Airborne measurement of liquid and total water content

Disagreement between probes was even larger when detecting ice water content (IWC). Measurement differences were attributed to different collection efficiencies resulting from preferred particle size, shape, and density and local aerodynamic effects around the aircraft. Measurements from a single probe are subject to uncertainty at a single point in time beyond the noise and drift level of the instrument.

This uncertainty is evaluated considering particle habit, diameter, and density, and probe geometry and size, in addition to particle impact, breakup/splash, and bounce. From a working point of view, the intercomparison of several probes is subject to real but unknown spatial differences because of different locations between air samples. Comparison of identical probes is not appropriate because each measurement in itself is unique by definition.

Thus, instead of duplication of instruments, subject to these levels of agreement, the use of a single probe is a practical approach while remaining aware of its limitations and capabilities.