ARGO upper salinity measurements: perspectives for L-band radiometers calibration and retrieved sea surface salinity validation

Abstract :

With the view of preparing the strategy for the Cal/Val of future L-band satellite radiometers, we examine the salinity variability recorded by ARGO floats in the upper 10m layer of the surface ocean. Using one year of ARGO measurements, we show that the surface salinity variability at 10 days and 200km scales is above +/-0.1psu for 30% of the drifters and that this variability is larger than 0.2psu in tropical regions affected by strong river discharges and by precipitations, and in frontal areas caracterized by strong mesoscale activity. Vertical gradient observed between 5m and 10m depth is much lower than the horizontal variability but leads to systematic biases in the tropics. The southern Pacific Ocean appears to be the less variable both vertically and horizontally.