ESA Sea Surface Salinity Climate Change Initiative (Sea_Surface_Salinity_cci): Version 1.8 data collection

These data comprise v1.8 of the Sea Surface Salinity (SSS) Essential Climate Variable (ECV) dataset produced as part of the European Space Agency's (ESA) Climate Change Initiative (CCI) programme. The ESA CCI Sea Surface Salinity ECV data have been produced at a spatial resolution of 50 km and spatiallly resampled on a 25km EASE (Equal Area Scalable Earth) grid and a) with a time resolution of 1 week and 1 day of time sampling and b) a time resolution of 1 month and 15 days of time sampling.

This first version (v1.8) of the CCI+SSS products is a preliminary version issued for evaluation purposes by voluntary scientists and for framing future CCI+SSS products. This product has not been fully validated yet and may contain flaws. In case you discover some, the CCI Sea Surface Salinity project ([e-mail]) are very keen to get your feedback. In case you would like to use them in a presentation or publication, please be aware of the following caveats:

CAVEATS

- The SSS random error in the weekly product is overestimated by a factor ~1.4.
- The Number of outliers is wrongly set to 'NaN' in the case where it is equal to zero.
- Products have not yet been not optimised for some issues encountered at high latitudes (i.e. remaining ice, RFI pollution, biases due to land-sea contamination and dielectric constant in cold waters).
- The criteria for flagging data close to land (including islands) are conservative and likely to be too restrictive in places.
- There is a systematic global underestimation (-0.08) of SSS starting at the beginning of the data set, and gradually disappearing at the end of 2010.
- There is a seasonal varying bias (~0.1, peaking in the middle of the year) in the Pacific North of 25°N".

Acknowledgements: The authors thank the CCI+ SSS validation team, in particular S. Guimbard (ODL) and A. Martin (NOC), for their feedback on the products, R. Catany (ARGANS) for managing the project and P. Cipollini and C. Donlon (ESA) for their sound advice.