四川广汉机场云的周期性变化特征

摘要

基于1986-1995年民航广汉机场气象台逐日逐时人工观测资料,利用统计分析,带通滤波方法、功率谱分析和小波分析等方法,分析了广汉机场云的周期性变化特征.结果表明:广汉机场主要受层积云Sc、积云Cu两种低云影响,且二者具有相反的日变化特征,碎层云Fs、雨层云Ns和碎雨云Fn等出现频率很低.广汉机场云量的变化明显具有60-120 d的准季节周期、30-60 d季节周期和10-20 d准双周振荡.%Based on the hourly manual observational data from meteorological station at Guanghan airport from 1986 to 1995 ,the periodic characteristics of low cloud were analyzed by band-pass filtering method,power spectram analysis method and wavelet analysis method.The results indicate that Guanghan airport is influenced by stratocumulus (Sc) and cumulus ( Cu), and the daily variation characteristics of the two clounds are contrary.Other clouds such as stratus fractus (Fs), nimbostratus (Ns) and fracto-nimbus (Fn) seldom appear at Guanghan airport.Variations of the cloud cover show an obvious quasi-seasonal cycle of 60-120 day, an intra-seasonal cycle of 30-40 day and a quasi-biweekly oscillation cycle of 10-20 day.