In this paper we extract components in extended-range forecast for the coming 10-30 days by the Butterworth Band-pass filter using the NCEP/NCAR reanalysis daily data of geopotential height from 1978 to 2007 and from January 6th to February 4th, and at the same time extract the basic function of climate state by empirical orthogonal function （EOF）. And we use the same way to deal with the daily data of geopotential height during the snow storm event in January 2008 by the Butterworth Band-pass Filter. We use the contribution rate to explain the variance of EOF and the elements which influence this weather process in a period of 10-30 days. Stable components in extended-range forecast for the coming 10-30 days can be divided into two parts according to the contribution rate analysis： climatic stable components and abnormal stable components. Results show that climatic stable components are in the subject status during the snow storm event in January 2008 while abnormal stable components are equivalent to a disturbed value superimposed on climatic stable components. The influence of abnormal stable components cannot be neglected, and they can play quite a significant role. The circulation patterns of abnormal stable components correspond well to anomalies in Pacific region. These conclusions deepen our understanding of 10-30 days components and provide a new way to think and solve the problem of extended range forecast for the coming 10-30 days.%对北半球1978-2007年1月6日-2月4日逐日500hPa高度场资料带通滤波，得到10-30d时间尺度分量，结合经验正交函数分解方法（empificl oahogonal function，EOF）提取出气候态基底．同样滤波北半球2008年1月冰冻雨雪事件的逐日实况资料，并将其投影到气候态基底上，利用各贡献率作为考察该EOF分量对原场的影响指标．从10-30d延伸期预报的角度提取稳定分量进行诊断分析，探讨影响此次天气过程的主要因素．通过贡献率分析方法把10-30d延伸期稳定分量划分为气候态稳定分量和异常型稳定分量两个部分．结果表明：气候态稳定分量在我国南方2008年1月冰冻雨雪事件中占主体地位，异常型稳定分量相当于在气候态稳定分量的基础上叠加的扰动值，但异常型稳定分量在本次过程中的作用不能忽视，甚至起到关键性的作用，并且与实况距平在太平洋地区整体环流形势有较好的对应．这些结论加深了对10-30d时间尺度可预报性的认识，为10-30d延伸期预报提供了一种新的思路和解决问题的途径．
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