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The paper studies inverse problems of determining unknown coefficients in various semi-linear and quasi-linear wave equations. We introduce a method to solve inverse problems for non-linear equations using interaction of three waves, that…

Analysis of PDEs · Mathematics 2023-05-10 Ali Feizmohammadi , Matti Lassas , Lauri Oksanen

Passive remote sensing techniques have become more and more popular for detection and characterization purposes. The advantage of using the Global Navigation Satellite Systems (GNSS) are the well known signals emitted and the availability…

Atmospheric and Oceanic Physics · Physics 2013-12-23 Arnaud Coatanhay , Alexandre Baussard

Increasing practical interest has been shown in regression problems where the errors, or disturbances, are centred in a way that reflects particular characteristics of the mechanism that generated the data. In economics this occurs in…

Statistics Theory · Mathematics 2009-09-07 Peter Hall , Ingrid Van Keilegom

The estimation of surface integrals on the boundary of an unknown body is a challenge for nonparametric methods in statistics, with powerful applications to physics and image analysis, among other fields. Provided that one can determine…

Statistics Theory · Mathematics 2011-03-09 Raúl Jiménez , J. E. Yukich

The mapping of ocean floor layers is a current challenge for the oil industry. Existing solution methods involve mapping through seismic methods and wave inversion, which are complex and computationally expensive. The introduction of…

Machine Learning · Computer Science 2024-12-10 Guilherme G. D. Fernandes , Vitor S. P. P. Oliveira , João P. I. Astolfo

Ocean wind waves are a fundamental manifestation of complex dynamics in geophysical fluid systems, characterized by a rich interplay between dispersion and nonlinearity. While linear wave theory provides a first-order description of wave…

Atmospheric and Oceanic Physics · Physics 2026-04-20 Davide Maestrini , Giovanni Dematteis , Alvise Benetazzo , Miguel Onorato

Using polarization measurements in remote sensing and optical studies allows retrieving more information. We consider relationship between the reflection coefficients of plane and rough surfaces for linearly polarized waves. Certain…

Optics · Physics 2012-12-14 Yu. K. Shestopaloff

Accurate mapping of ocean bathymetry is a multi-faceted process, needed for safe and efficient navigation on shipping routes and for predicting tsunami waves. Currently available bathymetry data does not always provide the resolution to…

Fluid Dynamics · Physics 2020-03-12 N. K. -R. Kevlahan , R. A. Khan

We study an inverse problem for the wave equation, concerned with estimating the wave speed, aka velocity, from data gathered by an array of sources and receivers that emit probing signals and measure the resulting waves. The typical…

Numerical Analysis · Mathematics 2025-08-19 Liliana Borcea , Josselin Garnier , Alexander V. Mamonov , Jörn Zimmerling

In this paper we consider fundamental processes of the disturbance and propagation of internal gravity waves in the ocean modeled as a vertically stratified, horizontally non-uniform, and non-stationary medium. We develop asymptotic methods…

Fluid Dynamics · Physics 2013-08-20 Vitaly V. Bulatov , Yuriy V. Vladimirov

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

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

A spectrogram of a ship wake is a heat map that visualises the time-dependent frequency spectrum of surface height measurements taken at a single point as the ship travels by. Spectrograms are easy to compute and, if properly interpreted,…

Patterns and nonlinear waves, such as spots, stripes, and rotating spirals, arise prominently in many natural processes and in reaction-diffusion models. Our goal is to compute boundaries between parameter regions with different prevailing…

Pattern Formation and Solitons · Physics 2025-03-11 Wenjun Zhao , Samuel Maffa , Björn Sandstede

In this article, we propose an inverse technique that accurately reconstructs the ocean's density stratification profile simply from free surface elevation data. Satellite observations suggest that ocean surface contains the signature of…

Fluid Dynamics · Physics 2019-06-27 Subhajit Kar , Anirban Guha

There is a growing interest in developing covariance functions for processes on the surface of a sphere due to wide availability of data on the globe. Utilizing the one-to-one mapping between the Euclidean distance and the great circle…

Applications · Statistics 2015-04-09 Jaehong Jeong , Mikyoung Jun

This work aims at generating a model of the ocean surface and its dynamics from one or more video cameras. The idea is to model wave patterns from video as a first step towards a larger system of photogrammetric monitoring of marine…

Computer Vision and Pattern Recognition · Computer Science 2013-10-01 Mauro de Amorim , Ricardo Fabbri , Lucia Maria dos Santos Pinto , Francisco Duarte Moura Neto

Seismic waves are the most sensitive probe of the Earth's interior we have. With the dense data sets available in exploration, images of subsurface structures can be obtained through processes such as migration. Unfortunately, relating…

Geophysics · Physics 2009-05-05 R. B. Schlottmann

In many temporally ordered data sets, it is observed that the parameters of the underlying distribution change abruptly at unknown times. The detection of such changepoints is important for many applications. While this problem has been…

Methodology · Statistics 2025-06-30 Surojit Biswas , Buddhananda Banerjee , Arnab Kumar Laha

Revealing the ongoing changes in ocean dynamics and their impact on marine ecosystems requires the joint analysis of multiple variables. Yet, global observational records only cover a few decades, posing a challenge in the separation of…

Atmospheric and Oceanic Physics · Physics 2025-05-01 Bruno Buongiorno Nardelli , Daniele Iudicone