A5065967673- Climate variability and models
- Meteorological Phenomena and Simulations
- Atmospheric and Environmental Gas Dynamics
- Oceanographic and Atmospheric Processes
- Tropical and Extratropical Cyclones Research
- Plant Water Relations and Carbon Dynamics
- Geophysics and Gravity Measurements
- Cryospheric studies and observations
- Atmospheric Ozone and Climate
- Geological Studies and Exploration
- Energy Load and Power Forecasting
- Arctic and Antarctic ice dynamics
- Hydrology and Drought Analysis
- Species Distribution and Climate Change
- Ocean Waves and Remote Sensing
- Soil Moisture and Remote Sensing
- Climate change and permafrost
- Methane Hydrates and Related Phenomena
- Atmospheric chemistry and aerosols
- Climate change impacts on agriculture
- Hydrology and Watershed Management Studies
- demographic modeling and climate adaptation
- Ocean Acidification Effects and Responses
- Marine and coastal ecosystems
- Reservoir Engineering and Simulation Methods
University of Oxford
2016-2025
European Centre for Medium-Range Weather Forecasts
2016-2025
National Centre for Atmospheric Science
2015-2024
Met Office
2008-2022
Science Oxford
2021
NOAA Oceanic and Atmospheric Research
2020
University of Tsukuba
2016
Google (United States)
2005-2008
London School of Economics and Political Science
2003-2007
Danish Meteorological Institute
2005
Abstract. In this paper we describe SEAS5, ECMWF's fifth generation seasonal forecast system, which became operational in November 2017. Compared to its predecessor, System 4, SEAS5 is a substantially changed system. It includes upgraded versions of the atmosphere and ocean models at higher resolutions, adds prognostic sea-ice model. Here, configuration summarise most noticeable results from set diagnostics including biases, variability, teleconnections skill. An important improvement...
The last decade has seen the success of stochastic parameterizations in short-term, medium-range and seasonal forecasts: operational weather centers now routinely use parameterization schemes to better represent model inadequacy improve quantification forecast uncertainty. Developed initially for numerical prediction, inclusion not only provides estimates uncertainty, but it is also extremely promising reducing longstanding climate biases relevant determining response external forcing. This...
Seasonal climate forecasts are being used increasingly across a range of application sectors. A recent UK governmental report asked: how good seasonal on scale 1-5 (where 5 is very good), and can we expect them to be in 30 years time? made from ensembles integrations numerical models climate. We argue that 'goodness' should assessed first foremost terms the probabilistic reliability these ensemble-based forecasts; reliable inputs essential for any forecast-based decision-making. propose '5'...
Trustworthy probabilistic projections of regional climate are essential for society to plan future change, and yet, by the nonlinear nature climate, finite computational models inherently deficient in their ability simulate climatic variability with complete accuracy. How can we determine whether specific may be untrustworthy light such generic deficiencies? A calibration method is proposed whose basis lies emerging notion seamless prediction. Specifically, calibrations ensemblebased change...
A new 46‐year hindcast dataset for seasonal‐to‐annual ensemble predictions has been created using a multi‐model of 5 state‐of‐the‐art coupled atmosphere‐ocean circulation models. The outperforms any the single‐models in forecasting tropical Pacific SSTs because reduced RMS errors and enhanced dispersion at all lead‐times. Systematic are considerably over previous generation (DEMETER). Probabilistic skill scores show higher than DEMETER 4–6 month forecast range. However, substantially...
Members in ensemble forecasts differ due to the representations of initial uncertainties and model uncertainties. The inclusion stochastic schemes represent has improved probabilistic skill ECMWF by increasing reliability reducing error mean. Recent progress, challenges future directions regarding at are described this article. coming years likely see a further increase use methods assimilation. This will put demands on used perturb forecast model. An area that is receiving greater attention...
Based on skill estimates from hindcasts made over the last couple of decades, recent studies have suggested that considerable success has been achieved in forecasting winter climate anomalies Euro‐Atlantic area using current‐generation dynamical forecast models. However, previous‐generation models had shown forecasts 1960s and 1970s were less successful than 1980s 1990s. Given more decades dominated by North Atlantic Oscillation (NAO) its positive phase, it is important to know whether...
Abstract The relative merits of three forecast systems addressing the impact model uncertainty on seasonal/annual forecasts are described. One system consists a multi‐model, whereas two other sample uncertainties by perturbing parametrization reference models through perturbed parameter and stochastic physics techniques. Ensemble re‐forecasts over 1991 to 2001 were performed with coupled climate started from realistic initial conditions. Forecast quality varies due different strategies for...
Abstract Recent studies of individual seasonal forecast systems have shown that the wintertime North Atlantic Oscillation (NAO) can be skillfully forecast. However, it has also been suggested these skillful forecasts tend to underconfident, meaning there is too high a proportion unpredictable noise in forecasts. We assess skill and overconfidence/underconfidence contributing EUROpean Seasonal Interannual Prediction (EUROSIP) multimodel ensemble system. Five seven studied significant for...
[1] The European summer 2003 is a prominent example for an extreme hot and dry season. main mechanisms that contributed to the growth of heat wave are still disputed state-of-the-art climate models have difficulty realistically simulate conditions. Here we analyse simulations using recent versions Centre Medium-Range Weather Forecasts seasonal ensemble forecasting system present, first time, retrospective forecasts which accurately not only abnormal warmth but also observed precipitation...
The finite resolution of general circulation models the coupled atmosphere–ocean system and effects sub-grid-scale variability present a major source uncertainty in model simulations on all time scales. European Centre for Medium-Range Weather Forecasts has been at forefront developing new approaches to account these uncertainties. In particular, stochastically perturbed physical tendency scheme backscatter algorithm atmosphere are now used routinely global numerical weather prediction. also...
Abstract. The Climate SPHINX (Stochastic Physics HIgh resolutioN eXperiments) project is a comprehensive set of ensemble simulations aimed at evaluating the sensitivity present and future climate to model resolution stochastic parameterisation. EC-Earth Earth system used explore impact physics in large 30-year integrations five different atmospheric horizontal resolutions (from 125 up 16 km). includes more than 120 both historical scenario (1979–2008) change projection (2039–2068), together...
Abstract The influence of tropical precipitation variability on summertime seasonal circulation anomalies in the Euro-Atlantic sector is investigated. dominant mode maximum covariance analysis (MCA) between and reveals a cyclonic anomaly over extratropical North Atlantic, contributing to anomalously wet conditions western Europe dry eastern Scandinavia (in positive phase). related associated with Pacific SST closely linked El Niño–Southern Oscillation (ENSO). second MCA consists weaker but...
Abstract The role of model resolution in simulating geophysical vortices with the characteristics realistic tropical cyclones (TCs) is well established. push for increasing continues, general circulation models (GCMs) starting to use sub-10-km grid spacing. In same context it has been suggested that stochastic physics (SP) may act as a surrogate high resolution, providing some benefits at fraction cost. Either technique can reduce uncertainty, and enhance reliability, by more dynamic...
© 2024 The Author(s). Published by the American Meteorological Society. This is an Author Accepted Manuscript distributed under terms of Creative Commons Attribution 4.0 International (CC BY 4.0) License . * Corresponding author, email: Antje.Weisheimer@physics.ox.ac.uk
Abstract The 2021 Pacific Northwest heatwave was so extreme as to challenge conventional statistical and climate-model-based approaches weather attribution. However, state-of-the-art operational prediction systems are demonstrably able simulate the detailed physics of heatwave. Here, we leverage these show that human influence on climate made this event at least 8 [2–50] times more likely. At current rate global warming, likelihood such an is doubling every 20 [10–50] years. Given...
Most seasonal forecasts of Atlantic tropical storm numbers are produced using statistical‐empirical models. However, can also be made numerical models which encode the laws physics, here referred to as “dynamical models”. Based on 12 years re‐forecasts and 2 real‐time forecasts, we show that so‐called EUROSIP (EUROpean Seasonal Inter‐annual Prediction) multi‐model ensemble coupled ocean atmosphere has substantial skill in probabilistic prediction number storms. The correctly distinguished...
[1] The probabilistic skill of ensemble forecasts for the first month and season is assessed, where model uncertainty represented by a) multi-model, b) perturbed parameters, c) stochastic parameterisation ensembles. main foci assessment are Brier Skill Score near-surface temperature precipitation over land areas spread-skill relationship sea surface in tropical equatorial Pacific. On monthly timescale, forecast system with provides overall most skilful forecasts. seasonal timescale results...
Abstract. In this paper we describe SEAS5, ECMWF’s fifth generation seasonal forecast system, which became operational in November 2017. Compared to its predecessor, System 4, SEAS5 is a substantially changed system. It includes upgraded versions of the atmosphere and ocean models at higher resolutions, adds prognostic sea ice model. Here, configuration summarise most noticeable results from set diagnostics including biases, variability, teleconnections skill. An important improvement...