中国区域植树造林对地表温度的影响

The influence of afforestation on land surface temperature in China

近些年随着中国植树造林计划的持续进行,植被覆盖不断增长,进而影响中国地表环境。地表温度是表征地表物理过程的重要参数,是地表—大气能量交换中的驱动因子,广泛应用于气候、水文、生态及气象等研究中,是众多基础学科研究的关键参数之一。为了分析植树造林战略对局地和区域尺度的影响,以指导相应政策的制定,本文采用IBM(Intrinsic Biophysical Mechanism)方法研究了中国区域植树造林对地表温度的影响,并讨论了辐射效应与非辐射效应以及不同林地类型对地表温度的影响。结果表明:(1)植树造林对地表温度的影响在高纬度地区的寒冷季节表现为增温作用,而在温暖季节各纬度均表现为降温作用。(2)寒冷季节高纬度地区植树造林对地表温度的辐射效应较为强烈,而在其他季节各纬度植树造林对地表温度的非辐射效应占主导作用,辐射效应较为微弱。(3)开阔地转为林地时,不同林地类型对地表温度有不同的影响特征。开阔地转为落叶阔叶林时对地表温度的影响与植树造林对地表温度的总体影响变化具有相似特征,表现为在寒冷季节高纬度地区为增温作用,在低纬度地区均表现为降温作用,开阔地转为常绿针叶林、常绿阔叶林时对地表温度的影响均表现为降温作用。

In recent years,as China’s afforestation plan continues,vegetation cover has continued to increase,which in turn affects China’s surface environment.Land Surface Temperature(LST)is an important parameter that characterizes the physical processes of the surface,and is the driving factor for the energy exchange between the surface and the atmosphere.It is widely used in the research of basic subjects such as climate,hydrology,ecology and meteorology,and is one of the key parameters in many basic researches.To study the impact of afforestation strategies on local and regional scales and guide the implementation of corresponding policies,this study uses the IBM(Intrinsic Biophysical Mechanism)method to investigate the impact of afforestation in China on LST,and discusses the effects of radiative and non-radiative forcing and different vegetation cover types on LST.The results show that:(1)the influence of afforestation on LST is shown as a warming effect in the cold season in high latitudes,but as a cooling effect at all latitudes in the warm season.(2)The radiative effect of afforestation on LST in high latitude areas in cold season is relatively strong,while in other seasons,the non-radiative effect of afforestation on LST at various latitudes is dominant,and the radiative effect is relatively weak.(3)When open land is converted to forest land,different types of forest land cover have different characteristics of impact on LST.When open land is converted to deciduous broad-leaved forest,the impact on LST is similar to the overall impact of afforestation on LST,showing a warming effect in high latitude areas in the cold season,and a cooling effect in low latitude areas.The effect of open land into evergreen coniferous forests and evergreen broad-leaved forests on LST is shown as a cooling effect.This study analyzes the impact of afforestation on LST in the context of continuous afforestation in China.The research has practical significance for current afforestation policies and provides theoretical guidance for future afforestation strategies.