Multiscale Examination on the Temperature and Precipitation Series in Tianjin during 1921-2010

A multiscale examination of temperature and precipitation in Tianjin during 1921-2010 was performed using the EMD (Empirical Mode Decomposition) method. Moreover, power spectrum analysis was performed on the IMFs (Intrinsic Mode Functions) derived from EMD. This analysis indicates that the variations of the annual mean temperature are mainly characterized by high-frequency oscillations, with 2-3-year periods and quasi-5-year periods detected in the first two IMFs, and a long-term V-shaped variation in the trend component. In addition, interdecadal variations were detected in the fourth and fifth IMFs. The precipitation series are also mainly characterized by high-frequency oscillations, with periods of 2-3, 4.5, and 9 years detected in the first two IMFs. It is concluded that the interdecadal variations and the long-term trend are more apparent in the temperature series, and therefore have a much smaller contribution to precipitation variation.