郑州浅山区村落街巷微气候影响机制分析

Analysis on the microclimate impact mechanism of village streets in the low mountain areas of Zhengzhou

【目的】探究村落街巷空间微气候的影响因素与调节机制,创造更加舒适的夏季微气候环境,减少能源消耗,提升农村居民生活品质。【方法】以郑州市浅山区典型村落的90个街巷样地为研究对象,通过实地调研和无人机测绘等方式采集数据,利用ENVI-met软件建立样地实况模型对微气候参数进行模拟,借助统计学分析方法探究街巷高宽比、街巷走向、植被覆盖度3项要素与街巷微气候的影响机制。【结果】1)高宽比(height-width ratio,H/W)主要通过降低平均太阳辐射温度(mean radiant temperature,MRT)来调节夏季街巷空间的微气候;植被覆盖度(fractional vegetation cover,FAC)主要通过增加相对湿度进而调节夏季街巷空间的微气候;而空气温度(air temperature,TA)、相对湿度(relative humidity,RH)、平均太阳辐射温度均会受到街巷走向的影响;2)通过极差分析可得,当高宽比达到1.1后,即可有效缩短街巷处于“极端”热应激等级的时间;3)在村内单位面积植被覆盖度≥10%时,通过和街巷高宽比结合设计的方式可最大程度地发挥植被增湿降温作用;4)南北走向(North-South direction,N-S)的街巷内夏季的空气温度、相对湿度、平均太阳辐射温度均优于东西走向(East-West direction,E-W)。【结论】街巷高宽比、街巷走向、植被覆盖度对郑州浅山区村落街巷微气候的影响机制各不相同,三者之间具有一定的关联性且存在最佳阈值。可从微气候的角度对村落街巷空间进行改造和设计,提升乡村人居环境品质的规划设计策略,为相同地理环境下的村落改造提供参考借鉴。

【Objective】This study aims to explore the influencing factors and regulatory mechanisms of micro-climate in village streets,create a more comfortable summer microclimate enviorment,reduce energy consumption and improve the quality of life of villagers.【Method】The street sample plots of 90 typical villages in the shallow mountainous areas of Zhengzhou City were taken as the research objects,and the data were collected through field research and drone mapping,etc.The real-time model of the sample plot was established by ENVI-met software,and microclimate parameters were simulated.Using statistical analysis methods,the impact mechanism of the three influencing factors of street aspect ratio,direction,and vegetation coverage in streets and alleys was explored.【Result】1)The research results of influencing factors indicate that the aspect ratio mainly regulates the microclimate of summer street space by reducing MRT;The vegetation coverage mainly regulates the microclimate of summer street and alley spaces by increasing RH;TA,RH,and MRT are all affected by the direction of the streets and alleys;2)Through range analysis it can be concluded that when H/W reaches 1.1,it can effectively shorten the time when streets and alleys are under extreme heat stress levels;3)When the vegetation coverage in the village is≥10%,the maximum effect of vegetation humidification and cooling can be achieved;4)The summer TA,RH,MRT,in North-South streets and alleys are better than those in East-West directions.【Conclusion】The influence mechanisms of H/W,FAC and direction on street microclimate in shallow mountain villages in Zhengzhou are different,and there is a certain correlation and optimal value among them.From the perspective of microclimate,the village street space can be transformed and designed,and the planning and design strategies can be improved to enbance the quality of rural human settlements.This study can provide reference for village renovation in similar geographical environments.