Aircraft measurements of potential vorticity and Richardson number in baroclinic zones

Abstract

AbstractThis paper describes a novel technique for deriving potential vorticity and Richardson number from aircraft cross‐sections of baroclinic zones. It exploits the fact that gravity waves distort isentropic surfaces, so that an aircraft flying horizontally can measure a vertical profile of temperature and wind under favourable conditions. The technique is applied to two flights of the UK Meteorological Research Flight's C‐130 Hercules aircraft, in April 1983 and June 1991. It is found to work reasonably well only when large‐amplitude gravity waves are present. Values of potential vorticity so derived agree with those calculated in the conventional manner from cross‐sections, and are found to correlate well with ozone mixing ratio.