沙漠化与气候变化互馈机制研究进展

Progress on Feedback Mechanism between Aeolian Desertification and Climate Change

沙漠化与气候变化是当前全世界面临的两大热点问题,尤其是二者之间的互馈机制是研究的热点和难点。气候条件的恶化如持续干旱等可以引起土地的沙漠化,而沙漠化又可以通过生物地球物理互馈机制、增加沙尘气溶胶和温室气体等途径反作用于气候变化,并可能在局地形成正反馈,导致沙漠化向恶性方向发展。笔者在查阅大量文献的基础上,系统回顾了气候变化对沙漠化影响的研究历史,并从生物地球物理互馈机制、沙尘增多及温室气体增加对气候的影响三个方面概述了沙漠化对气候变化的反馈研究。在研究中存在如下瓶颈:①生物地球物理互馈机制发生的尺度;②沙尘和降水的因果关系;③数据的不一致性及数据特征的差异;④沙漠化过程中自然因素与人为因素的剥离。笔者认为:未来研究应从地球系统科学的角度出发,综合研究沙漠化与气候变化问题,并将模型研究与实地观测并重。

Aeolian desertification and climate change are two hotspots people are facing today. Much attention is paid on the feedback loops between them two. Deterioration of climate conditions, continuous desiccation for instance, can lead to aeolian desertification, and aeolian desertification can give a negative reaction to climate change through biogeophysical feedback, releasing more dust aerosol and increasing green-house gases concentration. In local areas, this kind of interaction may come into being positive loops, allowing the disturbance to be amplified. Based on the analysis of a large amount of literatures, the authors reviewed the existing research systematically through analyzing the feedback loops between climate change and biogeophysical feedback mechanism, dust aerosol and greenhouse gases. There are four bottlenecks in the research： ①the scale that biogeophysical feedback mechanism takes effect; ②causality between dust aerosol and precipitation; ③disagreement of the data used and the differences of their characters; Omethods to distinguish the human-induced and natural factors that lead to aeolian desertification. The authors claim that scientists should study the interactions between aeolian desertification and climate change system-atically in earth system science terms, and pay more attention on both model research and field observation.