Title: The Ultrawideband Software-Defined Microwave Radiometer (UWBRAD)
Presenting Author: Mustafa Aksoy / Joel T. Johnson
Organization: The Ohio State University

Abstract:
Existing space and airborne remote sensing instruments have pushed the state-of-the-art in the characterization of ice sheet behaviors with the exception of one key parameter: internal ice sheet temperature. The Ultrawideband Software-Defined Microwave Radiometer (UWBRAD) Instrument Incubator Program will address this gap to provide researchers with the capability to measure ice sheet internal temperatures at depth. UWBRAD data will enhance the research community's ability to determine the ease at which ice deforms internally and the rate at which the ice sheet flows across its base. It will also enhance the community's ability to compile mean annual temperatures and monitor climate change. The UWBRAD concept is the product of extensive modeling studies and research activities, including analyses of ESA's 1.4 GHz Soil Moisture and Ocean Salinity satellite microwave radiometry data that probed deep ice sheet properties at Lake Vostok, Antarctica. Research and technology development activities have confirmed that relative changes in ice sheet internal temperature can be gleaned from multi-frequency emission data over the range 0.5 to 2 GHz, and that a multi-frequency radiometer has the potential to separate temperature and electromagnetic properties in the ice sheet through a model-based retrieval approach. Current radiometers operating in the protected portion of L-band provide only partial ice sheet temperature information due to their single frequency measurements. In contrast, UWBRAD will provide brightness temperatures in 15 channels over the ultra-wideband 0.5-2GHz range and in environments containing radio frequency interference (RFI). To enable operations outside the protected portion of the spectrum, UWBRAD incorporates full bandwidth sampling with software defined algorithms to provide real-time detection and mitigation of interference and a cognitive radiometry method for locating and utilizing portions of the spectrum free of RFI. A 0.5-2 GHz antenna commensurate with instrument and science requirements and capable of airborne deployment is also under development. The project is currently in a year one instrument and antenna design phase; progress in both the instrument plan and the retrieval process will be reported. The overall project plan includes completion of the instrument in year two and deployment in test flights over Greenland ice sheets in year three for validation of science performance.