Journal metrics

Journal metrics

  • IF value: 2.289 IF 2.289
  • IF 5-year value: 2.756 IF 5-year 2.756
  • CiteScore value: 2.76 CiteScore 2.76
  • SNIP value: 1.050 SNIP 1.050
  • SJR value: 1.554 SJR 1.554
  • IPP value: 2.65 IPP 2.65
  • h5-index value: 30 h5-index 30
  • Scimago H index value: 41 Scimago H index 41
Volume 14, issue 3 | Copyright
Ocean Sci., 14, 503-514, 2018
https://doi.org/10.5194/os-14-503-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 22 Jun 2018

Research article | 22 Jun 2018

Acoustic mapping of mixed layer depth

Christian Stranne1,2, Larry Mayer3, Martin Jakobsson1,2, Elizabeth Weidner3, Kevin Jerram3, Thomas C. Weber3, Leif G. Anderson4, Johan Nilsson2,5, Göran Björk4, and Katarina Gårdfeldt6 Christian Stranne et al.
  • 1Department of Geological Sciences, Stockholm University, Stockholm, Sweden
  • 2Bolin Center for Climate Research, Stockholm University, Stockholm, Sweden
  • 3Center for Coastal and Ocean Mapping, University of New Hampshire, Durham, New Hampshire, USA
  • 4Department of Marine Sciences, University of Gothenburg, Gothenburg, 40530, Sweden
  • 5Department of Meteorology, Stockholm University, Stockholm, Sweden
  • 6Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, Sweden

Abstract. The ocean surface mixed layer is a nearly universal feature of the world oceans. Variations in the depth of the mixed layer (MLD) influences the exchange of heat, fresh water (through evaporation), and gases between the atmosphere and the ocean and constitutes one of the major factors controlling ocean primary production as it affects the vertical distribution of biological and chemical components in near-surface waters. Direct observations of the MLD are traditionally made by means of conductivity, temperature, and depth (CTD) casts. However, CTD instrument deployment limits the observation of temporal and spatial variability in the MLD. Here, we present an alternative method in which acoustic mapping of the MLD is done remotely by means of commercially available ship-mounted echo sounders. The method is shown to be highly accurate when the MLD is well defined and biological scattering does not dominate the acoustic returns. These prerequisites are often met in the open ocean and it is shown that the method is successful in 95% of data collected in the central Arctic Ocean. The primary advantages of acoustically mapping the MLD over CTD measurements are (1) considerably higher temporal and horizontal resolutions and (2) potentially larger spatial coverage.

Download & links
Publications Copernicus
Download
Short summary
The ocean surface mixed layer depth (MLD) is an important parameter within several research disciplines, as variations in the MLD influence air–sea CO2 exchange and ocean primary production. A new method is presented in which acoustic mapping of the MLD is done remotely by means of echo sounders. This method allows for observations of high-frequency variability in the MLD, as horizontal and temporal resolutions can be increased by orders of magnitude compared to traditional in situ measurements.
The ocean surface mixed layer depth (MLD) is an important parameter within several research...
Citation
Share