Research On Microclimate Numerical Simulation Method For Urban Residential Communities Under Snow-Covered Ground Surface Condition

The urban microclimate has a direct impact on the quality of life of city residents.As the most fundamental part of urban design and an important living space for residents,their health comfort and safety are closely linked to their outdoor microclimate environment.At present,research on microclimate in summer residential areas has achieved fruitful results.However,there is a lack of research on winter urban microclimate in cold regions.The snow-covered ground surface is a reflection of the special characteristics of the winter urban substrate in cold regions,and is also an important element affecting the microclimate of winter residential communities in cold regions.Based on the physical properties of the snow-covered ground surface,this thesis establishes an atmosphere-snow mass exchange model and couples the mature three-dimensional microclimate model ENVI-met to carry out a quantitative microclimate simulation method for urban residential areas in severe cold regions during winter.The simulation method is of great importance to study the improvement of urban microclimate in very cold regions in winter.First of all,the characteristics of the ENVI-met microclimate model are analyzed.From the perspective of overall energy balance,the coupling strategy between the consortium model and ENVI-met is finally established by considering both the physical characteristics of the snow and ice subsurface and the microclimate influence parameters.Then,a data aggregation and analysis platform is established in the ArcGIS software environment,which is used to transfer the initial conditions and meteorological boundary conditions of the joint thermal mass exchange model,as well as to visualize and analyze the data,so as to achieve quantitative simulation prediction and evaluation of the microclimate of urban residential areas under snow conditions.Secondly,The properties of the ENVI-met microclimate model are analyses and a coupling strategy between the combined model and ENVI-met is determined by integrating the physical properties of the snow subsurface and the microclimate parameters into the total energy balance,and then the data aggregation analysis platform is established in the ArcGIS software environment to transfer the initial conditions and meteorological boundary conditions of the combined thermal mass exchange model.At the same time,the data are visualized and analyzed to realize the quantitative simulation prediction and evaluation of urban residential microclimate under snow environment.Thirdly,the previously established coupled simulation method is integrated,and a series of field tests are conducted for the physical quantities of residential microclimate conditions,The measured data were compared and analyses with the model simulations,and the snow and ice subsurface temperature fields and snow albedo were analyzed.The validation results show that the combined atmosphere-snow heat mass transfer model can more accurately describe the subsurface temperature variation of snow and ice;compared with the simple ENVI-met model,the coupled simulation method can more accurately simulate the microclimate of urban residential area under snow-covered ground surface conditions quantitatively,which can meet the microclimate research needs of cold urban residential area.The coupled simulation method can quantify the microclimate of urban residential areas under snow conditions more accurately,which can meet the needs of microclimate research in cold urban residential areas.Finally,the coupled simulation method is used to quantify the effects of different snow cover and hard fragmentation on the outdoor microclimate of the outer environment of the residential area by using the actual meteorological data to simulate the example model based on the characteristics of the cold residential area.Based on the quantitative simulation results,we propose some sustainable landscape design strategies for winter outdoor microclimate in urban residential areas from the perspective of snow-covered ground surface.