Instruments calibration and data quality monitoring
Calval (CALibration / VALidation) is what determines data quality. This step involves a series of quality controls designed to ensure a continuous supply of data.
Calval teams calibrate the satellite instruments and determine the parameters, corrections, bias and so on to be applied to measurements. In particular, this task involves validating and refining algorithms in close collaboration with processing system development teams and users.
Once the mission is fully under way, routine Calval operations consist in determining data quality and keeping a check on instrument drift. Quality control is achieved through statistical data analysis, analyses at crossover points, and comparisons between orbit cycles. Data are also compared with other missions and with in situ sites and networks.
- Cycle per cycle, for Saral, Jason-2, Jason-1, Envisat and Topex/Poseidon
- Cycle per cycle for Envisat cross-calibration reports
- 2012 Annual reports
- Latest results are summarized here
- Jason-2 2012 annual validation report (March 2013, (pdf, 18 Mb)
- Reprocessing of Jason-2 GDRs in version D (Sept 2013, pdf, 15 Mb)
- Jason-1 2012 annual validation report (March 2013, pdf, 15 Mb)
- Envisat 2012 annual validation report (March 2013, pdf, 17 Mb)
- 2012 annual validation report of comparison of altimetric data with tide gauge measurements (March 2013, pdf, 7 Mb)
- 2012 annual validation report of comparison of altimetric data with in-situ T/S ARGO profiles (March 2013, pdf, 5 Mb)
- Previous annual reports
- Jason-2 2011 annual validation report (June 2012) (pdf 16 Mb)
- Jason-1 2011 annual validation report (June 2012) (pdf, 22 Mb)
- Envisat 2011 annual validation report (June 2012) (pdf, 13 Mb)
- 2011 Validation report of the Envisat reprocessing (June 2012) (pdf, 13 pdf
- 2011 annual validation report of altimetric data by comparison with tide gauge measurements (June 2012, pdf, 7.5 Mb)
- 2011 annual validation report of altimetric data by comparison with in-situ T/S ARGO profiles (June 2012, pdf 8 Mb)
- 2010 annual validation report of absolute CalVal (April 2011, 1.9 Mb)
- 2010 Envisat annual validation report (July 2011) (pdf, 21 Mb)
- Topex/Poseidon 2005 annual validation report (January 2006) (pdf, 26.1 Mb)
- ERS-2 2005 annual validation report (January 2006) (pdf, 5.8 Mb)
- Saral/AltiKa Joint Calval Plan (pdf): This is the plan objective for Saral satellite during and beyond the calibration/validation phase, conducted by the two partners Cnes and Isro project teams.
In situ comparisons
- dedicated sites and campaigns
- global analysis (comparison with tide gauge network)