The NDSC Microwave Ozone Profiling Instrument at Mauna Loa Observatory
Alan Parrish
University of Massachusetts, Amherst 01003
B. J. Connor
NIWA, Lauder, New Zealand
J. J. Tsou
GATS, Inc., Hampton, Virginia 23666
We have operated a microwave instrument that measures the vertical profiles of stratospheric ozone at Mauna Loa Observatory (MLO) since July 1995. (We also operate a similar instrument at Lauder, New Zealand.) We retrieve ozone profiles covering an altitude range of 20-64 km from our measurements of a pressure-broadened spectral line produced by a rotational transition of ozone at 110.836 GHz. The vertical resolution of the measurements is 8-10 km from 20-40 km, degrading above. A typical profile, measured during the MLO ozone profile intercomparison of July-August 1995, is shown in the Climate Monitoring and Diagnostics Laboratory No. 23 Summary Report 1994-1995, chapter 4.2.
Measurements were made at MLO from July-September 1995; November 1995-March 1996; and from July 1996 to the present. During these periods, the instruments have generally been operated continuously in clear weather. Raw data are recorded every 20 minutes. For our standard data product, these are averaged into four time periods: midnight to just before local dawn, morning, afternoon, and evening (up to the next midnight). Fully processed and calibrated data from these measurements are deposited in the database for the Network for Detection of Stratospheric Change.
Details on the instruments and measurements may be found in the following references: The instrument, calibration, and profile retrieval: Parrish et al. [1992]. Technique of error analysis: Connor et al. [1995]. (The results of the error analysis given in this paper apply to particular early measurements; for results applicable to the current measurements, see the following reference.) Results of a long term intercomparison between one of the microwave instruments and colocated lidar and SAGE-II overpasses: Tsou et al. [1995]. The above references describe results from observations made at the Jet Propulsion Laboratory Table Mountain Facility in Wrightwood, California, between 1989 and 1992 with the instrument that is now in New Zealand. The MLO instrument is essentially identical.
References
Connor, B.J., A. Parrish, J.-J. Tsou, and M.P. McCormick, Error analysis for the ground-based microwave ozone measurements during STOIC, J. Geophys. Res., 100(D5), 9283-9221, 1995.
Parrish, A., B.J. Connor, J.J. Tsou, I.S. McDermid, and W.P. Chu, Ground-based microwave monitoring of stratospheric ozone, J. Geophys. Res., 97(D2), 2541-2546, 1992.
Tsou, J.J., B.J. Connor, A. Parrish, I.S. McDermid, and W.P. Chu, Ground-based microwave monitoring of middle atmosphere ozone: Comparison to lidar and Stratospheric and Gas Experiment II satellite observations, J. Geophys. Res., 100(D2), 3005-3006, 1995.