Studies Of Urbanization Influences On Meteorological Field Simulation

With the development and enlargement of the urban area of the city, causes theurban climate strengthen constantly, the change of land use and underlying surfacewill influence the local meteorology greatly. According to the average buildingheight of Beijing offered by Beijing City Surveying Institute, the thesis revises theterrain height and the soil type of the underlying surface. Impact on the Beijing areameteorological simulation result under the stable weather condition of the change ofunderlying surface which induced by the urbanization process is tested, using themesoscale model MM5, basic simulation and test simulation in August of 2005 andthe observation data of Beijing Olympic stations. And then change the convectionparameter course, studies the impact on meteorological simulation of the differentconvection parameter course under the stable weather condition.The result shows, there is a good dependence in the simulation to theatmospheric pressure, temperature and relative humidity of MM5 and observationresults, this correlation obviously increases in the test simulation result which theunderlying surface has changed. It is indicated that while employing the change ofunderlying surface, the city warming gets better embodiment, the warming area andtopography change heavy area have fine correspondence, urban wind speedsimulation value reduce obviously. The contrast in the Olympic Green station finds,the test simulation result is closer to the observation on tendency, the simulationvalue of the temperature is increased, the simulation value of the wind speed isreduced, the simulation result of the wind direction gets obvious improvement, andthe statistics deviation of atmospheric pressure and wind speed are obviously reduced.The contrast results under the stable weather condition also display obviously that temperature rises and wind speed reduce. This revealed the meteorologicalsimulation of Beijing area under the stable weather condition and the real-timeprediction must consider the meticulous terrain and the underlying surface condition.The analysis of the simulation result of different cumulus convection parametercourse is found that, under the stable weather condition, some difference has existedto the simulation of temperature and the wind of ground in different parametercourses, the contrast results between simulation and observation in Olympic Parkstation indicate that the simulation results of pressure, relative humidity andtemperature are closer to the observation in KF simulation scheme, but the windspeed simulation in Grell scheme is obviously better. So describe truly and rationallycumulus convection and precipitation course followed in the simulation atmosphereare very important.