京津冀区域霾天气特征

汇总京津冀区域内107个地面站的气象资料,利用14时实测的气象要素和天气现象资料对霾日进行判别,统计出各个站点1980~2008年中逐年及各月的霾日数.结果表明,北京、天津、河北霾天气整体变化趋势和波动特征较为相似,且均呈增加趋势,非城区站点平均霾日数明显呈增加趋势,且与市区站点霾日数的差距越来越小.京津冀区域霾日数的月际变化呈明显的双峰特征,即夏季和冬季霾日数较高.空间分布表明,霾日数高值区主要位于北京、天津、保定、石家庄、邯郸和邢台等地.多数站点霾日14时平均风速比非霾日低了1.0m/s以上,14时平均相对湿度则比非霾日高出20%以上.

Characteristics of hazy days in the region of Beijing, Tianjin, and Hebei.

Meteorological data(1980~2008) were collected from 107 ground stations in the BTH(Beijing,Tianjin,and Hebei) area.Monthly and Annual numbers of hazy day for each station were calculated using meteorological element and weather phenomena.The annual average hazy days for Beijing,Tianjin,and Hebei depicted similar fluctuations and same trends of increasing.Average number of hazy days at non-urban stations depicted an increasing trend,and the difference in the number of hazy days for urban and non-urban stations had been narrowing over time.Monthly variation of hazy days for the BTH area displayed bimodal trends,with more hazy days in the summer and winter.According to the spatial distribution,the areas with more hazy days were mainly located in Beijing,Tianjin,Baoding,Shijiazhuang,Handan,and Xingtai.At most of stations in the BTH area,average wind speed at 14 o’clock in hazy days was over 1.0m/s lower than non-hazy days,and average relative humidity at 14 o’clock in hazy days was over 20% higher than non-hazy days.