aosc670 wk4

confluence: the junction of two rivers, especially rivers of approximately equal width.

eddy: a circular movement of water, counter to a main current, causing a small whirlpool.

The geostrophic wind (/dʒiːɵˈstrɒfɨk/ or /dʒiːɵˈstroʊfɨk/) is the theoretical wind that would result from an exact balance between the Coriolis effect and the pressure gradient force.

coriolis effect = pressure gradient force

This condition is called geostrophic balance. The geostrophic wind is directed parallel to isobars (lines of constant pressure at a given height). This balance seldom holds exactly in nature. The true wind almost always differs from the geostrophic wind due to other forces such as friction from the ground. Thus, the actual wind would equal the geostrophic wind only if there were no friction and the isobars were perfectly straight. Despite this, much of the atmosphere outside the tropics is close to geostrophic flow much of the time and it is a valuable first approximation. Geostrophic flow in air or water is a zero-frequency inertial wave.

What the hell are the coriolis force and centrifugal force?

1. Newton’s laws only work i inertial frame of reference.

2. both forces are fictitious / pseudo forces.

3. Introducing them allows the Newton’s laws to work in a rotating system.

4. Coriolis force is perpendicular to rotating axis and object velocity and proportional to object velocity.

5. Centrifugal force Coriolis force is proportional to the distance of object from the rotating axis.

Newton's laws of motion describe the motion of an object in a (non-accelerating) inertial frame of reference. When Newton's laws are transformed to a uniformly rotating frame of reference, the Coriolis and centrifugal forces appear. Both forces are proportional to the mass of the object. The Coriolis force is proportional to the rotation rate and the centrifugal force is proportional to its square.

The Coriolis force acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame and is proportional to the object's speed in the rotating frame.

The centrifugal force acts outwards in the radial direction and is proportional to the distance of the body from the axis of the rotating frame.

These additional forces are termed inertial forces, fictitious forces or pseudo forces.

They allow the application of Newton's laws to a rotating system. They are correction factors that do not exist in a non-accelerating or inertial reference frame.