四川盆地区域性浓雾序列及其年际和年代际变化  

Regional Dense Fog Time Sequence with Its Annual and Decadal Variation in the Sichuan Basin

作　　者：周自江[1] 朱燕君[1] 姚志国[2] 鞠晓慧[1] 

机构地区：[1]国家气象信息中心,北京100081 [2]四川省气象局,成都610071

出　　处：《应用气象学报》2006年第5期567-573,共7页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(40305008);国家科技基础条件平台工作重点项目(2004DKA20170)共同资助。

摘　　要：利用四川盆地20个国家级基本气象站1954-2005年的大雾和能见度等资料,探讨了区域性浓雾的认定标准,建立起该地区较完整的区域性浓雾日数序列,分析了其年际、年代际变化及可能原因。结果表明：①盆地内区域性浓雾主要发生在秋冬季(9月至次年2月),占总数的92．8％,这也就决定了浓雾日数序列是一个跨年度统计的序列；②1954-1976年盆地内浓雾处于偏少的负位相,尤以20世纪60年代为最少,相反,20世纪80-90年代浓雾频次高、强度大,处于多雾的正位相,但是近些年有明显的减弱；③在浓雾的年际和年代际变化中,大气中凝结核的数量(背景大气浑浊度)起着主导作用,同时,干湿状况是决定浓雾年代际变化另一主要原因,局地气候变暖对浓雾的影响具有不确定性；④90年代以后盆地内浓雾的减弱是3个因子共同作用的结果。According to the definition in the Surface Meteorological Observation Manual, dense fog is a kind of disastrous weather phenomenon that the visibility is less than 500 meters caused by abundant tiny water drops floating in the low atmosphere layer. Since the 1980s, the traffic has increased sharply with the developing of the national economy, and the damage caused by dense fog becomes more and more severe in China. As a result, much attention has been paid to studies on dense fog. Based on the available observation data set from 20 meteorology stations located in the Sichuan Basin where dense fog occurs frequently during 1954-2005, the time series of regional dense fog has been constructed under the criterion, during the same observation day there are 5 or more stations where dense fog emerge together, in the Sichuan Basin. Furthermore, the annual and decadal variation of this time series and possible change mechanism are discussed. Results show that most regional dense fogs occur mainly during autumn and winter （September to next February） ,and account for 92.8% of the annual amount. In summer, dense fog events are not prone to happening, only accout for 1.4%. So it means that the time sequence of dense fog in the Sichuan Basin spans two years, from July to June of next year. Taking the 51 years as a whole, regional dense fog has an increasing tendency with 2.96 days per decade in the Sichuan Basin. During 1954-1976, regional dense fog events are less than the average of 51 years, keeping a negative phase and 18.2 days per year, especially the 1960s is the least ten years, only 15 days per year. On the contrary, dense fogs are frequent and severe through 1980s and 1990s, keeping a positive phase. In recent years, dense fogs in the Sichuan Basin are decreasing, but the number is still more than that in the 1960s. There are significant negative correlation coefficients, not only at inter-decadal scales but also inter-annual scales, between dense fogs and visibilities of background atmosphere with no fog weat

关 键 词：四川盆地 区域性浓雾 年代际变化 大气浑浊度 

分 类 号：P426.4[天文地球—大气科学及气象学]