# 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

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

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.

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.

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

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

7
Q

Rotational momentum:

A

Rotation around an axis (less effort)

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

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
10
Q

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)

11
Q

QG Height Tendency Equation

A
12
Q

The following equation represents

A

QG height tendency equation

13
Q

Term A corresponds to

A

local horizontal advection of geostrophic vorticity

14
Q

Term B correspond to

A

change in temperature advection with height

15
Q

QG omega equation

A
16
Q

The following equation represents

A

QG omega equation

17
Q

Term A correspond to

A

change in vorticity advection with height

18
Q

Term B correspond to

A

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

23
Q

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
Q

you can find which is dominant cold advection or cyclonic by

A

Q vectors because they are working against each other

“rate of change of potential temperature in geostrophic balance”

26
Q

If term A and B are working together

A

PVA and WAA are on top of each other

27
Q

The Q-vector is defined as

A

the change of the potential temperature gradient vector of a parcel following the geostrophic motion.

28
Q

Q-vector equation

A
29
Q

the following equation is for

A

Q-vectors

30
Q

What does each term in the Q-vector equation mean?

A

dg /dt : rate of change of potential temperature gradient in geostrophic motion

0: potential temperature

31
Q

for the equation both terms on the LHS are the

A

both terms are the second derivative of omega

the first term is horizontally the second term is vertically (the divergence of Q)

32
Q

in the equation w is

A

w is proportional to -2 grad Q

w depends on divergence and convergence of Q

33
Q

when Q is positive and when its negative……

A

+ve > sinking air > divergence

-ve> rising air > convergence

34
Q

A

Divergence on the ground

35
Q

the purpose of Q-vectors

A

to solve conflict between omega equation

36
Q

Q vectors are useful for the following reason

A

Eliminates competition between terms in the QG 𝜔 equation

37
Q

The weaknesses of Q-vectors are as follows

A

It contains all of the limiting assumptions of QG theory (i.e. neglect of diabatic heating/cooling, variations in static stability, etc.)

38
Q

𝑄 is typically evaluated within ………………………..because this brackets the level of non-divergence ………………………..

A

400-700 mb

(~550 mb )

39
Q

in the upper trough the gradient is from

A

high to low

40
Q

in the upper ridge …..

A

warming in the upper air > stable air > ridge

41
Q

A and B are areas of

A

A: cooling

B: Warming