湿热地区高校人工湖热环境实测研究

Measurement and Analysis of Thermal Environment of Artificial Lake in Universities in Hot and Humid Regions

湿热地区气候具有高温高湿的特征。相关研究表明,在夏季居民常常反映自己处于偏热的状态,并普遍希望能够降低所处环境的气温。为此,作为一种城市冷源,开放的水面常常被应用于各种尺度的城市、社区与校园中,并与植被、遮阳等措施共同改善城市热环境。目前,国内外有较多学者开展水体对水滨热环境影响的研究,研究结果表明,水体对于湿热地区的日间水滨热环境有一定的降温增湿作用,但对于较寒冷地区与夜间也具有一定增温作用。对于水体热环境的研究主要采取模拟研究与现场实测的方式,在室外热环境模拟领域广泛使用的ENVI-met在水体模拟方面存在一定缺陷,主要表现在对夜间的水温模拟有较大的误差;水体实测研究则缺乏以湿热地区校园人工湖尺度水体为对象的相关研究。以湿热地区某高校人工湖为例,监测其周围的气象参数,并据此明确对高校湖滨热环境的主要影响因素,得出高校人工湖尺度的开放水面对湖滨热环境的影响规律,为高校人工湖滨环境设计提供实测基础。选取广州市某高校内人工湖作为实验对象,在人工湖周围、上方及水下布置了共24个测点,进行了为期25 h的实测,得到了全天的水体温度、空气温度、相对湿度、风速、风向、太阳辐射量等参数,并对其展开多层次的分析。结果表明:人工湖对湖滨环境有着较为显著的降温与增湿作用。日间由于水分蒸发吸收周围环境的热量达到降温的效果,而在夜间并未观测到对周围环境显著的升温效应,此外,未观测到距湖滨距离变化的稳定温湿度变化梯度。水体温度与水面上方气温随时间变化趋势一致,但水体内部温度较水上气温稳定,在11:00-18:00水体温度持续低于水上气温,在6:00-10:00及19:00至次日7:00水体温度持续高于水上气温,水下温度峰值与水上气温峰值均较水面温度有不同程度延迟。风向对湖滨气温与湿度分布有较大影响,水体下风向测点相较上风向测点有着更低的温度与更高的相对湿度。

The climate in hot and humid regions is characterized by high temperature and high humidity.Relevant studies have shown that residents often reflect that they are in a relatively hot state and generally hope to lower the temperature of their environment in summer.For this reason,as a kind of urban cold source,open water is often used in cities,communities and campuses of various scales,and together with vegetation,shading and other measures to improve the local thermal environment.In recent years,many scholars have conducted research on the impact of water bodies on the local thermal environment.The results of the research show that water bodies have a certain degree of cooling and humidification effects on the local thermal environment during the day in areas with higher temperatures.However,in colder areas or at night,open water bodies also have a warming effect on the local microclimate.At present,researchers mainly adopt the methods of simulation research and field measurement for the research of the thermal environment of water bodies.ENVI⁃met software is often used in simulation research,but its water plate has some defects,which leads to large errors in the simulation of night water temperature.On the other hand,there are few existing researches on campus artificial lake⁃scale water bodies in hot and humid areas.The author takes an artificial lake in a university in a hot and humid area as an example,monitors the surrounding meteorological parameters,and analyzes the impact of the open water of the artificial lake in the university on the lakeside thermal environment.Then,the author derives the corresponding artificial lake layout strategy based on this,in order to provide guidelines for the artificial lakeside environment design of universities in hot and humid regions.For the actual measurement experiment,an artificial lake in the University City campus of South China University of Technology was selected as the experimental object.The author placed a total of 24 measurement points around,above,or under the artificial lake,and conducted a 25⁃hour field measurement.Through this experiment,the author obtained comprehensive parameters,such as water temperature,air temperature,relative humidity,wind speed,wind direction,solar radiation,etc.,and carried out a multi⁃level analysis on this basis.The results show that the campus artificial lake has a significant cooling and humidification effect on the lakeside environment.The water body releases cold to the surrounding environment during the day,but no significant warming effect on the surrounding environment is observed at night.In addition,the results showed that no obvious temperature drop and humidity increase gradient were observed.The results of this study show that the campus artificial lake has a significant cooling and humidification effect on the lakeside environment.The water body releases cold to the surrounding environment during the day,but no significant warming effect of the water body on the surrounding environment is observed at night.The temperature of the water body is consistent with the change of the temperature above the water surface over time,but the temperature inside the water body is more stable than the temperature above the water.The water temperature is continuously lower than the water temperature from 11:00 to 18:00,and is continuously higher than the latter from 6:00 to 10:00 and 19:00 to 7:00 the next day.The peaks of both the underwater temperature and the above⁃water temperature are delayed from the surface temperature.The airflow has a great impact on the distribution of lakeside temperature and humidity.Compared with the upwind measurement point,the water body’s downwind measurement point has lower temperature and higher relative humidity.