城市热岛效应与生态系统的关系及减缓措施

Urban heat island effect and urban ecosystems

城市热岛效应是人为影响气候最显著的特征之一.热岛引起地表温度的升高和水分改变,对城市生态系统的物质能量流动和城市生态系统结构与功能必将产生深远的影响.城市中的自然生态系统或自然—人工生态系统可通过改善城市下垫面的热属性,对热岛效应有一定的缓解作用.本文综述了城市热岛效应及其特征、城市热岛对植被物候和碳氮循环的影响及生态系统在减缓热岛效应中的作用.理解城市热岛效应的特征、影响因素及其与生态系统的关系,对开展缓解城市热岛的策略研究、改善城市生态环境具有重要意义.

Urban heat island(UHI)is a well-known form of anthropogenic climate modification,which is studied in large cities around the world.UHI influences material and energy flows,structure and function of urban ecosystems by changing land surface temperature and hydrology.Impacts of UHI on urban ecosystems,the physical,chemical and biological characters of soil and vegetation,are profound,with influences on the urban biogeochemical cycle.Urban natural ecosystem,on the other hand,could mitigate UHI effect by modifying urban surface thermal properties.UHI characters and seasonal variations,impact of UHI on urban ecosystems,role of ecosystem in mitigating UHI effect are reviewed in the present work.Research in related fields should be considered when planning future research directions,to deepen the understanding of UHI,and to correlate UHI and ecosystems.Mitigation strategies of UHI should also be encouraged to improve urban ecoenvironment and livability levels.Regarding the heat island phenomenon,further development and application of efficient mitigation technologies are needed.The mitigation potential of cooling systems should involve all major factors.We recommend the following:to deepen studies on urban heat islands,to determine optimum land-use patterns,to meliorate cooling effect of urban water body and wetland,to develop new and more efficient materials and procedures,to improve green roofs.Future research and development are necessary to enhance scientific and technological measures to counterbalance the impact of UHI and to improve comfort in urban environments.