Articles | Volume 11, issue 5
https://doi.org/10.5194/os-11-695-2015
https://doi.org/10.5194/os-11-695-2015
Technical note
 | 
07 Sep 2015
Technical note |  | 07 Sep 2015

Technical Note: Remote sensing of sea surface salinity using the propagation of low-frequency navigation signals

I. Astin and Y. Feng

Abstract. This paper introduces a potential method for the remote sensing of sea surface salinity (SSS) using the measured propagation delay of low-frequency Loran-C signals transmitted over an all-seawater path between the Sylt station in Germany and an integrated Loran-C/GPS receiver located in Harwich, UK. The overall delay variations in Loran-C surface waves along the path may be explained by changes in sea surface properties (especially the temperature and salinity), as well as atmospheric properties that determine the refractive index of the atmosphere. After removing the atmospheric and sea surface temperature (SST) effects from the measured delay, the residual delay revealed a temporal variation similar to that of SSS data obtained by the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) satellite.

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Short summary
This paper introduces a potential method for determining the salinity of the ocean surface from long-wave radio signals used for navigation (and potentially other AM radio transmissions). Here we seek to retrieve ocean surface salinity averaged along a path across the North Sea between Denmark and the UK and compare our results with satellite-derived salinity.