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View article: Forecast Error Diagnostics in Neural Weather Models Using Gridpoint Relaxation
Forecast Error Diagnostics in Neural Weather Models Using Gridpoint Relaxation Open
In physics-based numerical weather prediction models, underlying physical laws and numerical discretisation schemes offer some interpretability of the simulated processes and point to potential sources of errors. In contrast, data-driven d…
View article: Variability and trends of the Pacific Walker circulation indices in multiple reanalyses
Variability and trends of the Pacific Walker circulation indices in multiple reanalyses Open
The Pacific Walker Circulation (PWC) is an important part of the global atmospheric circulation. Its strength is changing constantly due to internal variability, such as ENSO, IPO, and multi-decadal climate variability, as well as the forc…
View article: Exploring a neural network-based background-error covariance model
Exploring a neural network-based background-error covariance model Open
Data assimilation of atmospheric observations traditionally relies on variational and Kalman filter methods. Several ideas of merging data assimilation with machine learning have emerged in recent years. One possibility would be to perform…
View article: The Changes of the Northern Hadley Cell Strength in Reanalyses and Radiosonde Observations
The Changes of the Northern Hadley Cell Strength in Reanalyses and Radiosonde Observations Open
This study investigates the mean meridional wind patterns and their long-term trends within the Northern Hadley Cell (NHC) from 1980 to 2022, using reanalysis datasets and radiosonde observations. The Hadley circulation, a key component of…
View article: Towards higher resolution data assimilation in ECMWF IFS
Towards higher resolution data assimilation in ECMWF IFS Open
Enhancing the spatial resolution of global analyses and forecasts enables weather prediction systems to more accurately capture rapidly evolving mesoscale and convective-scale atmospheric phenomena. The Integrated Forecast System (IFS) of …
View article: A neural network-based observation operator for weather radar data assimilation
A neural network-based observation operator for weather radar data assimilation Open
Forecasting convective storms remains a significant challenge in Numerical Weather Prediction (NWP). Data Assimilation (DA) plays a crucial role by improving the initial conditions for forecasts through the integration of observational dat…
View article: Forecast error diagnostics in neural weather models
Forecast error diagnostics in neural weather models Open
Deep-learning (DL) weather prediction models offer some notable advantages over traditional physics-based models, including auto-differentiability and low computational cost, enabling detailed diagnostics of forecast errors. Using our conv…
View article: A neural network-based observation operator for weather radar data assimilation
A neural network-based observation operator for weather radar data assimilation Open
Forecasting convective storms is one of the most challenging tasks in Numerical Weather Prediction (NWP). Data Assimilation (DA) methods improve the initial condition and subsequent forecasts by combining observations and previous model fo…
View article: The Changes of the Northern Hadley Cell Strength in Reanalyses and Radiosonde Observations
The Changes of the Northern Hadley Cell Strength in Reanalyses and Radiosonde Observations Open
This study examines mean meridional winds and their trends in the Northern Hadley Cell (NHC) from 1980 to 2022 using reanalysis datasets and radiosonde observations. Compared to radiosonde data, reanalyses underestimate the mean upper-trop…
View article: Decomposition of the Horizontal Wind Divergence Associated With the Rossby, Mixed Rossby‐Gravity, Inertia‐Gravity, and Kelvin Waves on the Sphere
Decomposition of the Horizontal Wind Divergence Associated With the Rossby, Mixed Rossby‐Gravity, Inertia‐Gravity, and Kelvin Waves on the Sphere Open
The paper presents a new method for the decomposition of the horizontal wind divergence among linear waves on the sphere: inertia‐gravity (IG), mixed Rossby‐gravity (MRG), Kelvin and Rossby waves. The work is motivated by the need to quant…
View article: 3D‐Var data assimilation using a variational autoencoder
3D‐Var data assimilation using a variational autoencoder Open
Data assimilation of atmospheric observations traditionally relies on variational and Kalman filter methods. Here, an alternative neural network data assimilation (NNDA) with variational autoencoder (VAE) is proposed. The three‐dimensional…
View article: Towards higher resolution data assimilation in ECMWF IFS
Towards higher resolution data assimilation in ECMWF IFS Open
The Integrated Forecast System (IFS) of ECMWF comprises an Earth-system model coupled with an advanced data assimilation system, which was recently experimentally rescaled to higher resolution. The higher resolution initial conditions were…
View article: The Global Extremes Digital Twin of Destination Earth: successes and challenges
The Global Extremes Digital Twin of Destination Earth: successes and challenges Open
At the end of the first phase of the Destination Earth initiative in May 2024, ECMWF will deliver a prototype of the global component of the Weather-Induced Extremes Digital Twin (or Global Extremes DT). The Global Extremes DT will monitor…
View article: Decomposition of the horizontal wind divergence associated with the Rossby, inertia-gravity, mixed Rossby-gravity and Kelvin waves on the sphere
Decomposition of the horizontal wind divergence associated with the Rossby, inertia-gravity, mixed Rossby-gravity and Kelvin waves on the sphere Open
The paper presents a new method for the decomposition of the horizontal wind divergence among the linear wave solutions on the sphere: inertia-gravity (IG), mixed Rossby-gravity (MRG), Kelvin and Rossby waves. The work is motivated by the …
View article: Decomposition of Vertical Velocity and Its Zonal Wavenumber Kinetic Energy Spectra in the Hydrostatic Atmosphere
Decomposition of Vertical Velocity and Its Zonal Wavenumber Kinetic Energy Spectra in the Hydrostatic Atmosphere Open
The spectrum of kinetic energy of vertical motions (VKE) is less well understood compared to the kinetic energy spectrum of horizontal motions (HKE). One challenge that has limited progress in describing the VKE spectrum is a lack of a uni…
View article: 3D-Var Data Assimilation using a Variational Autoencoder
3D-Var Data Assimilation using a Variational Autoencoder Open
Data assimilation of atmospheric observations traditionally relies on variational and Kalman filter methods. Here, an alternative neural-network data assimilation (NNDA) with variational autoencoder (VAE) is proposed. The three-dimensional…
View article: Pacific Walker circulation indices in ERA5 reanalysis
Pacific Walker circulation indices in ERA5 reanalysis Open
The Pacific Walker circulation (PWC) is an integral part of the tropical atmospheric circulation that influences weather patterns globally, including the global distribution of mean precipitation. It also affects the rate of global warming…
View article: Flow‐dependent wind extraction in strong‐constraint 4D‐Var
Flow‐dependent wind extraction in strong‐constraint 4D‐Var Open
In the process of data assimilation for numerical weather prediction, biases in the model and observations can induce spurious analysis increments, which degrade the quality of the analyses. For this reason, the feedback of atmospheric com…
View article: Indices of Pacific Walker Circulation Strength
Indices of Pacific Walker Circulation Strength Open
The Pacific Walker circulation (PWC) significantly affects the global weather patterns, the distribution of mean precipitation, and modulates the rate of global warming. In this study, we review and compare 10 different indices measuring t…
View article: Indices of Pacific Walker Circulation strength (submitted version)
Indices of Pacific Walker Circulation strength (submitted version) Open
This is a collection of open data sources related to the study of the sensitivity of the Pacific Walker circulation (PWC) strength and its trends to the applied PWC strength measure. The applied metrics are described in manuscript: Kosovel…
View article: Indices of Pacific Walker Circulation strength: trends, correlations and uncertainty
Indices of Pacific Walker Circulation strength: trends, correlations and uncertainty Open
The strength of Pacific Walker circulation (PWC) significantly affects the global weather patterns, the distribution of mean precipitation, and modulates the rate of global warming. Different indices have been used to assess the PWC streng…
View article: Metrics of the Hadley circulation strength and associated circulation trends
Metrics of the Hadley circulation strength and associated circulation trends Open
<p>This study compares trends of the Hadley cell (HC) strength using different metrics applied to the European Centre for Medium-range Weather Forecasts ERA5 and ERA-Interim reanalyses in the period 1979-2018. The HC strength is comm…
View article: Recent Hadley circulation strengthening: a trend or multidecadal variability?
Recent Hadley circulation strengthening: a trend or multidecadal variability? Open
<p>This study explores the possible drivers of the recent Hadley circulation strengthening in modern reanalyses. Predominantly, two recent generations of reanalyses provided by the European Centre for Medium-range Weather Forecasts (…
View article: Forecasting the Daily Temperature Extremes from Radiosonde Measurements Using Neural Networks
Forecasting the Daily Temperature Extremes from Radiosonde Measurements Using Neural Networks Open
<p>This study investigates the potential of direct prediction of daily extremes (maximum and minimum) of 2-m temperature from a radiosonde measurement using neural networks (NNs). The analysis is based on 3800 daily profiles measured…
View article: Metrics of the Hadley circulation strength and associated circulation trends
Metrics of the Hadley circulation strength and associated circulation trends Open
This study compares trends in the Hadley cell (HC) strength using different metrics applied to the ECMWF ERA5 and ERA-Interim reanalyses for the period 1979–2018. The HC strength is commonly evaluated by metrics derived from the mass-weigh…
View article: zaplotnik/Metrics-of-Hadley-circulation-strength
zaplotnik/Metrics-of-Hadley-circulation-strength Open
Hadley cell strength This is a collection of open data sources related to the study of the sensitivity of the trend of Hadley cell (HC) strength to the applied HC strength measure. The applied metrics are described in manuscript: Pikovnik,…
View article: zaplotnik/Metrics-of-Hadley-circulation-strength
zaplotnik/Metrics-of-Hadley-circulation-strength Open
Hadley cell strength This is a collection of open data sources related to the study of the sensitivity of the trend of Hadley cell (HC) strength to the applied HC strength measure. The applied metrics are described in manuscript: Pikovnik,…
View article: Zonal wavenumber spectra of the vertical velocity and horizontal wind divergence associated with the Rossby and non-Rossby waves in the tropics
Zonal wavenumber spectra of the vertical velocity and horizontal wind divergence associated with the Rossby and non-Rossby waves in the tropics Open
<div>In contrast to the kinetic energy spectrum of the horizontal motions, the spectrum of kinetic energy of vertical motions (vertical kinetic energy spectrum) is poorly known because the vertical velocity is not an observed quantit…
View article: Recent Hadley circulation strengthening: a trend or multidecadal variability?
Recent Hadley circulation strengthening: a trend or multidecadal variability? Open
<p>This study explores the possible drivers of the recent Hadley circulation strengthening in the modern reanalyses. Predominantly, two recent generations of reanalyses provided by the European Centre for Medium-Range Weather Forecas…
View article: Recent Hadley Circulation Strengthening: A Trend or Multidecadal Variability?
Recent Hadley Circulation Strengthening: A Trend or Multidecadal Variability? Open
This study explores the possible drivers of the recent Hadley circulation strengthening in the modern reanalyses. Predominantly, two recent generations of reanalyses provided by the European Centre for Medium-Range Weather Forecasts are us…