Page History

...

Expand

title	Parametrization of sub-grid scale processes

Multiexcerpt

MultiExcerptName	PATT2018

Time

Monday

Tuesday

Wednesday

Thursday

Friday

9.15

Introduction to the course

Director of Research and Sarah Keeley

Expand

title	Land Surface (1): Introduction

By the end of the session students should be able to:

recognise land elements relevant to weather,
review land modelling strategies to heterogeneity

Gianpaolo Balsamo

Expand

title	Land Surface (2):

This session will have two main components:

An overview of the role of snow in the climate system from observations, models and forecasts; with a description of the current representation of snow in the ECMWF model.
An overview of the role of vegetation in NWP with a description of the evolution of vegetation representation in the ECMWF model, supported by some evaluation examples.

By the end of the session, the students should be able:

Identify the main processes associated with snow and vegetation in NWP
Describe the main components related to snow and vegetation scheme in the ECMWF land surface model

Souhail Boussetta

Expand

title	Radiation (3)

This module aims to introduce the fundamentals of radiative transfer theory and its role within the global atmospheric circulation. The lectures will also cover the techniques of numerical modelling of the radiative transfer equations in global-circulation models with a particular focus on the code in use in the ECMWF Integrated Forecasting System.

By the end of the session students should be able to:

• Identify the key processes controlling the atmospheric radiative balance

• Recognize the role of the radiative transfer in the Earth energy balance

• Estimate the impact of changes in the radiative parameterizations on climate

Additional outcomes:

• Develop skills in data analysis and numerical modelling

Alessio Bozzo

Expand

title	Parametrization and Data Assimilation

This three-hour lecture will start by explaining the role and main ingredients of data assimilation in general. The widely used framework of variational data assimilation will then be gradually introduced. The challenges associated with the necessary inclusion of physical parametrizations in the data assimilation process will be highlighted. The concept of adjoint model as well as the techniques to derive it will be introduced. The importance of the linearity constraint in 4D-Var and the methods to address it will be detailed. The set of linearized physical parametrizations used at ECMWF will then be briefly presented. Finally, various examples of the use of physical parametrizations in variational data assimilation and its impact on weather forecast quality will be given.

By the end of the session, the students should be able:

• to name the main ingredients of a data assimilation system.

• to tell why physical parametrizations are needed in data assimilation.

• to identify the role of the adjoint code in 4D-Var.

• to recognize the importance of the regularization of the linearized code.

Philippe Lopez

10.45

Expand

title	Overview of online training modules.

This session is to give you the opportunity to discuss anything that you have not understood or would like to know more about from the elearning modules.

By the end of the online learning modules you should be able to:

understand the basic notion of parametrisation
discuss the interaction between the large-scale circulation and the convection including: radiative-convective equilibrium and convectively-coupled large-scale waves

Peter Bechtold,

Expand

title	Clouds (2)

This session describes the representation of subgrid-scale variability of humidity, cloud and precipitation and how this can be parametrized in atmospheric models.

By the end of the session you should be able to:

• recognise the reasons for representing the subgrid variability of humidity and cloud in an atmospheric model

• explain how the key quantity of cloud fraction is related to subgrid heterogeneity assumptions

• describe the different types of subgrid cloud parametrization schemes.

Richard Forbes

Expand

title	Diagnostics

Increasing observation volumes and model complexity, decreasing errors, and a growing desire for
uncertainty information, all necessitate developments in our diagnostic tools. The aim of these
lectures is to discuss some of these tools, the dynamical insight behind them, and the residual
deficiencies that they are highlighting.

By the end of the lectures you should be aware of:

Some of the key weakness of the ECMWF forecast system
Some of the diagnostic tools used to identify and understand these weaknesses

Mark Rodwell

Expand

title	Convection (3)

Convection affects all atmospheric scales. Therefore, the convection session aims to provide a deeper understanding of the atmospheric general circulation and its interaction with convective heating and vertical transports. The notions and techniques acquired during the course should be useful for developers of convective parametrizations, forecasters and for analysing ouput from high-resolution convection resolving models.

By the end of the session you should become familiarised with

• the interaction between the large-scale circulation and the convection including radiative-convective equilibrium and convectively-coupled large-scale waves

• the notion of convective adjustment and the mass flux concept in particular

• the basic concepts behind the ECMWF convection parametrization and some useful numerical tricks

• forecasting convection including convective systems and the diurnal cycle

• diagnose forecast errors related to convection.

Peter Bechtold

Expand

title	Land Surface (3): Surface Energy, Water Cycle

By the end of the session, the students should be able:

relate flux and storage
recognise land surface predictors and land diagnostic quantities

Gianpaolo Balsamo

11.55

Moist Processes Games

Richard Forbes and Peter Bechtold

Expand

title	Radiation (2)

This module aims to introduce the fundamentals of radiative transfer theory and its role within the global atmospheric circulation. The lectures will also cover the techniques of numerical modelling of the radiative transfer equations in global-circulation models with a particular focus on the code in use in the ECMWF Integrated Forecasting System.

By the end of the session students should be able to:

• Identify the key processes controlling the atmospheric radiative balance

• Recognize the role of the radiative transfer in the Earth energy balance

• Estimate the impact of changes in the radiative parameterizations on climate

Additional outcomes:

• Develop skills in data analysis and numerical modelling

Robin Hogan

Expand

title	Convection (2)

Convection affects all atmospheric scales. Therefore, the convection session aims to provide a deeper understanding of the atmospheric general circulation and its interaction with convective heating and vertical transports. The notions and techniques acquired during the course should be useful for developers of convective parametrizations, forecasters and for analysing ouput from high-resolution convection resolving models.

By the end of the session you should become familiarised with

• the interaction between the large-scale circulation and the convection including radiative-convective equilibrium and convectively-coupled large-scale waves

• the notion of convective adjustment and the mass flux concept in particular

• the basic concepts behind the ECMWF convection parametrization and some useful numerical tricks

• forecasting convection including convective systems and the diurnal cycle

• diagnose forecast errors related to convection.

Peter Bechtold

Expand

title	Clouds (3)

Building on the previous two Cloud sessions, the practical implementation of a cloud parametrization is described, using the ECMWF global model as an example appropriate for global weather forecasting.

By the end of the session you should be able to:

• explain the key sources and sinks of cloud and precipitation required in a parametrization

• describe the main components of the ECMWF stratiform cloud parametrization

• recognise the limitations of approximating complex processes.

Richard Forbes

Expand

title	Model Evaluation: Clouds and Boundary Layer

This session will give an overview of techniques and data sources used for the verification of the boundary layer scheme. We will use examples from the IFS to explore how verification methods can help to identify systematic errors in the model's boundary layer parameterization, and guide future model development.

By the end of this session you should be able to:

• Identify data sources and products suitable for BL verification

• Recognize the strengths and limitations of the verification strategies discussed

• Choose a suitable verification method to investigate model errors in boundary layer height, transport and cloudiness.

Maike Ahlgrimm

14.15

Expand

title	Radiation (1)

This module aims to introduce the fundamentals of radiative transfer theory and its role within the global atmospheric circulation. The lectures will also cover the techniques of numerical modelling of the radiative transfer equations in global-circulation models with a particular focus on the code in use in the ECMWF Integrated Forecasting System.

By the end of the session students should be able to:

• Identify the key processes controlling the atmospheric radiative balance

• Recognize the role of the radiative transfer in the Earth energy balance

• Estimate the impact of changes in the radiative parameterizations on climate

Additional outcomes:

• Develop skills in data analysis and numerical modelling

Robin Hogan

Expand

title	Boundary Layer (2)

This session focuses on representation of the surface layer, i.e. the layer between the surface and the first model level. More particularly, it explains how the surface fluxes are parametrized, and it gives insights on the representation of the surfaces roughness lengths which are one of the crucial aspects of the formulation of the surface fluxes.

Expected outcomes:

• be aware of the difficulties related to the representation of the surface layer in a numerical model

• understand how the surface fluxes are parametrized

Irina Sandu

Expand

title	Boundary Layer (3)

This session explains the different approaches used in numerical models to parametrize the turbulent mixing taking place at the subgrid scale, above the surface layer. Various turbulence closures are presented before describing closure currently used in the ECMWF model.

Expected outcomes:

• understand what a turbulence closure is and what are the types of closures encountered in numerical models

• have an overview of the parameterization of turbulent mixing in the ECMWF model

Irina Sandu

Expand

title	Parametrization and Data Assimilation

This three-hour lecture will start by explaining the role and main ingredients of data assimilation in general. The widely used framework of variational data assimilation will then be gradually introduced. The challenges associated with the necessary inclusion of physical parametrizations in the data assimilation process will be highlighted. The concept of adjoint model as well as the techniques to derive it will be introduced. The importance of the linearity constraint in 4D-Var and the methods to address it will be detailed. The set of linearized physical parametrizations used at ECMWF will then be briefly presented. Finally, various examples of the use of physical parametrizations in variational data assimilation and its impact on weather forecast quality will be given.

By the end of the session, the students should be able:

• to name the main ingredients of a data assimilation system.

• to tell why physical parametrizations are needed in data assimilation.

• to identify the role of the adjoint code in 4D-Var.

• to recognize the importance of the regularization of the linearized code.

Philippe Lopez

Expand

title	Parameterization of Sub-grid Orography

On the basis of simple gravity wave theory, the concepts of sub-grib turbulent form drag, flow blocking, and gravity wave excitation will be introduced. The ECMWF formulations will be described, and the impact will be discussed.

By the end of the session students should be able to:

• Describe the relevant physical mechanisms related to sub-grid orography that have impact on flow in the atmosphere.

• Describe the impact of sub-grid orography.

Anton Beljaars

15.40

Expand

title	Clouds (1)

This session gives a brief overview of cloud parametrization issues and an understanding of the basic microphysics of liquid, ice and mixed phase cloud and precipitation processes.

By the end of the session you should be able to:

• recall the basic concepts for the design of a cloud parametrization

• describe the key microphysical processes in the atmosphere

• recognize the important microphysical processes that need to be parametrized in a global NWP model.

Richard Forbes

Radiation exercises

Alessio Bozzo and Robin Hogan

Land Surface exercises

Gianpaolo Balsamo and Souhail Boussetta

Boundary Layer & Cloud exercises

Irina Sandu, Maike Ahlgrimm and Richard Forbes

Moist Processes Exercises

Richard Forbes and Peter Bechtold

16.40

Expand

title	Boundary Layer (1)

This session gives a theoretical introduction of the planetary boundary layer, including its definition, classification, notions about turbulence within the boundary layer, differences between clear and cloudy boundary layers, and equations used to describe the mean state in a numerical model.

Expected outcomes:

• understand what is the boundary layer, its characteristics and why it is important to study it and represent it correctly in numerical models

• understand the difference between the various boundary layer types

Irina Sandu

Radiation exercises

Alessio Bozzo and Robin Hogan

Land Surface exercises

Gianpaolo Balsamo and Souhail Boussetta

Boundary Layer & Cloud exercises

Irina Sandu, Maike Ahlgrimm and Richard Forbes

Course wrap up and certificates

Introduction to the course

Expand

title	Predictability and ocean-atmosphere ensemble forecasting	Using stochastic physics to represent model error

After this lecture, students will be able to:

explain the physical and practical motivations for using stochastic physics in an ensemble forecast;
describe the two stochastic parameterization schemes used in the IFS ensemble, and their respective purposes;
be able to identify the improvement in forecasting skill from the inclusion of stochastic physics.

Multiexcerpt

MultiExcerptName	PRTT2018

Time:

Monday

Tuesday

Wednesday

Thursday

Friday

9.15-10.15

Expand

title	Initial Uncertainties (2)

The aim of this session is to introduce the ECMWF ensemble of data assimilation (EDA). The rationale and methodology of the EDA will be illustrated, and its use in to simulate initial uncertainties in the ECMWF ensemble prediction system (ENS) will be presented.

By the end of the session you should be able to:

know what is the ECMWF EDA
illustrate how the EDA is used to simulate initial uncertainty in ensemble prediction
understand the main differences between singular vectors and EDA-based perturbations

Simon Lang

Expand

title	Diagnostics (1)

Increasing observation volumes and model complexity, decreasing errors, and a growing desire for uncertainty information, all necessitate developments in our diagnostic tools. The aim of these lectures is to discuss some of these tools, the dynamical insight behind them, and the residual

deficiencies that they are highlighting.

By the end of the lectures you should be aware of:

Some of the key weakness of the ECMWF forecast system
Some of the diagnostic tools used to identify and understand these weaknesses

Mark Rodwell

Expand

title	Coupled ocean-atmosphere variability

This lecture provides a broad overview of the role of the ocean on the predictability and prediction of weather and climate. It introduces some basic phenomena needed to to understand the time scales and nature of the ocean-atmosphere coupling.

Magdalena Balmaseda

Expand

title	Stratospheric impacts

Andrew Charlton-Perez

10.45

Expand

title	Introduction to Chaos

The aim of this session is to introduce the idea of chaos. We will discuss the implications this has for numerical weather prediction.

By the end of the session you should be able to:

describe what limits the predictability of the atmosphere
understand the need for probabilistic forecasting

Antje Weisheimer

Expand

title	Ensemble verification (1)

Abstract: The lectures introduce methods of ensemble verification. They cover the verification of discrete forecasts (e.g. dry/wet) and continuous scalar forecasts (e.g. temperature). Various scores such as the Brier score and the continuous ranked probability score are introduced.

After the lectures you should be able to

explain what a reliable probabilistic forecast is and how to measure reliability
understand why resolution and sharpness of a probabilistic forecast matter
compute several of the standard verification metrics used for ensemble forecasts

Martin Leutbecher

Expand

title	Weather regimes

Franco Molteni

Expand

title	Air-sea interaction and the coupled model at ECMWF

This lecture provides a broad overview of the role of the ocean on the predictability and prediction of weather and climate. It introduces some basic phenomena needed to to understand the time scales and nature of the ocean-atmosphere coupling.

Kristian Mogensen

Expand

title	Initializaton techniques in coupled forecasting

Magdalena Balmaseda

11.55

Expand

title	Sources of uncertainty

The aim of this session is to introduce the main sources of uncertainty that lead to forecast errors. The weather prediction problem will be discussed, and stated it in terms of an appropriate probability density function (PDF). The concept of ensemble prediction based on a finite number of integration will be introduced, and the reason why it is to be the only feasible method to predict the PDF beyond the range of linear growth will be illustrated.

By the end of the session you should be able to:

explain which are the main sources of forecast error
illustrate why numerical prediction should be stated in probabilistic terms
describe the rationale behind ensemble prediction

Antje Weisheimer

Expand

title	Using stochastic physics to represent model error

After this lecture, students will be able to:

explain the physical and practical motivations for using stochastic physics in an ensemble forecast;
describe the two stochastic parameterization schemes used in the IFS ensemble, and their respective purposes;
be able to identify the improvement in forecasting skill from the inclusion of stochastic physics.

Sarah-Jane Lock

Expand

title	Clustering techniques and their applications

The aim of this session is to understand the ECMWF clustering products.

By the end of the session you should be able to:

explain how the cluster analysis works
use the ECMWF clustering products

Laura Ferranti

Expand

title	Coupled land-atmosphere variability

Land surface is a potential source of predictability of weather variability, such as warm or cold spells or precipitation. We will review the way land surface affects the atmospheric conditions, and the criteria that need to be fulfilled to contribute to predictability. A number of land-atmosphere coupling metrics are discussed, as well as a number of studies on the effect of realistic land surface initialization reported in literature.

Bart van den Hurk

Expand

title	The monthly forecast system at ECMWF

The aim of this session is to provide a general overview of monthly forecasting at ECMWF. We will review the main sources of predictability for the sub-seasonal time scale, including the Madden Julian Oscillation, sudden stratospheric warmings (SSWs), land initial conditions and their simulation by the coupled IFS-NEMO system. The skill of the ECMWF operational monthly forecasts

will also be discussed.

By the end of the session you should be able to:

List the different sources of predictability for extended-range forecasts
Describe the operational system used to produce the ECMWF monthly forecasts
Assess the skill of the monthly forecasting system

Frederic Vitart

14.15

Expand

title	Sources of predictability beyond the deterministic limit

The aim of this session is to understand how we are able to provide forecasts at long time horizons given the chaotic nature of the atmosphere.

After this session you should be able to:

describe the Lorenz idea of Predictability of the first and second kind
list examples of the elements of the Earth system that provide predictability on longer timescales
understand the type of forecast that we are able to provide beyond the deterministic limit

Franco Molteni

Expand

title	Post-processing of ensemble forecasts

This lecture gives an overview of ensemble and post-processing and calibration techniques. The presentation is made from the medium-range forecast perspective. The (relative) benefits of calibration and multi-model combination for medium-range forecasting are also discussed.

By the end of this lecture, you should be able to:

describe a wide range of possible calibration methods for ensemble systems
explain which methods are suitable in which circumstances
discuss the merits of calibration and multi-model combination

Tim Stockdale

Expand

title	Diagnostics (2)

Increasing observation volumes and model complexity, decreasing errors, and a growing desire for uncertainty information, all necessitate developments in our diagnostic tools. The aim of these lectures is to discuss some of these tools, the dynamical insight behind them, and the residual
deficiencies that they are highlighting.

By the end of the lectures you should be aware of:

Some of the key weakness of the ECMWF forecast system
Some of the diagnostic tools used to identify and understand these weaknesses

Mark Rodwell

Expand

title	Coupled ocean-atmosphere variability - MJO

Frederic Vitart

Expand

title	The seasonal forecast system at ECMWF

This lecture covers the essentials of building a numerical seasonal forecast system, as exemplified by the present prediction system at ECMWF.

By the end of this lecture, you should be able to:

explain the scientific basis of seasonal forecast systems
describe in outline ECMWF System 4 and its forecast performance
discuss the critical factors in further improving forecast systems

Tim Stockdale

15.40

Expand

title	Initial uncertainties in the medium-range ENS (2)

In this session the generation of the perturbed initial condition of the ECMWF ensemble will be presented. We will discuss the ratio behind using singular vectors in the ensemble and how they are calculated. Then it will be explained how the singular vectors are combined with perturbations from the ensemble of data assimilations to construct the perturbations for the ensemble.

By the end of the session you should be able to:

explain the idea behind using singular vectors in the ensemble
describe how singular vectors are calculated
describe the construction of the ensemble perturbations

SImon Lang

Expand

title	Ensemble verification (2)

Abstract: The lectures introduce methods of ensemble verification. They cover the verification of discrete forecasts (e.g. dry/wet) and continuous scalar forecasts (e.g. temperature). Various scores such as the Brier score and the continuous ranked probability score are introduced.

After the lectures you should be able to

explain what a reliable probabilistic forecast is and how to measure reliability
understand why resolution and sharpness of a probabilistic forecast matter
compute several of the standard verification metrics used for ensemble forecasts

Martin Leutbecher

Practical Session:

Expand

title	Lorenz '95 model

You get the opportunity to experiment yourself with an ensemble prediction system for a chaotic low-dimensional dynamical system introduced by Edward Lorenz in 1995. Experiments permit to study the role of the initial condition perturbations and the representation of model uncertainties. Various metrics introduced in the ensemble verification lectures will be applied in this session.

After the practice session, you will be able to use the toy model as an educational tool.

Martin Leutbecher

Practical Session:

Expand

title	Visualisation and Use of Ensembles - a real world example

During this session you will use metview to produce some standard ensemble visualisations such as:

stamp maps
spaghetti plumes
cluster analysis

This will be used in a real world situation to decide whether to run a flight campaign or not.

Glenn Carver, Sarah Keeley

Question and Answer Session

Course Wrap up

16.45-17.15

Lecture and Ice Breaker Game Session:

Expand

title	Application of ENS: Flood

Abstract: The lecture is a short introduction to operational hydrological ensemble prediction systems, with focus on flooding. The European Flood Awareness System (EFAS) is described. The lecture also contains a short interactive exercise in decision making under uncertainty using prbabilistic forecasts as an example.

By the end of the session you should be able to:

Describe the components in hydrological ensemble prediction systems (HEPS).
Describe the major sources of uncertainty in HEPS and how they can be reduced.
Explain the difficulties in using probabilistic flood forecasts in decision making.

Fredrik Wetterhall

5.15 ice breaker

Expand

title	Introduction to ensembles practical session

Glenn Carver

Practical extensionPractical extension

Space shortcuts

Page tree

Versions Compared

Old Version 31

New Version 32

Key