A weather system in which temperature and pressure surfaces are coincident, i.e., temperature is uniform (no temperature gradient) on a constant pressure surface. Barotropic systems are characterized by a lack of
wind shear , and thus are generally unfavorable areas for
severe thunderstorm development. See
baroclinic zone . Usually, in operational meteorology, references to barotropic systems refer to
equivalent barotropic systems - systems in which temperature gradients exist, but are parallel to height gradients on a constant pressure surface. In such systems, height contours and
isotherms are parallel everywhere, and winds do not change direction with height. As a rule, a true equivalent barotropic system can never be achieved in the real atmosphere. While some systems (such as
closed lows or
cutoff lows ) may reach a state that is close to equivalent barotropic, the term barotropic system usually is used in a relative sense to describe systems that are really only close to being equivalent barotropic, i.e., isotherms and height contours are nearly parallel everywhere and
directional wind shear is weak.
