Float of the Month (December)

December Float of the Month is the North Atlantic array of floats.  I wrote on Twitter:

"Float(s) of the month. Surface ocean % oxygen saturation versus time of year for all floats in the North Atlantic (2005 to present). Lots of concern about ocean oxygen at COP25. A full BGC-Argo array would provide a real-time observing system."

The animated GIF shown below accompanied the tweet.

This data were all obtained from the Argo GDAC Sprof.nc files.  Only about half the oxygen data at the GDAC has been qc'd, as many of the GDACs are overworked or don't have the necessary expertise.  As a result, if one uses the data downloaded directly, there will be many errors.  To correct for this, this data were all adjusted for storage drift and quality controlled for erroneous values using statistical methods if they were not already corrected.

Plots below the animated GIF show surface (upper 10 m) oxygen percent saturation versus time for 20 degree latitude bands in the North Atlantic and marginal seas (including the Baltic, with some really neat data).  Bands of data that are clearly offset from around 100% very likely represent problems in the automated qc.  For example, the red ovals in the 0 to 20N band show 3 sets of data that are in most likely in error.  The two high values are in regions that appear to have shallow river plumes and the sharp gradients upset our statistical procedure.   The lower oval is a failed sensor that somehow eluded our statistical evaluation.

Getting the qc and adjustments correct is the largest challenge facing BGC-Argo.  SOCCOM has shown how to do this.  Our job is now to pass the tools and knowledge on the remainder of the community.





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