Study On Transfer Of Feature Infrared Radiant Energy For Urban Thermal Environment Analysis

Since the reform and opening up,China's urbanization process is developing rapidly.By the end of 2015,the rate of China's urbanization has reached 56.1%.The large-scale urbanization movement has caused more and more prominent problems,such as traffic congestion,serious air pollution,urban waterlogging and so on.The urban thermal environment has become increasingly prominent problems,as the main composition of the urban structure is a concrete,its low heat capacity,high thermal conductivity,coupled with the building block of the wind.At present,improvement measures of urban thermal environment mainly focus on the green layout,water planning,urban ventilation,improvement of the underlying surface material and so on.However,these measures have significant limitations,so it is very urgent to explore the new ideas of improvement scheme of urban thermal environment.In this paper,it get rid of the traditional concept of heat transfer and transformation in the city,and explores a new way to improve the urban thermal environment,that is to study the radiation heat transfer law of urban features and space.Under the above guiding ideology and the two theoretical basis that 8~12?m band is atmospheric thermal infrared window and the main features of radiant energy concentrated in the 6~18?m band,this paper studied the following three aspects.Firstly,this paper analyzes the structure and composition of the atmosphere,summarizes the calculation method of atmospheric absorption of infrared radiation,and then established the calculation theory and method of the spectrum of atmospheric absorptivity.According to this method,this paper obtain the absorptivity spectral of summer and winter tropospheric atmosphere in the mid latitude standard atmosphere model to the 8~14?m band infrared radiation,and the hourly absorptivity spectrum of the troposphere atmosphere of actual atmospheric model on September 12,2016 to September 19,2016 in Shapingba District of Chongqing to the 8~14?m band infrared radiation.The following conclusions are summarized: the absorptivity range of summer tropospheric atmosphere in the mid latitude standard atmosphere model to the 8~14?m band infrared radiation were 37.8%~100%,the average absorptivity is 59.3%;the absorptivity range of winter tropospheric atmosphere in the mid latitude standard atmosphere model to the 8~14?m band infrared radiation were 12.4%~100%,the average absorptivity is 32.9%;and the actual atmospheric model tropospheric absorptivity is maximum amplitude changes in September 12,2016,the absorptivity changes slowly decreased from September 12 th to September 15 th,the atmospheric absorptivity is very close in September 15 th,the atmospheric absorption rate has gradually increased from September 15 th to September 19 th.Secondly,based on the features emissivity spectral in the features spectrum database and the hourly temperature of typical features,this paper analyzes the static transmission of features infrared radiation in standard latitude in summer and winter atmospheric model,and the dynamic transmission of features infrared radiation in the actual atmosphere mode.Thus,this paper concluded that the radiation energy of the features in the 8~14?m band in different atmospheric modes,the absorption energy of the atmosphere in the troposphere to the features radiation energy in 8~14?m band,and the features radiation energy in 8~14?m band through the troposphere atmosphere.The results showed that the energy absorbed by tropospheric atmosphere of standard midlatitude atmospheric model in summer is about 2.32 times higher than that in winter,because the absorptivity in winter is much less than that in summer.In the same atmospheric model,the energy absorbed by the troposphere to different features is close,the maximum difference is not more than 22.2%.In the sunny atmosphere mode,the difference between the infrared radiation energy of the same features at different time is much larger than that of the different objects at the same time.In the rainy day atmosphere model,the radiation energy of different features at the same time as well as the radiation energy of the same features at different time are very close to each other.Finally,this paper analyzes the absorption spectrum of urban boundary layer atmosphere to infrared radiation and the transmission of infrared radiation in the boundary layer atmosphere,and also compared with features infrared radiation energy and convective heat transfer of features and near ground atmosphere.The results showed that the absorption of infrared radiation by the urban boundary layer is dominant in the troposphere.Under the standard atmosphere model,the infrared radiant energy absorbed by the atmospheric boundary layer in summer is 77.9% of tropospheric absorption energy,and that in winter is 50.5%.Under actual atmospheric model,the absorptivity of the atmospheric boundary layer accounts for about 75.2% of the absorptivity in the troposphere.The influence of the features infrared radiation energy on the urban thermal environment is much larger than the convective heat transfer between the surface and the atmosphere.By analyzing the convective heat transfer of features and boundary layer atmosphereQH,the features radiation energy in 8~14?m band? E?,and features infrared radiation energy absorbed by boundary layer atmosphere in 8~14?m band? Ea,it can summarized that the ratio of QH/ ? E? and QH/ ? Eain September 12,2016 was 16.70% and 36.19%,respectively,and it was 4.19% and 8.52% in September 15,2016,respectively.