Assessment Of The Potential Ability Of Urban Ventilation And Identification Of The Ventilation Channel In Green Heart Area Of Changsha-Zhuzhou-Xiangtan Urban Metropolitan Region

In order to further improve the climate environment of the urban agglomeration,build up a green ventilation corridor in the summer in the green heart area of the ChangZhuTan urban agglomeration,and provide a theoretical application basis for the construction of a low-carbon city,this study uses the 2020 remote sensing images of the green heart area as the basic data,and applies the numerical model WRF coupled with the urban canopy parameter scheme UCM under the typical summer sunny monsoon weather conditions,and uses the surface morphology and thermal factors The existing ventilation potential is evaluated as indicators for evaluating the ventilation performance,and the ventilation channels are identified and optimized from both dynamic and thermal perspectives,and the results are as follows.(1)The areas with the best ventilation potential are located along the Xiangjiang River,the local area of Zhaoshan Mountain,and the area of Wuyunfeng Forest Park;the areas with better ventilation potential are Gao Yun Nongjiao Park and the large cultivated area near Liuyang River in the northern part of Jumping Horse Town;the ventilation performance of the large mixed area of savanna and woods in the green center is average,and the ventilation performance of the central part of the green center is poor due to the obstruction of the mountain.Most of the areas with good ventilation potential are located around the green center near the urban area,which provides better basic conditions for connecting the open space inside and outside the green center.(2)Based on the assessment of the ventilation potential,three levels of summer ventilation corridors were identified,among which two primary ventilation corridors with Xiangjiang River as the main body,the border area between northern Zhuzhou and the Green Center and the large cultivated area in the northern part of the Green Center have better ventilation potential and follow the summer monsoon direction,which can also build up the main ventilation corridors.(3)Through the optimization of the summer ventilation corridor,the wind speed in 80%of the Green Center area increased by 0.10 m.s-1-0.25 m.s-1,with the most obvious increase of wind speed in the central part of the Green Center and the eastern Xiangjiang River area,reaching about 0.20 m.s-1,forming a large wind speed zone through the Green Center;the wind speed in Changsha and Zhuzhou city areas were also improved to some extent.The improvement of ventilation performance has reduced the temperature of 95%of the area within the green heart of ChangZhuTan urban cluster by 0.3℃-1.8℃,and the average temperature within the whole area by 0.77℃;among the three surrounding cities,the temperature reduction in Changsha is the most obvious.(4)The factor with the greatest influence on the ventilation potential is the rough length of the sub-bedding surface,which has an influence value of 0.90;followed by the land use type,which has an influence value of 0.63 on the ventilation potential;in addition,the building density,temperature field distribution,elevation and road network density also have a significant influence on the ventilation potential.In summary,through the evaluation of ventilation potential,identification of ventilation channels and further optimization,the wind-heat environment of ChangZhuTan urban cluster has been further improved.