开平单站降水的多尺度振荡特征

Characteristics of Multi-scale Oscillations of Precipitation for the Single Station at Kaiping

利用开平市国家气象观测站1959—2016年逐日降水数据,通过功率谱分析、Morlet小波分析等方法对开平单站雨量数据中存在的振荡变化特征进行初步分析。结果表明:开平单站逐年降水、逐日降水不存在稳定的振荡周期,其中逐年降水表现为多尺度的阶段性变化,逐日降水中季节内振荡信号最强,并存在相对较弱的5 d及以下尺度振荡、准双周振荡等;通过对汛期逐日降水振荡变化的分析发现,开平汛期降水偏多年,逐日降水易表现为低频振荡;汛期降水偏少年,逐日降水易表现为高频振荡。

Using the daily precipitation data for a national weather station at Kaiping from 1959 to 2016 and with the methods of power spectrum and Morlet wavelet analysis, we preliminarily studied the character- istics of the oscillatory variation existent in the rainfall data. The result is shown as follows. For the single station, no stable oscillatory periods are found in the yearly and daily precipitation, and the former varies on multiple scales while the latter has the largest signal in intraseasonal oscillation, accompanied by relatively weak oscillations at 5 d and less and by-weekly oscillation. Through analysis of the oscillatory variation of daily precipitation during flooding seasons, it is found that the precipitation of Kaiping is usually of low-fre- quency in the years of anomalously large rainfall but of high-frequency in the years of anomalously small rain- fall.