土地利用/覆盖变化对气候的反馈作用

The feedback of land use/cover change on climate

土地利用与土地覆盖的变化直接反映了引起全球变化的主导因子———人类活动， 关于土地利用与土地覆盖变化的研究将有助于加深对全球变化与陆地生态系统相互作用的理解。文中基于地球表面的能量与水分平衡方程， 从理论上探讨了土地利用和土地覆盖对于气候的反馈作用， 研究表明：①植被对于降水的作用不大，植被的存在有助于减少径流，增加保水能力， 对于全球气候变化有减缓作用； ②植被对于气候变化的作用是增温还是降温须视具体地点的情况而定； ③对于中纬度地区，当下垫面反射率的变化与径流量的变化满足以下关系时：Δｆ＝ ５ Δα×１０－ ４ｇ／ｃｍ２ ·ｍｉｎ下垫面变化对于地表温度无影响。这表明在制定全球变化对策时必须因地制宜。

Land Use /Cover Change (LUCC) directly reflects the dominant factor leading to global change—human activities.The study on LUCC will enhance the understanding of the interaction between global change and terrestrial ecosystems,and improve the accuracy of evaluating and predicting the responses of terrestrial ecosystems to global change.In this paper,based on the two well known balance equations—heat and water balance equations on the earth's surface,the authors discuss the feedback of LUCC on climate.The study shows:(a)Vegetation has the function of reducing runoff,storing water and mitigating the effects of global climate change.The effect of vegetation on precipitation may not be considered.(b)The effect of vegetation on climate depends on specific regions.(c)In the middle latitude areas,if changes of the surface albedo and runoff meet the following relationship,Δf=5Δα×10-4g/cm2·min vegetation will not have an effect on earths surface temperature.This result indicates that strategies concerning global change should be suitable to local conditions.