11.3. Centrifugal Force#

If the flow is curved, as in troughs and ridges, another force must be considered, the centrifugal force (CENTF). This force is also known as the centripetal acceleration. The centrifugal force acts to push outward from the center of the turn. For example, if you are in a car and take a corner holding constant speed, you will feel like you are being pushed away from the turn, that is the centrifugal force at work. The centrifugal force can be written in algebraic form as,

where $R$ is the radius of curvature. The radius of curvature, $R$, is positive for cyclones and negative for anticyclones in the Northern Hemisphere. Therefore, in low pressure, the centrifugal force acts opposite the direction of the PGF, but in high pressure it acts in the same direction. Again, unit analysis indicates that the centrifugal force has the same units as PGF and CF and is $m$ $s^{-2}$.