Abstract:

 The condition of natural ecoenvironment in Yinchuan plain located in the arid northwestern area is typical in China.MODIS NDVI is one of the important indexes that represent the condition of natural ecoenvironment,which is influenced by various factors. Groundwater is the most important one among the factors,but it is difficult to make full use of data concerning groundwater to establish a mathematical model and to draw a quantitative conclusion.Currently,the study on the mixture of distributions has received widespread attention,but the reliable estimation of the parameters in the mixture of distributions is quite difficult.A method, based on the relation between the mixture of distributions and the histogram of data, and using least squares to estimate the parameters, is introduced in this paper.The relation between groundwater and vegetation in Yinchuan Plain is discussed on the basis of the new method, using MODIS NDVI and groundwater monitoring data.The normal distribution of the effect of groundwater on vegetation in Yinchuan plain is founded.

Key words:

Key words: mixture of distributions; least squares; histogram of data; NDVI; groundwater