Influence of the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation on Global Temperature by Wavelet-Based Multifractal Analysis

Abstract

Oceanic-atmospheric patterns, Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO), and their respective influence on the global warming hiatus were the main interests of this study. In general, a fractal property is observed in the time series of dynamics of complex systems; hence, we investigated the relations among the AMO, PDO, and El Niño-Southern Oscillation (ENSO) from the point of view of multifractality, in which changes in fractality were detected with multifractal analysis using wavelet transform. For the periods 1950-1976 and 1998-2012, global temperature increased little, with positive AMO and negative PDO indices; subsequently, the rate of temperature increase weakened. Global temperature increased again in 1976, with the reversal of the AMO and PDO indices from negative to positive. More specifically, AMO, PDO, and Niño3.4 (ENSO index) exhibited fractality change from multifractality to monofractality, providing them stability. Generally, the PDO was influenced largely by the ENSO. But, around 1960 and around 2000, whose periods corresponded to hiatus periods in global warming, the influence of the ENSO on the PDO was weak. In 1998, the AMO increased and PDO decreased and global temperature increased little and the multifractality of PDO, and Niño3.4 was weak, which corresponded to the change from multifractality to monofractality in 1976. Wavelet analysis showed the leads of PDO and Niño3.4 indices with respect to global temperature. Consequently, the PDO and ENSO showed large influence on global temperature and, further, on the global warming hiatus.

Trends in the differences between homogenized ground surface temperature and surface air temperature in China during 1961–2016 and its possible causes

“…SAT is a component of SATDs, so the global warming should affect the SATDs. Previous research have found the global warming hiatus during 1951-1976and 1998(Kosaka and Xie 2013Maruyama 2019). It denotes the fluctuations in global cooling or warming at a decadal scale.…”