ABSTRACT
This chapter will discuss the derivation of vorticity as well as interpret its significance when applied to simple patterns on the weather Vorticity is a measure of rotation or spin. It may be defined as circulation per unit area, or as the quantity which, when integrated over the area, gives the circulation. Since vorticity can be measured in terms of rotation or angular velocity it is clearly a function of the curvature of the path around which the parcel or element travels. The curvature of the isobars is therefore of prime importance in estimating the horizontal vorticity of the wind field in the atmosphere. Vorticity is also a function of another parameter, namely shear. Thus, in meteorology, horizontal shear exists if, for example, the pressure gradient changes in a direction along the gradient, that is across the isobars. In other words, we see that vorticity has been generated by the shear. It is shear vorticity as distinguished from curvature vorticity.
