Study of Turbulence and Sea Surface Roughness in Ducted Environments
Abstract
The Ohio State University-ElectroScience Laboratory (OSU-ESL) is pleased to submit the proposal titled "Study of Turbulence and SeaSurface Roughness in Ducted Environments," in response to ONR Announcement #N00014-23-S-B001. ESL is a major independent "Center-of-Excellence" within the OSU and is one of the largest university Radio Frequency (RF) research laboratories in the world. Our researchers and students are involved in all aspects of electromagnetic and RF technologies.There recently has been significant interest in understanding, modeling and sensing/forecasting lower atmospheric ducting including the ONR-sponsored large scale projects such asCoastal Land-Air-Sea Interaction (CLASI) and Coupled Air-Sea Processes and EM Ducting Research (CASPER). Up to this point, most studies focused on the effects of ducting on signal amplitude and its effects on US Navy communication and radar system performance. Recent cheap commercial-off-the-shelf (COTS) software-defined-radio (SDR) based systems enabled us to perform phase-coherent measurements in addition to the classical refractivity-from-clutter (RFC) methods used by marine radars, and drone-based systems that measurevertical EM field. There are current studies exploring these new sources of data on how to improve our understanding and estimationof atmospheric ducts.All of these studies, however, focus on the mean EM signal (the first moment) and ignores the higher order moments such as signal amplitude variance (scintillation/fading) and phase variance and interaction of these higher order moments with the stochastic atmospheric (turbulence) and sea surface processes operating within a duct. The main goal of this proposal is to better understand the signal amplitude and phase fluctuations and how they are linked to turbulence/sea surface roughness, and ducting. Another aspect of the proposal is helping with the Radar and Electromagnetic wave Ducting in the Stable Atmosphere over Water (REDSAW) project intendingto quantify the refractivity profiles in the stable boundary layer and their impact on electromagnetic wave (EM)propagation. The goal of the experiment is to develop improved representations of the evaporation ducts in the stable surface layers and their resultant impact on EM propagation, including seeking improvement or replacement of MOST in stable surface layer relatedto the flux-profile relationship. We plan to make systematic sensitivity tests using a propagation model with various characteristics of the stable surface layer refractivity profile to identify the role of evaporation duct height, strength, and the vertical gradient and curvature of refractivity profiles. Extensive measurements will be conducted over the Salton Sea where stable thermal stratifications prevail. OSU team currently plans to use the Lower Atmospheric Propagation (LATPROP) Ultra-Wide Band (UWB) System to support REDSAW. The ultimate objective of this research is better understanding of evaporative ducting under stable atmosphere thru meteorological and EM measurements to advance the field of detection, discrimination, tracking, and fusion of data of difficult targets in rapidly varying non-standard atmospheric conditions utilizing electromagnetic theory and situational awareness methodologies, andto improve communication link design and performance analysis under ducting conditions.Approved for Public Release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 12, 2023
- Source ID
- N000142312256
Entities
People
- Caglar Yardim
Organizations
- Office of Naval Research
- Ohio State University
- United States Navy