f-plane

In geophysical fluid dynamics, the f-plane approximation is an approximation where the Coriolis parameter, denoted f, is set to a constant value.

This approximation is frequently used for the analysis of highly idealized tropical cyclones. Using a constant Coriolis parameter prevents the formation of beta gyres which are largely responsible for the North-westward direction of most tropical cyclones. Rossby waves also depend on variations in f, and do not occur in the f-plane approximation.

In reality, the Coriolis parameter varies with latitude, and so the f-plane approximation is not appropriate when considering flows over large length scales. The f-plane approximation is also poor near the equator, where variations in f are on the same order of magnitude as f. The beta plane approximation is an improvement on the f-plane approximation which takes leading-order variations in f into account.

References

• Peng, Melinda S.; Jeng, Bao-Fong; Williams, R. T. (1999). "A Numerical Study on Tropical Cyclone Intensification. Part I: Beta Effect and Mean Flow Effect". Journal of the Atmospheric Sciences. 56 (10): 1404–1423. Bibcode:1999JAtS...56.1404P. doi:10.1175/1520-0469(1999)056<1404:ANSOTC>2.0.CO;2.
• Isaac Held: Rotating radiative-convective equilibrium

See also

• Beta plane
• Coriolis effect
• Coriolis frequency