Isobar

Isobar: A line on a weather map drawn through points of equal pressure reduced to mean sea level. Isobars show the pressure distribution at any given time.

The isobaric surface contours vary with height so the geostrophic wind velocity above a given point also varies with height. The wind vector difference between the two levels above the point, the vertical wind shear, is called the thermal wind, i.

See also: Atmosphere, Stability, Speed, Section, Cloud