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Flashcards in Q vector Deck (41)
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1

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

hydrostatic balance and geostrophic balance

2

What will QG Theory do for us?

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

evolution of three-dimensional synoptic-scale weather systems

3

What will QG Theory do for us?

It predicts the evolution of synoptic-scale systems by

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

4

What will QG Theory do for us?

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

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

5

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

mass fields (via horizontal temperature advection)

momentum fields (via horizontal vorticity advection)

vertical circulations

 

6

What will QG Theory do for us?

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

vertical motion and the cloud/precipitation patterns

7

Rotational momentum:

Rotation around an axis (less effort)

8

Momentum equations and linear momentum

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

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

9

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

  • 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

meaning of adiabatic

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

QG Height Tendency Equation

12

The following equation represents

QG height tendency equation

13

Term A corresponds to

local horizontal advection of geostrophic vorticity

14

Term B correspond to

change in temperature advection with height

15

QG omega equation

16

The following equation represents

QG omega equation

17

Term A correspond to 

change in vorticity advection with height

18

Term B correspond to 

local maximum in temperature advection

19

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

large vertical motions

20

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

vertical motion

21

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

deep layer of rising

22

The QG omega equation is proportional to

vorticity advection & advection of maximum temperature (local)

23

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

opposite to each other

24

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

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