锡林河流域降水量时空动态及对NDVI的影响

Temporal and Spatial Dynamics of Precipitation in Xilin River Basin and Its Effect on NDVI

以锡林河流域为研究对象,基于1960~2015年间锡林浩特气象站降水日值资料,运用Mann-Kendall非参数统计检验等方法,开展不同时间尺度降水量趋势分析和突变检验;利用2008~2015年锡林浩特气象站及流域内CMADS站点对锡林河流域年降水量进行空间插值,分析多年平均降水量空间变化规律;通过对比典型水文年各月份降水量与NDVI的变化关系,揭示NDVI空间异质性。结果表明:时间上,年均降水量和汛期平均降水量均呈不显著下降趋势,春、夏、秋三季降水变化均不显著,而冬季呈显著上升趋势(P<0.05);空间上,年降水量呈现由东南向西北减小趋势,典型水文年月降水量与各月NDVI呈显著相关(R^2=0.733,P<0.01),尤其丰水年内各月降水量与月NDVI的相关系数介于-0.76~0.99,二者呈现良好的一致性。

Taking Xilin river basin as the research object of this project,based on the daily precipitation data of Xilinhot Meteorological Station from 1960 to 2015,Mann-Kendall non-parametric statistical test was used to carry out the trend analysis and mutation test of precipitation at different time scales.The data from the Xilinhot Meteorological Station and the CMADS site in the basin from 2008 to 2015 were used to spatially interpolate the annual precipitation in the Xilin river basin,and to analyze the spatial variation of the average annual precipitation.The spatial heterogeneity of NDVI was revealed by comparing the relationship between precipitation and NDVI in typical hydrological years.The results showed the average annual precipitation and the average precipitation in flood season show no significant downward trend in the timescale,and the precipitation changes in spring,summer and autumn were not significant,while the precipitation in winter was significant upward trend (P<0.05).In space,the annual precipitation showed a decreasing trend from southeast to northwest.Furthermore,and the monthly precipitation in typical hydrological years was significantly correlated with the monthly NDVI (R^2=0.733,P < 0.01) especially the monthly precipitation and monthly NDVI during the wet season.The correlation coefficient was between -0.76 and 0.99,which showed good consistency.Since the important role of precipitation in increasing forage productivity and vegetation coverage,this paper can provide a basis for rational utilization of water resources and scientific management of grassland resources in Xilin river basin.