Abstract:

The urban canopy parameterizations was developed substantially and was coupled to the mesoscale meteorological model successfully to study urban boundary layer processes in the last 20 years.Different studies showed that such parameterizations were sensitive to the urban canopy parameters that defined the urban morphology.At the same time,the urban canopy parameters were sensitive to the simulation performance,and highresolution surface data was helpful for the simulative effects.At present,the urban canopy schemes coupled to WRF model included Singlelayer (UCM) scheme,Building Environment Parameterization (BEP) scheme and Building Environment Model (BEP+BEM) scheme.BEP and BEP+BEM need to confirm more parameters and waste more time than UCM,but whether they can improve the simulative effects requires further investigation.Different from plain cities,the mountain cities have complex terrain and land surface characteristics,which cause great difficulties for studying the mountain cities by model.Is simulation performance of WRF model coupled with urban canopy schemes better than which is not?Which urban scheme is most applicable to simulate 2 m temperature and wind in Chongqing?This paper intends to solve the above problems.Taken the typical mountain city(Chongqing) as the research object,combined the highresolution GIS data (333*333 m),we used three different urban canopy schemes coupled to WRF model to simulate Chongqing highdensity buildings thermal environment for two days.The main results are as follows.(1)The simulated temperature and wind of WRF without urban canopy scheme had rather big difference with the observations,the RMSE between observation and simulation without urban canopy scheme of 2 m temperature reached 32℃.(2)Results of BEP+BEM scheme was the best and results of UCM scheme was the worst.The RMSE (between observation and simulation,in 10 urban stations) of BEP+BEM,BEP and UCM schemes were 13℃,14℃,21℃,respectively.(3)The difference of results of BEP and BEM+BEP scheme was tiny and the results showed good agreement with observations in simulation of windspeed at 10m,but deviation of that of UCM scheme was bigger.The results of winddirection at 10 m were satisfactory in three urban canopy schemes simulations