Description: At the conclusion of Phase II, a dual-wire universal water content (UWC) sensor has been demonstrated in Anasphere’s icing wind tunnel and in flight. Most notably, the sensor has demonstrated the use of a hydrophilic capture gel to capture all condensed phases of water: ice, supercooled liquid, and above-freezing liquid. With one sensing wire thus measuring all condensed phases, and a second wire selectively measuring only supercooled liquid water, it is possible for the sonde to measure all three condensed phases of water and determine their speciation in clouds. While the basic functionality of the UWC sensor has been clearly addressed in Phase II, there are two specific areas in which further work would improve the utility of the sensor. First, very few suitable flight opportunities emerged late in Phase II to demonstrate the complete UWC sensor in a variety of cloud conditions. Second, during flights and tunnel tests late in Phase II, it was found that the sensing wires as currently constructed can become unstable under certain combinations of velocity and water accumulation rate. Two specific areas of work will be conducted in Phase II-E to address these areas. First, more flight tests will be completed using the latest UWC sensor designs. Second, a combination of further icing tunnel tests and computer-based modeling will be completed in concert with the flight tests to predict envelope expansion and cross-check flight results. The ultimate outcome of this work should be an expanded operating envelope for the UWC sensor that will enable its successful adoption into atmospheric research.

Benefits: Cloud and precipitation research Decadal Survey Foundational Observation: Clouds, Convection, and Precipitation Radiation Sciences Program: FIRE (First International Satellite Cloud Climatology Project Regional Experiment) Earth Observing System: CERES (Clouds and the Earth’s Radiant Energy System experiment) Aviation Safety

Atmospheric radiative transfer studies (DOE ARM program) Cloud studies Icing research