isallobar

plural isallobars

1. climatologyA line joining points of equal pressure change during a specific time interval, especially over three hours.

   If your barometer has dropped 0.05 of an inch in the last three hours, you are on the -0.05 isallobar.

   1977, Blair & Ketchum's Country Journal, volume 4, page 27

   2 more examples

   Seasonal variations of atmospheric pressure are illustrated by the isallobaric chart […] which gives the differences between mean pressure in July–August, and in January–February. The position of the isallobars on this chart is largely indicative of the role of monsoonal factors […]

   1965, L. V. Kool', “The pressure field of the Atlantic trade-wind belt and its changes with height”, in Oceanology, volume 5, numbers 4-6, page 35

   Successive values of pressure provide figures for the barometric tendency, permitting the plotting of isallobars […] This is called tendency analysis.

   1977, Edward Linacre, John E. Hobbs, Ann McGrath, The Australian climatic environment, page 153