A calorimetric jet engine technique for estimating the condensed water mixing ratio in cumulus clouds for cloud physical and weather modification research

A technique has been developed for deriving estimates of condensed water mi xing ratio in cumulus clouds from measurements of potential temperature in the air in the compressor of a jet engine. Condensate that enters. the engi ne at low temperatures (near -10 degreesC) is evaporated in the compressor, causing a cooling of the air that is proportional to the amount of condens ate evaporated. An important element of the technique is a correction for t he time response of the temperature measurement system mounted in the compr essed air. This new technique is simpler and more robust than an earlier te chnique based on measurement of the vapor concentration in the compressed a ir by an optical extinction (at Lyman-alpha wavelength) method. The values of condensed water mixing ratio derived from the new system are shown to be similar to those from the optical extinction system, previously reported i n the literature.