Marta Umbert

Detecting the surface salinity signature of Gulf Stream cold-core rings in Aquarius synergistic products

New sea surface salinity (SSS) observations derived from satellite remote sensing platforms provide a comprehensive view of salt exchanges across boundary currents such as the Gulf Stream. The high resolution (45 km spatial resolution and 3 day repeat subcycle) of the Soil Moisture and Ocean Salinity (SMOS) observations allows detection (and tracking) of meander and ring structures of the Gulf Stream from SSS maps. These structures are, however, not resolved by the relatively lower resolution (100 km and 7 day repeat subcycle) of Aquarius observations. A recently developed fusion technique, based on singularity analysis, is applied in this study to reconstruct these mesoscale (from 100 km and 3 days) features in Aquarius-derived products. New quarter-degree SSS maps are obtained by fusing Aquarius data with three different geophysical templates: sea surface height (SSH) from AVISO, SSS from SMOS, and sea surface temperature (SST) from AVHRR. The proposed method exploits the theoretical correspondence among the singularity exponents of different maps of ocean-surface remotely sensed scalar fields. The analysis results over the year 2012 show that merging Aquarius with SSH data provides a series of negative salinity anomalies that better collocate with the position of the cyclonic eddies identified from sea level anomaly maps. This result is consistent with the hypothesis that this SLA derived cyclonic eddies in this area are indeed CCRs shed off the GS.

The contribution of the Barcelona World Race to improved ocean surface information. A validation of the SMOS remotely sensed salinity

Summary. The oceans not only cover about three quarters of the Earth’s surface but they also constitute the most relevant climate driver. However, our present knowledge about the oceans is by no means comparable to that of terrestrial or atmospheric systems. Salinity and temperature are key parameters to understand the dynamics of the oceans; but a global network of observations is lacking in spite of valuable data on the oceans that are being accumulated through oceanographic campaigns and by using automated devices, fixed moorings, drifting instrumented buoys, and ships of opportunity. In addition, during the last 40 years, remotely sensed data from satellites have offered almost synoptic information describing the Earth’s surface. This information includes sea surface temperature, which has been routinely monitored; by contrast, ocean surface salinity was not remotely measured until very recently. The Soil Moisture and Ocean Salinity (SMOS) satellite, launched in November 2009, has been the first attempt to obtain remotely sensed surface salinity data. In this context, the Barcelona World Race has provided new opportunities not only to obtain a worldwide sequence of sea surface temperature and salinity data, through one of the participating ships, but also to validate the first salinity data obtained by the SMOS.