青藏高原NDVI变化趋势及其对气候的响应

Variation Trend of NDVI and Response to Climate Change in Tibetan Plateau

高原脆弱生态区对全球变化具有放大镜效应,利用长时序遥感数据及气象观测资料探索青藏高原对全球气候变化的响应具有重要意义。以1982—2012年GIMMS NDVI数据及同时期气象观测数据为数据源,借助于最大值合成、相关性分析和线性回归等数据分析技术,分析了青藏高原4 000m高海拔区域的NDVI的变化趋势以及气候响应。结果表明:(1)近31年来,青藏高原对全球变化响应明显,年降水量、温度均呈显著增长趋势(p<0.05),NDVI年变化率为正值、植被覆盖度呈增长趋势,均表明近年来青藏高原植被长势渐变良好。(2)青藏高原NDVI与降水、温度弱相关,温度对高海拔地区NDVI的影响超过降水,且降水对青藏高原NDVI的影响具有滞后性。(3)从青藏高原不同区域海拔高度和NDVI等值线的分布来看,地势对NDVI具有显著影响,海拔高度较高的区域NDVI值普遍较小。

The fragile ecological regions of plateau have zoom function on global change.Using the remote sensing data and meteorological data with long time series to explore the response of Tibetan Plateau to global climate change is of great significance.Variation trend of NDVI and response to climate change in 4 000 m altitude region of Tibetan Plateau were analyzed by means of maximum value composite,correlation analysis and linear regression and using 1982-2012 global inventory modeling and mapping studies normalized difference vegetation index and meteorological data contemporary with GIMMS NDVI.The results show that:(1)Tibetan Plateau has remarkable response to global change,annual precipitation and temperature show the significant growth(p<0.05),the annual change rate of NDVI is positive and vegetation coverage shows growth trend over the past 31 years,suggesting that vegetation in Tibetan Plateau has been growing better;(2)NDVI of Tibetan Plateau is not significantly associated with precipitation and temperature,the effect of temperature on NDVI exceeds precipitation in the regions with high altitudes,and the effect of precipitation on NDVI shows hysteresis with 3 years;(3)the terrain has the significant influence on NDVI depending on altitudes and distributions of NDVI contour lines in different regions of Tibetan Plateau,and NDVI in regions with higher altitude is little.