中国东北地区植被NDVI对气候变化的响应

Responses of vegetation NDVI in Northeast China to climate change

结合1982—2003年GIMMS-NDVI数据集和GIS技术,应用基于像元的相关分析方法,分析了东北地区植被NDVI对气候变化的响应。结果表明:1)1982—2003年,东北地区年平均气温呈上升趋势,而年降水量呈下降趋势;东北地区植被NDVI与年平均气温呈显著正相关的像元占12.84%,主要分布在松嫩平原南部、三江平原中部和西辽河平原,植被类型为农田、阔叶林、草原。植被NDVI与年平均气温几乎不存在显著负相关性;植被NDVI与年降水呈显著和极显著正相关的像元比例为4.55%,主要植被类型为草原和农田;植被NDVI与年降水量呈显著负相关的像元比例为7.52%,主要植被类型为针叶林和阔叶林。2)东北地区植被与生长季气温显著正相关和显著负相关的比例分别为3.96%和4.35%;植被与生长季降水显著正相关和显著负相关的比例分别为8.81%和8.54%。3)东北地区58.21%的植被像元与春季气温显著或极显著正相关,主要分布在大兴安岭中部、小兴安岭、长白山及完达山-张广才岭等地区,主要植被类型为阔叶林、农田、针叶林和草甸;植被NDVI与春季气温几乎不存在显著负相关性。植被NDVI与春季降水呈显著正相关和显著负相关的比例分别为4.81%和1.67%。4)东北地区植被NDVI与夏季气温和降水呈显著相关的比例明显少于春季,与夏季气温正相关的比例为7.61%,与夏季降水显著负相关的比例为6.29%。秋季气温和降水对东北地区植被NDVI影响较小,其中植被NDVI与秋季气温显著正相关的像元占植被像元总数的6.05%,几乎不存在与秋季气温显著负相关的植被像元;植被NDVI与秋季降水显著负相关的比例为5.43%,几乎不存在与秋季降水显著正相关的植被像元。

With the combination of 1982-2003 GIMMS-NDVI datasets and GIS technology, and applying correlation analysis based on each pixel, the responses of the vegetation NDVI in Northeast China to climate change were analyzed. In 1982-2003, the mean annual air temperature in study area had an increasing trend, while the annual precipitation was in adverse. The pixels whose NDVI had significant positive correlations with mean annual temperature occupied 12. 84% of the total, mainly distributed in south Songnen Plain, central Sanjiang Plain, and west Liaohe Plain. Their vegetation types were cropland, broadleaf forest, and steppe, and the NDVI had less negative correlation with mean annual air temperature. The pixels whose NDVI significantly positively correlated with annual precipitation occupied 4.55%, and their main vegetation types were steppe and cropland. The pixels whose NDVI significantly negatively correlated with annual precipitation occupied 7.52%, and the main vegetation types were coniferous forest and broadleaf forest. The vegetations significantly positively and negatively correlated with the air temperature in growth season occupied 3.96% and 4. 35% of the all, while those having significant positive and negative correlations with the precipitation in growth season occupied 8.81% and 8.54%, respectively. There were 58.21% pixels whose NDVI significantly correlated with the air temperature in spring, mainly distributed in central Great Xingan Mountains, Small Xingan Mountains, Changbai Mountains, and Wanda-Zhangguangcai Mountains. Their main vegetation types were broadleaf forest, cropland, coniferous forest and meadow, and the NDVI had less negative correlation with the air temperature in spring. The pixels whose NDVI significantly positively and negatively correlated with the precipitation in spring was 4.81% and 1.67%, while those whose NDVI having significant positive correlation with the air temperature in summer and negative correlation with the precipitation in summer were 7.16% and 6. 29%, respectively. The air temperature and precipitation in autumn had smaller effects on the vegetation NDVI. There were 6. 05% of pixels whose NDVI significantly positively correlated with the air temperature in autumn, and few had significant negative correlation with it. The proportion of the pixels whose NDVI significantly negatively correlated with the precipitation in autumn was 5.43%, and hardly any pixels whose NDVI had significant positive correlation with autumn precipitation.