Skip to main content
Satellite and In Situ Salinity: Understanding Near-Surface Stratification and Sub-Footprint Variability
Bulletin of the American Meteorological Society
  • J. Boutin, Sorbonne Universités - Paris, France
  • Y. Chao, Remote Sensing Solutions - Pasadena
  • We Asher, University of Washington - Seattle
  • T. Delcroix, Laboratoire d’Etudes en Géophysique et Océanographie Spatiale - Toulouse, France
  • R. Drucker, University of Washington - Seattle
  • K. Drushka, University of Washington - Seattle
  • N. Kolodziejczyk, Sorbonne Universités - Paris, France
  • T. Lee, Jet Propulsion Laboratory - Pasadena
  • Reul Nicolas, IFREMER - Toulon, France
  • G. Reverdin, Sorbonne Universités - Paris, France
  • J. Schanze, Earth & Space Research - Seattle
  • Alexander Soloviev, Nova Southeastern University
  • L. Yu, Woods Hole Oceanographic Institution
  • J. Anderson, University of Washington - Seattle
  • L. Brucker, National Aeronautics and Space Administration
  • E. Dinnat, National Aeronautics and Space Administration
  • As Garcia, University of Central Florida
  • W. I. Jones, University of Central Florida
  • C. Maes, Laboratoire de Physique des Océans, CNRS-IFREMER-IRD-UBO - Plouzané, France
  • T. Meissner, Remote Sensing Solutions - Pasadena
  • W. Tang, Jet Propulsion Laboratory - Pasadena
  • N. Vinogradova, Atmospheric and Environmental Research - Lexington
  • B. Ward, National University of Ireland - Galway
Document Type
Publication Date
Remote sensing of salinity using satellite-mounted microwave radiometers provides new perspectives for studying ocean dynamics and the global hydrological cycle. Calibration and validation of these measurements is challenging because satellite and in situ methods measure salinity differently. Microwave radiometers measure the salinity in the top few centimeters of the ocean, whereas most in situ observations are reported below a depth of a few meters. Additionally, satellites measure salinity as a spatial average over an area of about 100x100 km2. In contrast, in situ sensors provide pointwise measurements at the location of the sensor. Thus, the presence of vertical gradients in, and horizontal variability of, sea surface salinity complicates comparing satellite and in situ measurements. This paper synthesizes present knowledge of the magnitude, and the processes that contribute to the formation and evolution of, vertical and horizontal variability in near-surface salinity. Rainfall, freshwater plumes and evaporation can generate vertical gradients of salinity, and in some cases these gradients can be large enough to affect validation of satellite measurements. Similarly, mesoscale to submesoscale processes can lead to horizontal variability that can also affect comparisons of satellite data to in situ data. Comparisons between satellite and in situ salinity measurements must take into account both vertical stratification and horizontal variability.

©2016 American Meteorological Society

Citation Information
J. Boutin, Y. Chao, We Asher, T. Delcroix, et al.. "Satellite and In Situ Salinity: Understanding Near-Surface Stratification and Sub-Footprint Variability" Bulletin of the American Meteorological Society Vol. 97 Iss. 8 (2016) p. 1391 - 1407 ISSN: 1520-0477
Available at: