Atlantic and Pacific multidecadal variability influence on Taiwan winter temperature centennial trend during the period 1911 - 2010

The sea surface temperature (SST) of the marginal seas off the East coast of China is known for its large warming trend during the twentieth century. The station data in Taiwan is of particular importance as a reliable complementing measurement for SST. This paper analyzes the temperature from 1911 - 2010 at six stations using the data adaptive method Ensemble Empirical Mode Decomposition (EEMD). Multidecadal modes (period > 40 years) in winter with the warm (1931 - 1950) and cold (1971 - 1980) phases are identified. In addition to the warm and cold phases, the 1951 - 1970 period is identified as the cooling phase, a transition phase from a warm to a cold regime, while the 1911 - 1930 and 1991 - 2010 periods are identified as the warming phase. The multidecadal variability in the Taiwan winter temperature is robust because it is rooted in the major multidecadal variability modes of the global SST, the Atlantic multidecadal oscillation (AMO), and the Pacific Decadal Oscillation (PDO). The centennial secular trend (ST) shows much larger warming rate than the linearly regressed. Because the multidecadal mode has been in a warming phase since 1991, the surpassed warming rate is likely due to a compensation effect to the decadal or sub-decadal scale cooling variations, while the possibility of anthropogenic influence cannot be ruled out.