Results 81 to 90 of about 5,322 (250)

Forecast‐Error Diagnostics in Neural Weather Models

open access: yesQuarterly Journal of the Royal Meteorological Society, EarlyView.
Deep learning weather prediction models enable efficient forecast‐error diagnostics through auto‐differentiation and low computational cost. We apply grid‐point relaxation and gradient‐based error sensitivity to identify key forecast‐error sources. Results show that medium‐range forecasts in the midlatitudes benefit most from relaxing the stratosphere ...
Uroš Perkan   +2 more
wiley   +1 more source

Impact of Weak‐Constraint Four‐Dimensional Variational data assimilation on the prediction of a sudden stratospheric warming event in 2024

open access: yesQuarterly Journal of the Royal Meteorological Society, EarlyView.
The Weak‐Constraint Four‐Dimensional Variational (WC‐4DVAR) system markedly improved the analysis and forecasting of the 2024 sudden stratospheric warming (SSW) event. It reduced biases and enhanced 7–9 day predictions of temperature across the SSW life cycle, with the most pronounced gains for winds also during the critical onset period.
Shaoying Li   +5 more
wiley   +1 more source

Snapshot and time-dependent inversions of basal sliding using automatic generation of adjoint code on graphics processing units

open access: yesJournal of Glaciology
Basal sliding and other processes affecting ice flow are challenging to constrain due to limited direct observations. Inversion methods, which typically fit an ice-flow model to observed surface velocities, enable the reconstruction of basal properties ...
Ivan Utkin   +3 more
doaj   +1 more source

Coupled observation‐operator approximations in outer‐loop coupling data assimilation

open access: yesQuarterly Journal of the Royal Meteorological Society, EarlyView.
We present a methodology for coupled variational data assimilation that allows the effect of coupled observation operators whilst maintaining separate minimisations across model components. This allows us to constrain the atmosphere, ocean, and sea‐ice components of our coupled model directly from satellite radiances. We illustrate the system in action
P. A. Browne   +5 more
wiley   +1 more source

On the utilization of the adjoint method in microwave tomography

open access: yesInternational Journal for Numerical Methods in Biomedical Engineering
AbstractIn microwave imaging, the adjoint method is widely used for the efficient calculation of the update direction, which is then used to update the unknown model parameter. However, the utilization and the formulation of the adjoint method differ significantly depending on the imaging scenario and the applied optimization algorithm.
Damla Alptekin Soydan   +2 more
openaire   +2 more sources

Hierarchical Differentiable Fluid Simulation

open access: yesComputer Graphics Forum, EarlyView.
We introduce a two‐step algorithm that significantly reduces memory usage for solving control problems using differentiable fluid simulation techniques: our method first optimizes for bulk forces at reduced resolution, then refines local details over sub‐domains while maintaining differentiability. In trading runtime for memory, it enables optimization
Xiangyu Kong   +4 more
wiley   +1 more source

Survey on differential estimators for 3d point clouds

open access: yesComputer Graphics Forum, EarlyView.
Abstract Recent advancements in 3D scanning technologies, including LiDAR and photogrammetry, have enabled the precise digital replication of real‐world objects. These methods are widely used in fields such as GIS, robotics, and cultural heritage. However, the point clouds generated by such scans are often noisy and unstructured, posing challenges for ...
Léo Arnal–Anger   +4 more
wiley   +1 more source

Non‐Rigid 3D Shape Correspondences: From Foundations to Open Challenges and Opportunities

open access: yesComputer Graphics Forum, EarlyView.
Abstract Estimating correspondences between deformed shape instances is a long‐standing problem in computer graphics; numerous applications, from texture transfer to statistical modelling, rely on recovering an accurate correspondence map. Many methods have thus been proposed to tackle this challenging problem from varying perspectives, depending on ...
A. Zhuravlev   +14 more
wiley   +1 more source

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