Analysis of Heavy Fog in Hefei Area in Recent 50 Years
WEI Wen-hua et al(Nanjing University,Nanjing,Jiangsu 210039)
[Objective] The research aimed to analyze the basic characteristics of heavy fog in Hefei area and provide reference data for transportation departments.[Method] Based on the long-term data series of Hefei weather station(mainly from 1954 to 2006),the annual,monthly and daily change characteristics and the duration of heavy fog in Hefei area were studied.[Result] The average annual days of heavy fog in Hefei area was over 16 d and it had obvious annual change characteristics.At the same time,heavy fog in Hefei area had obvious seasonal characteristics and it was concentrated in winter(from December to February in next year) and the heavy fog in summer was little.The occurrence time of heavy fog in this area was concentrated from the time after midnight to the time before and after sunrise in wee hours.In different duration,the annual changes of occurrence frequency of heavy fog in Hefei area were different.The heavy fog with the duration of 2～6 h had the most occurrence times in January,while that with the duration of 6～12 h had the most occurrence times in December and that with the duration of over 12 h only occurred from November to February in next year.[Conclusion] Heavy fog in Hefei area belonged to radiation fog basically.
【CateGory Index】： P468.02