Chapter 5. SPATIALLY-COHERENT STRUCTURES
surfactants in the surface renewal process, are of substantial interest for
studying the air-sea exchange and global balance of greenhouse gases like
CO 2 .
5.9 Conclusions
Spatially coherent organized motions are an inherent part of the upper
ocean turbulent boundary layer dynamics. These motions perform nonlocal
transport of properties.
Observation of coherent structures in the open ocean is not a simple
experimental task. Though several types of these structures have been
observed in oceanic turbulence studies, most of our knowledge of this
phenomenon in the ocean is either fragmentary or mainly based on the
analogy between atmospheric and oceanic boundary layers, and on
laboratory studies. A major problem of applying the knowledge acquired in
the atmospheric boundary layer to its oceanic counterpart is in the huge
difference between the air and water densities. In particular, the air-sea
interface from the waterside behaves like a free surface (which, in particular,
requires different surface boundary conditions.)
The elements of the theory for the coherent structures in the upper ocean
do exist, but they often come from different areas of science and still require
substantial efforts to apply them to the upper ocean situation. The theoretical
models of organized structures are often detached from real observations,
while the existing observations could validate theories only in a few
successful cases. This is an indication that this area of physical
oceanography requires special attention.
393