中国植被物候研究进展及展望

Vegetation phenology response to climate change in China

本文围绕气候变化背景下的中国植被物候研究,梳理了植被物候对气候变化的响应机制,分析了中国植被物候变化对陆地生态系统碳、水和能量循环的影响,植被物候变化对局地气候的反馈机制以及通过大气环流对气候系统的影响.主要结论:1)中国植被生长季开始日期提前1~6 d·(10 a)^(-1),结束日期推迟2~5 d·(10 a)^(-1),生长季显著延长;2)中国中高纬度地区植被对温度的响应明显高于亚热带和热带地区,温度在控制植被物候的过程中起到多重作用,降水主要影响干旱和半干旱地区的植被物候;3)植被生长季延长增加陆地生态系统生产力,增加中国碳汇;4)植被物候变化改变植被的蒸散发量,从而改变我国的流域尺度河流径流;5)在中国大部分地区,植被物候变化对气候系统产生负反馈作用,甚至影响大气环流过程.中国植被物候的研究越来越多,但仍存在亟待解决的科学问题,比如未来中国植被物候研究需要更加关注遥感数据反演精度,明确物候响应气候变化机制的尺度效应,结合机器学习等智能算法改进物候模型提高物候模拟精度,并重视农作物物候,加强物候与森林管理结合研究以提高我国生态系统碳汇能力,积极面对碳中和带来的机遇与挑战.

This article reviews response mechanisms of vegetation phenology to climate change, clarifies impacts of vegetation phenological changes on carbon, water, and energy cycles of terrestrial ecosystems, and feedback mechanisms of vegetation phenological changes on local climate and the climate system through atmospheric circulations. The start of the vegetation growing season in China was found to have an advanced trend(about 1-6d·(10 a)^(-1)),the end of the growing season has a delayed trend(about 2-5 d·(10 a)^(-1)),growing season significantly extended. Responses of vegetation phenology to temperature in mid-high latitudes are now significantly higher than in subtropical and tropical regions. Temperatures were found to play multiple roles in controlling vegetation phenology.Precipitation was found to mainly affect vegetation phenology in arid and semi-arid regions. Vegetation phenological changes( growing season prolonged, photosynthesis of vegetation greater than respiration, thereby fixing more carbon) were found to increase productivity of terrestrial ecosystems and increase China’s carbon sink. Vegetation phenological changes could adjust vegetation evapotranspiration, thereby changing China ’s watershed-scale river runoff. Vegetation phenological changes have a negative feedback effect on climate system in most parts of China,and affect atmospheric circulation process. Therefore,temporal and spatial characteristics and trends of vegetation phenology provide reference for reducing emissions and increasing carbon in different regions of China. Although works on vegetation phenology in China have been done,certain uncertainties remain to be resolved. Future works should pay more attention to inversion accuracy of remote sensing data,clarify scale effect of phenological response to climate change, combine machine learning, manipulative experiments and ecophysiological methods to improve accuracy of phenology simulation. Also we should focus on crop phenology to ensure food insecurity, strengthen researches on combination of phenology and forest management to improve carbon sink capacity of ecosystem. We must face opportunities and challenges brought about by carbon neutrality.