广州市城市热岛时间变化特征及与大气总悬浮颗粒物关系的研究(英文)

Variations of urban heat island and its relationships with total suspended particulates in Guangzhou,China

文章研究了1985—2005年期间广州市城市热岛强度时间变化及与大气总悬浮颗粒物浓度的关系。结果表明,由于经济的快速增长和城市化进程不断加快,广州市城市热岛效应十分明显,年平均热岛强度在0.20～2.10℃之间波动。受季风等大范围气候背景及降雨的影响,月平均热岛强度具有明显的季节变化特征,总体上呈"U"字形变化,其中7月份热岛强度最低,11月份最高。不同时次(02:00,08:00,14:00和20:00)的热岛强度以08:00时最高,而以14:00最低。最低温度下的热岛强度呈现出稳定增长的趋势(平均值为1.09℃),显示出广州近地面平均气温上升以最低温度最为明显。自1994年之后广州市大气总悬浮颗粒物水平呈现出明显的下降趋势,然而1982年到1998年期间仍然超过了国家大气质量二级标准所规定的浓度限值0.200mg/m3。研究还表明,广州城市年平均热岛强度与年平均大气总悬浮颗粒物浓度之间存在显著的负相关,负相关系数为-0.676。尽管市区大气总悬浮颗粒物可以反射太阳辐射,降低日照时间,最终产生致冷效应,但是广州城市热岛效应是全球气候变暖下的大气增温和悬浮颗粒物降温之间平衡作用的结果。

Variations of urban heat island （UHI） intensity and its relationships with total suspended particulate （TSP） levels in developed areas of Guangzhou from 1985 to 2005 were studied in this paper. The results showed that annual mean UHI intensity ranged from 0.20 to 2.10 ℃, and was increasingly severe with the improvement of urbanization of Guangzhou in recent decades. Due to the effect of large scale weather background, monsoon circulation and rainfall, monthly mean UHI intensity had an obvious seasonal pattern, which presented ＂U＂ shape with a kurtosis at both sides and the minimum in July. According to daily data at 02：00, 08：00, 14：00 and 20：00 from 1959 to 2005, the maximum intensity appeared at 08：00 and the minimum at 14：00. Daily minimum temperature had taken on a trend of stable growth, with a mean UHI intensity of 1.09 ℃ during 1985 and 2005. On the whole, TSP levels showed a decreasing tendency since 1994. However, TSP levels exceeded the limit of 0.200 mg/m^3 for State Ambient Air Quality Standard （GB 3095-1996） especially during 1982 and 1998. Based on the linear trend, it was showed that UHI intensity was significantly negatively correlated with TSP levels in developed areas of Guangzhou, with a negative correlation coefficient of-0.676 Although TSP will reflect sunlight to space, decrease the sunshine duration and have a cooling effect in urban area, the UHI effect in Guangzhou is a result of a balance between the atmospheric heating and TSP cooling.