基于偏相关分析的区域植被覆盖变化

利用西北地区植被数据(GIMMS-NDVI),以绿度变化率和偏相关分析法为基础,分析了西北地区不同生态分区NDVI的年际变化,并研究了植被覆盖变化对气候要素在空间上的响应。结果表明,西北地区的东部和西北部植被覆盖较好,研究区的西部盆地区和西南部的高寒区,植被覆盖较差;不同生态分区NDVI的变化与气温的相关性明显高于与降水的相关性,但降水是限制性因子,决定着ND-VI与降水相关的密切程度;水热条件较好的区域主要分布在西北地区中东部,NDVI与水热要素的相关性由草原、草甸、阔叶林向荒漠逐步减弱,极端干旱荒漠区相关性最小。

Regional Vegetation Cover Change Based on Partial Correlation Analysis

Using 15-day GIMMS-NDVI data from 1982-2006,based on GRC and partial correlation analysis,this paper investigated the variation of annual average NDVI both in the overall northwest China and in different eco-geographical regions.The spatial characteristics of the response of NDVI to climatic factors(temperature and precipitation) in different eco-geographical regions were assessed.As indicated by the results,the vegetation cover is good in the east and northwest area of Northwest China,but worse in the west basin and southwest area of the study area.The correlation between the NDVI change of different eco-geographical areas and temperature is higher than that between the NDVI change and precipitation,the precipitation is limiting factor,which determines the relations between NDVI and precipitation,the good water and heat conditions are mainly distributed in the central and eastern part of Northwest China,the correlation between NDVI and water and heat conditions decreases in the order from grassland,meadow,broad-leaved forest to desert,and it is the weakest in the extreme dry desert.