MIMOC: A global monthly isopycnal upper-ocean climatology with mixed layers

A monthly, isopycnal/mixed-layer ocean climatology (MIMOC), global from 0 to 1950dbar, is compared with other monthly ocean climatologies. All available quality-controlled profiles of temperature (T) and salinity (S) versus pressure (P) collected by conductivity-temperature-depth (CTD) instruments from the Argo Program, Ice-Tethered Profilers, and archived in the World Ocean Database are used. MIMOC provides maps of mixed layer properties (conservative temperature, , absolute salinity, SA, and maximum P) as well as maps of interior ocean properties (, SA, and P) to 1950dbar on isopycnal surfaces. A third product merges the two onto a pressure grid spanning the upper 1950dbar, adding more familiar potential temperature () and practical salinity (S) maps. All maps are at monthly 0.5 degrees x0.5 degrees resolution, spanning from 80 degrees S to 90 degrees N. Objective mapping routines used and described here incorporate an isobath-following component using a Fast Marching algorithm, as well as front-sharpening components in both the mixed layer and on interior isopycnals. Recent data are emphasized in the mapping. The goal is to compute a climatology that looks as much as possible like synoptic surveys sampled circa 2007-2011 during all phases of the seasonal cycle, minimizing transient eddy and wave signatures. MIMOC preserves a surface mixed layer, minimizes both diapycnal and isopycnal smoothing of -S, as well as preserves density structure in the vertical (pycnoclines and pycnostads) and the horizontal (fronts and their associated currents). It is statically stable and resolves water mass features, fronts, and currents with a high level of detail and fidelity.