status at real-time.Compared with TVDI N which built by NDVI and TVDI E which built by EVI,TVDI E is more suitable for the monitoring of summer drought.The TVDI grade distribution of woodland and grassland is more uniform.So there is strongest water conservation capacity for the woodland and grassland,sparse second,the cultivated land weakest.Vegetation cover is very helpful for the water conservation and drought resistance,and soil moisture and land use types exist certain correlation.