Planetary Wave Two Signatures in CRISTA 2 Ozone and Temperature Data

The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) instrument has flown on two shuttle missions providing observations of constituents and temperature throughout the stratosphere and mesosphere at high vertical and horizontal resolution. During the second mission (CRISTA 2: August 7-17, 1997) a wave two signature was observed in the southern midlatitudes in the temperature data between 17 and 80 km and in the ozone data between 17 and 63 km (the limits of ozone data availability for the current data version). This signature has a period of ~12.5 days and a vertical wavelength of ~45 km. It is one of the few observational instances showing vertical and equatorward propagation of a planetary wave well into the mesosphere. The relative phase of the signature in the temperature and ozone varies with height with the two being in phase below 30 km and 180 degrees out of phase above 40 km. These signatures are consistent with those expected from a migrating planetary wave with the ozone signature being dynamically driven at lower altitudes and photochemically driven at higher altitudes. The CRISTA results above the middle stratosphere show a greater agreement with photochemical equilibrium calculations than previous analyses. These results clearly illustrate the penetration of a dynamical feature from the tropopause into the mesosphere and its effect on constituent distributions throughout this height range.