利用MODIS遥感数据集的归一化植被指数(NDVI)分析2000-2017年中国西北地区植被NDVI时空变化特征，探究其与气象因子的相关关系。结果表明，中国西北地区植被覆盖具有显著的空间差异性，其东南部的NDVI明显高于其他地区，陕西地区总体较高，新疆地区总体较低。在18 a间中国西北地区NDVI总体呈上升趋势，但因年际间气象因子作用的差异性而具有一定的波动性。基于148个气象站点的气象资料和非参数百分法确定的极端气候指数，西北地区的气温和降水在18 a间，整体上有着上升的变化情况，极端降水事件和极端高温事件在不同程度上都有增加，同时极端低温事件情况发生得越来越少，极端低温事件的减少速率快于极端高温事件的增加速率，气温日较差的变化表现出逐年减小的趋势，与此同时严寒天气的出现频率呈现增大的趋势。对中国西北地区NDVI和气象因子的相关分析结果表明，NDVI随着气温的上升而增加，两者的正相关性较显著，同时随着极端低温日数的增加而下降，两者的负相关性较显著。

Based on the MODIS-NDVI remote sensing dataset from 2000 to 2017, this paper analyzes the correlation between the NDVI variation and meteorological factors in Northwest China. The results show that the spatial heterogeneity of Vegetation Coverage is significant in Northwest China. NDVI in the Southeast is apparently higher than other regions, with NDVI of Shaanxi province ranking the highest and Xinjiang province ranking the lowest. During the past 18 years, NDVI of Northwest China has been increasing, together with fluctuation in case of meteorological factors’ distinct affection. Through the meteorological data from 148 stations and extreme climate indices, the temperature and precipitation in Northwest China keep increasing. The frequencies of extreme precipitation event and extreme high temperature event are in the upward trend, while the frequency of extreme low temperature event is decreasing. The frequency of extreme low temperature declines faster than the frequency of extreme high temperature does. The diurnal temperature ranges become smaller, while the severe cold weather occurs more frequently. NDVI has a strong and positive relation with temperature, and a significantly negative correlation with the extreme low temperature.