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In this chapter we review methods by which near--surface ocean currents can be measured remotely using images of the water surface, as obtained by X-band radar in particular. The presence of a current changes the dispersive behavior of…

Fluid Dynamics · Physics 2022-05-12 Benjamin K. Smeltzer , Simen Å. Ellingsen

The upper few meters of the ocean play a key role in air-sea exchanges of momentum and energy. Two important properties of this layer are the vertical shear of current velocity and the surface velocity. Vertical shear reflects momentum…

Atmospheric and Oceanic Physics · Physics 2026-05-29 G. Hasson , S. Støle-Hentschel , T. Vrećica , V. Shrira , Y. Toledo

Real world water waves often propagate on current. And, the measurement of waves and current is an important task for coastal and marine engineers. Modern marine measurement technologies (i.e. unmanned autonomous vehicles, drones) often…

Fluid Dynamics · Physics 2020-07-31 David M. Kouskoulas , Yaron Toledo

A real time assimilation and forecasting system for coastal currents is presented. The purpose of the system is to deliver current analyses and forecasts based on assimilation of high frequency radar surface current measurements. The local…

Atmospheric and Oceanic Physics · Physics 2012-10-01 Øyvind Breivik , Øyvind Saetra

A new inversion method for determining near-surface shear currents from a measured wave spectrum is introduced. The method is straightforward to implement and starts from the existing state-of-the-art technique of assigning effective depths…

Atmospheric and Oceanic Physics · Physics 2020-02-19 Benjamin K. Smeltzer , Eirik Æsøy , Anna Ådnøy , Simen Å. Ellingsen

We investigate the possibility of detecting extensive air showers by the radar technique. Considering a bistatic radar system and different shower geometries, we simulate reflection of radio waves off the static plasma produced by the…

We investigate the feasibility of detecting extensive air showers by the radar technique at viewing angles smaller than $\sim 25^\circ$ to the shower axis. Considering a bistatic radar setup and shower geometries in which the receiver…

High Energy Astrophysical Phenomena · Physics 2016-08-11 J. Stasielak , S. Baur , R. Engel , P. Neunteufel , J. Pekala , R. Šmída , F. Werner , H. Wilczyński

The dispersive motion of surface waves is now routinely used to remotely measure the currents close beneath the surface of oceans and other natural flows. The current manifests as wavelength-dependent Doppler shifts in the spatiotemporal…

Atmospheric and Oceanic Physics · Physics 2024-08-27 Stefan Weichert , Benjamin K. Smeltzer , Simen Å. Ellingsen

A combined radar remote sensing and in situ data set is used to track packets of nonlinear internal waves as they propagate and shoal across the inner shelf (40m - 9m). The dataset consists of high space-time resolution (5m, 2min) radar…

Atmospheric and Oceanic Physics · Physics 2024-04-30 Alexandra J. Simpson , Jacqueline M. McSweeney , James A. Lerczak , Merrick C. Haller

Radar and camera fusion yields robustness in perception tasks by leveraging the strength of both sensors. The typical extracted radar point cloud is 2D without height information due to insufficient antennas along the elevation axis, which…

Computer Vision and Pattern Recognition · Computer Science 2024-04-10 Huawei Sun , Hao Feng , Gianfranco Mauro , Julius Ott , Georg Stettinger , Lorenzo Servadei , Robert Wille

Reflection of radio waves off the short-lived plasma produced by the high-energy shower particles in the air is simulated, considering various radar setups and shower geometries. We show that the plasma produced by air showers has to be…

Instrumentation and Methods for Astrophysics · Physics 2016-08-10 J. Stasielak , R. Engel , S. Baur , P. Neunteufel , R. Šmída , F. Werner , H. Wilczyński

The Alderney Race has been identified as a future site for the development of tidal energy, due to its bidirectional strong current reaching 5 m/s during spring tides. This hydrodynamics is very difficult to measure by in situ or remote…

Atmospheric and Oceanic Physics · Physics 2024-07-08 Dylan Dumas , Anne-Claire Bennis , Charles-Antoine Guérin , Guiomar Lopez , Laurent Benoit

Spectrum sharing is a new approach to solve the congestion problem in the RF spectrum. A spatial approach for spectrum sharing between a radar and a communication system was proposed, which mitigates the radar interference to communication…

Information Theory · Computer Science 2016-11-17 Awais Khawar , Ahmed Abdelhadi , T. Charles Clancy

Real-time estimation of ocean wave heights using high-frequency (HF) radar has attracted great attention. This method offers the benefit of easy maintenance by virtue of its ground-based installation. However, it is adversely affected by…

Numerical Analysis · Mathematics 2025-05-20 Kaede Watanabe , Toshiaki Yachimura , Tsubasa Terada , Hiroshi Kameda , Ryuhei Takahashi , Hiroshi Suito

Refraction is the predominant mechanism causing spatially inhomogeneous surface gravity wave fields. However, the complex interplay between depth- and current-induced wave refraction remains poorly understood. Assuming weak currents and…

Atmospheric and Oceanic Physics · Physics 2025-09-17 Trygve Halsne , Yan Li

Remotely measuring subsurface water currents from imagery of the wave field has become a much-used technique. We study the biases and errors in such measurements due to spectral leakage, and suggest mitigating procedures. Deviations between…

Atmospheric and Oceanic Physics · Physics 2023-11-03 Stefan Weichert , Benjamin K. Smeltzer , Simen Å. Ellingsen

Current global precipitation estimates from spaceborne precipitation radars are limited by their sensitivity to light and frozen precipitation, leading to systematic underestimation of precipitation at high latitudes. Because passive…

Atmospheric and Oceanic Physics · Physics 2026-05-11 Simon Pfreundschuh , Christian D. Kummerow

Traditional significant wave height (SWH) estima- tion from HF radar typically relies on spectral analysis of the received radar signals. This process was previously simplified by establishing a linear relationship between SWH and the…

Atmospheric and Oceanic Physics · Physics 2026-03-19 Senal Chandrasekara , Reza Shahidi

Surface roughness and dielectric properties are crucial in characterizing radar backscattering from bare soil surfaces. However, their estimation depends on the surface size of the sampling profile, and the complex relative permittivity is…

Applied Physics · Physics 2023-12-27 Zhihua Wang , Ying Yang , Kun-Shan Chen

The analysis of surface wave dispersion curves is a way to infer the vertical distribution of shear-wave velocity. The range of applicability is extremely wide going, for example, from seismological studies to geotechnical characterizations…

Geophysics · Physics 2021-02-25 Giulio Vignoli , Julien Guillemoteau , Jeniffer Barreto , Matteo Rossi
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