11 meeting of the International Argo Steering Team Scripps ...

For each potential TNPD microleakers, the time series of the differences is plotted to look for
evidence of the Druck microleak (cold bias in strong thermocline, saline anomaly at depth and
negative anomaly for the pressure).
The method is clearly able to detect APEX TNPD microleakers. Large drifts are obvious.
Complementary diagnostics are required to detect smaller drifts. Using ADJUSTED data and
excluding suspicious floats from the analysis should help refine the detection of the TNPD
microleakers.
Action item 10: Ask CSIRO to redo their comparisons to look at buddy pairs by launch
year to help identify possible errors in pressure by year for a correction or error to add
into files.
5.2.3 Progress on Argo Reference Database
S Diggs was unable to attend the AST-11 meeting, so the status report on the current state of
the acquisition and dissemination of Ship-Based CTD data was presented by M Scanderbeg.
After briefly reviewing the original need for these data and the tri-agency structure of the CTD
data acquisition team, recent work by J Gilson, M Scanderbeg and S Diggs was shown. The
most recent CTD database (CTD_for_DMQC_2010V1) and the “Argo Float” database
(Argo_for_DMQC_2009V4) were used within the Owens and Wong (OW) salinity calibration tool
to ‘map’ the climatology of the South Pacific and Southern Oceans. This analysis attempts to
quantify those regions where new CTD data are most necessary to improve the Argo DMQC
reference database (CTD) and simultaneously to confirm ocean state changes measured by the
Argo float database.
In addition, the presentation included a Google Earth animation highlighting the lack of publicly
available CTD profiles in the Southern Ocean in the last ten years. However, the CCHDO's
involvement in the US Repeat Hydrography Program as well as the new GO-SHIP project will
give the Argo data team rapid access to a significant number of high-quality CTD data from
research cruises scheduled in the coming months and years. Unfortunately, identifying
temporally relevant CTD observations data from the Southern Indian Ocean continues to be a
challenge. Further direction and feedback from the Steering Team would help the Data Team
continue to refine its objectives and insure success with this project.
5.2.4 Other reports and open discussion on pressure issues
S Wijffels reported on an analysis by CSIRO of pressure adjustments in the Argo APEX data set
downloaded from the GDACs in December 2008. This analysis is currently in review, and is
focused on producing a version of the Argo data set appropriate for studying changes in global
ocean heat content (GOHC). It was noted that as the pressure sensors deployed in Argo has
changed over time, the bias in the DAC data set has changed. Early float sensors (Ametek and
Paine) typically drifted positive while Druck sensors typically have little drift or strong negative
drift (when afflicted by a micro-leak) – figure X.
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