Based On MM5 Model To Research The Effect Of Climate Change For The Urban Development Of Chengdu City

The expanding of a city makes the scale of it's urban land more and more rough, and the underlying surface situation is one of the important factors of climate formation. Between the atmosphere and the ground there is a complex and widespread exchange and balance of water, heat and material, and the ground is the interface of air movement, so the nature of the underlying surface directly affects the distribution of temperature, radiation, humidity, atmospheric stability, wind and other meteorological factors, which plays an important role in the formation of local climate. As the concentration of population to cities, the original village has undergone a fundamental change in the natural environment, loose, moist, with the pastoral vegetation cover was brick, asphalt, cement and other solid, watertight, thermal conductivity, large shop building materials building, flat or gentle slope on the low land forest of tall buildings and farmhouse are interwoven vertical and horizontal replaced street canyons, which greatly changed the original land surface state of nature and the natural environment.This article maked Chengdu satellite images grided, and then amended each mesh type of landuse, re-use in mesoscale numerical model MM5, respectively in Chengdu and optimizing the status quo after the greening program of temperature and humidity fields simulation. The results show that the current situation from the best amenities in the city of Chengdu, there is a gap, but have reached the appropriate residence requirements. Simulation to optimize the program, the effect of significantly reducing urban temperatures, indicating increasing green area of the cooling effect, but the cooling makes the city the other hand, increased humidity, leading to Chengdu in the winter "wet cold" weather region stronger, so consequently carrying out scientific planning urban greening should not blindly pursue high green ratio. Additional, results from a comparative analysis of two surface types can be found after the change trend of the simulation results are quite different, the cooling effect of the city significantly, reducing the value of wind speed simulation.This conclusion reveals that under the stable weather conditions in Chengdu field simulation of real-time weather forecasting must consider the refinement of the underlying surface conditions. This will improve the model simulation results, real-time forecast results will certainly improve the role and help, while it's a good reference to the urban environmental planning.