1982～2015年渭河流域植被变化特征及气候因素影响

基于GIMMS NDVI3g（the third generation of Global Inventory Modeling and Mapping Studies Normalized Difference Vegetation Index）数据,结合趋势分析、Mann-Kendall检验和Pearson相关分析等方法,识别了渭河流域19822015年不同时间尺度（年、月及季节）植被NDVI的动态变化特征及气候因素影响。结果表明,近34年渭河流域NDVI呈现增长趋势,且20002015年NDVI较19821999年显著增长,趋势线斜率分别为0.003和0.001,退耕还林后植被覆盖状况明显改善;年均NDVI与气温呈显著正相关,与降水的正相关性较弱;月均NDVI与气温和降水都表现为显著正相关,相关系数分别为0.926,0.743;春秋季NDVI与气温呈现显著正相关,夏季NDVI与气温、降水的相关性不明显,冬季NDVI与前期气温存在滞后相关。

Vegetation Change Characteristics in Weihe River Basin during 1982-2015 and Its Related Climatic Factors

Based on GIMMS NDVI3g (the third generation of Global Inventory Modeling and Mapping Studies Normalized Difference Vegetation Index) data, combinedwith trend analysis, Mann-Kendall trend test and Pearson correlation analysis, the characteristics of vegetation change in different time scales (year, monthand season) and its relationship with the climate factors in the Weihe River Basin from 1982 to 2015 were identified. The results show that NDVI indicate an increasetrend in the Weihe River Basin in the past 34 years, and an increase tread of NDVI from 2000 to 2015 is significantly higher than that from 1982 to 1999, andthe slope of the trend line are 0.003 and 0.001. The vegetation cover was significantly improved after returning farmland to forest. There is a significant positive correlationbetween the mean annual NDVI and temperature, while the positive correlation between mean annual NDVI and precipitation is weak. The mean monthlyNDVI is significantly and positively correlated with the temperature or precipitation, and the correlation coefficients are 0.926 and 0.743. There is a significant positivecorrelation between NDVI and temperature in spring and autumn. The correlation between NDVI and temperature or precipitation in summer is not obvious,and there is a certain lag in NDVI and early temperature in winter.