Atmospheric motion

Question 1

what is steady flow

Answer 1

The air is subject to Newton’s second law of motion: it accelerates when there is an unbalanced force.
When the forces are balanced, the airflow is steady.

Question 2

There are 3 forces with influence on horizontal airflow:

Answer 2

Pressure gradient force (p.g.f. or Fp)
Coriolis force (Fc)
Frictional drag (Fd)

Question 3

what are the main driving force of wind

Answer 3

horizontal pressure gradients

Question 4

how does wind move

Answer 4

from high to low pressure

Question 5

what is the coriolis force

Answer 5

The Coriolis force is an apparent force, introduced to account for the apparent deflection of a moving object observed from within a rotating frame of reference – such as the Earth.

Question 6

why do we have an apparent fore?

Answer 6

An object moving in a circle is accelerating
Its velocity is continually changing with time
If we view motion from an accelerating frame of reference, we must introduce apparent forces to allow for this

Question 7

At what angle does the Coriolis force act

Answer 7

at right angles both to the direction of motion and the spin axis of the rotating reference frame

Question 8

where does the steady flow tend to lie

Answer 8

Steady flow tends to lie parallel to the isobars, so that the pressure gradient and Coriolis forces balance. This is termed geostrophic balance, and Vg is the geostrophic wind speed.

Question 9

what is centripetal acceleration

Answer 9

Motion around a curved path requires an acceleration towards the centre of curvature

Question 10

why is centripetal acceleration required

Answer 10

because of the imbalance between the pressure and Coriolis force

Question 11

in a low is pressure force or the Coriolis effect more powerful

Answer 11

pressure is greater than Coriolis

Question 12

in a high is pressure force or the Coriolis effect more powerful

Answer 12

Coriolis is greater than pressure

Question 13

how much does turbulent mixing effect the friction above the surface

Answer 13

100m - 15km

Question 14

what is the Ekman Spiral

Answer 14

When surface water molecules move by the force of the wind, they, in turn, drag deeper layers of water molecules below them. Each layer of water molecules is moved by friction from the shallower layer, and each deeper layer moves more slowly than the layer above it, until the movement ceases at a depth of about 100 meters (330 feet)