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Data assimilation of observational data into full atmospheric states is essential for weather forecast model initialization. Recently, methods for deep generative data assimilation have been proposed which allow for using new input data…

We derive formulae connecting the frequency variations in the spectrum of solar oscillations to the dynamical quantities that are expected to change over the solar activity cycle. This is done for both centroids and the asymmetric part of…

Astrophysics · Physics 2009-11-10 W. A. Dziembowski , P. R. Goode

The Galilean satellites' dynamics has been studied extensively during the last century. In the past it was common to use analytical expansions in order to get simple models to integrate, but with the new generation computers it became…

Earth and Planetary Astrophysics · Physics 2018-07-27 Giacomo Lari

The interactions between climate and the environment are highly complex. Due to this complexity, process-based models are often preferred to estimate the net magnitude and directionality of interactions in the Earth System. However, these…

Atmospheric and Oceanic Physics · Physics 2015-09-30 Erik Casagrande , Brigitte Mueller , Diego Miralles , Dara Entekhabi , Annalisa Molini

Over the southern African region the geomagnetic field is weak and changes rapidly. For this area series of geomagnetic field measurements exist since the 1950s. We take advantage of the existing repeat station surveys and observatory…

Geophysics · Physics 2010-04-07 Anne Geese , Michael Hayn , Vincent Lesur , Mioara Mandea

The recently developed method (Paper 1) enabling one to investigate the evolution of dynamical systems with an accuracy not dependent on time is developed further. The classes of dynamical systems which can be studied by that method are…

Instrumentation and Methods for Astrophysics · Physics 2018-11-05 V. G. Gurzadyan , A. A. Kocharyan

Using models of the Earth's core evolution and the length of the day observations the change of the dimensionless geodynamo parameters is considered. The evolutionary model includes cooling of the liquid adiabatic core, growing solid core,…

Geophysics · Physics 2019-05-31 M. Yu. Reshetnyak

We invert for motions at the surface of Earth's core under spatial and temporal constraints that depart from the mathematical smoothings usually employed to ensure spectral convergence of the flow solutions. Our spatial constraints are…

Geophysics · Physics 2023-12-18 Olivier Barrois , Nicolas Gillet , Julien Aubert

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

This paper presents a learning-based framework for approximating an exact magnetic-field interaction model, supported by both numerical and experimental validation. High-fidelity magnetic-field interaction modeling is essential for…

Robotics · Computer Science 2026-04-24 Yuta Takahashi , Hayate Tajima , Shin-ichiro Sakai

Analyzing the validity and success of a data assimilation algorithm when some state variable observations are not available is an important problem in meteorology and engineering. We present an improved data assimilation algorithm for…

Analysis of PDEs · Mathematics 2016-08-18 Aseel Farhat , Evelyn Lunasin , Edriss S. Titi

For a better understanding of magnetic field in the solar corona and dynamic activities such as flares and coronal mass ejections, it is crucial to measure the time-evolving coronal field and accurately estimate the magnetic energy.…

Solar and Stellar Astrophysics · Physics 2020-02-26 Shin Toriumi , Shinsuke Takasao , Mark C. M. Cheung , Chaowei Jiang , Yang Guo , Keiji Hayashi , Satoshi Inoue

We consider the assimilation of Lagrangian data into a primitive equations circulation model of the ocean at basin scale. The Lagrangian data are positions of floats drifting at fixed depth. We aim at reconstructing the four-dimensional…

Optimization and Control · Mathematics 2009-11-13 Maëlle Nodet

Spatial interaction and spatial autocorrelation are two different fields of geo-spatial analysis, revealing the internal relationship between the two fields will help to develop the theory and method of geographical analysis. This paper is…

Physics and Society · Physics 2023-05-30 Yanguang Chen

Understanding the principles of geophysical phenomena is an essential and challenging task. "Model-driven" approaches have supported the development of geophysics for a long time; however, such methods suffer from the curse of…

Geophysics · Physics 2020-09-30 Siwei Yu , Jianwei Ma

Fast changes of Earth's magnetic field could be explained by inviscid and diffusion-less quasi-geostrophic (QG) Magneto-Coriolis modes. We present a hybrid QG model with columnar flows and three-dimensional magnetic fields and find modes…

Geophysics · Physics 2021-02-24 Felix Gerick , Dominique Jault , Jerome Noir

We study the general-relativistic dynamics of matter being accreted onto and ejected by a magnetised and nonrotating neutron star. The dynamics is followed in the framework of fully general relativistic magnetohydrodynamics (GRMHD) within…

High Energy Astrophysical Phenomena · Physics 2022-09-21 Sercan Çıkıntoğlu , K. Yavuz Ekşi , Luciano Rezzolla

The seismological dynamics of magnetars is largely determined by a strong hydro-magnetic coupling between the solid crust and the fluid core. In this paper we set up a "spectral" computational framework in which the magnetar's motion is…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Maarten van Hoven , Yuri Levin

In meteorology, engineering and computer sciences, data assimilation is routinely employed as the optimal way to combine noisy observations with prior model information for obtaining better estimates of a state, and thus better forecasts,…

Geophysics · Physics 2009-08-12 M. J. Werner , K. Ide , D. Sornette

We employ multiple-scale analysis to systematically derive analytical approximations describing the cosmological propagation of gravitational waves beyond general relativity, in a framework with two interacting spin-2 fields with…

General Relativity and Quantum Cosmology · Physics 2025-11-25 Marco de Cesare , Mairi Sakellariadou , Benjamin Sutton
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