柴达木盆地德令哈地区MODIS-NDVI时空变化及其与气候的关系

Spatial-temporal variations of MODIS-NDVI and its correlations with climate in Delingha Region,Qaidam Basin

利用遥感与GIS手段,分析了12年来柴达木盆地德令哈地区MODIS-NDVI的时空变化及其与气温、降水量的空间相关性.研究表明:2000-2011年柴达木盆地德令哈地区生长季NDVI平均值年际变化趋势中,改善区、稳定区、退化区和无植被生长区的面积分别占总面积的49.13%,32.14%,0.51%,18.21%;山地和绿洲生长季NDVI平均值的增长率分别为3.9%/10a,2.9%/10a.在山地的各海拔高度带上,12年NDVI平均值越大的区域,植被改善趋势越强烈,反之改善趋势越微弱.山地改善区在海拔较低、坡度较小的区域以及南坡所占的面积百分比较大,绿洲植被改善显著的典型区域主要分布在农场区域和临近河流的部分区域,退化显著的区域主要分布在城镇建设区域,植被砍伐、铁路和公路修建区域.12年来德令哈地区气候呈暖湿化趋势.德令哈地区植被的生长状况与生长季降水量和生长季前期气温呈较强的正相关关系,而与生长季气温和前期降水量的相关性并不显著.春季较高的温度和较多的降水量、夏季较多的降水量以及前一年冬季较高的温度是植被生长的有利条件.

Based on RS and GIS technology, the spatial-temporal changes of NDVI in Delingha Region and its spatial correlation with temperature and precipitation were analyzed and the results showed that the greening area, stable area, degraded area and bare area accounted for 49.13%, 32.14%, 0.51%and 18.21%of the total area respectively in the variation trend of growing-season vegetation NDVI averages from 2000 to 2011. The growth rate of growing-season vegetation NDVI averages in mountain and oasis region was 3.9%/10 a and 2.9%/10 a. In all the altitude rings of the mountainous region, the bigger the NDVI value, the more intense the vegetation greening trend;the smaller the NDVI value, the weaker the vegetation greening trend. The greening area in the mountain region was larger in lower altitudes, concentrated on gentle slopes and south sides. The greening area in oasis region was mainly distributed in farming areas and riversides, the degraded area was mainly distributed in urban construction zones, and vegetation deterioration mainly occurred along railway and highway construc-tion areas. The climate in Delingha Region became warmer and wetter in the last 12 years. Vegetation growth conditions in Delingha Region had positive correlations with growing-season precipitation and prophase temper-ature, but were uncorrelated with growing-season temperature and prophase precipitation. Higher temperature and more precipitation in the spring, more precipitation in the summer and higher temperature in the winter of the previous year was beneficial to vegetation growth.