An Automated Method for Preparing and Calibrating Electrochemical Concentration Cell (ECC) Ozonesondes

Abstract. In contrast to the legacy manual method used to prepare, condition, and calibrate the Electrochemical Concentration Cell (ECC) ozonesonde an automated digital calibration bench similar to one developed by MeteoSwiss at Payerne, Switzerland was established at NASA's Wallops Flight Facility and providesreference measurements of the same ozone partial pressure as measured by the ECC. The purpose of an automated system is to condition and calibrate ECC cells before launching on a balloon. Operation of the digital calibration bench is simple and real-time graphs and summaries are available to the operator; all information is archived. The parameters of interest include ozone partial pressure, airflow, temperature, background current, response, and time (real and elapsed). ECC cells, prepared with 1.0 percent solution of potassium iodide (KI) and full buffer, show increasing partial pressure values when compared to the reference as partial pressures increase. Differences of approximately 5–6 percent are noted at 200 nb. Additional tests with different concentrations revealed the Science Pump Corp (SPC) 6A ECC with 0.5 percent KI solution and one-half buffer agreed closer to the reference than the 1.0 percent cells, this is in agreement with results of multi-sonde comparisons obtained during BESOS. The information gained from the automated system allowsa compilation of ECC cell characteristics, as well as calibrations. The digital calibration bench is recommended for ECC studies asit conserves resources.