The Influence Of Urban Rivers On Microclimate In Blocks

The climate change in the city has produced a variety of weather phenomena such as high-temperature heat waves,storms,floods,and haze,which have brought many disadvantages to production and life.Studying the urban climate,exploring the underlying principles and mechanisms,and providing improved decision-making advice can promote the sound development of urban climate and provide residents with a healthy production and living environment.But,as for the blocks that are closely related to people's life,its microclimate impacts are neglected,the microclimate study of a river block is relatively weak.It is well known that river water body has natural ecological effect value;it's cooling and humidifying function can effectively adjust the local microclimate.Therefore,it is of great significance to study the influence of urban river and river layout on the microclimate of the block,to improve the microenvironment of the neighborhood,to optimize the layout of the water body,and to improve the residential comfort level of the neighborhood.First of all,this article investigates river districts in Shanghai,Then,analyzes the type of layout of the river in the neighborhood,and sums up the types of river neighborhoods in this paper into three categories: crossing type,waterfront type,and confluence type,the final study objects are identified as 11 typical determinant river blocks with multi-storey building heights.Secondly,this paper compares the measured data with hand-held meteorological instrument(Kestrel 5000,error of 0.5±1°C)and ENVI-met simulated data,and verifies the validity of ENVI-met.Furthermore,the article simulates and analyzes the effect of cooling and humidification in river blocks,and the differences in microclimate effects among different river layout blocks.Finally,the multiple regression analysis are used to analyze the influence factors of microclimate effects in 11 river blocks.The research results show that :(1)the overall microclimate comfort of a river block is good,and the simulation analysis of river blocks has a strong cooling and humidification effect within 110 m.(2)In different river layout blocks,if the river is in the middle of the block and the river is in the upwind direction of the prevailing summer wind direction,then the micro-environment of the block is better.With the same size of blocks,increasing the proportion of water can reduce the temperature of the block and increase the humidity in the block.However,the larger the proportion of water,the better the thermal comfort of the micro-environment in the neighborhood.(3)By analyzing the microclimate influence factors in 11 small and medium-sized river blocks,it was found that the average radiant temperature of micro-environmental factors had a greater environmental impact on the neighborhood;the ratio of water body in the river factors,and the index of landscape shape were all related to the micro-environment of the block,and their influence is obvious;among the spatial elements in the neighborhood,the microclimate is affected more significantly by the building's SVF,the integrated SVF of the building and the vegetation,the ratio of street paving,and the volume ratio of the neighborhood.