Changes in the North Pacific Current divergence and California Current transport based on HadGEM2-ES CMIP5 projections to the end of the century

Abstract

This study aims to evaluate the potential changes to the strength of the North Pacific Current (NPC) and its position of divergence, which would alter the variability of the Alaska (AC) and California (CC) currents throughout the century. For this, the volume transports of these currents were evaluated using the historical CMIP5 and RCP4.5 experimental results of the HadGEM2-ES model from 1985 to 2100. In general, the NPC will migrate to the north, in accord to the northwestward expansion of North Pacific High, which would alter the positioning and the amount of flow entering the AC and CC systems by 2100. Along with the bifurcation shift, changes in the two main modes of variability, i.e., the bifurcation and breathing modes, are expected. The bifurcation mode will become responsible for only 11% of the total variability while presenting a positive anomaly throughout the century. These results indicate the role of NPC migration on the southward transport of enriched waters and the possible impact on the primary productivity along the North American coast.