1970—2015年蚌埠地区霾日气候资料重建及时空变化特征

Climatic data reconstruction of haze days and its temporal-spatial characteristics in Bengbu area from 1970 to 2015

利用1970—2015年蚌埠地区4个气象站点逐日4个时次的相对湿度、能见度和天气现象等观测资料,通过霾的客观判别方法,重建了近46 a蚌埠地区霾日的气候序列,并系统分析了蚌埠地区霾日的时空分布特征及其与关键气象要素的关系。结果表明:采用日平均值法重建的蚌埠地区霾日序列能较完善的表征霾天气的长期变化特征,且与基于天气现象得到的霾日序列具有较好的一致性,二者显著相关。1970—2015年蚌埠地区不同气象站点间霾日数差异较大,呈南多北少的空间分布特征,其中蚌埠站霾总日数最多;霾日数表现为秋冬季多、夏季少的季节变化特征。近46 a蚌埠地区霾日数具有明显的年代际变化特征,整体呈增加的趋势,尤其是2000年以后霾日数增长速率达4.8 d·a-1,变化趋势显著; 20世纪80年代后期至90年代前期霾日数略有减少。近地面弱偏东风控制、相对湿度偏高、混合层厚度偏低、逆温为蚌埠地区霾天气发生发展的有利气象条件,气温和气压与霾日数的关系不显著。

Based on the observational data four times a day at four meteorological stations in Bengbu from 1970 to 2015,including relative humidity,visibility,weather record,etc,and using an objective method to identify haze events,the climatic time series of haze days in recent 64 years were reconstructed and its spatiotemporal characteristics and relationship with criteria meteorological parameters were analyzed.The results showed that haze days series reconstructed from the daily mean value method can reasonably represent the long-term characteristics of haze events,which is well consistent with the haze days series obtained from the weather records,showing a significant correlation between them.The haze days number varied largely at different meteorological stations in Bengbu from 1970 to 2015,with larger value in south and smaller value in north.The largest total haze days number occurs at Bengbu station.The number of haze days in Bengbu is large in autumn and winter and small in summer,and it exhibits obvious decadal variation in the past 46 years.The number of haze days increases generally.After 2000,its increasing rate reaches 4.8 d·a-1.However,it decreases slightly in the period from the late 1980s to the early 1990s.The favorable meteorological conditions for the formation and development of haze events in Bengbu include the easterly wind in the near surface layer,high relative humidity,shallow mixing layer height,and the existence of temperature inversion.The relationship between haze days number and air temperature and pressure is not significant.