Vorticity and Circulation Questions and Answers

Q: Which limitation does the barotropic model have?

With no divergence and no baroclinicity, the barotropic model conserves absolute vorticity and can move existing systems but cannot intensify them. That is why it forecasts the movement of long waves well and cyclogenesis not at all. Advection is precisely what it does represent, it integrates easily, and it needs only a single level wind or height analysis to start.

Q: Which additional physics does a baroclinic model include?

A baroclinic model carries at least two levels so that vertical motion, temperature advection and the conversion of available potential energy can be represented, which is what permits development. Friction and radiation are optional additions rather than the defining difference. The beta effect is present in barotropic models too and is indeed what allows them to propagate Rossby waves at all. A single measurement chosen to respond to the one asymmetry beats several that respond to shared behaviour.

Q: Assertion (A): An air column that is stretched vertically acquires greater cyclonic vorticity. Reason (R): Potential vorticity, the absolute vorticity divided by the depth, is conserved following the motion. Select the correct answer from the options below.

If the ratio of absolute vorticity to depth is fixed, increasing the depth requires the absolute vorticity to increase in proportion. The reason therefore explains the assertion exactly. This single argument accounts for lee cyclogenesis east of mountain ranges, for the intensification of columns moving from shallow to deep water in laboratory experiments, and for much of the vorticity budget of developing cyclones.

Q: Assertion (A): Tropical cyclones cannot form at the equator. Reason (R): The planetary vorticity vanishes at the equator so there is nothing for convergence to amplify. Select the correct answer from the options below.

Stretching amplifies the existing absolute vorticity, so with the planetary contribution zero and relative vorticity initially small there is nothing for the convergence to work on. The reason therefore explains the assertion. In practice storms require about five degrees of latitude, and the rare exceptions involve unusually strong pre-existing relative vorticity supplied by some other mechanism.

Q: Assertion (A): Relative vorticity is conserved for frictionless barotropic non-divergent flow. Reason (R): The vorticity equation reduces to a statement of conservation under those conditions. Select the correct answer from the options below.

The reason is correct but the conserved quantity is the absolute vorticity, not the relative vorticity, because a parcel changing latitude exchanges relative for planetary vorticity. That exchange is precisely the beta effect and the mechanism of Rossby waves. The assertion would be true only on an f-plane where the planetary contribution is fixed, which is a special case rather than the general result.

Q: Statement I: Cyclonic vorticity is positive in the northern hemisphere. Statement II: Cyclonic vorticity is positive in the southern hemisphere. In the light of the above statements, choose the correct answer.

Positive vorticity means anticlockwise rotation by convention, and cyclonic means anticlockwise in the north but clockwise in the south, so the sign of cyclonic vorticity reverses between hemispheres. This is why the word cyclonic is preferred to any statement about sign when a result is meant to apply globally, and why southern hemisphere charts of vorticity are often plotted with the sign reversed to preserve visual familiarity.

Q: Statement I: Circulation is an integral quantity around a closed curve. Statement II: Vorticity is a local quantity defined at a point. In the light of the above statements, choose the correct answer.

Both statements are correct, and Stokes' theorem connects them: the circulation around a curve equals the integral of the vorticity over any surface bounded by it. That connection is what allows a theorem about the circulation around a material loop to be translated into a statement about the vorticity of the enclosed fluid, which is how Kelvin's and Bjerknes' results are applied in practice.

Q: Consider the following statements about potential vorticity. 1. It is conserved for adiabatic frictionless motion. 2. It can be inverted to recover the wind and mass fields. 3. It is unaffected by latent heat release. Which of the statements given above is or are correct?

Conservation and invertibility are the two properties that make potential vorticity so powerful, but latent heat release is a diabatic process and therefore destroys the conservation. Indeed the low level potential vorticity anomaly generated by condensational heating is an important contributor to rapid cyclogenesis, so the third statement is not merely wrong but wrong in an interesting and useful way.

Q: Consider the following pairs of term and its role in the vorticity equation. Stretching - convergence concentrates vorticity Tilting - horizontal vorticity becomes vertical Beta - advection of planetary vorticity Solenoidal - friction at the surface How many of the pairs given above are correctly matched?

The last pairing fails: the solenoidal term arises from intersecting pressure and density surfaces and has nothing to do with surface friction, which appears as a separate dissipation term. The other three are correctly described. Knowing which term does what is what allows the equation to be simplified appropriately for a given scale of motion rather than being carried around in full.

51.

Which limitation does the barotropic model have?

A.It cannot be integrated numerically
B.It requires observations of temperature as well as wind in order for the initial state to be specified
C.It cannot represent development
D.It cannot represent the advection of vorticity by the wind at the single level it is applied to

Answer: C

With no divergence and no baroclinicity, the barotropic model conserves absolute vorticity and can move existing systems but cannot intensify them. That is why it forecasts the movement of long waves well and cyclogenesis not at all. Advection is precisely what it does represent, it integrates easily, and it needs only a single level wind or height analysis to start.

Discuss in Forum

52.

Which additional physics does a baroclinic model include?

A.Surface friction, which is what allows the model to represent the spin-down of a decaying vortex
B.Radiation
C.The variation of the Coriolis parameter with latitude, which is absent from every barotropic formulation
D.Vertical motion and temperature advection

Answer: D

A baroclinic model carries at least two levels so that vertical motion, temperature advection and the conversion of available potential energy can be represented, which is what permits development. Friction and radiation are optional additions rather than the defining difference. The beta effect is present in barotropic models too and is indeed what allows them to propagate Rossby waves at all. A single measurement chosen to respond to the one asymmetry beats several that respond to shared behaviour.

Discuss in Forum

53.

Assertion (A): An air column that is stretched vertically acquires greater cyclonic vorticity.

Reason (R): Potential vorticity, the absolute vorticity divided by the depth, is conserved following the motion.

Select the correct answer from the options below.

A.Both A and R are true, and R is the correct explanation of A
B.Both A and R are true, but R is not the correct explanation of A
C.A is true but R is false
D.A is false but R is true

Answer: A

If the ratio of absolute vorticity to depth is fixed, increasing the depth requires the absolute vorticity to increase in proportion. The reason therefore explains the assertion exactly. This single argument accounts for lee cyclogenesis east of mountain ranges, for the intensification of columns moving from shallow to deep water in laboratory experiments, and for much of the vorticity budget of developing cyclones.

Discuss in Forum

54.

Assertion (A): Tropical cyclones cannot form at the equator.

Reason (R): The planetary vorticity vanishes at the equator so there is nothing for convergence to amplify.

Select the correct answer from the options below.

A.A is false but R is true
B.Both A and R are true, and R is the correct explanation of A
C.Both A and R are true, but R is not the correct explanation of A
D.A is true but R is false

Answer: B

Stretching amplifies the existing absolute vorticity, so with the planetary contribution zero and relative vorticity initially small there is nothing for the convergence to work on. The reason therefore explains the assertion. In practice storms require about five degrees of latitude, and the rare exceptions involve unusually strong pre-existing relative vorticity supplied by some other mechanism.

Discuss in Forum

55.

Assertion (A): Relative vorticity is conserved for frictionless barotropic non-divergent flow.

Reason (R): The vorticity equation reduces to a statement of conservation under those conditions.

Select the correct answer from the options below.

A.Both A and R are true, but R is not the correct explanation of A
B.A is true but R is false
C.A is false but R is true
D.Both A and R are true, and R is the correct explanation of A

Answer: C

The reason is correct but the conserved quantity is the absolute vorticity, not the relative vorticity, because a parcel changing latitude exchanges relative for planetary vorticity. That exchange is precisely the beta effect and the mechanism of Rossby waves. The assertion would be true only on an f-plane where the planetary contribution is fixed, which is a special case rather than the general result.

Discuss in Forum

56.

Statement I: Cyclonic vorticity is positive in the northern hemisphere.

Statement II: Cyclonic vorticity is positive in the southern hemisphere.

In the light of the above statements, choose the correct answer.

A.Both Statement I and Statement II are correct
B.Both Statement I and Statement II are incorrect
C.Statement I is incorrect but Statement II is correct
D.Statement I is correct but Statement II is incorrect

Answer: D

Positive vorticity means anticlockwise rotation by convention, and cyclonic means anticlockwise in the north but clockwise in the south, so the sign of cyclonic vorticity reverses between hemispheres. This is why the word cyclonic is preferred to any statement about sign when a result is meant to apply globally, and why southern hemisphere charts of vorticity are often plotted with the sign reversed to preserve visual familiarity.

Discuss in Forum

57.

Statement I: Circulation is an integral quantity around a closed curve.

Statement II: Vorticity is a local quantity defined at a point.

In the light of the above statements, choose the correct answer.

A.Both Statement I and Statement II are correct
B.Both Statement I and Statement II are incorrect
C.Statement I is correct but Statement II is incorrect
D.Statement I is incorrect but Statement II is correct

Answer: A

Both statements are correct, and Stokes' theorem connects them: the circulation around a curve equals the integral of the vorticity over any surface bounded by it. That connection is what allows a theorem about the circulation around a material loop to be translated into a statement about the vorticity of the enclosed fluid, which is how Kelvin's and Bjerknes' results are applied in practice.

Discuss in Forum

58.

Consider the following statements about the vorticity equation.

1. The stretching term dominates at synoptic scales.

2. The tilting term is central to supercell dynamics.

3. The solenoidal term is large in pressure coordinates.

Which of the statements given above is or are correct?

A.1, 2 and 3
B.1 and 2 only
C.1 and 3 only
D.2 and 3 only

Answer: B

The first two statements are correct. The solenoidal term is in fact very small when pressure is used as the vertical coordinate, because pressure surfaces are then coordinate surfaces and the term nearly vanishes. That is one of the practical advantages of pressure coordinates for synoptic work, and it is why the synoptic vorticity budget is usually written with only advection, stretching and friction retained. The quantity that varies and the quantity that does not are worth naming before any substitution is attempted. Most errors here come from carrying a result across from a neighbouring case where it does not hold. A limit that survives making every external component ideal is an intrinsic one, and worth knowing for that reason. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Discuss in Forum

59.

Consider the following statements about potential vorticity.

1. It is conserved for adiabatic frictionless motion.

2. It can be inverted to recover the wind and mass fields.

3. It is unaffected by latent heat release.

Which of the statements given above is or are correct?

A.2 and 3 only
B.1, 2 and 3
C.1 and 2 only
D.1 and 3 only

Answer: C

Conservation and invertibility are the two properties that make potential vorticity so powerful, but latent heat release is a diabatic process and therefore destroys the conservation. Indeed the low level potential vorticity anomaly generated by condensational heating is an important contributor to rapid cyclogenesis, so the third statement is not merely wrong but wrong in an interesting and useful way.

Discuss in Forum

60.

Consider the following pairs of term and its role in the vorticity equation.

Stretching - convergence concentrates vorticity

Tilting - horizontal vorticity becomes vertical

Beta - advection of planetary vorticity

Solenoidal - friction at the surface

How many of the pairs given above are correctly matched?

A.Only one
B.Only two
C.All four
D.Only three

Answer: D

The last pairing fails: the solenoidal term arises from intersecting pressure and density surfaces and has nothing to do with surface friction, which appears as a separate dissipation term. The other three are correctly described. Knowing which term does what is what allows the equation to be simplified appropriately for a given scale of motion rather than being carried around in full.

Discuss in Forum

Loading…

Topics

Other Subjects

Tags: Vorticity and Circulation Questions and Answers || Vorticity and Circulation MCQ Questions and Answers || Vorticity and Circulation GK Questions and Answers || Vorticity and Circulation GK MCQ Questions || Vorticity and Circulation Multiple Choice Questions and Answers || Vorticity and Circulation GK || GK on Vorticity and Circulation || Atmospheric Dynamics Questions and Answers || Atmospheric Dynamics MCQ Questions and Answers || Atmospheric Dynamics GK Questions and Answers || GK on Atmospheric Dynamics

Vorticity and Circulation Questions and Answers

Topics

Other Subjects

About Us

Stay informed about all important Dates & Notifications