ECMWF/EUMETSAT NWP SAF Workshop on the treatment of random and systematic errors in satellite data assimilation for NWP

ECMWF | Reading | 2-5 November 2020

#NWPSAF2019

Workshop description

Dealing with random and systematic errors in observations and models is at the heart of satellite data assimilation for Numerical Weather Prediction (NWP). This invitation-only workshop will capture recent progress and the state of the art in this area, identify key issues and limitations, and discuss avenues for further developments. It is organised in collaboration with the EUMETSAT NWP SAF.

The workshop will cover the following main themes:

1) Estimating uncertainties

Knowledge about observational and model errors and uncertainties informs our treatment of these in the assimilation. This theme covers recent activities ranging from thorough characterisation of satellite instruments, better estimation and modelling of other error contributions (such as radiative transfer/observation operator errors or other representation errors), the use of reference observations, to advances in diagnostic methods.

2) Correction of observational and model biases in data assimilation

Correction of observational biases is essential for the successful assimilation of many satellite observations. Adaptive bias correction methods are now commonly used, but separation of observation and forecast model biases continues to be challenging. This is particularly true in our present era with an ever increasing number of observations needing bias correction, but also in systems with highly variable observational coverage such as reanalysis. In addition, estimation of model bias during the assimilation is also becoming a reality, further probing our ability to separate different sources of errors and biases. This theme covers practical experiences with these issues, including approaches to introduce further prior knowledge to constrain or aid the separation of different sources of bias.

3) Representing observation errors in data assimilation

The description of the random component of observation error is key to optimising the impact of any observation, and this area has seen considerable progress in recent years. Many satellite observations are strongly affected by representation error, and this is often situation-dependent and correlated between different observations. This is now increasingly taken explicitly into account, with the treatment of inter-channel error correlations for satellite radiances, for instance, becoming wide-spread. The treatment of spatially and temporally correlated observation errors is also emerging. This poses questions not only in terms of how to estimate and specify such correlations, but also how to account for them in a computationally affordable way. This theme covers recent advances in the more complete specification of observation errors, including technical as well as conceptual challenges.

While the primary application focus of the workshop will be Numerical Weather Prediction (NWP), the way in which these issues impact climate re-analyses based on NWP systems will also be examined.

Workshop aims

The aim of this workshop is to capture the state of the art in the treatment of random and systematic errors in satellite data assimilation for NWP, to identify key issues and limitations, and to identify avenues for further progress. Recent developments and open issues will be covered through oral and poster presentations, and targeted working groups will be established to identify and recommend future research needs. The output will be in the form of working group reports, identifying key recommendations for NWP centres.

Timetable

The workshop will start at 14:00 GMT on 2 November 2020 and finish at 16:00 GMT on 5 November 2020.

Attendance

This is an invitation-only workshop. If you have not been invited yet and would like to be considered for an invitation, please contact us.

Oral and poster presentations

We will individually invite speakers during the first half of 2020 to give one of a limited number of oral presentations. Nearer the time, these speakers will be asked to provide an abstract, and other invitees will be able to propose poster abstracts. Since this is a workshop, attendance that contributes only to the working groups and discussions is also welcome.

Timeline

30 June 2020 - Draft programme, call for poster abstracts

30 September 2020 - Registration closes

2-5 November 2020 - Workshop

Organising committee

Niels Bormann
William Bell
Patrick Laloyaux

Scientific organising committee

Massimo Bonavita (ECMWF)
Mark Buehner (ECCC)
Sarah Dance (Uni Reading)
John Eyre (Met Office)
Daryl Kleist (NOAA)
Tony McNally (ECMWF)
Paul Poli (EUMETSAT)
Anthony Weaver (CERFACS)
Peter Weston (ECMWF)