基于逐时资料的黄山雾凇特征及气象条件分析

Climatic Features and Meteorological Conditions of Rime in Huangshan Based on Hourly Data

利用2004—2016年黄山气象站逐日、逐时地面气象观测资料分析了雾凇的时间分布特征及气象条件。结果表明:(1)黄山年平均雾凇日61.6d,年份之间差异明显;雾凇初日主要在11月,终日主要在3—4月;连续雾凇日数多在3～4d,占40%,各年均出现了连续雾凇日数≥10d的情况。(2)雾凇出现在10月至次年4月,其中12月至次年3月雾凇日数占89.8%;月平均雾凇日数与月平均气温呈显著负相关。雾凇还存在一定的日变化,08:00—09:00最多,18:00最少。(3)逐日资料统计表明,适宜雾凇出现的气象条件是雾日且日平均气温在-8～2℃之间、平均相对湿度≥80%、平均风速2～9m/s。(4)逐时资料统计表明,雾凇的形成主要受气温影响,雾凇形成前需7h以上的累计低温(≤0℃),适宜雾凇形成的气象条件是有雾且气温在-6～1℃之间,湿度≥95%,风速2～11m/s,较好地反映了雾凇形成的临界气象条件。

Based on the daily and hourly surface meteorological observation data of Huangshan Station from2004 to 2016,the temporal distribution and climatic conditions of rime are analyzed.The results show that:(1)The annual average number of rime days in Huangshan is 61.6,with obvious differences between years.The earliest day of rime was mainly in November and the latest day was mainly in March and April.The number of consecutive rime days is often 3 to 4 days,accounting for 40%of the total number.In each year there were continuous rime days of≥ 10 days.(2)The rime appeared mainly from October to next April,of which the number of rime days from December to next March accounted for 89.8%.The monthly mean number of rime days is significantly negatively correlated with the monthly mean temperature.There was a certain daily change in rime,with the highest number at 09:00,and the least at18:00.(3)Analysis results of daily data show that suitable meteorological conditions for rime are:foggy days and daily mean temperature between-8 and 2 ℃,daily mean humidity ≥ 80%,daily mean wind speed between 2 and 9 m/s.(4)The statistics of hourly data shows that rime formation is mainly affected by air temperature.There needs a period of≤ 0 ℃ low temperature of more than 7 hours before the formation of rime.The suitable meteorological conditions for rime are foggy and the temperature being between-6 and 1℃,humidity≥95%,wind speed between 2 and 11 m/s,which reflect well the critical conditions of rime formation.