Enhanced North Pacific Victoria mode in a warming climate

Abstract

The Pacific Decadal Oscillation (PDO), renowned as the dominant sea surface temperature (SST) fluctuation in the North Pacific and extensively scrutinized for its extensive influence on global climate patterns, stands in stark contrast to the Victoria mode (VM). Traditionally, the VM, representing the second most prominent SST pattern in the North Pacific, has not garnered comparable attention. However, our investigation unveils a remarkable surge in the low-frequency VM variability, spanning periods greater than 8 years, over the course of a century. Astonishingly, this enhanced VM variability now surpasses the PDO’s variability in recent decades, signifying a notable shift. Consequently, the heightened VM variability assumes newfound significance in shaping climate systems across the entire North Pacific region and in distant locales. This intensified VM behavior could be attributed to amplified atmospheric variability in the Hawaiian region, primarily stemming from the reinforced variability in the tropical central Pacific (CP) SST in recent decades. As greenhouse warming escalates CP SST variability, the VM’s enhanced variability may further intensify, yielding broader and more profound repercussions in the future.