树冠空间结构对微气候影响的模拟

随着城市化水平的提高，人们对于健康舒适的公共空间的要求也日益增加。为了更加科学地从空间结构的角度对微气候环境提出改善策略，运用ENVI-met模拟软件，以理想状态下的纯乔木林环境为研究对象，针对南京市的气候条件，分析5种常见的乔木树冠形态（圆柱形、圆球形、倒卵形、三角形和倒三角形）和3种平面布局形式（规则散点式、集中块状式、自然集群式）对微气候环境的温度、湿度及人体热舒适度（PMV指数）的影响。研究表明:树冠形态和布局形式对群落的降温增湿效应具有显著影响（P < 0.05）。“上大下小”型的倒卵形和倒三角形树冠的乔木群落降温增湿强度最高、人体热舒适度体验也最好。集中块状式布局的群落降温增湿强度要明显高于规则散点式和自然集群式，但自然集群式布局时人体热舒适度体验更好。

Microclimate changes with simulated canopy spatial structures

The microclimatic environment created by a plant community could provide wonderful rest space for people. This study focused on how to regulate the microclimate by improving the structure and characteristics of a plant community. The microclimatic environment of Nanjing, a typical city with high temperature and humidity in summer, was studied. Using simulation software, ENVI-met, pure forests in ideal conditions were selected to analyze the impact of five common canopy shapes (cylindrical, spheroidal, obovate, triangular, and inverted triangular) and three layout forms (regular-scatter, centralized-block, and natural-distribution) on temperature, humidity, and thermal comfort (PMV) of a plant community in Nanjing during summer. Results indicated that canopy shapes and layout forms had a significant influence on the cooling and humidification effect of a plant community (P < 0.05). The tree communities with an obovate canopy or inverted triangular canopy, which were typically large in the upper part of the canopy and small in the lower part, had the highest cooling and humidification efficiency which could provide the best thermal comfort experience. The cooling and humidification efficiency of the communities planted in a centralized-block form were higher than those in a regular-scatter or natural-distribution form; whereas, the thermal comfort experience of the community planted in a natural-distribution form was better.