1982-2003年东北林区森林植被NDVI与水热条件的相关分析

以气象站点为研究单元,将1982—2003年东北林区森林植被月平均、季平均和年平均NDVI数据与其对应的水热条件(温度和降水)进行相关、偏相关和复相关分析。结果表明:温度是影响东北林区森林植被NDVI的最主要气候因子。春季、秋季不同森林植被平均NDVI与温度和降水呈极显著相关(P<0.01),其与温度的相关性高于其与降水的相关性。寒温带针叶林NDVI在生长季与温度和降水呈极显著相关(P<0.01),其与降水的相关性略高于其与温度的相关性,而全年温度对寒温带针叶林生长的影响高于降水。寒温带针叶林NDVI在4月份与降水的时滞偏相关性高于其他月份,相关系数达-0.385。温带针阔叶混交林NDVI在4—7月与温度的时滞偏相关性较高,相关系数分别为0.581,0.490,-0.266和-0.297。暖温带落叶阔叶林NDVI在4月份与温度的时滞偏相关性高于其他月份,相关系数为0.571;在7月份与降水时滞偏相关性高于其他月份,相关系数为-0.367。森林植被生长增长阶段NDVI受综合水热条件(温度和降水)的滞后影响显著。

Correlations between forest vegetation NDVI and water/thermal condition in Northeast China forest regions in 1982-2003

The correlation between the monthly,seasonal and yearly mean NDVIs of forest vegetations and corresponding water/thermal conditions(precipitation and temperature) in Northeast China from 1982 to 2003 were analyzed.Results showed that,temperature was the primary climatic factor affecting the NDVIs.The mean NDVIs of various forest vegetations had significant correlations(P<0.01) with the temperature and precipitation in spring and autumn,and the correlation coefficient with temperature was higher than that with precipitation.For cool-temperate needleleaf forest,its NDVI had significant correlation(P<0.01) with the temperature and precipitation of growing season,the correlation between NDVI and precipitation was higher than that with temperature but was adverse for the whole year.The time lag partial correlation between NDVI of cool-temperate needleleaf forest and precipitation is higher in April,with a correlation coefficient of-0.385.For temperate needleleaf and broadleaf mixed forest,the time lag partial correlation of its NDVI with temperature was higher in April-July,with a correlation coefficient of 0.581,0.490,-0.266 and-0.297,respectively.For warm-temperature deciduous broadleaf forest,the time lag partial correlation between its NDVI and temperature was higher in April,with a correlation coefficient of 0.571,while the coefficient between NDVI and precipitation was higher in July with a correlation coefficient of-0.367.During growth period,the effects of water/thermal conditions(precipitation and temperature) on forest vegetation NDVI were lagged significantly.