A5081807068- Meteorological Phenomena and Simulations
- Climate variability and models
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Fusion materials and technologies
- Geophysics and Gravity Measurements
- Atmospheric chemistry and aerosols
- Oceanographic and Atmospheric Processes
- Ocean Waves and Remote Sensing
- Tropical and Extratropical Cyclones Research
- Nuclear Materials and Properties
- Particle physics theoretical and experimental studies
- Ion-surface interactions and analysis
- Radiation Detection and Scintillator Technologies
- Solar and Space Plasma Dynamics
- Hydrology and Drought Analysis
- Fluid Dynamics and Turbulent Flows
- Coastal and Marine Dynamics
- Atmospheric aerosols and clouds
- Nuclear reactor physics and engineering
- Particle Detector Development and Performance
- Radioactive contamination and transfer
- Radiation Therapy and Dosimetry
Memorial Sloan Kettering Cancer Center
2025
United Kingdom Atomic Energy Authority
2022-2024
Culham Science Centre
2015-2023
Culham Centre for Fusion Energy
2015-2023
University of Edinburgh
2010-2013
Scottish Universities Physics Alliance
2011-2013
University of Leicester
2009-2010
European Centre for Medium-Range Weather Forecasts
1994-2008
Institute of Aviation Medicine
2008
University of Reading
1974-1976
Abstract An order of magnitude reduction in the cost four‐dimensional variational assimilation (4D‐Var) is required before operational implementation possible. Preconditioning considered and, although it offers a significant cost, seems that unlikely to provide as large an magnitude. approximation 4D‐Var, namely incremental approach, then and shown produce same result at end window extended Kalman filter which no approximations are made assimilating model but instead simplified evolution...
Abstract In the first of this set three papers, formulation European Centre for Medium‐Range Weather Forecasts (ECMWF) implementation 3D‐Var is described. second, specification structure function presented, and last devoted to results extensive numerical experimentation programme which was conducted. The uses a spherical‐harmonic expansion, much as ECMWF optimal interpolation (OI) scheme used an expansion Bessel functions. This introduced using convolution algebra over sphere expressed...
Abstract Recent verification statistics show a considerable improvement in the accuracy of forecasts from three global numerical weather prediction systems. The amounts to about 1‐day gain predictability mean‐sea‐level pressure and 500 hPa height over last decade northern hemisphere, with similar 3 years southern hemisphere. Differences between initial analyses systems have been substantially reduced. Detailed study European Centre for Medium‐Range Weather Forecasts verifications shows that...
This paper analyses the statistical structure of errors short-range wind forecasts used in global data assimilation system at ECMWF, by verifying against radiosonde over North America. The kinematics two-dimensional homogeneous turbulence is to partition perceived forecast into prediction which are horizontally correlated, and observational assumed be uncorrelated. theory further partitions three components, viz. large-scale, rotational divergent provides a spectral description covariance...
The Global and Regional Earth System Monitoring Using Satellite In Situ Data (GEMS) project is combining the manifold expertise in atmospheric composition research numerical weather prediction of 32 European institutes to build a comprehensive monitoring forecasting system for greenhouse gases, reactive aerosol, regional air quality. funded by Commission as part Environment Security (GMES) framework. GEMS has extended data assimilation Centre Medium-Range Weather Forecasts (ECMWF) include...
Abstract The adjoint method has been used to calculate the sensitivity of short‐range forecast errors initial conditions. gradient energy day 2 error with respect conditions can be interpreted as a sum rapidly growing components analysis error. An modified by subtracting an appropriately scaled vector, proportional gradient, provides for ‘sensitivity integration’ that diagnose effect initial‐data on errors. Statistics calculations month April 1994 characterize patterns small‐scale, middle or...
Abstract Recent advances in meteorological forecast skill now enable significantly improved estimates of precipitation quantity, timing and spatial distribution to be made up 10 days ahead for model scales 40 km mode. Here we outline a prototype methodology downscale these using regional Numerical Weather Prediction models appropriate hydrological forecasting then use drive high‐resolution scale (1 or 5 grid scale) water balance rainfall‐runoff models. The aim is develop European Flood...
Abstract Structure functions for the 3D‐Var assimilation scheme of European Centre Medium‐Range Weather Forecasts are evaluated from statistics differences between two forecasts valid at same time. Results compare satisfactorily with those reported in existing literature. Non‐separability correlation is a pervasive feature. Accounting non‐separability necessary to reproduce geostrophic characteristics statistics, such as increase length‐scale height horizontal mass variable, sharper vertical...
The forecast skill of the European Centre for Medium-Range Weather Forecasts Ensemble Prediction System (EPS) in predicting precipitation probabilities is discussed. Four seasons are analyzed detail using signal detection theory and reliability diagrams to define objective measure predictive skill. First, EPS performance during summer 1997 Attention focused on Europe two local regions, one centered around Alps other Ireland. Results indicate that can give skillful prediction low amounts...
Abstract. This paper presents a summary of the measurements made during heavily-instrumented Reactive Halogens in Marine Boundary Layer (RHaMBLe) coastal study Roscoff on North West coast France throughout September 2006. It was clearly demonstrated that iodine-mediated particle formation occurs, driven by daytime low tide emission molecular iodine, I2, macroalgal species fully or partially exposed receding waterline. Ultrafine concentrations strongly correlate with rapidly recycled reactive...
We report experimental upper limits on WIMP-nucleon elastic scattering cross sections from the second science run of ZEPLIN-III at Boulby Underground Laboratory. A raw fiducial exposure 1344 kg⋅days was accrued over 319 days continuous operation between June 2010 and May 2011. total eight events observed in signal acceptance region nuclear recoil energy range 7–29 keV, which is compatible with background expectations. This allows exclusion scalar cross-section above 4.8×10−8 pb near 50...
Abstract In this third and final paper of a series, we assess the performance three‐dimensional variational data assimilation scheme, in light results from extensive pre‐operational programme numerical experimentation. Its is compared with that previous operational scheme at European Centre for Medium‐Range Weather Forecasts, which was based on Optimal Interpolation. The main features new are illustrated, particular effects non‐separable structure functions improved usage. TIROS‐N...
We present the results of a series forecasts on seven weather situations from February 1976 using two models which differ only in their physical parameterizations. One set parameterizations was developed at Geophysical Fluid Dynamics Laboratory (GFDL) some years ago, other more recently European Centre for Medium Range Forcasts (ECMWF). The resolution model (N48, 15 levels) that ECMWF has used first phase operations, began August 1979. particular aim experiments to study importance...
Part I of this study analysed the statistical structure mid-latitude errors short-range wind forecasts used in global data assimilation system at ECMWF, by comparing with verifying radiosonde over North America. After an analysis corresponding statistics for height forecasts, paper studies covariance and forecast errors.The methods I, based on kinematics homogeneous turbulence, are to provide a spectral description autocovariance function cross-covariances stream velocity potential....
The purpose of this paper is to demonstrate the ability a modern data assimilation system provide long-term diagnostic facilities monitor performance observational network. Operational systems use short-range forecasts background, or first-guess, field for analysis. We make detailed study apparent perceived error these when they are verified against radiosondes. On assumption that radiosondes horizontally uncorrelated, forecast can be partitioned into prediction error, which correlated, and...
Substantial changes were made to the ECMWF model in May 1985. The extensive revisions physical parameterizations designed improve treatment of large-scale flow tropics. In addition, resolution was increased substantially a triangular truncation at T106. purpose this paper is evaluate performance new forecasting system on analysis and easterly waves their associated tropical storms over Africa Atlantic. A wave history generated for months August September 1985 with use operational analyses...
Abstract Ensemble integrations for 14 cases are described. These test the relative impact of increase in ensemble size and resolution model used to integrate ensemble. The ensembles evaluated using a variety statistical tests. Some these indicate advantage an size, whilst most tests suggest resolution. However, overall, best performance was obtained by combining enhancement (from T63L19 T106L31) with 32 50 members).
Abstract A rapidly growing instability in energy‐enstrophy conserving finite difference forms of the primitive equations is described. The unusual that it purely internal. It arises because linearized do not conserve momentum. modifications necessary to control are discussed.
Abstract. The NERC UK SOLAS-funded Reactive Halogens in the Marine Boundary Layer (RHaMBLe) programme comprised three field experiments. This manuscript presents an overview of measurements made within two simultaneous remote experiments conducted tropical North Atlantic May and June 2007. Measurements were from mobile one ground-based platforms. heavily instrumented cruise D319 on RRS Discovery Lisbon, Portugal to São Vicente, Cape Verde back Falmouth, was used characterise spatial...
We studied the application of statistical reconstruction algorithms, namely maximum likelihood and least squares methods, to problem event in a dual phase liquid xenon detector. An iterative method was developed for in-situ PMT light response functions from calibration data taken with an uncollimated gamma-ray source. Using techniques described, performance ZEPLIN-III dark matter detector 122 keV gamma-rays. For inner part (R<100 mm), spatial resolutions 13 mm 1.6 FWHM were measured...
Satellite instruments specifically designed to monitor atmospheric carbon dioxide concentrations have not been flown date but, high‐resolution infrared sounders, being launched in the next few years, may offer possibility of at least a basic monitoring capability. This paper explores sensitivity this new generation advanced sounders changing and also compares with uncertainties due temperature, water vapor, minor constituent using current background errors numerical weather prediction models...