Chapter 1: Analysis of Mid-lat syn systems using balance equations Flashcards
the two derived scalar quantities of the horizontal wind
Stream function
velocity potential
stream function is represented by
velocity potential is represented by
The horizontal wind is then represented by these scalars as:
the term means
the term means
psi represents
Stream function
chi represents
velocity potential
the following equation is the
The horizontal wind
the rotational (non-divergent) part of horizontal wind is represented by the term
the divergent (irrational) part of horizontal wind is represented by the term
Stream function, velocity potential are the
two derived scalar quantities of the horizontal wind
The scalar equations for u and v can then be written in form of (stream function) and (velocity potential)as
If one of the scalars (stream function) or (velocity potential) is set equal to zero, then the wind that remains can be one of the following
Non-divergent or Rotational wind:
in non-divergent:
Non-divergent or Rotational wind:
in scalar notation:
irrotational or divergent wind:
the irrotational wind:
irrotational or divergent wind:
in scalar notation:
the following stands for
vorticity
vorticity in terms of stream function
For horizontal motion that is rotational (non-divergent), the velocity components are given by
Vorticity (ع ) in terms of streamfunction
substituting u and v for ع
the velocity field and the vorticity can both be represented in terms of
the variation of the single scalar field, (psi)
…………………………… and ……………………… can both be represented in terms of the variation of the single scalar field, (psi)
the velocity field
the vorticity
Obtain an expression for divergence of an irrotational wind
The barotropic vorticity is written as
the barotropic vorticity states that
the absolute vorticity is conserved following the hor. motion.
The barotropic vorticity equation can be written as
prognostic eqn. for vorticity
The barotropic vorticity equation can be written as a prognostic eqn. for vorticity in the form:
the following term represents
local tendency of relative vorticity
the following term represents
advection of absolute vorticity
prognostic equation for vorticity’s condition
prognostic equation for vorticity can be solved
numerically
prognostic equation for vorticity can be solved numerically to
predict the evolution of the streamfunction
prognostic equation for vorticity can be solved numerically to predict the evolution of the stream function, and hence
of the vorticity and wind fields.
The QG vorticity equation in pressure coordinates can be written as
the following equation is a
prognostic equation for the geostrophic relative vorticity.
The QG vorticity equation in pressure coordinates states that
the local change of geostrophic relative vorticity is a function of three terms
The QG vorticity equation in pressure coordinates states that the local change of geostrophic relative vorticity is a function of three terms
- A) the geostrophic horizontal advection of geostrophic relative vorticity,
- (B) the geostrophic meridional advection of planetary vorticity, and
- (C) the vertical stretching of planetary vorticity .
terms A and B in the QG vorticity equation related to
horizontal advection of geostrophic relative vorticity and meridional advection of planetary vorticity.
A
B
C
D