M. Menna,G. Notarstefano and P.-M. Poulain OGS – Trieste - Italy

Delay-mode quality control of Argo float salinity data in the Mediterranean Sea

M. Menna,G. Notarstefano and P.-M. Poulain

OGS – Trieste - Italy

Fourth Argo Delay-Mode Quality Control Workshop (DMQC-4)Toulouse, France, 28 September 2009


Contents

1.Reference database used in the DMQC

2.MedArgo status in September 2009

3.DMQC in the Mediterranean Sea

4.Conclusion

5.Future work

Reference Databases for Mediterranean – As of today, we have:

• Ref. Database Eflubio-2 (2005)

• Ref. Database Eflubio-3 (2004)

• Ref. Database Coriolis 2008V02 (1991-2008)

• Ref. Database Egitto-1 (2006)

• Ref. Database Enea (Borghini – 2004-2006)

• Ref. Database Enea (Santoleri - 2004)

• Ref. Database MFSTEP (2003)

• Ref. Database MREA07 – IT_NAVY Aretusa (2007)

• Ref. Database MREA07 – IT_NAVY Galatea (2007)

• Ref. Database MREA07 – NURC Leonardo (2007)

• Ref. Database MREA07 NURC Leonardo LASIE07 (2007)

• Ref. Database MREA07 – TNO Snellius (2007)

• Ref. Database NODC odv-1 (2000)

• Ref. Database NODC odv-2 (2006)

• Ref. Database SESAME IT2 (2008)Coriolis rer. database (1991-2008)


27 MFSTEP + 1 SPAIN + 27 FRANCE + 29 NAVO + 4 US/GREECE = 88 Floats 22 Floats still active on 11 September 2009 (2 US, 3 MFSTEP, 17 FRANCE)

MedArgo status – September 2009

MedArgo Network: Active floats


Delayed Mode Data Control Example: Provor Float 1900589, ~1.5 years (November 2005 to May 2007), >100 cycles

Spatial decorrelation scale: large scale 6°LON 5°LAT; small scale 2°LON 1.67°LAT

Temporal decorrelation scale: 10 years



Green curve ± std: correction “r” (least square piece-wise linear fit)

Red curve: Weighted mean, for each profile, of the ratio Cθs/Cθf on 10 θ-levels where salinity has minimal variance.

DMQC proposed correction for salinity:

CrCrS )1()1( 0

C0 = mean vertical conductivityC’ = anomaly with respect to C0




Delayed Mode Data Control Example: Apex Float 1900630, >3 years (November 2005 to January 2009), >200 cycles





CrCrS )1()1( 0






Delayed Mode Data Control Example: Apex Float 6900287, ~1 year (December 2004 to September 2005), ~50 cycles





CrCrS )1()1( 0






Delayed Mode Data Control Example: Apex Float 6900301, >2 years (May 2005 to June 2007), 150 cycles





CrCrS )1()1( 0






Delayed Mode Data Control Example: Apex Float 6900501, (January 2008 – still active)





CrCrS )1()1( 0






Delayed Mode Data Control Example: Apex Float 6900665, (June 2008 – still active)





CrCrS )1()1( 0





• The water column (top 1000 m) of some geographical areas is too variable for the DMQC statistical methods to be of any use use other ways to determine the reliability of the float data: analyzing the deeper (> 700 m) profiles where theta-S relationship is uniform; comparing to the variability of the historical data

• The correction proposed has to be applied only if it is larger than the Argo accuracy (0.01 PSU) but also larger than the natural variability of the reference dataset

Conclusion


Conclusion

• DMQC has been applied to 40 floats in the Mediterranean Sea (MFSTEP project):

6 floats do not need any salinity correction

18 floats are good but they still probably have a too short life to be affected by biofouling

7 floats are probably good but this has to be verified

9 floats have to be checked using other methods: 2 floats are good and 7 have to be checked


Future work

1.Transfer files to Coriolis

2.Continue the DMQC (Med and Black Sea)

3.Web page dedicated on DMQC download DMQC results

4. Implement (update) reference database


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M. Menna,G. Notarstefano and P.-M. Poulain OGS – Trieste - Italy

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