The maps we present here (named ‘LOCEAN_v2013’ maps) are obtained using the weight averaging method described in Yin et al. (2012) and the flag sortings described in Boutin et al. (2013), except that the galactic noise flag was not tested (data affected by large galactic noise are nevertheless sorted out), and land mask is only 40km.

These maps contain SSS averaged over 10days or one month, and over 100x100km2 and sampled over a 0.25x0.25° grid.  These averages are deduced from SSS derived from either ascending orbits only (‘_A_’), descending orbits only (‘_D_’) or a combination of both (‘_AD_’). From our experience, AD orbits give often the most accurate SSS.

In 2010 and 2011, we use the ESA v5 level 2 reprocessed Level 2 Ocean Salinity (L2OS) products. These products are available in 'REPR' directory.

In 2012, we use the ESA v5 near real time (NRT) L2OS products. Given that strong biases have been observed on NRT 2012 products by ESA expert support laboratories, we apply an additional bias correction on retrieved SSS that we derive from observed differences between SMOS SSS and WOA 2009 climatology in the ‘OTT region’ (S.E. Pacific Ocean; 140°W-95°W; 45°S-5°S). This 2012 data set is provisional and will be replaced by maps obtained from the ongoing ESA 2012 reprocessing as soon as they are available. These products are available in 'OCOR' directory.

More information on ESA OS-L2 products can be found on http://www.argans.co.uk/smos/.

References :

J. Boutin, N. Martin, G. Reverdin, X. Yin and F. Gaillard, Sea surface freshening inferred from SMOS and ARGO salinity: Impact of rain, Ocean Sci., 9, 183-192, doi:10.5194/os-9-183-2013, 2013.

X. Yin, J. Boutin, and P. Spurgeon, “First assessment of SMOS data over open ocean: part I Pacific Ocean,” IEEE Transactions on Geoscience and Remote Sensing, 10.1109/TGRS.2012.2188407, 2012.