MAS MEASUREMENTS OF THE LATITUDINAL DISTRIBUTION OF WATER-VAPOR AND OZONE IN THE MESOSPHERE AND LOWER THERMOSPHERE

We present measurements of the latitudinal variation of nighttime O-3 and H2O in the mesosphere and (for O-3) lower thermosphere obtained wi th the Millimeter-wave Atmospheric Sounder (MAS) instrument during the ATLAS 2 mission (8-15 April 1993). These are the first such measureme nts that have ever been reported. They indicate an O-3 mixing ratio mi nimum at mid-latitudes in the upper mesosphere, with maxima in the tro pics and at high latitudes. The H2O retrievals indicate H2O mixing rat ios decreasing toward the poles in both hemispheres in the upper mesos phere. We also present measurements of the diurnal variation of O-3 at southern mid-latitudes, at higher vertical resolution than has ever b een reported previously. The results are generally consistent with pre vious measurements and modeling studies.