西安近10年植被覆盖变化及其与气候因子的相关性研究

研究分析了西安市2002年12月—2012年11月逐年、季、月植被NDVI序列,结合同期西安市的观测数据,总结出西安市NDVI的变化特点及其与气候因子的关系.结果表明:(1)近10年西安市NDVI呈整体上升趋势,年均值在0.237 8~0.252 5之间;春季NDVI增加量最大,为0.004/a.(2)10年来西安市年降水量呈递减趋势,气温基本持平,气候驱动力不利于植被覆盖增长;年降水量主要集中在夏、秋季,雨热同期满足了植被生长发育需求.(3)年和季NDVI总体上与同期平均气温、上期降水相关性较好.(4)西安市植被对降水变化的滞后时间约为1个月.(5)人为因素在植被变化中发挥着重要的作用.

Correlation between Vegetation Change and Climatic Factors of Xi'an

Based on the analysis of the monthly, quarterly and yearly vegetation NDVI （Normalized Difference Vegetation Index） sequences from December 2002 to November 2012 of Xi＇an and the synchro- nous observation data from seven national weather stations in the city, the characteristics of the NDVI changes and the correlation of the changes with climatic factors were summarized. The results show that in the past 10 years the NDVI of the city has shown an overall upward trend,the annual average NDVI fluctu- ates between 0. 237 8~0. 252 5 and in spring the NDVI has the biggest increment of 0. 004/a;in the past 10 years the annual precipitation of the city has showed a decreasing trend and the rainy periods are mainly in summer and autumn;the annual NDVI has a good correlation with the synchronous average temperature and the precipitation of the previous year;the NDVI of each season has a good correlation with its average temperature and the precipitation of the previous quarter;vegetation change is about one month behind the rainfall of the city,and human factors has an important effect in vegetation change.