ABSTRACT
The synoptic features are continuously changing by modifying intensifying, interacting, weakening, decaying and reforming. Systematic analyses became possible in the late nineteenth century with the widespread adoption of the telegraph and dissemination of observations. A frontal zone separates air masses of different densities, temperature, humidity or some other physical property. The derived parameter of vorticity generally shows a high degree of consistency and is an effective frontal marker. The most important front is the polar front which separates polar air from tropical air. In an idealized picture, the polar front circles the earth in the middle latitudes in both hemispheres. Convergence occurs on an even larger scale if the trade winds from either hemisphere meet in a narrow zone, the intertropical convergence zone (ITCZ). The Ekman layer wind profile shows that wind in the friction layer actually blows cross-isobarically into the low pressure.
