中文摘要：

利用GIMMS-NDVI遥感数据和GIS技术，结合多种统计、计算方法，定量分析了1982-2002年青藏高原植被覆盖随时间和空间的变化规律，评定了植被变化的自然和人类的影响。结果表明，21年来，青藏高原植被覆盖呈总体增加的变化趋势，平均增长率为3961．9km^2／年，仅局部出现退化现象，人类对高原植被覆盖未造成破坏性影响。1982-1991年，高原植被呈现良好增加趋势，增加幅度从东部南部向西部北部逐渐减弱，表明由东南向西北逐步减弱的有利气候条件具有经向和纬向的变化规律。1992-2002年，高原中部和西北地区植被呈现退化趋势，强烈退化的地区集中在长江、黄河、澜沧江和怒江的源头地区，显示了高原中部和西北地区的气候条件向不利于植被生长方向转变，高原中部和西北地区植被是响应气候变化的最敏感区。高原植被变化具有7年、3．5年两个显著周期，均为温度所致，表现对温度的变化敏感性。21年期间，高原的8种主要植被类型中有7种类型表现为波动上升的趋势，且寒区旱区植被表现出脆弱性和难恢复性。

英文摘要：

Analysis of the vegetation coverage paper to study the regularity of the regional changi ng with the time in the last 21 years is the purpose of this ent in the Tibetan plateau. Based on the remote sensing data GIMMS NDVI, statistical processing and analysis, also evaluations of the variability of vegetated rate of the Tibetan calculation, the paper gives quantitative analyses and plateau. In the last 21 years, the regional vegetation coverage has been on the slow increase at the rate of 3 961.9 km^2/a as a whole, except for some place degradation, and also the human have not done damage to the eeo-environment. From 1982 to 1991, the vegetation coverage of the whole region increased, except for degrading region at the middle and the west of the area. The value increased is decreasing from the south and the east to the north and the west. The induction, the climate benefiting the vegetation growing, changing with degree of longitude and latitude, can be worked out. It＇s the main period from 1992 to 2002 that the vegetation degrade, those deteriorated regions are located in the resource regions of the Yangtze river, the Yellow river, the Laneangjiang river and the Nujiang river, which indicates the changing climate would be adverse to the vegetation. The NDVI also has two significant periods of 7 years and 3.5 years, caused by the same significant periods of the temperature, and that indicates that the plateau plant is more senstive to the temperature than to the precipitation. Over 21 years, there are 7 from 8 types vegetation coverage which are raising unstably ineluding clod-arid-region plant with vulnerability and difficult recovery.