单 位：
西藏阿里地区气象局;西藏高原大气环境科学研究所;西藏昌都地区气象局
关键词：
西藏阿里;草地;NDVI;覆盖度;时空变化
摘 要：
利用MODIS MOD13Q1(V005L3)遥感数据和GIS技术,结合多种统计、计算方法,对西藏阿里地区2000~2012年期间草地覆盖的时空变化进行研究,结果如下:①阿里地区NDVI总体呈正态分布,平均植被覆盖度为18.6%,其中覆盖度为20%~40%的比例最大,占总面积的46%,表明阿里地区植被总体长势较稀疏。②从植被覆盖度变化趋势看,稳定或无变化区域占整个地区面积的69%,而轻微退化和显著退化区域占13.3%,轻微改善和显著改善区域占13.2%,表明阿里地区植被覆盖度处于较稳定状态,年际变化分析表明进入2010年以来植被长势有所改善。从空间分布上看变好区域主要分布在改则、措勤、普兰等县,特别是改则县北部羌塘自然保护区域内改善比较明显,退化的区域主要分布在革吉、噶尔、日土等县的部分区域。③从每年的6月初至9月底为植被生长最好季节,8月份最好,2月份最差。季节上春、冬、秋、夏植被依次变好,特别是秋冬季好于春季,说明阿里地区由于受降水的影响植被返青期较晚,随着温度的上升枯黄期也推迟。
译 名：
Spatial and Temporal Change of Grassland Coverage Based on Time-series of MODIS-NDVI Data in Ali Region
作 者：
BIAN Duo;PU Bu-ciren;NI Zhen;LIU Kui-jun;Tibet Institute of Plateau Atmospheric and Environmental Science;Changdu Meteorological Bureau;Ali Meteorological Bureau;
关键词：
Ngari region;;Grassland;;NDVI;;Coverage;;Temporal and spatial variation
摘 要：
Using MODIS MOD13Q1V005(L3)remote sensing data and GIS technology along with a variety of statistics and calculation method,the temporal and spatial variations of grass coverage were investigated in Ngari region of Tibet during 2000-2012.The results were as follows:(1)The NDVI normally distributed in Ngari region as a whole and the average vegetation coverage was 18.6%.The biggest area with the coverage ranges from 20%to 40%almost accounting for 46% of the total area,which presented that the vegetation in Ngari region was quite sparse.(2)Considering the variation trend of vegetation coverage,the stable or no change area accounted for 69% of the entire area,while a slight degradation and significant degradation area accounted for 13.3%,a slight and significant improvement area accounted for 13.2%,which showed that the vegetation coverage in Ngari region was in a relatively stable state,the vegetation was improved obviously since the 2010s.The areas with better vegetation were mainly located in Gaize,Cuoqin,Pulan County,especially in Qiangtang nature reserve while the degradation areas were mainly located in Geji,Gaer,Ritu County.(3)According to the NDVI variation with different temporal scale such as 16days,monthly and seasonal distribution,it was the best growing period of vegetation from early June to the end of September for each year,and August was the best and the worst in February.The vegetation was getting better from spring,winter,autumn to summer,especially the vegetation in autumn and winter was better than that in spring.The results showed that turning green period delayed since the influence of precipitation,and the vegetation had a longer withering period with the temperature rising.
