干旱河岸林生态系统对局地地表温度影响的生物物理机制研究  

Studies of the Effects of Biophysical Factors on Surface Temperature over Arid Riparian Ecosystems in Northwest China

作　　者：罗凡迪 陈惠玲 朱高峰[2] LUO Fandi;CHEN Huiling;ZHU Gaofeng(College of Ecology,Lanzhou University,Lanzhou 730000,Gansu,China;College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,Gansu,China)

机构地区：[1]兰州大学生态学院,甘肃兰州730000 [2]兰州大学资源环境学院,甘肃兰州730000

出　　处：《高原气象》2023年第2期427-434,共8页Plateau Meteorology

基　　金：国家自然科学基金项目(41871078)。

摘　　要：森林在全球碳循环和调节局地温度等方面具有重要的作用。但是,关于干旱区森林生物物理过程如何影响局地温度的研究仍然未得到充分的重视。在本研究中,以西北干旱区内陆河典型河岸林生态系统和荒漠为研究对象,通过综合利用野外观测数据和温度分解方法(Decomposed Temperature Metric,DTM),系统分析了河岸林生态系统对局地温度的影响机制。结果表明:与荒漠相比,河岸林生态系统冠层净辐射量要显著高于周围荒漠(35.4 W·m^(-2));河岸林生态系统整体表现为降温作用,年均降温值为−1.28℃。但具有明显的季节变化特征,即从11月到次年2月,河岸林冠层温度略高于荒漠地表温度(ΔTs=0.5℃);从3-10月,河岸林冠层温度则要低于荒漠,表现为降温效应(ΔTs为−3.6~−0.6℃)。DTM方法表明:向下长波辐射的增加和地表反照率的下降是导致河岸林冠层温度升高的主要因素,而蒸散发是降低河岸林冠层温度的主要驱动因素。该研究不仅有助于提升我们对干旱生态系统与气候相互作用的认识,也对合理评估干旱生态系统的生态服务功能具有重要的参考意义。Forests play an important role in the global carbon cycle and modification of local climate through the biochemical and biophysical processes.However,the biophysical effects of afforestation in arid regions on local surface temperature have received little attentions over the past 30 years.Therefore,in this study,we combined in situ eddy covariance flux measurements from a neighboring pair of forested and the background desert sites with the decomposed temperature metric(DTM)method to systematically analyze the impacts of arid forests on surface temperature(Ts).Results showed that despite absorbing more net radiation(35.4 W·m^(-2))than the desert,the riparian forests tended to cool Ts(−1.28℃)on annual basis.Meanwhile,this cool effect shows a significant seasonality.Specifically,afforestation may lead to a net cooling effect(ΔTs ranging from−3.6 to−0.6℃)from March to October,and a slightly warming effect in other months(ΔTs=0.5℃).The DTM method revealed that evapotranspiration played a dominant role in cooling surface temperature,while surface albedo and incoming longwave radiation acted together to increase forest surface temperature.Therefore,this study not only improves our understanding of interaction between arid ecosystem and climate,but also has important reference for assessing ecological service function of in arid ecosystem.

关 键 词：河岸林 干旱区 地表温度 生物物理作用 净辐射 

分 类 号：Q148[生物学—生态学]