Abstract: Based on the monthly average temperature and precipitation at Shenyang station during 1951-2016, the multi-scale temporal characteristics of annual average temperature and precipitation anomaly were analyzed by using the ensemble empirical mode decomposition (EEMD) method, firstly. Then, the periods of main intrinsic mode functions (IMFs) of two elements were discussed by using power spectrum analysis method. And on this basis, the series of two elements based on the components of IMFs were rebuilt and compared. The results show that the variation of annual mean temperature was mainly caused by the oscillation of the first two components with high frequency and the trend component of IMFs in Shenyang during 1951-2016, which reflected the periodic changes with quasi-5-year, quasi-7-year, and long-term upward tendency, respectively. The impact of the third component of IMFs with quasi-14-year period on the annual average temperature wasn’t ignorable. In addition, the variations of the fourth and fifth components of IMFs with longer interdecadal time scales were consistent with the trend component after the 1980s, which indicated the obvious increase of temperature in Shenyang after the 1980s. The variation of annual precipitation series was mainly caused by the high-frequency oscillations of the first two components of IMFs with quasi-3-year and quasi-5-year periods, respectively, while the trend component with quasi-64-year period of annual precipitation reflected the trend change with the decrease initially and followed by the increase before and after the 1980s in general. Compared with the temperature series, the contribution of interdecadal and long-term trend change to the precipitation series was limited.

Key words: temperature, precipitation, EEMD, power spectrum, Shenyang

摘要： 应用集合经验模态分解（EEMD）方法，对1951—2016年沈阳年平均气温和年降水量序列进行多尺度分析，并结合功率谱分析了两要素主要本征模态函数（IMF）分量的周期变化特征。在此基础上，进行了序列重建与对比。结果表明：近66 a来，沈阳年平均气温的变化主要由第1、第2高频分量和趋势项的振荡造成，分别反映了准5 a和准7 a的周期变化以及长期的缓慢增温过程；准14 a的年代际振荡第3分量对沈阳年平均气温变化的作用也不可忽视，而反映更长时间尺度的第4和第5分量在1980年代后与趋势项的变化特征基本一致，表明1980年代后沈阳明显增暖。年降水量的变化主要由第1、第2分量的年际振荡造成，振荡周期分别为准3 a和准5 a，而趋势项则呈现出准64 a的周期变化，总体反映出年降水量在1980年代前后呈现先减后增的变化趋势。与年平均气温序列相比，年降水序列的年代际尺度变化和长期趋势变化的贡献明显偏小。

关键词: 气温, 降水, EEMD, 功率谱, 沈阳