Journal Highlights

Exploring the role of slope water in altering the characteristics of bottom water

Editor’s Highlight—

 

This study examines interannual variability of dissolved oxygen and physical water properties in the northern California Current System (CSS) using a 25-year numerical hindcast. Focusing primarily on the continental slope, the study uses the hindcast fields to examine how winds, alongshore transport and water masses affect long-term trends and year-to-year anomalies in dissolved oxygen. The model results show that a trend of increasing Pacific Equatorial Water is partially responsible for long-term declines in oxygen. In addition to upwelling-favorable wind stress, the strength of the California Undercurrent is found to influence the magnitude and cross-shelf structure of dissolved oxygen anomalies. Interestingly, wintertime downwelling is also shown to affect subsurface oxygen anomalies during the following summer under certain conditions. This study contributes a new perspective to the subject of hypoxia in the northern CCS because historical observations are limited, and previous modeling studies of dissolved oxygen in this region have not extended this far back in time. The paper should be of interest to scientists across multiple disciplines, as well as both modelers and observational oceanographers.