Proof-of-concept of use of a short-wavelength dual-polarization radar detecting in-flight icing conditions was accomplished through several FAA-sponsored field experiments culminating in the Mt. Washington Icing Sensors Project in 1999. The utility of microwave radiometers for measuring cloud liquid water was previously demonstrated, and used en tandem with the radar in these experiments. NOAA/ETL's objectives have since been to establish design requirements for a reliable, operation-grade, 8-mm dual-polarization radar and microwave radiometer combined system for continuous, unattended, long-term monitoring and research of such conditions, and then to build and demonstrate this new instrument. The system is intended to assess conditions in the flight terminal area or similar locale. The full engineering Preliminary Design for this Ground-based Remote Icing Detection System (GRIDS) was completed in FY2001 and has now become the final design.

Here we outline some of the features of the evolved design system architecture and icing detection algorithm development, progress in building the system, and additional applications of the system, and plans for its demonstration. Among its potential multiple applications beyond its core mission of icing detection, GRIDS is expected to also be useful in measuring and assessing winter weather, ceiling and visibility, and in-cloud turbulence, and in providing measurements to anchor and validate satellite icing and cloud-property algorithms, in-flight icing models, and other forecast and climate/radiation models.