Effect Of Street Geometry On Outdoor Thermal Comfort In Summer Days Of Wuhan City

Massive and intensive urbanization process not only brings about rapid population growth and economic development,but also leads to climate abnormality in higher frequency and furtherly affects citizens’ health and living quality.Urban overheat phenomenon triggers diseases and even deaths of people living in cities,which makes activities in outdoor spaces dangerous.Among those spaces,urban street canyons make up the most proportion and thus should be paid much attention.Although there are gradually increasing researches in outdoor thermal comfort,connections in urban planning/urban design and outdoor thermal comfort are scares.The reasons lie in two parts,one of which is complexity in human sense for temperature while another is that most of comfort researches are related to meteorology and air-conditioning/week electricity subjects.Therefore,it is important and necessary to provide strategies and measurements suggestions to thermal environment design in the context of urban planning and canyon street design.Wuhan is chosen as a case study,where is especially hot during summer days.This research provides a method for analyzing the most appropriate street geometry range and combinations for outdoor thermal comfort in summer days.Firstly,according to behaviors of land surface temperature and main land use function,three areas with high LST and function as living,business and public uses are picked up.Then with meteorological data from automatic weather stations nearby as boundary conditions,simulations in hourly mean radiant temperature in targeted blocks are finished.Spatial analysis and statistics are then used to calculate street geometry parameters,aspect ratio and street orientation respectively.Through subdividing street into segments,it provides more detailed street geometry features in micro level.Finally,mathematical statistics are taken based on above works.Ranges in most comfort and worst comfort caused by different combinations of aspect ratio and orientation are given.Furtherly,some advice and strategies in approving outdoor thermal environment and comfort level are suggested for Wuhan city,in reference of both industry standard and common means.