陕西省1982—2015 NDVI时空分布特征及其与气候因子相关性

The variation characteristics of NDVI and relationship with climatic factors in Shanxi Province from 1982 to 2015

基于1982—2015年8 km的GIMMS NDVI和气象资料,结合陕西省土地利用类型数据,利用斜率分析以及相关分析等方法,对陕西省近34 a来植被指数NDVI的时空分布特征、变化规律及其与气候因子之间的相关性进行了深入研究,得到如下主要结论:(1)1982—2015年陕西省年均NDVI呈现出明显南高北低的地理特征,年均NDVI分布的空间差异性与下垫面类型密切相关,年均NDVI呈轻度上升趋势,局部地区(如渭河流域)增长尤为明显。(2)NDVI年际变化具有阶段性明显特征,1982—1990间增长显著,1991—2000和2001—2015年两段时期增长较为缓慢;NDVI年内变化差异明显,夏季NDVI最高,冬季最低,春季上升趋势最为明显。月均NDVI变化曲线呈单峰型,6—8月NDVI最高。(3)研究区NDVI与同期降水之间的响应最为明显,而草地、农地相比于整体区域以及林地与滞后1月的气温敏感性高于同期。

Based on the GIMMS NDVI data and meteorological data from1982to2015,the temporal and spatial distribution characteristics of NDVI in recent34years in Shanxi Province were analyzed by means of slope analysis and correlation analysis.The results are as follows.(1)From1982to2015,the annual average NDVI of Shanxi Province showed an obvious geographical characteristic from south to the north,in which the NDVI of south was higher than the north.With the spatial difference of the annual NDVI distribution,there was an significant correlation between NDVI and land use types.In general,the average annual NDVI showed a slight upward trend,and in some areas(such as the Weihe River Basin)the growth was particularly evident.(2)The interannual variability of NDVI had obvious characteristics.During the period from1982to1990,NDVI grew obviously,but increased slowly from1991to2000and from2001to2015.The NDVI was the highest in summer and the lowest in winter,and the increase trend was the most obvious in spring.The monthly average NDVI curve showed a single peak,and the NDVI was the highest between June and August.(3)The response of NDVI to precipitation in the same period was the most obvious,while the sensitivity to temperature of1month lag in grassland and agricultural land was higher than that of whole land and woodland of the same period.