Sarah-Jane Lock

Sarah-Jane Lock
European Center For Medium Range Weather Forecasts · Research Department

PhD

About

21
Publications
6,804
Reads
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625
Citations
Citations since 2017
8 Research Items
557 Citations
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
Additional affiliations
January 2013 - October 2015
European Center For Medium Range Weather Forecasts
Position
  • Researcher
September 2008 - December 2012
University of Leeds
Position
  • PostDoc Position

Publications

Publications (21)
Article
The Stochastically Perturbed Parametrisations scheme (SPP) represents model uncertainty in numerical weather prediction by introducing stochastic perturbations into the physical parametrisation schemes. The perturbations are constructed in such a way that the internal consistency of the physical parametrisation schemes is preserved. We developed a...
Article
Full-text available
In the simulation of complex multi-scale flows arising in weather and climate modelling, one of the biggest challenges is to satisfy strict service requirements in terms of time to solution and to satisfy budgetary constraints in terms of energy to solution, without compromising the accuracy and stability of the application. These simulations requi...
Article
Full-text available
The continuous partial differential equations (PDEs) governing a given physical phenomenon, such as the Navier-Stokes equations describing the fluid motion, must be numerically discretised in space and time in order to obtain a solution otherwise not readily available in closed (i.e., analytic) form. While the overall numerical discretization plays...
Article
The Stochastically Perturbed Parametrization Tendencies (SPPT) scheme is used in ensemble forecast systems to represent uncertainties due to the atmospheric physics parametrizations. The scheme works by introducing random perturbations to the tendencies from the physics schemes. The size of the perturbations is modulated by the size of the net tend...
Article
Full-text available
In the simulation of complex multi-scale flow problems, such as those arising in weather and climate modelling, one of the biggest challenges is to satisfy operational requirements in terms of time-to-solution and energy-to-solution yet without compromising the accuracy and stability of the calculation. These competing factors require the developme...
Article
Full-text available
Members in ensemble forecasts differ due to the representations of initial uncertainties and model uncertainties. The inclusion of stochastic schemes to represent model uncertainties has improved the probabilistic skill of the ECMWF ensemble by increasing reliability and reducing the error of the ensemble mean. Recent progress, challenges and futur...
Article
Full-text available
The Stochastically Perturbed Parametrisation Tendencies (SPPT) scheme is used at weather and climate forecasting centres worldwide to represent model uncertainty that arises from simplifications involved in the parametrisation process. It uses spatio-temporally correlated multiplicative noise to perturb the sum of the parametrised tendencies. Howev...
Article
Full-text available
Ensemble forecasts depend on representations of model uncertainties. Here, we introduce a model uncertainty representation where a novel approach is taken to the established methodology of perturbing model parameters. The Stochastically Perturbed Parametrisations (SPP) scheme applies spatially and temporally varying perturbations to 20 parameters a...
Technical Report
Full-text available
The aim of Working Group 1 (WG1) was to identify the key issues and recommend priorities for future research directions for ECMWF and the wider research community to understand the sources of uncertainty and improve the representation of uncertainty in models. This summary provides a brief record of some of the main points discussed by the Working...
Technical Report
Full-text available
The aim of Working Group 1 (WG1) was to identify the key issues and recommend priorities for future research directions for ECMWF and the wider research community to understand the sources of uncertainty and improve the representation of uncertainty in models. This summary provides a brief record of some of the main points discussed by the Working...
Article
With the prospect of exascale computing, computational methods requiring only local data become especially attractive. Consequently, the typical domain decomposition of atmospheric models means horizontally-explicit vertically-implicit (HEVI) time-stepping schemes warrant further attention. In this analysis, Runge–Kutta implicit-explicit schemes fr...
Conference Paper
Full-text available
Recent studies have highlighted the potential from using the Monte-Carlo Spectral Integration (McSI) radiation scheme for weather and climate simulations. By stochastically sampling the spectral intervals used to represent the long-wave and short-wave spectra, the cost of the radiative transfer computations can be significantly reduced while introd...
Article
Full-text available
Several tests of a model with a cut-cell representation of orography are presented: a resting atmosphere test, advection across a hill and a warm rising bubble over hills with different gradients. The tests are compared with results from terrain-following models. Results indicate that errors associated with terrain-following coordinates are reduced...
Article
Full-text available
Many operational weather forecasting centres use semi-implicit time-stepping schemes because of their good efficiency. However, as computers become ever more parallel, horizontally explicit solutions of the equations of atmospheric motion might become an attractive alternative due to the additional inter-processor communication of implicit methods....
Article
Full-text available
Advances in computing are enabling atmospheric models to operate at increasingly fine resolution, giving rise to more variations in the underlying orography being captured by the model grid. Consequently, high-resolution models must overcome the problems associated with traditional terrain-following approaches of spurious winds and instabilities ge...
Article
Doppler-On-Wheels radar observations made during the Convective and Orographically-induced Precipitation Study (COPS) on 12 August 2007 showed that precipitating clouds only developed between the north–south orientated Murg and Nagold Valleys of the northern Black Forest. The clouds produced moderate precipitation. The Weather Research and Forecast...
Article
Full-text available
Moves to increasingly high-resolution models give rise to more variations in the underlying orography being captured by the model grid. Consequently, high-resolution models must overcome instabilities associated with terrain-following (see Fig. 1a) approaches. This work further explores the capabilities of a cut-cell representation of orography for...

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