Study On The Influence Factors Of Cold Island Effect In Urban Parks In Hot And Humid Regions

Global warming and the Urban Heat Island Effect has proven that even though the process of global warming is moving at a slow pace,the great loss it is causing to a city's energy usage and economy is inevitable and difficult to estimate.Not like those tropical cyclones or heavy rains,the urban heat island effect itself does not cause direct natural disasters,but by changing the local energy balance,the water cycle process,the atmospheric boundary layer structure pollutant propagation and diffusion laws,and thus the production of human life resulting in indirect hazards.Urban green spaces and parks are one of the effective ways in mitigating the urban heat-island effect.Urban parks can lower the overall environment temperature and relieving the urban heat-island effect.Thus this phenomenon has been named the Urban Park Cool Island Effect.There have been both international and domestic studies done on the Urban Park Cool Island Effect.But the existing research only focuses on one or two factors that influence the Urban Park Cool Island Effect,fewer studies tend to focus on the overall effect of the internal and external environments of the parks.This research focuses on how external environment and internal design of an urban park can influence the Urban Park Cool Island Effect.By using methods including but not limited to numerical simulation and mathematical statistics,a thorough analysis is done on the city of Shen Zhen and how the external park environments together with the internal designs affected the Cool Island Effect of Shen Zhen's city parks.Potential urban park locations and strategic park interior design plans can be drawn from the research of this paper.This research concludes that different environment affects the overall surface and atmosphere temperature,and also the relative humidity level.The overall land surface and atmosphere temperature of low density environments are higher when compared to high density environments,while the latter has a higher humidity level.Some exceptions to this conclusion exist,but only on a small scale.The existence of parks has an obvious cooling effect on the different external environment's temperature.Internal environment differences are a leading influential factor of the Urban Park Cool Island Effect.All in al,no matter a low or high density environment,when the tree coverage rate of an urban park is between 40% to 60%,and has a 15% concentrated water body with a 20% pavement coverage,the Cool Island Effect will have the best result,along with the overall temperature and humidity level.Based on the proposed design strategy for better urban parks in warm and humid climates,an urban park in Shen Zhen was chosen for simulation and validation on the research results.The simulation results show that after applying the optimization strategy,the overall surface temperature,the overall atmospheric temperature and the relative humidity of the park are all optimized,which is effectively improving the thermal environment quality.It is proved that the above mentioned design strategies yielded from this research offers a practical solution to solving the problems produce by urban heat-islands.