User:Andymayor/Geophysical fluid dynamics

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Geophysical Fluid Dynamics
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Geophysical fluid dynamics (GFD) is a branch of physics that studies the large scale natural occurring density stratified fluid flows on rotating planets. Some examples of these flows are the atmospheric cyclones and anticyclones, ocean currents and waves, subsurface solid earth convection flows (plate tectonics), and the Jupiter Giant Red Spot to name a few. The science of GFD is mathematical in nature and overlaps many scientific fields of study e.g. applied mathematics, physics, dynamical meteorology, dynamical oceanography, planetary sciences and even magnetohydrodynamics. Although being a relatively young field of science GFD is having a central role within the environmental sciences because of its successes in explaining many dynamical phenomena in meteorology and climatology. In spite of its broad overlapping role within many environmental and earth sciences, traditionally, GFD is referred and confined exclusively to the fluid dynamics of the Earth‘s atmosphere and oceans.

GFD has two distinguishing attributes that sets the difference between GFD and other traditional fluid dynamics, that of the the rotation of the Earth and density stratification on the vertical. Because of the large spatial and temporal scale of flows and due to the fact that these flows are relatively slow and are moving on a rotating spherical planet geophysical flows are subjected to the Coriolis force. Having spatial scales ranging from hundred kilometres to the size of the planet and with a travel time exceeding 24 hours geophysical flows tend to deflect cum sole, to the right in the northern hemisphere and to the left in the southern hemisphere. A second distinguishing attribute is due to the variation of moisture in the atmosphere and salinity in the ocean and of temperature in either, density of the fluid is modified to such an extent that buoyancy forces are comparable to other existing forces. This has the consequence that geophysical flows become vertically stratified.

The mathematical equations that describe flow motion in GFD are basically the same as in other Newtonian fluid flows. The difference is that there are parameters present in GFD whilst absent in traditional fluid dynamics that makes it more complex in nature these are referred to the presence of a free surface, bottom topography and density stratification. For insight into the dynamical equations governing flow in the oceans see Ocean Dynamics

GFD is a very specialized and mathematical rigorous practice and is mainly studied by applied mathematicians and physicist employed by research institutions e.g. Met Office, GFDL(NOAA), NOCS(NERC), SIO(UCSD), and University Departments e.g. The Department of Earth, Atmospheric, and Planetary Sciences at MIT, Department of Meteorology at University of Reading, DAMTP at University of Cambridge.

See also

Ocean Dynamics

Fluid Dynamics

Applied Mathematics

Dynamic meteorology

physical oceanography

Geophysics

Navier-Stokes equations

Bibliography

Joseph Pedlosky, Geophysical Fluid Dynamics, second edition, 1986, Springer-Verlag, ISBN 0-387-96387-1.

Adrian E.Gill, Atmosphere-Ocean Dynamics, volume 30, international geophysical series, 1982, academic press, ISBN 0-12-283522-0.

G.K.Batchelor, H.K.Moffat, M.G.Worster, Perspectives in Fluid Dynamics - a collective introduction to current research, Cambridge university press,2000, ISBN 0-521-78061-6.