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城市森林冠层对小气候调节作用

花匠小妙招
2024-11-06 23:30

摘要： 为了客观反映城市森林冠层的温湿效应，发挥城市森林冠层调节小气候的作用，使用Decagon微气象监测系统对南京城市森林冠层光照、温度、相对湿度等微气候因子进行长期监测，以林外的实验观测作为对照，分析了城市森林冠层内部小气候特征和对小气候的调节作用。结果表明：生长期冠层内部太阳辐射呈双峰或多峰曲线变化，林外与冠层内部太阳辐射差由大到小为夏季、秋季、春季、冬季；冠层内部与林外的气温和相对湿度日变化规律均呈抛物线变化，夏、秋季冠层降温作用高于春、冬季，春、夏、秋季白天冠层与林外温差大，夜间温差小，春、夏、秋季冠层相对湿度在任意时段均高于林外，冬季午后冠层相对湿度低于林外，城市森林冠层在夏、秋季的保湿效果优于春、冬季，城市森林冠层气温日最高值出现时刻比林外约晚30 min；除冠层内部太阳辐射与林外气温相关性不显著外，其他气象因子之间均呈极显著的相关性（P＜0.01）。城市森林冠层在削减太阳辐射、降温增湿、缓和冠层内部温湿度变化和对高温的滞后效果等调节小气候和改善气候舒适度方面具有显著的作用。

关键词: 刺槐群落, 乡土植物群落, 功能结构, 黄土丘陵区

Abstract:

To clarify the adjusting effects of urban forest canopy on microclimate, a Decagon micrometeorological monitoring system was used to conduct longterm monitoring on illumination, temperature, relative humidity and other microclimate factors of urban forest canopy in Nanjing. In contrast to the experimental observations outside the forest, the microclimate characters inside the urban forest canopy and the effect of forest canopy on adjusting microclimate were analyzed. The results showed that during growing season, the solar radiation inside forest canopy fluctuated along a bimodal curve or multi peak curve. Seasonal solar radiation difference between the inside and outside of the forest canopy was in descending order of summer, autumn, spring and winter. The daily variations in temperature and relative humidity inside the forest canopy were similar to that outside the canopy, showing a parabolic change. The forest canopy exerted a greater cooling effect in summer and autumn than in spring and winter; during spring, summer and autumn, the temperature difference between the inside and outside was large in the daytime, but small at night. The relative humidity inside the forest canopy at any time during spring, summer and autumn was unexceptionally higher than that of the outside. In winter, the relative humidity inside the forest canopy was lower than that of the outside after noon. The forest canopy performed better in moisture preservation in summer and autumn than in spring and winter. The advent of maximum temperature inside the canopy was about 30 minutes later than that of the outside. Except that there was no significant correlation between solar radiation inside the forest canopy and the temperature outside, all meteorological factors were significantly correlated each other (P<0.01). Collectively, urban forest canopy plays a significant role in adjusting microclimate and improving comfortable level of climate, for example, reducing solar radiation, cooling and humidification, mitigating the change in temperature and humidity inside the forest canopy and delaying the advent of maximum temperature.

Key words: hilly-gully region of Loess Plateau, Robinia pseudoacacia community, native plant community, functional structure.