基于NDVI的重庆市植被覆盖变化及其对气候因子的响应

运用美国NASA发布的MOD13Q1级产品16d最大值合成数据结合重庆市34个气象站点的气候资料，分析2000～2011年重庆市植被变化状况以及NDVI与主要气候因子温度、降水的相互关系。结果表明：12 a来重庆市年均NDVI呈增长趋势，但空间时间尺度上有所差异，从空间尺度上看NDVI增长区域主要分布在东北、东南、西南部区域，NDVI降低区域主要分布在重庆主城区、区县城区及长江沿岸、三峡库区消落带；从时间尺度上看，春季、秋季NDVI有一定幅度的增长，夏季NDVI趋于稳定，冬季NDVI有所下降；NDVI在年际尺度上与温度和降水相关并不显著，但在月份尺度上与气温降水均呈显著相关关系，且与气温相关性大于降水

VEGETATION COVERAGE CHANGE BASED ON NDVI AND ITS RELATIONSHIP WITH CLIMATE FACTORS IN CHONGQING

The relationships between vegetation and climate are always an important domain in ecological research．NDVI((Normalized Difference Vegetation Index) is a effective index that reflects the vegetation change．In recent years，the relationships between NDVI and climatic factors have been studied in many papers and the relative conclusions were different．Chongqing include the most part of Three Gorges Reservoir Area.In these area，vegetation cover are various，and the eco environment is relatively fragile．Therefore，it is worth to study the features of vegetation cover and the relations between vegetation and climate． In this paper，MODIS NDVI dataset was combined with climatic dataset to analyze vegetation cover changes and the correlation with climate factors in the study area during the periods of 2000 2011．NDVI images came from NASA，the spatial resolution was 250 m，which were treated with cloud checkout，atmosphere rectification and maximum value composite every 16 days．Climate indices included monthly average precipitation，monthly average atmospheric temperature，yearly average atmospheric temperature，yearly average precipitation obtained from 34 weather stations in Chongqing．The correlation coefficients of NDVI with all climatic factors were calculated with SPSS．The results showed that the annual average NDVI of Chongqing was on the rise, but some differences existed in time and space scales in the 12 years. Judging from the spatial scale，the NDVI growth areas were mainly located in the northeast，southeast，southwest region．The NDVI lower areas were mainly located in metropolitan area, county city，the Yangtze River and Three Gorges Reservoir area．Judging from the time scale, the NDVI had some growth in spring and autumn，and was very stable in summer，but declined in winter．The correlation of NDVI with temperature and precipitation was not significant in the interannual scales，while the temperature and precipitation showed a significant correlation in the month scale，and the correlation with temperature was greater than precipitation．