Development of Cloud Water Content Meter, EWER.

Abstract : An instrument for measuring the total water content of condensed phase(s) in clouds at flight levels to 6 km is described. The instrument is designed to evaluate erosive environment for reentry vehicles where the total water content of particles is less than 1 g/cu m of air. The instrument is part of a system that offers real-time readout of condensate or recordings that can be analyzed by post-flight data reduction procedures. The system has been calibrated in the laboratory and flown in a C130E aircraft under a variety of conditions. Results obtained on one flight are compared with data from a Particle Measuring Systems probe, also operational on this flight. Laboratory calibration of the Lyman-alpha humidiometer used in the instrument showed that the effective absorption coefficient was about half that given for Lyman-alpha due to the broad spectrum in the output of the hydrogen lamp. Recommendations for certain modifications to the instrument/system and a preliminary design of the improved version of the instrument are given. (Author)