重庆市2000—2015年植被覆盖度时空变化特征

Spatial and Temporal Variation Characteristics of Fractional Vegetation Coverage in Chongqing from 2000 to 2015

以2000年2月至2015年9月的188期MODIS NDVI数据为基础,结合土地利用现状数据,采用像元二分模型法,提取重庆市近16年来的植被覆盖度(FVC)数据,并进一步分析研究区的植被覆盖度时空分布特征。结果表明:(1)从时间序列上来看,2000—2015年,研究区的多年均植被覆盖度为91.58%,年际之间的变化除个别年份由于极端气候影响(2006年干旱)出现低值外,16年来年最大植被覆盖度呈现较为稳定和升降交替的趋势;月均值呈规律性波动,5—8月最高,12月至次年3月最低。(2)研究区空间分异特征明显,总体上呈西低东高,由西向东南和东北两翼增加,其中秦巴山地和武陵山区的植被覆盖情况最好;就区县行政单元划分,城口县的多年平均植被覆盖度为97.28%,为全市最高,主城6区为84.87%,为全市最低。

Based on 188 monthly MODIS NDVI data from February 2000 to September 2015,combined with the data of land use status,the dimidiate pixel model method was used to extract fractional vegetation coverage（ FVC） data in Chongqing of the past 16 years,and the spatial and temporal distribution characteristics of FVC in the study area were further analyzed. The results showed that：（ 1） for the time series,the annual mean FVC in the study area was 91. 58% from 2000 to 2015,and the maximum FVC showed a stable rise-fall trend in16 years,except for a low interannual variation value in several years due to the extreme climate（ for example,the drought in 2006）; the monthly mean FVC fluctuated regularly,reached the highest value during period from May to August,and hit the lowest value during the period from December to March next year;（ 2） the spatial variation characteristics were apparent,generally lower in the west and higher in the east,and increased from the west to the southeast and northeast flanks,among which the FVCs of Qinba Mountain and Wuling Mountain areas were the highest; in terms of district / county level administrative units,the annual mean FVC of Chengkou County was 97.28%,which was the highest in Chongqing,and that of six districts was 84. 87%,which was the lowest in Chongqing.