Mixed Layer Depth in the Australian Region

Mixed layer depth was calculated from the oceanographic temperature and salinity cast data used to generate CARS2000. It was defined to be the minimum (shallower) depth of depths zt and zs, where zt and zs are the shallowest depths such that abs(T(zt)-T(10m)) >= .4C and abs(S(zs)-S(10m)) >= 0.03 PSU. These values were then mapped onto a regular .5 degree grid using a loess filter, as used in CARS2000, simultaneously fitting quadratic spatial functions and annual harmonics. These fields were then linearly interpolated to the required 1/10th degree spatial resolution. The provided "annual amplitude" is simply the magnitude of the fitted annual sinusoid. CARS is a set of seasonal maps of temperature, salinity, dissolved oxygen, nitrate, phosphate and silicate, generated using Loess mapping from all available oceanographic data in the region. It covers the region 100-200E, 50-0S, on a 0.5 degree grid, and on 56 standard depth levels. Higher resolution versions are also available for the Australian continental shelf. The data was obtained from the World Ocean Atlas 98 and CSIRO Marine and NIWA archives. It was designed to improve on the Levitus WOA98 Atlas, in the Australian region.