Radar scattering behavior of estuarine outflow plumes

• Published in: IEEE transactions on geoscience and remote sensing Vol. 42; no. 2; pp. 367 - 379
• Main Authors: Xuehu Zhang, Twarog, E.M., McLaughlin, D.J., Sletten, M.A., Marmorino, G.O., Trump, C.L., Allan, N.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-02-2004; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied geophysics; Brackish; Breaking; Earth sciences; Earth, ocean, space; Electromagnetic scattering; Exact sciences and technology; Internal geophysics; Marine; Marine geology; Outflow; Plumes; Polarization; Radar; Radar echoes; Radar imaging; Radar remote sensing; Radar scattering; Remote sensing; Rough surfaces; Sea measurements; Surface waves; Trapping; Water pollution; United States; Chesapeake Bay; ocean currents; wave scattering; plumes; breaking waves; remote sensing; hydrodynamics; North America; coastal environment; sea coast; imagery; radar imaging; polarization; radar methods
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2003.821056

We present results of dual-polarized radar scattering measurements of the Chesapeake Bay outflow plume. Near-unity polarization ratios (ratios of horizontally polarized radar echoes over vertically polarized ones) are observed in large incidence angle (60/spl deg/ to 80/spl deg/) radar echoes from the outflow plume and its frontal boundary (normally referred to as a front) under strong surface current convergence (0.008-0.02 S/sup -1/), suggesting the existence of steepened and breaking waves in the regions. Cumulative distribution functions of the horizontally polarized radar returns from the front show approximately 90% of the radar echoes are from steepened and breaking waves. Vertically polarized echoes do not show this effect. These experimental results substantiate early modeling investigators' speculation of featured scattering contributing to horizontally polarized radar signatures of oceanic fronts. Our results also suggest that horizontal radar polarization can be used to remotely sense additional hydrodynamic processes such as wave trapping, blocking, and breaking near oceanic fronts better than what is possible with only vertical polarization.