Study On The Temporal And Spatial Evolution Of Heat Island Effect In The Central City Of Zhengzhou From The Perspective Of Landscape Architecture

It is the common pursuit of today's society to build an ecological and sustainable urban environment and a healthy city.However,in recent years,with the continuous expansion and spread of the city and the sharp decrease of green space,a series of climate and environmental problems have been brought about.The high temperature phenomenon in the city is frequent and concentrated in the heat island effect,which threatens the urban ecological security and residents' health.In this context,considering the importance of urban green space to alleviate the heat island effect and the suitability of Zhengzhou Central City as a case city,this paper studies the temporal and spatial evolution of urban heat island effect from the perspective of landscape architecture.First of all,based on remote sensing data,the summer heat island layout of Zhengzhou Central Urban Area in the past 20 years(2000,2004,2009,2013 and 2019)is obtained,and its spatial-temporal evolution characteristics are summarized.It is found that the thermal environment of the study area has been significantly improved,and the overall characteristics of "gathering before leaving" of the heat island.It was found that the thermal environment of the study area has improved significantly in the past 20 years,and the overall characteristics of "gathering before leaving" of heat island.After that,taking the scale of urban green space,vegetation coverage and the centrality of spatial form as the breakthrough point,the paper analyzes the influencing factors behind the change of characteristics,and finds that: compared with the scale characteristics,the shape and layout change of green space has a more prominent effect on the mitigation of heat Island,and considers that the planning strategy of "one ring,four wedges and seven chains" improves the spread of green space and effectively regulates it In addition,compared with the city with a single center,the multi center and cluster urban spatial form with concentrated blocks and overall dispersion has a significant negative correlation with the surface temperature,especially in the early stage of rapid urbanization construction,the average increase of 10% of the vegetation coverage can reduce the surface temperature by 1 ?;in addition,compared with the city with a single center,the urban spatial form of multi center and cluster with centralized blocks and overall dispersion has a significant negative correlation with the surface temperature It is very beneficial to reduce the intensity of urban relative heat island.Finally,by comparing five park green patches with similar built-up environment and outstanding cooling effect in urban area,the landscape characteristics that have significant impact on the cooling effect of green space are summarized.It is considered that the green space with outstanding shrub dominance and good connectivity,small and scattered lawn and rich water boundary shape can better play its ecological effect of regulating surface temperature.Based on the clue of finding problems,investigating problems,analyzing problems and solving problems,this paper reveals the evolution of heat island effect in the central urban area of Zhengzhou in the past 20 years,explores the key factors influencing the evolution of heat island effect and the landscape characteristics of bringing green space cooling effect into play,in order to make up for the lack of research on urban heat environment in China at present,and at the same time,to make sustainable development for future planning and construction The healthy city of the exhibition provides reference.