西部人居环境学刊2023，Vol.38Issue(6)：9-14,6.DOI:10.13791/j.cnki.hsfwest.20230602
湿热地区城市静态水体能量分配特征研究
Characteristics of Energy Partitioning of Static Urban Water Bodies in Hot-Humid Regions:A Case Study of Liwan Lake in Guangzhou
摘要
Abstract
Urban areas play a fundamental role in local-to large-scale planetary processes by altering heat,moisture,and chemical budgets.As urbanization continues globally,it is vital to acknowledge the consequence of converting natural landscapes into the built-up environment.Cities around the world are experiencing elevated temperatures and extreme heat events due to the combined effects of global warming and urbanization.Recognizing cities as primary responders to global change,considerable efforts are currently dedicated worldwide to monitor and understand urban atmospheric dynamics.Additionally,various adaptation and mitigation strategies aimed to offset the impacts of rapid urban sprawl and urban overheating are being developed,implemented,and evaluated. Urban surfaces can influence the near-surface urban climate through three primary mechanisms,i.e.,radiative exchange,sensible heat exchange between urban surface and ambient air,and latent heat exchange via evaporation and transpiration.It is documented that urban surfaces could drive up to 25%of variation in air temperature.Urban water bodies,hailed as a nature-based solution,have emerged as an important potential strategy in tempering urban climates and enhancing thermal environments to design sustainable thermally-safe cities.The cooling benefits of water bodies have been widely investigated concerning their influence on surface and air temperatures.However,a better metric of thermal behavior of water bodies requires the consideration of the overall energy balance,including radiative energy exchange,convective heat transfer,evaporation,and heat storage and release.Analyzing the characteristics of energy partitioning of urban water bodies is the key to understanding and capturing the impacts of water bodies on urban thermal environment.However,due to the lack of systematic quantitative methods and adequate data support,the energy allocation of water bodies,i.e.,the physical process of energy exchange between water bodies and the surrounding environment,has not been investigated and elaborated thoroughly. Based on the energy balance theory,this study has further developed the energy balance observation methodology by integrating the Bowen ratio and energy balance equation.In comparison to the methods such as the Bulk coefficient and Eddy correlation methods,the Bowen ratio method offers a distinctive advantage in quantifying the energy components of water bodies,based on routine meteorological observations,considering both daytime and nighttime,as well as the calm wind conditions.In hot and humid regions of China,there is a dense network of rivers,streams,and canals,and water systems are well developed,closely intertwined with human settlements.Simultaneously,hot-humid regions are characterized with consistently high temperatures and high humidity throughout the year.With the exacerbation of global climate change,the urban heat environment issues in these regions are more severe than in other areas.Therefore,utilizing water bodies to improve the urban thermal environment is of significant importance for the construction of climate-resilience cities in hot-humid regions.Additionally,according to literature review,the thermal effects of water bodies vary by location.The response of water bodies in hot and humid areas to climate change differs from other regions.Further analysis of its physical characteristics can be conducted from the perspective of energy partitioning.Given the context above,the energy partitioning patterns of an urban lake located in the densely built-up areas of hot-humid regions,were obtained through continuous field measurements in summer and winter based on the Bowen ratio energy balance method,taking the Liwan Lake in Guangzhou as a case study. Results of this study demonstrated a multifaceted role played by the net radiation heat flux Q* in the energy balance of urban lakes.It was observed that the shortwave radiation functioned as the primary energy inputs during daylight hours,whereas longwave radiative cooling emerged as a significant heat release during nocturnal periods.Weather conditions exhibited varying impacts on distinct energy components of the lake,with net radiation heat flux Q* and latent heat flux QE being greater on clear and cloudless'ideal'days than on rainy and other days such as cloudy and overcast days.Conversely,sensible heat flux QH displayed negligible variations across the three weather conditions.The seasonal dynamics emerged as a critical determinant governing the energy allocation of the lake.In hot-humid summer,the heat storage flux Qs accounted for the highest percentage,indicating that a majority of the net radiation was directed towards heat storage.Conversely,during cold-arid winter,a significant portion of QE was observed,signifying that a substantial fraction of the energy inputs was converted into latent heat.These distinct seasonal trends underscored the adaptive nature of urban water bodies in redistributing energy based on prevailing climatic conditions.Findings of this study can provide a methodological reference for assessing the energy partitioning of static urban water bodies,provide data support of hot-humid regions for understanding the climate regulation effects of water bodies,and promote the construction of climate-resilience cities based on blue infrastructure.关键词
水体/能量平衡/波文比法/湿热地区Key words
Water Bodies/Energy Balance/Bowen Ratio Method/Hot-Humid Region分类
建筑与水利引用本文复制引用
姚灵烨,许亘昱,赵立华..湿热地区城市静态水体能量分配特征研究[J].西部人居环境学刊,2023,38(6):9-14,6.基金项目
国家重点研发计划政府间国家科技创新合作重点专项(2019YFE0124500) （2019YFE0124500）
广东省省级科技计划项目国际科技合作领域(2018A050501007) （2018A050501007）
亚热带建筑与城市科学全国重点实验室开放课题(2021ZB01) （2021ZB01）
广东省基础与应用基础研究基金自然科学基金面上项目 （）
