The Response Characteristics of Xilingol Grassland to Uneven Distribution of Precipitation at Temporal and Spatial Scale

Abstract

Precipitation is the most important source of water supply, which has important significance on the vegetation growth, also is an important factor affecting the drought severity in Xilingol grassland. Based on the precipitation of 15 weather stations and MODIS MOD13A3 NDVI data, Pearson correlation analysis was used to analysis the response characteristics of NDVI to precipitation at spatial and temporal scale. Results showed that from one month view, vegetation growth was the highest correlation with the precipitation of this month from May to July, but August and September were the highest correlation with the precipitation in July. Accumulated month view, the accumulated precipitation in the last three months was very important to the vegetation growth, and snowfall in the winter of previous year played an important role in May of next year. Spatially, from one month view, Erenhot and Sonid Youqi˄desert steppe region˅were the highest correlation with the precipitation in two months before, the others were the highest correlation with the precipitation in one month before. Accumulated month view, Erenhot and Sonid Youqi were the highest correlation with the accumulated precipitation in the last four months, the others were the highest correlation with the accumulated precipitation in the last three months.