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To explain grain growth and destruction in warm media, ice mantle formation and sublimation in cold media, and gas line emission spectroscopy, astrochemical models must mimic the gas--solid abundance ratio. Ice-sublimation mechanisms…

Astrophysics of Galaxies · Physics 2024-04-04 F. Kruczkiewicz , F. Dulieu , A. V. Ivlev , P. Caselli , B. M. Giuliano , C. Ceccarelli , P. Theulé

Observations from the Odin/Sub-Millimetre Radiometer (SMR) instrument have been assimilated into the DIAMOND model (Dynamic Isentropic Assimilation Model for OdiN Data), in order to estimate the chemical ozone (O$_{3}$) loss in the…

Space Physics · Physics 2017-05-23 Kazutoshi Sagi , Kristell Pérot , Donal Murtagh , Yvan Orsolini

Accurately predicting adsorption properties in nanoporous materials using Deep Learning models remains a challenging task. This challenge becomes even more pronounced when attempting to generalize to structures that were not part of the…

Semidiurnal atmospheric thermal tides are important for terrestrial exoplanets in the habitable zone of their host stars. With solid tides, they torque these planets, thus contributing to determine their rotation states as well as their…

Earth and Planetary Astrophysics · Physics 2017-10-20 Pierre Auclair-Desrotour , Stéphane Mathis , Jacques Laskar

Ecosystem respiration (Reco) represents a major component of the global carbon cycle, and accurate characterization of its dynamics is essential for a comprehensive understanding of ecosystem-climate interactions and the impacts of climate…

Dynamical Systems · Mathematics 2024-03-19 Maha Shadaydeh , Joachim Denzler , Mirco Migliavacca

Under cold conditions in dense cores, gas-phase molecules and atoms are depleted from the gas-phase to the surface of interstellar grains. Considering the time scales and physical conditions within these cores, a portion of these molecules…

Astrophysics of Galaxies · Physics 2021-08-11 V. Wakelam , E. Dartois , M. Chabot , S. Spezzano , D. Navarro-Almaida , J. -C. Loison , A. Fuente

Data assimilation addresses the problem of identifying plausible state trajectories of dynamical systems given noisy or incomplete observations. In geosciences, it presents challenges due to the high-dimensionality of geophysical dynamical…

Machine Learning · Statistics 2023-11-03 François Rozet , Gilles Louppe

Data assimilation is often viewed as a framework for correcting short-term error growth in dynamical climate model forecasts. When viewed on the time scales of climate however, these short-term corrections, or analysis increments, can…

Atmospheric and Oceanic Physics · Physics 2023-10-02 William Gregory , Mitchell Bushuk , Alistair Adcroft , Yongfei Zhang , Laure Zanna

This study demonstrates how the incremental 4D-Var data assimilation method can be applied efficiently preconditione d in an application to an oceanographic problem. The approach consists in performing a few iterations of the reduced-order…

Geophysics · Physics 2007-09-19 Céline Robert , Eric Blayo , Jacques Verron

We have extracted over 400 clusters, covering more than 2 decades in mass, from three simulations of the TCDM cosmology. This represents the largest, uniform catalogue of simulated clusters ever produced. The clusters exhibit a wide variety…

Astrophysics · Physics 2009-10-31 P. A. Thomas , O. Muanwong , F. R. Pearce , H. M. P. Couchman , A. C. Edge , A. Jenkins , L. Onuora

Recent progress in cosmology has relied on combining different cosmological probes. In earlier work, we implemented an integrated approach to cosmology where the probes are combined into a common framework at the map level. This has the…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-03 Andrina Nicola , Alexandre Refregier , Adam Amara

Lyman limit and damped Lyman-alpha absorption systems probe the distribution of collapsed, cold gas at high redshift. Numerical simulations that incorporate gravity and gas dynamics can predict the abundance of such absorbers in…

Astrophysics · Physics 2009-10-28 Jeffrey P. Gardner , Neal Katz , Lars Hernquist , David H. Weinberg

Data assimilation (DA) aims to estimate the full state of a dynamical system by combining partial and noisy observations with a prior model forecast, commonly referred to as the background. In atmospheric applications, this problem is…

Atmospheric and Oceanic Physics · Physics 2025-05-29 Jing-An Sun , Hang Fan , Junchao Gong , Ben Fei , Kun Chen , Fenghua Ling , Wenlong Zhang , Wanghan Xu , Li Yan , Pierre Gentine , Lei Bai

Sparse Identification of Nonlinear Dynamics (SINDy) has been shown to successfully recover governing equations from data; however, this approach assumes the initial condition to be exactly known in advance and is sensitive to noise. In this…

Dynamical Systems · Mathematics 2022-11-23 Baolei Wei

We present a methodology to simulate the impact of the atmospheric models in the background particle flux on ground detectors using the Global Data Assimilation System. The methodology was within the ARTI simulation framework developed by…

Instrumentation and Methods for Astrophysics · Physics 2021-10-20 Jennifer Grisales-Casadiegos , Christian Sarmiento-Cano , Luis A. Núñez , the LAGO Collaboration

This paper studies density estimation and regression analysis with contaminated data observed on the unit hypersphere S^d. Our methodology and theory are based on harmonic analysis on general S^d. We establish novel nonparametric density…

Statistics Theory · Mathematics 2023-01-10 Jeong Min Jeon , Ingrid Van Keilegom

Dust modeling is crucial to infer dust properties and budget for galaxy studies. However, there are systematic disparities between dust grain models that result in corresponding systematic differences in the inferred dust properties of…

Global climate models (GCMs) are the main tools for understanding and predicting climate change. However, due to limited numerical resolutions, these models suffer from major structural uncertainties; e.g., they cannot resolve critical…

Machine Learning · Computer Science 2023-12-05 Rambod Mojgani , Daniel Waelchli , Yifei Guan , Petros Koumoutsakos , Pedram Hassanzadeh

While the formulation of most data assimilation schemes assumes an unbiased observation model error, in real applications, model error with nontrivial biases is unavoidable. A practical example is the error in the radiative transfer model…

Methodology · Statistics 2016-11-17 John Harlim , Tyrus Berry

A simplified model of natural convection, similar to the Lorenz (1963) system, is compared to computational fluid dynamics simulations in order to test data assimilation methods and better understand the dynamics of convection. The…

Dynamical Systems · Mathematics 2012-04-23 Kameron Decker Harris , El Hassan Ridouane , Darren L. Hitt , Christopher M. Danforth