Pressure system minima in the pressure field. The minima are called low-pressure areas, and the maxima are called high-pressure areas. A "High" is often shown as H, and a "low" is shown as L. Elongated areas of low pressure, or troughs, are sometimes plotted as thick, brown dashed lines down the trough axis. Isobars are commonly used to place surface boundaries from the horse latitudes poleward, while streamline analyses are used in the tropics. A streamline analysis is a series of arrows oriented parallel to wind, showing wind motion within a certain geographic area. Cs depict cyclonic flow or likely areas of
Pressure head Pressure head In fluid mechanics, pressure head is the height of a liquid column that corresponds to a particular pressure exerted by the liquid column on the base of its container. It may also be called static pressure head or simply static head (but not static head pressure). It is mathematically expressed as: where Note that in this equation, the pressure term may be gauge pressure or absolute pressure, depending on the design of the container and whether it is open to the ambient air or sealed without air. Pressure head is a component of hydraulic head, in which it