Striped ocean

Image of the Month - March 2009

Map of the zonal (oriented east-west) velocity of mean geostrophic currents computed from the Mean Dynamic Topography, and filtered to exclude features larger than 4°; red indicates eastward currents, blue westward ones. Rectangles mark the domains where striations were confirmed using historical hydrographic data (Credits University of Hawaii)

 

With now more than 15 years of continuous, intercalibrated, altimetry data, the picture of the ocean is becoming both clearer and more complex. High-resolution mean dynamic ocean topography can be computed from altimetry, drifter, wind, and gravity data, showing the fine structure of stationary features of the ocean. A global pattern of alternating stripes (or striations) of eastward/westward flowing mesoscale currents, derived from this topography, is particularly amazing.

   
The same striations  are also found in  historical hydrographic data, at least down to a depth of 700 m and  in data  of the high-resolution ocean model. The physical process or processes, producing the striation, are still to be identified. Continuing the homogeneous altimetry data series should help.

 

See also:

Websites on this subject:

Reference:

  • Maximenko, N. A., O. V. Melnichenko, P. P. Niiler, and H. Sasaki (2008), Stationary mesoscale jet-like features in the ocean, Geophys. Res. Lett., 35, L08603, doi:10.1029/2008GL033267
    Link to data: http://apdrc.soest.hawaii.edu/projects/DOT/