An examination of horizontal advection and the causes of mixed layer variability in the northeast Pacific Ocean from 2001--05 using Argo data and the General Ocean Turbulence Model.

摘要

For unknown reasons, the mixed layer depth (MLD) in the Gulf of Alaska (GOA) has been shoaling over the past 50 years with the shallowest winter MLD from 2002--03. The 1-D General Ocean Turbulence Model (GOTM) was used to calculate the MLD at in the northeast Pacific Ocean from 2001--05 and sensitivity experiments were run to determine how atmospheric processes affect the MLD. To determine whether the 1-D assumption was realistic, a proxy to calculate advection was established based on changes to the observed heat content.; It was found that GOTM produced the most realistic MLD in the subtropical gyre despite significant advection because the method that GOTM used to calculate the MLD was more accurate in warmer water. In addition, although changes to the wind speed and heat fluxes can explain some MLD variability, the occurrence of anomalous atmospheric and oceanographic events also significantly impact the MLD.