Fundamentals of Atmospheric Circulation

Question 1

Fronts

Answer 1

region where atmospheric variables (e.g. temperature,
humidity) changes rapidly across a small horizontal distance.

Question 2

What forces affect large-scale atmospheric
movement of pollutants?

Answer 2

Real Forces:
- Gravitational force
- Pressure gradient force
- Frictional force

Apparent forces:
- Centrifugal force
- Coriolis force

Question 3

T/F: Apparent forces are real forces?

Answer 3

False, they arise purely because we are on a rotating sphere.

Question 4

Total force

Answer 4

The sum of all of these forces
dv/dt = 1/m Σi Fi
where i represents the sum over the different types of forces

Question 5

Pressure gradient force

Answer 5

The force that causes air to move from high to low pressure regions.

Proportional to the difference in pressure divided by the distance between the two locations

Question 6

Coriolis force

Answer 6

Air appears to accelerate to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Not a real force, it is an acceleration that arises when the Earth rotates under
a body (air in this case) in motion.

Zero at equator, maximum at the poles.

Question 7

Coriolis Force Per Unit Mass

Answer 7

CF = 2ΩV sinφ
Ω = rotation rate of Earth (7.29 x 10-5 radians s-1)
= 2pi / 86,164
V = speed (m s -1)
φ = latitude

CF higher for faster rotation rate
CF equals zero when object at rest
CF equals zero at the equator
CF maximum at the poles

Question 8

Coriolis Parameter

Answer 8

f = 2Ω*sin(ϕ)

Question 9

Cyclonic flow (North. Hemisphere) Force Balance

Answer 9

2ΩV sinφ+V^2/r = 1/ρ* Δp/Δr

r = distance from center of curvature
V^2/r = apparent centrifugal force per unit mass

Question 10

Anticyclonic Flow (North. Hemisphere) Force Balance

Answer 10

2ΩV sinφ = 1/ρ* Δp/Δr +V^2/r

Pressure gradients are weaker and winds are slower
around a center of high than around a center of low.

Question 11

Surface low characteristics

Answer 11

Friction force at surface drives convergence around low.
- Air rises -> precipitation

Question 12

Surface high characteristics

Answer 12

Friction force at surface drives divergence around high.
- Air sinks -> dry weather

Question 13

Geostrophic Wind

Answer 13

2 Forces:
Pressure gradient force
Apparent coriolis force

Straight winds aloft

Question 14

Gradient wind

Answer 14

3 Forces:
Pressure gradient force
apparent coriolis force
apparent centrifugal force

curved winds aloft

Question 15

Surface winds between straight isobars

Answer 15

3 Forces:
Pressure gradient force
Apparent Coriolis force
Friction Force

Straight

Question 16

Surface wind around pressure centers

Answer 16

4 forces:
Pressure gradient force
Apparent Coriolis force
Apparent centrifugal force
Friction Force

Curved

Question 17

Three- Cell Model

Answer 17

Study briefly the Three- cell model

Question 18

Sea/ Land Breeze Circulation

Answer 18

Study briefly