Variability of the mixed layer depth over the North Pacific simulated from a global OGCM

Abstract

Seasonal and spatial variability of the mixed layer depth (MLD) over the North Pacific was investigated using global OGCM simulations with various vertical mixing schemes. The OGCM used is GFDL MOM1.1, and was forced for about 30 years, using monthly-mean climatological wind, heat flux plus restoring, and restoring of the model sea surface salinity to Levitus data. The reproduced MLD from the OGCM is well matched with the calculated MLD using Levitus data in winter regardless of vertical mixing schemes, while the MLD in summer shows remarkable differences depending on vertical mixing schemes. It was also found that large MLD around 40N in winter is well reproduced and shows no significant dependency on vertical mixing schemes, although the model MLD tends to be larger than Levitus data.