“…Vertically, downward motion associated with an upper tropospheric trough results in an increase in total ozone, whereas upward motion in association with an upper level ridge results in a decrease [ Reed , 1950; Barsby and Diab , 1995]. Furthermore, regions of high total ozone content are associated with high mean integrated potential vorticity (MPV), low temperatures in the upper troposphere, a low tropopause, high temperatures in the lower stratosphere, and low pressures in both the upper troposphere and lower stratosphere [e.g., Normand , 1953; Ohring and Muench , 1960; Penn , 1964, 1965, 1966; Danielsen , 1968; Schubert and Munteanu , 1988; Orlanski et al , 1989; Mote et al , 1991; Riishøjgaard and Källén , 1997].…”