isobaarinen

Isobaarinen, or isobaric, refers to phenomena or processes that occur at constant pressure. In thermodynamics the term describes a type of process where the external pressure remains fixed while other state variables, such as temperature and volume, may change. In meteorology the term is used to describe lines on weather maps that connect points of equal atmospheric pressure, known as isobars.

In thermodynamics, an isobaric process is one that takes place at constant pressure. For an ideal gas, the relationship PV = nRT applies, and at constant P the volume V changes in direct proportion to the temperature T (V ∝ T). The work done by or on the system during an isobaric change is W = P ΔV. The internal energy change is ΔU = n Cv ΔT, while the enthalpy change is ΔH = n Cp ΔT, where Cp and Cv are the molar heat capacities at constant pressure and constant volume, respectively. For an ideal gas, Cp − Cv = R. The heat added at constant pressure satisfies Q = n Cp ΔT, linking heat transfer directly to temperature change.

In meteorology, isobars are lines on maps that connect locations with the same atmospheric pressure, typically near sea level. The spacing of isobars indicates wind strength: closely spaced isobars correspond to stronger winds, while widely spaced isobars indicate lighter winds. Isobaric patterns help identify high-pressure systems (anticyclones) and low-pressure systems (cyclones) and influence interpretations of weather fronts and storm development.

The term isobaarinen thus covers both the thermodynamic concept of constant pressure processes and the cartographic representation of pressure fields, with applications in physical chemistry, engineering, and meteorology.