中国东北多年冻土退化对植被季节NDVI的影响研究

Effect of Degradation of Permafrost in the Northeast of China on Seasonal Change of Vegetation NDVI

多年冻土作为冰冻圈的重要组成部分对气候变化十分敏感,尤其是多年冻土上的植被,易受气候变化影响。利用景观生态学中"空间替代时间"方法,分析多年冻土退化对植被产生的影响。结果表明,不同多年冻土区植被春、夏、秋三个季节平均NDVI均具有增加的趋势。分析不同多年冻土区植被NDVI与气候因子相关性表明,短期多年冻土退化对植被的生长具有积极促进作用;长期由气温升高所引起的植被覆盖增加的幅度具有减弱的趋势,多年冻土退化会阻碍植被的生长。

Permafrost is a main component of the cryosphere,which is extremely sensitive to climate change,and more sensitive to climate change is the vegetation on it.Vegetation not only is sensitive indicator of terrestrial ecosystems responding to global climate change,but also is primary producer in food chain and plays pivotal function in carbon cycle.The permafrost zone in the northeast of China,which is located within middle and high latitudes of the northern hemisphere and in the southern edge of the Eurasian cryolithozone,is the second-largest region of permafrost in China.It is helpful to analyze the effect of degradation of permafrost on the Normalized Difference Vegetation Index(NDVI) for our reasonable replying the climate change.The research results showed that the average NDVI of spring,summer and autumn tended to be significantly increasing in different permafrost zones.The correlation analysis of vegetation NDVI of different permafrost with climatic factors suggested that the degradation of permafrost in the northeast of China in short term played a positive role in vegetation development.Although permafrost degradation resulted from increasing temperature is favorable for vegetation development in short term,for long term,permafrost degradation or even disappearance may attenuate or even hinder vegetation development.