基于遥感技术的贵州春季土壤水分空间分异研究

Analysis on spatial variation of soil moisture in the spring in Guizhou based on RS

通过对已建立的土壤水分运动模拟模型的校正,使之适合于喀斯特环境的土壤水分运移,并以遥感和GIS技术为依托,反演出贵州省大尺度下的各陆表参数(如:地表温度、NDVI、气温、日照时数等),进而模拟出贵州省土壤水分运动转化过程,定量描述了喀斯特地区土壤水分变化,并对影响土壤水分变化的相关因子进行相关性分析。结果表明:贵州春季土壤水分含量均值为0.23mm/mm,次降雨通过蒸散发和下渗等作用在10天左右的时间之后,土壤水分含量及其增长率接近稳定状态,平均土壤水分变化率为1.16%;降水量对土壤水分变化的影响程度较其它的气象因子大,与土壤水分的净相关系数较大,是土壤水分变化的最主要的净影响因子;春季贵州省土壤水分空间分布总体上呈现东南、南部较高,而中部,北部、西部地区较低的分布特征,主要原因之一是中北部地区主要以黄壤或水稻土为主,土壤孔隙较大,漏水较为严重,土壤保水性不强。

The conversion flux of soil moisture between soil and vegetation, soil and parent rock determines the vitality of the soil ecosystem in karst areas, and it is also the key dynamic factor to soil degradation. So if the changed amount of water conversion fluxes among those interfaces at the facial scale the major mechanism of the moisture and energy motion in karst area will be revealed, which is very important to quantitative researching into ecologic devolution led by the soil degradation in karst area. There have been many different kinds of model related to soil moisture in different areas. The paper introduces a soil moisture model and rectifies it by many monitoring data and meteorological data to adapt to the soil moisture motion in karst areas. The paper also inverses the factors （e. g. the vegetation index, the surface temperature, the albedo and so on） needed in the model by remote sensing techniques. And further on, the process of soil moisture is modulated and described quantitatively, and correlation analysis to the related factors that influencing soil moisture variation is made. In spring, the mean value of the soil moisture in Guizhou is 0. 23mm/mm, the soil water increase rate gets to stable state after 10 days, and the mean soil water variation rate is 1.16%. The influence of precipitation on soil moisture is more important than other meteorological factors, the correlation between soil moisture and precipitation is very strong, and the precipitation might be the major factor in soil moisture variation. The soil moisture at southeast and south Guizhou province is higher than that at the middle, north and west areas. At the middle Guizhou province, the main soil types are yellow soil and paddy soil with bigger soil pore, more serious water leakage and low water capacity.