Introduction:

We have compiled a mixed layer depth (MLD) climatology using Argo profiles and a hybrid method (Holte and Talley 2009) for finding the MLD. The climatology incorporates over 1,000,000 Argo profiles (through May 2015). The new hybrid algorithm models the general shape of each profile, searches for physical features in the profile, and calculates threshold and gradient MLDs to assemble a suite of possible MLD values. It then analyzes the patterns in the suite to select a final MLD estimate. Results are also presented for MLDs calculated using de Boyer Montégut et al.'s (2004) threshold values.
Two forms of Argo MLDs are provided:
 Mixed layer depths and properties (density, temperature, and salinity) for every profile in the Argo data set.
 Climatology of monthly mixed layer depths (mean, median, maximum, and standard deviation) and properties (density, temperature, and salinity) averaged into 1 degree bins.
These files contain the mixed layer depths and properties as calculated by the density algorithm and the density threshold. Each also includes the mixed layer depths calculated by the temperature algorithm and the temperature threshold. A MATLAB version of the algorithm is also available here.


Data: 
The output includes more than 1,000,000 delayedmode and realtime Argo profiles, collected between January 2000 and May 2015. The profiles were screened with some simple quality controls.

Mixed layer depths and properties for all Argo profiles: 
Both versions contain the following fields calculated for each individual Argo profile:
 profile date
 profile latitude
 profile longitude
 float number (WMO number)
 profile number
 status (delayed mode corresponds to 1)
 mixed layer depth from density algorithm
 mixed layer average temperature using density algorithm MLD
 mixed layer average salinity using density algorithm MLD
 mixed layer average potential density using density algorithm MLD
 mixed layer depth from density threshold method
 mixed layer average temperature using density threshold MLD
 mixed layer average salinity using density threshold MLD
 mixed layer average potential density using density threshold MLD
 mixed layer depth from temperature algorithm
 mixed layer depth from temperature threshold method

Monthly mixed layer climatology: 
The climatology is determined by grouping the profiles into 1 degree bins and then calculating the mean, median, maximum, and standard deviation of the MLDs for each month, as well as the monthly mean mixed layer temperatures, salinities, and potential densities. These variables are calculated separately using the density algorithm and the density threshold. The maximum MLD is calculated as the mean of the three deepest MLDs. The monthly mean MLDs calculated by the temperature algorithm and the temperature threshold are also included. The climatology contains the following monthly fields averaged into 1 degree bins:
 density algorithm mean MLD
 density algorithm median MLD
 density algorithm maximum MLD
 density algorithm MLD standard deviation
 density threshold mean MLD
 density threshold median MLD
 density threshold maximum MLD
 density threshold MLD standard deviation
 mean mixed layer temperature, salinity, and potential density calculated with the density algorithm mean MLD
 mean mixed layer temperature, salinity, and potential density calculated with the density threhsold mean MLD
 temperature algorithm mean MLD
 temperature threshold mean MLD
If you use this data, please cite it as:
Holte, J., J. Gilson, L. Talley and D. Roemmich, 2010: Argo Mixed Layers, Scripps Institution of Oceanography/UCSD http://mixedlayer.ucsd.edu, (accessed [date]).

Links: 
Argo data browser
Ocean Sciences presentation on the Argo MLD climatology
Algorithm MATLAB code and demo
Holte and Talley, 2009 (JTECH paper on the algorithm)
de Boyer Montégut et al., (2004) MLD climatology

