Distinguish between barotropic & baroclinic conditions of the atmosphere

An air mass which is defined as a large body of air whose physical properties especially temperature, moisture & lapse rate are more or less uniform horizontally for hundreds of kilometers.

                            barotropic condition of atmosphere is theoretically ideal condition where surfaces of constant pressure are not intersected by isostereic(constant density) surfaces, so that in a vertical cross-section isobars(imaginary lines joining places of equal atmospheric pressure) & isotherms appear parallel i.e,zero baroclinicity.It is a rare phenomenon & is found in case of frontogenesis,separated by baroclinic front zone.

         Baroclinic condition of atmosphere is seen in comparatively narrow zones (perhaps 1000Km. in width) of thermal discontinuity also known as fronts in air mass property. They are belts of sharp meteorological gradient recognized as distinct factors in the origin of mid-latitude disturbances. The instability is associated with rising warm air which is driven by vertical wind shear & by the superimposition of tropospheric divergence over a baroclinic zone whose intensification further strengthens upper wind .Warm & cold air masses may be brought closer by induced circulation. Frontal weather largely depends on moisture & equilibrium properties of rising air mass. A weak front has cumulus humilis cloud while a strong front has cumulonimbus development.