Title: The Ultra-Wideband Software Defined Radiometer for Internal Ice Sheet Temperature Sensing: Results from 2016 flights in Greenland
Presenting Author: Joel T. Johnson
Organization: The Ohio State University
Co-Author(s): K. C. Jezek, M. Andrews, M. Durand, L. Tsang, A. Bringer, H. Li, D. Belgiovane, C. Chen, M. Brogioni, G. Macelloni, J. Miller, Y. Duan, S. Tan

Abstract:
The Ultra-Wideband Software Defined Radiometer (UWBRAD) is a 0.5-2 GHz microwave radiometer used to measure ice sheet brightness temperatures to derive internal ice sheet temperature information. The system is being developed under a Instrument Incubator Program begun in 2013. The instrument consists of a conical spiral antenna, RF front end including internal calibration sources, and a 12 channel digital backend sampling each channel at 250 MSPS. Due to UWBRAD's operation outside protected frequency bands, radio frequency interference (RFI) is a major concern, and is addressed through "software defined" approaches to detecting and filtering interference in each channel. The system was deployed in its first airborne campaign in September 2016 aboard a DC-3 aircraft provided by Ken Borek Airlines. The instrument recorded data on a transit flight from Calgary, Canada to Thule AFB in Greenland, and over near coastal portions of the Greenland Ice Sheet. The data recorded over the Greenland ice sheet shows brightness temperature signatures versus frequency consistent with the varying morphologies of the ice sheet in this region. A return campaign to Greenland is planned for September 2017 to acquire data over colder portions of the ice sheet to demonstrate internal temperature measurements. The presentation will review the UWBRAD instrument as well as the measurement results from the airborne campaign. Comparisons of forward models for ice sheet brightness temperatures with the observations will also be discussed, followed by plans for the September 2017 campaign.