广州市热岛效应与城市露水相互关系研究

Researches on the Relationships between Urban Heat Island and Urban Dew in Guangzhou, China

关于城市热岛效应的研究较多,而关于城市露水的研究较少,尤其是城市热岛作用下的城市露水研究则更少。探清城市露水与城市热岛的关系对增进城市露水凝结,改善城市水分平衡具有重要意义。为研究两者的相互关系,采用布片法(Cloth-plate Method)分别在广州的露水高发季节(8—11月,含秋季代表月份10月)和其他几个代表季节的1月(冬季)、4月(春季)、7月(夏季)进行了露水收集;采用常用的城郊平均温差表示热岛的统计方法对热岛进行统计分析;露水收集和热岛监测的4个点位分别选在广州的工业区、商业区、居住区、森林公园,为了比较分析也增设了郊区对照点位。结果显示,无论白天、夜间还是日平均热岛频率,其与城市露水均不存在显著的相关关系,即使城市地区存在高频率的热岛效应,也难以完全阻碍露水事件发生,无露水发生的天气其热岛频率比有露水发生时高10%左右。不论是白天、夜间还是日平均热岛强度,它们都与城市夜间露水量呈极显著负相关,城市各功能区露水量差异与该功能区内热岛强弱不无关系。城市热岛与城市露水的相互关系受多种因素的影响,热岛可能通过影响相对湿度、蒸发量来影响露水形成。结果表明,无热岛效应可能更有利于露水发生,热岛强度变化将直接影响露水凝结量的大小。

There are many researches about the urban heat island effect, but there are few studies on the urban dew, especially urban dew researches under the condition of on the urban heat island. The relationship between urban dew and urban heat island is very important for increasing urban dew condensation and improving urban water balance. In order to study the relationship between the urban dew and urban heat island, Cloth-plate Method and common heat island statistical methods were used. Investigations were carried out in 4 different experiment sites including Fangcun industry area, Tianhe Commercial area, Zhongda residential area,Baiyunshan forest park, Guangzhou, China. The experiment time was January, April, July, early August, September, October andearly November. January, April, July and October was represent Winter, Spring, Summer and Autumn, respectively. August,September and October is the dew season. Results showed that No matter during the day, night or daily average frequency of heatisland, and there was no significant correlation between the dew. Even if there is a high frequency of the urban heat island effect, butit is difficult to completely block the dew event. The frequency of urban heat island was higher in the weather of no dew event than that in the dew weather, with a ratio of 10%. Whether daytime, nighttime or daily mean heat island intensity, they are significantly negatively correlated with urban dew amounts. The difference of the dew amounts between the functional areas of the city was related to the heat island of the functional area. The relationship between urban heat island and urban dew is influenced by manyfactors. Heat island may influence dew formation by affecting relative humidity and evaporation. The results show that no heat island effect may be more beneficial to the dew, and the intensity of the heat island will directly affect the dew condensation amounts.