By the end of this chapter, you should be able to:
- explain mass conservation physically, recognize the mass conservation equation, and memorize its form when density is constant
- state the three main conservation laws in atmospheric science: the conservation of mass, the conservation of momentum, and the conservation of energy
- name and explain the three fundamental (real) forces in the atmosphere (gravity, pressure gradient, and friction)
- name and explain the two new (apparent) forces that emerge when momentum conservation is written in the rotating reference frame
- draw the balance of forces for geostrophic flow, gradient flow, geostrophic flow with friction, and cyclostrophic flow
- explain why midlatitude winds are westerly
- 10.4: What are the important real forces?
- There are three real forces important for atmospheric motion: (1) Gravitational Force, (2) Pressure Gradient Force (PGF), and (3) Friction.
Thumbnail: This low-pressure system over Iceland spins counterclockwise due to balance between the Coriolis force and the pressure gradient force. (Public Domain; NASA’s Aqua/MODIS satellite)