This proposal presents a ground-based program of microwave spectroscopic observations of the mesosphere and lower thermosphere. The molecular species O3, CO, HDO (deuterated water), and HO2 will be measured within the mesosphere (50-90 km); and NO will be measured within the lower thermosphere (90-120 km). In addition, mesospheric wind velocities (over 60-85 km) will be determined through measurement of doppler shifts in the CO and O3 lines. A wide variety of processes in the mesosphere/lower thermosphere will be studied with these observations. These include solar cycle, seasonal, and diurnal variations in lower thermospheric NO peak densities; seasonal and diurnal variations in mesospheric HO2, O3, HDO, and winds; the seasonal variation in mesospheric CO; the photochemical balance of Ox and HOx chemistry in the mesosphere; and the D/H ratio within mesospheric water vapor. Roughly three four- day periods of observing will be conducted each year at the Kitt Peak NRAO facility (30N latitude). One additional observing session per year is planned at the Mauna Kea CSO facility (22oN latitude). Observations at these various sites will be coordinated to study latitudinal variations, and possibly to obtain NO observations during periods of high auroral activity.
