摘要
利用2005年赤角能见度及东涌悬浮粒子(PM2.5)浓度的每小时数据,发现PM2.5浓度与能见度(撇除雨雾及相对湿度≥95%的个例)呈倒数关系,相关系数约为0.8。此外,出现低能见度(能见度低于8km,而雨雾及相对湿度≥95%的个例不计)的每月总时数与月平均PM2.5浓度都呈现相类似的季节趋势,即冬季较高,夏季较低。利用HYSPLIT作反轨迹图分析显示这现象跟影响香港的空气来源有关。来自内陆的轨迹中,出现低能见度的日平均时数及日平均PM2.5的浓度,分别远高于来自海洋的轨迹。文中还分析了一个有热带气旋接近本港的个例,论证气象条件对能见度及PM2.5浓度的重要性。
By making use of the 2005 hourly data of visibility at Chek Lap Kok and suspended particulate（PM2.5） at Tung Chung,PM2.5 concentration and visibility（excluding cases with mist,fog,rain or relative humidity≥95%） are found to have a reciprocal relationship with a correlation coefficient about 0.8.Besides,similar seasonal trends are exhibited in both the number of hours of reduced visibility（visibility below 8 km and excluding cases with mist,fog,rain or relative humidity≥95%） and PM2.5 concentration,i.e.with higher value attained in winter and lower value in summer.Backward trajectory analysis using HYSPLIT indicates that this phenomenon is related to the source of air mass affecting Hong Kong.For continental trajectories,the average daily occurrence of reduced visibility and the daily mean PM2.5 concentration were much higher than the corresponding occurrence of reduced visibility and mean PM2.5 concentration for maritime trajectories.A case study on an event with a tropical cyclone approaching Hong Kong is included to demonstrate the significance of meteorological conditions in determining the visibility and PM2.5 concentration.
出处
《气象学报》
CAS
CSCD
北大核心
2008年第3期461-469,共9页
Acta Meteorologica Sinica
关键词
能见度
悬浮粒子PM2.5
反轨迹
热带气旋
Visibility；Suspended particulate PM2.5；Backward trajectory；Tropical cyclone
