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In simulations of aqueous systems it is common to freeze the bond vibration and angle bending modes in water to allow for a longer time-step $\delta t$ for integrating the equations of motion. Thus $\delta t = 2$ fs is often used in…

Soft Condensed Matter · Physics 2023-08-17 Dilipkumar N. Asthagiri , Thomas L. Beck

Data-driven convective parameterization aims to accurately represent convective adjustments to large-scale forcings in a computationally economic manner. While previous studies have demonstrated success using various model architectures,…

Atmospheric and Oceanic Physics · Physics 2025-06-02 Qiyu Song , Zhiming Kuang

Deep learning has advanced weather forecasting, but accurate predictions first require identifying the current state of the atmosphere from observational data. In this work, we introduce Appa, a score-based data assimilation model…

Computing solutions to partial differential equations using the fast Fourier transform can lead to unwanted oscillatory behavior. Due to the periodic nature of the discrete Fourier transform, waves that leave the computational domain on one…

Numerical Analysis · Mathematics 2023-01-18 Anne Liu , Thomas Trogdon

The generation of initial conditions via accurate data assimilation is crucial for weather forecasting and climate modeling. We propose DiffDA as a denoising diffusion model capable of assimilating atmospheric variables using predicted…

Computational Engineering, Finance, and Science · Computer Science 2024-06-11 Langwen Huang , Lukas Gianinazzi , Yuejiang Yu , Peter D. Dueben , Torsten Hoefler

Artificial intelligence (AI)-based weather prediction research is growing rapidly and has shown to be competitive with the advanced dynamic numerical weather prediction models. However, research combining AI-based weather prediction models…

Machine Learning · Computer Science 2025-10-16 Shunji Kotsuki , Kenta Shiraishi , Atsushi Okazaki

Data Assimilation (DA) is a computational tool that uses value from the model and the real measurement to arrive to an optimally acceptable value. Rather, this technique relies on the idea of Kalman gain. We point out that DA has two…

Optimization and Control · Mathematics 2020-12-15 Mohammad N. Murshed , Zarin Subah , M. Monir Uddin

Although numerical weather forecasting methods have dominated the field, recent advances in deep learning methods, such as diffusion models, have shown promise in ensemble weather forecasting. However, such models are typically…

Machine Learning · Computer Science 2025-09-16 Kevin Valencia , Ziyang Liu , Justin Cui

Streamflow, as a natural phenomenon, is continuous in time and so are the meteorological variables which influence its variability. In practice, it can be of interest to forecast the whole flow curve instead of points (daily or hourly). To…

Applications · Statistics 2016-10-20 Pierre Masselot , Sophie Dabo-Niang , Fateh Chebana , Taha B. M. J. Ouarda

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

The ultra-long relaxation time of glass transition makes it difficult to construct atomic models of amorphous materials by conventional methods. We propose a novel method for building such atomic models using data assimilation method by…

Materials Science · Physics 2022-12-14 Yuansheng Zhao , Ryuhei Sato , Shinji Tsuneyuki

A closure model is presented for large-eddy simulation (LES) based on the three-dimensional variational data assimilation algorithm. The approach aims at reconstructing high-fidelity kinetic energy spectra in coarse numerical simulations by…

Fluid Dynamics · Physics 2024-07-02 Sagy Ephrati , Arnout Franken , Erwin Luesink , Paolo Cifani , Bernard Geurts

We study the probability distribution and the escape rate in systems with delayed dissipation that comes from the coupling to a thermal bath. To logarithmic accuracy in the fluctuation intensity, the problem is reduced to a variational…

Statistical Mechanics · Physics 2015-06-04 M. I. Dykman , I. B. Schwartz

Data assimilation techniques, developed in the last two decades mainly for weather prediction, produce better forecasts by taking advantage of both theoretical/numerical models and real-time observations. In this paper, we explore the…

Astrophysics · Physics 2015-05-13 Eric Bélanger , Alain Vincent , Paul Charbonneau

Reduced-order dynamical models play a central role in developing our understanding of predictability of climate irrespective of whether we are dealing with the actual climate system or surrogate climate-models. In this context, the…

Geophysics · Physics 2021-03-11 B. T. Nadiga

Conventional recursive filtering approaches, designed for quantifying the state of an evolving uncertain dynamical system with intermittent observations, use a sequence of (i) an uncertainty propagation step followed by (ii) a step where…

Probability · Mathematics 2015-06-18 Wonjung Lee , Chris Farmer

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…

We use transition path sampling to study evaporation in the SPC/E model of liquid water. Based on thousands of evaporation trajectories, we characterize the members of the transition state ensemble (TSE), which exhibit a liquid-vapor…

Soft Condensed Matter · Physics 2014-09-05 Patrick Varilly , David Chandler

Data assimilation algorithms integrate prior information from numerical model simulations with observed data. Ensemble-based filters, regarded as state-of-the-art, are widely employed for large-scale estimation tasks in disciplines such as…

Numerical Analysis · Mathematics 2024-05-24 Iris Rammelmüller , Gottfried Hastermann , Jana de Wiljes

We experimentally demonstrate that highly structured distributions of work emerge during even the simple task of erasing a single bit. These are signatures of a refined suite of time-reversal symmetries in distinct functional classes of…