the distribution of air pressure in the atmosphere. A barometric field at every given moment and on the average is characterized by fronts uniting places of equal pressure, called isobaric fronts. At the intersection of an even level with fronts, including with sea level, the isobaric fronts form lines of equal pressure, called isobars. It is possible to judge the degree of pressure change in a horizontal direction, or the horizontal pressure gradient, which is an important characteristic of barometric fields, by the thickness of the isobars on a pressure distribution chart.
The earth’s barometric field consists of numerous regions of lower and higher pressure called barometric systems. The heterogeneity of pressure along level fronts causes atmospheric currents. Barometric fields are constantly changing, which leads to corresponding changes in atmospheric currents.