Q vector Flashcards

1
Q

What will QG Theory do for us?
–It reveals how …………………………………….. and ………………………………… constrain and simplify atmospheric motions, but in a realistic manner

A

hydrostatic balance and geostrophic balance

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2
Q

What will QG Theory do for us?

It provides a simple framework within which we can understand and diagnose the ……………………………………

A

evolution of three-dimensional synoptic-scale weather systems

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3
Q

What will QG Theory do for us?

It predicts the evolution of synoptic-scale systems by

A

diagnosing changes in the local geopotential height field from the observed distributions of vorticity advection and temperature advection.

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4
Q

What will QG Theory do for us?

It estimates synoptic-scale ………………………………………………………….

A

vertical motions from the observed distribution of vorticity and temperature advection.

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5
Q

What will QG Theory do for us?

It helps us to understand how the ………………………………………………….and the ………………………………………………………………….interact to create ………………………………..that result in realistic synoptic scale weather patterns

A

mass fields (via horizontal temperature advection)

momentum fields (via horizontal vorticity advection)

vertical circulations

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6
Q

What will QG Theory do for us?

It offers physical insight into the forcing of ………………………………………………. and ……………………………………………………….associated with mid-latitude cyclones

A

vertical motion and the cloud/precipitation patterns

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7
Q

Rotational momentum:

A

Rotation around an axis (less effort)

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8
Q

Momentum equations and linear momentum

A

momentum equations: du/dt, dv/dt. dw/dt

linear momentum: ΣF = dp/dt = m* d/dt = ma

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9
Q

From our mathematical derivation of QG theory, QG theory has the following assumptions

A
  • Geostrophic balance (i.e. we neglect all local changes in the ageostrophic wind) >> No difference between geostrophic & wind (actual)
  • Hydrostatic balance >> No vertical motion (parcel of air at rest)
  • Horizontal advection by the geostrophic winds only (i.e. we neglect the advection of the ageostrophic momentum by the geostrophic wind and the vertical advection of momentum)
  • No friction or orographic effects
  • No diabatic heating / cooling
  • No spatial or temporal changes in static stability >> consider midlatitude weather is stable
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10
Q

meaning of adiabatic

A

No change of heat between air parcel and surrounding air “when air parcel is rising it will cool due to expansion/increase of volume”

(Source of heat must exist)

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11
Q

QG Height Tendency Equation

A
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12
Q

The following equation represents

A

QG height tendency equation

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13
Q

Term A corresponds to

A

local horizontal advection of geostrophic vorticity

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14
Q

Term B correspond to

A

change in temperature advection with height

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15
Q

QG omega equation

A
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16
Q

The following equation represents

A

QG omega equation

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17
Q

Term A correspond to

A

change in vorticity advection with height

18
Q

Term B correspond to

A

local maximum in temperature advection

19
Q

If large changes in the vorticity advection with height are observed, then you should expect…………………………………….

A

large vertical motions

20
Q

The stronger the temperature advection, the stronger the ……………………….

A

vertical motion

21
Q

If WAA is observed at several consecutive pressure levels, expect a…………………………………………………motion

A

deep layer of rising

22
Q

The QG omega equation is proportional to

A

vorticity advection & advection of maximum temperature (local)

23
Q

vorticity advection & advection of maximum temperature (local) usually work

A

opposite to each other

24
Q

if term A in the QG omega equation is +ve and term B is -ve the result is

A

rising air

25
you can find which is dominant cold advection or cyclonic by
Q vectors because they are working against each other "rate of change of potential temperature in geostrophic balance"
26
If term A and B are working together
PVA and WAA are on top of each other
27
The Q-vector is defined as
the change of the potential temperature gradient vector of a parcel following the geostrophic motion.
28
Q-vector equation
29
the following equation is for
Q-vectors
30
What does each term in the Q-vector equation mean?
dg /dt : rate of change of potential temperature gradient in geostrophic motion gradient of potential temperature 0: potential temperature
31
for the equation both terms on the LHS are the
both terms are the second derivative of omega the first term is horizontally the second term is vertically (the divergence of Q)
32
in the equation w is
w is proportional to -2 grad Q w depends on divergence and convergence of Q
33
when Q is positive and when its negative......
+ve \> sinking air \> divergence -ve\> rising air \> convergence
34
when grad Q is positive
Divergence on the ground
35
the purpose of Q-vectors
to solve conflict between omega equation
36
Q vectors are useful for the following reason
Eliminates competition between terms in the QG 𝜔 equation
37
The weaknesses of Q-vectors are as follows
It contains all of the limiting assumptions of QG theory (i.e. neglect of diabatic heating/cooling, variations in static stability, etc.)
38
𝑄 is typically evaluated within .............................because this brackets the level of non-divergence .............................
400-700 mb | (~550 mb )
39
in the upper trough the gradient is from
high to low
40
in the upper ridge .....
warming in the upper air \> stable air \> ridge
41
A and B are areas of
A: cooling B: Warming