Quantification Of Thermal Mitigation And Carbon Saving Effects In Urban Parks Of Greater Xi’an Under Hot Extremes

The blue-green infrastructure of the city not only provides leisure and activity venues for urban residents,but also plays a key role in regulating the urban climate.In hot extremes,urban green spaces provide residents with a comfortable outdoor thermal environment and reduce the consumption of air-conditioning and other refrigeration equipment.Thus saved a lot of carbon emissions for the city.However,few studies have quantified the heat mitigation and carbon saving effects of urban parks in hot extremes from the perspectives of maximization and accumulation.How to maximize the cooling services of urban parks in hot extremes is closely related to the well-being of urban residents.Based on remote sensing satellite data and GIS spatial analysis methods,this study explored the heat mitigation and carbon saving effects of park green spaces in Xi’an under hot extremes from the perspectives of maximization and accumulation,and analyzes its impact on urban carbon neutrality.contribute.The main conclusions are as follows:First,this study explored the thermal mitigation effects of 65 urban parks in Xi’an based on spatially continuous cooling curves using multi-period satellite images in the Xi’an area.From the perspective of maximization,the cooling range of urban parks in Xi’an is as long as 151.4 meters,and the average heat mitigation range is 63.62 ha area,which is about five times the average area of the city parks themselves;from the perspective of accumulation,the average heat mitigation intensity of urban parks is 0.78℃,and along the entire continuous thermal mitigation distance,the cumulative amount is 153.87℃·m.The cumulative heat mitigation effect of urban parks at hot extremes is stronger than at relatively normal temperatures.Thermal mitigation can be maximized in large,heavily wooded parks,as well as in parks of complex shapes that interact strongly with their surroundings.Small parks,such as neighborhood parks located in densely populated areas,are most efficient,with heat mitigation areas approximately nine times their own size,serving as efficient heat mitigation networks.Enhanced vegetation growth combined with blue and green infrastructure is always an effective way to increase the mitigation strength of accumulated heat in hot extremes regions.Secondly,a three-dimensional carbon saving model of the city was constructed,and two carbon saving indicators(Cs_A and Cs_E)were set to quantify the carbon savings of urban parks at an altitude of 70 m,of which the carbon savings were 734.3 t/day.And the indirect carbon saving effect of urban parks caused by the reduction of urban residents using refrigeration equipment was quantified by network analysis,and the carbon savings were 814.9 t/day.Overall,the results of carbon savings show that 55 of the 65 parks saved a total of 1,549.0 t/day of CO2,offsetting 3.6%of the region’s fossil fuel emissions.Building largescale ecological parks in areas with abundant land resources,while accelerating the construction of urban blue and green infrastructure,can maximize cumulative carbon savings.