POLAR FRONT

The narrow zone that separates polar and tropical air masses. The term originated in 1922 with the publication of the classic Norwegian model of a mid-latitude depression or cyclone. The atmospheric polar front is a narrow zone of strong temperature, potential temperature, humidity and wind differences, where the warm, light tropical air is forced to rise over the dense, cold polar air. It is clearly seen on surface synoptic charts, stretching for thousands of kilometres across the world’s oceans between 45° and 60° latitudes, but is usually disrupted over the main continental areas. satellite remote sensing since the 1960s has shown that polar front can be identified in satellite cloud photographs. It is now closely associated with the polar-front jet stream. The oceanic polar front (OPF) separates cold and warm water masses in an analogous way.

[See alsoantarctic front, arctic front, front]