4.1  Chemiluminescent Ozonesonde

As part of the validation of the ozone measurements, a chemiluminescent ozonesonde will be included with the payload.  Typical dimensions for this cylindrical device would be approximately 11 cm in diameter and 50 cm in length, weighing 2.5 kg.  This instrument uses the chemiluminescence reaction between ozone and Rhodamine B which provides an in situ ozone concentration once calibrated.  In situ measurements do not depend on lighting conditions, and the detector works equally well in day as at night.  Ambient air is sampled by a self-pumping technique as the sonde descends through the atmosphere. The flow rate past the detector is proportional to the pressure change in the chamber and the chemilumniescence is then proportional to the ozone flux.  This technology has been used for many years, and its reliability has been tested on many flights.  The vertical resolution of the ozonesonde is comparable to the ISP at 0.5-1 km, and the detector provides sufficient sensitivity for accurate measurements of ozone in the stratosphere.