ABSTRACT
This chapter provides the discussion about the equations of motion. The most important force in the equations of motion is the pressure gradient force. This arises as a result of the unequal distribution of the mass of the atmosphere over the surface of the earth. It is represented on weather maps by patterns of isobars which are recognized as pressure patterns such as anticyclones and cyclones or depressions. The pressure gradient force is measured in terms of the difference in pressure between two points. The chapter explores the derivaton of the Coriolis parameter for a spherical rotating earth, and also for the pressure gradient terms. It uses a plane rectangular coordinate system to express the accelerations in the equations of motion. The chapter suggests that in the southern hemisphere the terrestrial tangent plane rotates in a clockwise sense when viewed from above. By convention anticlockwise rotation is positive and clockwise rotation is negative.
