Ground-Based Millimeterwave Measurements of Mesosopheric and Stratospheric Ozone Employing an SIS Mixer Receiver.

Abstract

The J = 61, 5 - 60, 6 (110.8359 GHz) line of mesospheric and stratospheric ozone has been observed by employing a newly developed microwave ozone sensor equipped with a Nb SIS mixer receiver in a temporal manner. The SIS mixer has a receiver noise of 34 K (SSB) and the spectrometer covers >60 MHz bandwidth with a frequency resolution of 35 kHz. Altitude profiles of ozone concentration retrieved from observed line profiles are compared with those in Keating et al. (1990) and in Parrish et al. (1992) for inter-comparison and obtained agreement with an accuracy of about 10% in the altitude range between 40 and 50 km. From these observations, the following are concluded. (1) Time profiles of relative variations of mesospheric O3 concentration at dawn and dusk are obtained with a good time resolution. (2) Diurnal variations of ozone mixing ratio at various altitudes from 36 km through 76 km appear qualitatively in agreement with theoretical calculations and earlier observations except nighttime variations near the top of the mesosphere. (3) Ozone mixing ratio above 70 km shows nighttime variations variable from day to day with an amplitude of about 20% of the midnight values.