ECMWF, major forecasts update in 2023

Florence Rabier, Director General of ECMWF, has developed February the 13 th European Centre for Medium-Range Weather Forecast for 2023 (¹). She announced a major update to the forecasting model. IFS (²) scheduled for June 2023.

The year 2022 was a year of transition for ECMWF, with the installation of two new sites, in Bologna, Italy and Bonn, Germany, and with the migration of operations to the new high-performance computing center (³) in Bologna. That year, no IFS model upgrades have been performed, but the one scheduled for June of this year, Cycle 48r1 (⁴), has been prepared. This new cycle will be one of the highlights of the coming year and will contain many scientific improvements. Many of them are related to major improvements in ensemble forecasts., that depend on increased computing power. It will therefore be a major upgrade, that will benefit from the investment in IT by ECMWF and its Member States.

The 48r1 Cycle

The two main innovations will be a significant improvement in the resolution of global medium-range ensemble forecasts, which will increase from 18 km (0,16°) up to 9 km (0,08°), and more frequent wide-range forecasting with more ensemble components. The improvement in the medium-range means that there will be only one resolution up to 15 days, whereas currently there is only one high-resolution forecast at 9 km and an ensemble at 18 km.

Florence Rabier explains :

What matters more is the number of ensemble members. So, in the upgrade, We will increase it from 51 up to 101. We will also increase the frequency of extended-range forecasts, from twice a week to daily. The result is a big improvement in the quality of our ensemble forecasts in the medium range and the extended range. […] These include new models for ocean and sea ice, which need to be integrated into all our applications. ”

She adds :

We are also continuing to work on a different dynamical core, called the Finite-Volume Module (FVM), which may one day replace the current dynamical core of the IFS to achieve efficient higher-resolution global forecasts. ”

IT developments

We have just published our Software Strategy, which is the strategy for all of our code outside the IFS. Regarding the IFS, we are adapting our code to run some of it on GPUs (⁵). The Hybrid2024 project, for which we work very closely with Météo-France, aims to produce a version of the IFS model able to run on hybrid architectures, with a readiness date in 2024. Also, the European Weather Cloud, a cloud computing infrastructure which we have created together with EUMETSAT, will become operational. At the same time, C3S Climate Data Store will be turned into a joint C3S/CAMS Climate and Atmosphere Data Store. In parallel, we are a key partner in the EU's WEKEO platform for providing Copernicus atmosphere, to the climate, marine and land services. We are also going to develop a new data storage strategy, and we are holding the 20th workshop on HPC in meteorology in Bologna in October. ”

Open data

ECMWF will continue to open up its data by publishing more fields. A wide range of data has already been made available to the public.

Since July 2022, the data that has become available is based on a variety of high-resolution forecasts (HRES – horizontal resolution of 9 km) and ensemble forecasts (ENS – horizontal resolution of 18 km). They have also been available to application developers for a few months at a resolution of 0,4 degrees in GRIB-2 format.

Florence Rabier concludes :

2023 is the year we reap the benefits of our new setup as a multi-site organisation. It is also a year when we use our new computing infrastructure and capability to improve our numerical weather prediction for delivering the best possible forecasts to our Member States. Finally, but not least, it's a year where we focus on science going forward, with an open mind towards disruptive technologies. ”

Much more work is underway at ECMWF, that interested people can find in the complete document of Florence Rabier’s interview. (¹).

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(¹) Updating forecasts is at the heart of our plans to 2023
(²) Integrated Forecasting System
(³) HPCF = High-Performance Computing Facility
(⁴) The global Earth system model developed at ECMWF forms the basis for all data assimilation and forecasting activities. All the main applications required are available through an integrated IT system (a set of computer programs written in Fortran) called the Integrated Forecasting System or IFS. The IFS undergoes regular changes to improve forecasting. Changes are listed with an identifier, Cycle 32R1 (CY32R1) in example, or a specific title when the cycle number has not changed.
(⁵) Graphic Processing Unit = Graphic Processing Unit
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