baroclinity

[bhatt.vihang]

dear all,

can anyone suggest how to compute baroclinity from hydrographic data.

regards

vihang bhatt

[vinu]

Hi Bhatt,

I am not aware of a particular estimation for baroclinicity. I try initiate
discussion on your question, may be some one else bring the exact
answer you are looking for.

A fluid is said to be baroclinic when the pressure surfaces do not coincide with the density surfaces. That is, they have an angle to each other, and baroclinicity is measured as a vector product,

Baroclinicity = (del.P X del.Rho). Please read it as a mathematical
expression.

If the surfaces of density and pressure are parallel or coincide then the
vector product becomes zero, or the fluid is said to be barotropic.


Now, to look at the baroclinicity from hydrographic observations, make
the vertical section of dynamic height, which is equal to vertical
integral of specific volume anomaly from the reference level (say 1000 m).
Also overlay the plot of potential density on the same graph. Then you can
see the dynamic height (equivalent to pressure surfaces) angle with the
potential density surfaces. Then the fluid is baroclinic. see
an example picture attached below. (Any fundamental books of
dynamic oceanography have these calculations). Also you can find the
gesotrophic currents at each depth from the dynamic height and you
may find the flow has different magnitude with depth. i.e. a vertical shear
in the flow. This is is due to the baroclinicity of the fluid. Through these way
you can see the baroclinic structure of your ocean.


-Thanks