Analysis of variations in the surface temperature of tropical and Northern Pacific Ocean

Abstract

Studies on the analysis of the Pacific Ocean surface temperature are presented based on the data of the NCEP/NCAR reanalysis. Two methods are used in the work. The first is a classical analysis of the empirical orthogonal functions (EOFs) that makes it possible to identify the El Niño and La Niña phenomena in tropics. In this case, the anomalies of the ocean surface temperature (OST) are reconstructed during these events with quite high accuracy when using several first EOFs. In contrast, at the time between these events, more harmonics are required for the reconstruction. The OST variability in the middle and high latitudes cannot be identified highly accurately based on this approach, since it is considerably weaker than a strong signal in tropics. This signal was detected by the method of cluster analysis. The results show that, in addition to the signal in tropics, there are well-pronounced quasi-decadal signals between the eastern and western Pacific, as well as in the region of the Kuroshio continuation and in the subpolar gyre that can be identified with Pacific decadal oscillations (PDOs).