青藏高原植被生长季NDVI时空变化与影响因素

Spatiotemporal variation and driving factors of growing season NDVI in the Tibetan Plateau,China

青藏高原是中国乃至亚洲的生态屏障,研究其植被对气候变化的响应对区域生态保护具有重要的现实意义。基于MOD09A1数据反演的生长季归一化植被指数(NDVI),分析2001—2018年青藏高原植被生长季NDVI时空特征和变化趋势,结合气象站点数据阐释NDVI与气候因子的关系。结果表明:研究期间,青藏高原植被生长季NDVI呈缓慢上升趋势,不同气候区生长季NDVI年际变化差异明显,NDVI值波动幅度表现为高原湿润气候区>半湿润气候区>半干旱气候区>干旱气候区。青藏高原湿润气候区、半湿润气候区、干旱气候区、半干旱气候区NDVI显著升高和降低面积占比分别为1.4%和1.9%、4.9%和1.5%、16.4%和0.8%、7.0%和2.0%,干旱和半干旱气候区NDVI升高面积占比明显大于湿润和半湿润气候区。气温是影响湿润气候区和半湿润气候区NDVI变化的主导因子,而在干旱气候区,降水对NDVI的影响明显强于其他气候因子。气温对整个青藏高原植被生长季NDVI的驱动作用强于降水和相对湿度。

It is important to understand the response of vegetation to climate change in Tibetan Plateau(TP),an ecological barrier for China and Asia.The spatiotemporal variation of the normalized difference vegetation index(NDVI)of vegetation growing season were analyzed based on the gro-wing season NDVI retrieved from MOD09 A1.The relationship between NDVI and climate factors was analyzed by combining the data of meteorological stations in TP from 2001 to 2018.The results showed that NDVI in the growing season showed a slow upward trend during the study period.There was substantial interannual variation of NDVI in different climate regions.The fluctuation magnitude of NDVI value was plateau humid climate region>semi-humid climate region>semi-arid climate region>arid climate region.The proportion of area with increasing and decreasing NDVI in humid climate region,semi-humid climate region,arid climate region,semi-arid climate region on TP were 1.4%and 1.9%,4.9%and 1.5%,16.4%and 0.8%,7.0%and 2.0%,respectively.The areas of increasing NDVI in arid and semi-arid climate region was significantly larger than humid and semi-humid region.Temperature was the leading factor affecting the change of NDVI in humid and semi-humid region.The impact of precipitation on NDVI was significantly stronger than that of other climate factors in arid region.The impact of air temperature in growing season on NDVI was stronger than that of precipitation and relative humidity.