【摘要】 利用谐波分析、功率谱分析的方法,对陕西82个站点1962~2006年逐日降水资料进行气候平均分析,研究气候平均态下陕西降水季节及季节内振荡的时空分布特征。结果表明,陕西大部分地区降水主要以季节变化(年循环)为主,降水准双周振荡在全省范围都比较显著,降水30~60 d季节内振荡的显著分布区域主要集中在关中和陕南,这种地域分布与副热带高压随东亚夏季风南北移动有很大关系;气候平均态下降水的准双周振荡幅度于4月中旬开始逐渐加强,7~9月振幅最强,10~11月开始逐渐减弱;降水准双周振荡显著时期主要在夏季,而30~60 d季节内振荡在全省全年都存在,夏季比冬季振幅大,陕南和关中地区最大振幅出现在7月初。更多还原

【Abstract】 Based on the daily rainfall data at 82 observational stations in Shaanxi Province from 1962 to 2006,the temporal and spatial distributions of the climatological seasonal and intraseasonal oscillation of rainfall were studied by using the harmonic analysis and power spectrum analysis methods. The results show that the rainfall in most parts of Shaanxi Province has an obvious seasonal variation. The quasi- biweekly oscillation( QBWO) of rainfall was significant in the whole area of Shaanxi,while the madden Julian oscillation( MJO) mainly occurred in the central Shaanxi plain( named as Guanzhong) and southern Shaanxi. The distribution characteristic was related to moving north or south of the subtropical high with the eastern Asian summer monsoon. The amplitudes of QBWO of rainfall gradually strengthened from mid April and reached the strongest from July to September,and weakened from October. Therefore,the QBWO of rainfall was significant in summer. Although the MJO of rainfall existed in the whole year,the amplitude in summer was stronger than that in winter,and the peak of amplitudes occurred in July in Guanzhong plain and the southern Shaanxi,which was not obvious in the northern Shaanxi.更多还原