中国季节性昼夜增温的不对称性及其对植被活动的影响

基于1982—2015年气象数据,采用线性趋势分析和GIS空间分析方法对我国近34年季节性昼夜增温的时空格局进行分析;并结合GIMMS-NDVI 3g遥感数据和植被区划数据,采用偏相关分析方法探讨不同植被分区植被对季节性不对称性增温的响应。结果表明:(1)近34年来中国昼夜气温普遍存在极为显著的上升趋势;昼夜增温在各季节均表现出不对称特征,且该不对称特征存在明显的季节性差异,春季、夏季、秋冬和冬季白天增温速率分别为夜间增温速率的1.49倍、0.98倍、0.73倍和1.69倍;(2)不同分区植被对季节性昼夜不对称增温的响应各异:相对于夜间增温,白天增温对植被活动影响程度更大,影响区域更为广泛;春季和冬季昼夜增温对植被活动的影响范围更广,且春、秋季昼夜增温对植被NDVI的上升普遍起到促进作用;(3)季节非对称性昼夜增温对不同分区的植被活动有不同的影响,这种影响程度随季节的变化存在明显差异。通过分析中国昼夜增温的季节性变化趋势及其对不同类型植被的影响,有助于加深我们对全球气候变化背景下季节性昼夜不对称增温对中国陆地植被动态影响的认识。

Asymmetric seasonal variability in day-and night-time warming and their effects on vegetation activity in China

This study examines asymmetric variations in day-and night-time warming using a least squares linear regression analysis, and characterizes the different effects of seasonally asymmetric warming on vegetation activities in China using a two-order partial correlation analysis method. Using normalized difference vegetation index, vegetation type, and meteorological data, the following results were obtained. (1) There was a significant trend of day-and night-time warming during the growing season from 1982 to 2015. Day-and night-time warming rates were seasonally asymmetric:the day-time warming rate in spring, summer, autumn, and winter was 1.49, 0.98, 0.73, and 1.69 times higher, respectively, than that at night. (2) Day-time warming had a significantly greater and more extensive impact on vegetation than night-time warming. The areas affected by asymmetric seasonal warming in spring and winter were larger than those in summer and autumn. (3) Different vegetation types responded differently to seasonal asymmetry in day-and night-time warming, and the degree of responses varied distinctly between different seasons. This analysis of seasonal variations in day-and night-time warming and the impacts of seasonal warming on different types of vegetation directly contributes to our understanding of the local and regional effects of warming on terrestrial vegetation in China within the context of global climate change.