Isobar Maps

Isobar Maps


Where Isoline maps represent areas of a number of different equivalences, isobar maps have lines representing areas of equal pressure. When constructing isobar maps, a few general rules are followed, these include the fact that the isobars may not touch or cross. Isobars may only pass through areas in intervals of + or - 4 millibars, and that the atmospheric pressure is always given in terms of millibars. Also, since pressure lines are normally corrected for sea level, differences in pressure due to altitude are ignored. The map below displays the isobars representing the average differences in atmospheric pressure across the United States for September of 1998.

http://www.uwlax.edu/faculty/skala/Air-Pressure.htm