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This paper investigates unmanned aerial vehicle (UAV) data collection systems with different multiple access schemes, where a rotary-wing UAV is dispatched to collect data from multiple ground nodes (GNs). Our goal is to maximize the…

Information Theory · Computer Science 2021-08-03 Xidong Mu , Yuanwei Liu , Li Guo , Jiaru Lin , Zhiguo Ding

We show how the 3DVAR data assimilation methodology can be used in the astrophysical context of a two-dimensional convection flow. We study the way this variational approach finds best estimates of the current state of the flow from a…

Solar and Stellar Astrophysics · Physics 2013-08-09 Andreas Svedin , Milena C. Cuellar , Axel Brandenburg

This paper addresses the impact of assimilating data from the Earth Networks Total Lightning Network (ENTLN) during two cases of severe weather. Data from the ENTLN serve as a substitute for those from the upcoming launch of the GOES…

Optimization and Control · Mathematics 2013-06-11 Razvan Stefanescu , I. Michael Navon , Henry Fuelberg , Max Marchand

This paper discusses the practical use of the saddle variational formulation for the weakly-constrained 4D-VAR method in data assimilation. It is shown that the method, in its original form, may produce erratic results or diverge because of…

Numerical Analysis · Mathematics 2021-05-31 S. Gratton , S. Gürol , E. Simon , Ph. L. Toint

This paper focuses on continuous data assimilation (CDA) for the Navier-Stokes equations with nonlinear slip boundary conditions. CDA methods are typically employed to recover the original system when initial data or viscosity coefficients…

Numerical Analysis · Mathematics 2025-03-28 W. C. Wu , H. Y. Dong , K. Wang

Variational Data Assimilation (DA) has enabled huge improvements in the skill of operational weather forecasting. In this study, we use a simple solar-wind propagation model to develop the first solar-wind variational DA scheme. This scheme…

Space Physics · Physics 2018-10-19 Matthew Lang , Mathew Owens

We present a novel framework for assimilating planar PIV experimental data using a variational approach to enhance the predictions of the Spalart-Allmaras RANS turbulence model. Our method applies three-dimensional constraints to the…

Fluid Dynamics · Physics 2026-01-27 Uttam Cadambi Padmanaban , Bharathram Ganapathisubramani , Sean Symon

There is an urgent need to build models to tackle Indoor Air Quality issue. Since the model should be accurate and fast, Reduced Order Modelling technique is used to reduce the dimensionality of the problem. The accuracy of the model, that…

In meteorological and oceanological studies the classical approach for finding the numerical solution of the regional model consists in formulating and solving the Cauchy-Dirichlet problem. The related boundary conditions are obtained by…

Atmospheric and Oceanic Physics · Physics 2008-01-14 F. I. Pisnichenko , I. A. Pisnichenko , J. M. Martinez , S. A. Santos

Deep neural operators, such as DeepONets, have changed the paradigm in high-dimensional nonlinear regression from function regression to (differential) operator regression, paving the way for significant changes in computational engineering…

We develop and apply a novel shape optimization exemplified for a two-blade rotor with respect to the figure of merit ($FM$). This topologically assisted optimization (TAO) contains two steps. First a global evolutionary optimization is…

In this work, we consider the two dimensional tidal dynamics equations in a bounded domain and address some optimal control problems like total energy minimization, minimization of dissipation of energy of the flow, etc. We also examine an…

Optimization and Control · Mathematics 2020-10-06 Manil T. Mohan

In-situ ocean wave observations are critical to improve model skill and validate remote sensing wave measurements. Historically, such observations are extremely sparse due to the large costs and complexity of traditional wave buoys and…

Atmospheric and Oceanic Physics · Physics 2020-03-11 Pieter B. Smit , Isabel A. Houghton , Kalina Jordanova , Thomas Portwood , Evan Shapiro , David Clark , Michael Sosa , Tim T. Janssen

Accurate estimation of error covariances (both background and observation) is crucial for efficient observation compression approaches in data assimilation of large-scale dynamical problems. We propose a new combination of a covariance…

Numerical Analysis · Mathematics 2021-06-11 Sibo Cheng , Didier Lucor , Jean-Philippe Argaud

4D-variational data assimilation is applied to the Lorenz '63 model to introduce a new method for parameter estimation in chaotic climate models. The approach aims to optimise an Earth system model (ESM), for which no adjoint exists, by…

Atmospheric and Oceanic Physics · Physics 2025-04-18 Philip David Kennedy , Abhirup Banerjee , Armin Köhl , Detlef Stammer

We consider a recently introduced continuous data assimilation (CDA) approach for downscaling a coarse resolution configuration of the 2D Benard convection equations into a finer grid. In this CDA, a nudging term, estimated as the misfit…

Optimization and Control · Mathematics 2015-12-22 M. U. Altaf , E. S. Titi , O. M. Knio , L. Zhao , M. F. McCabe , I. Hoteit

We study the numerical performance of a continuous data assimilation (downscaling) algorithm, based on ideas from feedback control theory, in the context of the two-dimensional incompressible Navier--Stokes equations. Our model problem is…

Dynamical Systems · Mathematics 2016-05-04 Masakazu Gesho , Eric Olson , Edriss S. Titi

The vertical trajectory optimization for the en route descent phase is studied in the presence of both along track and cross winds, which are both modeled as functions of altitude. The flight range covers some portion of a cruise segment…

Optimization and Control · Mathematics 2015-08-11 Sang Gyun Park , John-Paul Clarke

Data assimilation (DA) in the geophysical sciences remains the cornerstone of robust forecasts from numerical models. Indeed, DA plays a crucial role in the quality of numerical weather prediction, and is a crucial building block that has…

Estimating background-error covariances remains a core challenge in variational data assimilation (DA). Operational systems typically approximate these covariances by transformations that separate geostrophically balanced components from…

Atmospheric and Oceanic Physics · Physics 2026-01-21 Boštjan Melinc , Uroš Perkan , Žiga Zaplotnik