An evaluation of the MRI continuous total water content instrument /TWCI/

The design and performance of the TWCI airborne instrument designed for continuous measurement of hydrometeor mass concentrations are discussed. TWCI evaluations show that, in rain, TWCI measurements of average water content are very satisfactory. In ice conditions, additional measurements, such as radar or 2-D probes, appear to be necessary in the evaluation. The TWCI's variable instrument delay (of about 20 to 30 sec, depending on the amount of water content being sampled) and its time constant of 15 to 24 sec point to poor spatial resolution in widely varying conditions of water content.