EUMETSAT at 40: Turning satellite data into time-critical warnings
An interview with Sarah Jones, President of the Deutscher Wetterdienst (DWD), on four decades of partnership and what EUMETSAT’s new generation satellites will bring.
How does DWD build a severe weather warning, and where do EUMETSAT satellite data come in?
Taking a recent example: on 28 August, following hot, dry conditions, a severe convective system developed and a line of severe thunderstorms travelled across Germany overnight. With an event like that, we move through a warning chain, from initial awareness a few days ahead to very specific warnings and guidance when it hits.
In the early stages we rely on our numerical weather prediction models to tell us whether conditions are likely to be favourable for severe thunderstorms, heavy rainfall or damaging winds. EUMETSAT satellite data are really essential for the accuracy of these predictions: about four-fifths of the observations in our global prediction model come from satellites, most of them from EUMETSAT instruments or through EUMETSAT's data exchange, and it is almost impossible to envisage how we would make those predictions without them.
As we get closer to the storms hitting, our predictions get more detailed, indicating which regions are likely to be threatened and how intense the systems might be. Here, direct observations become increasingly important: radar, surface and aircraft observations and satellite data together give us a picture of what is actually happening.
The continuous coverage over Europe from Meteosat satellites lets us see cloud systems develop and move, and we are very excited about the new generation, Meteosat Third Generation, because it lets us observe rapidly developing convection in much greater detail. It's a bit like watching a detailed film of how the convective systems then develop.
For the next hour or few hours we rely on nowcasting, which takes what the radar and satellites are seeing now and extrapolates where the storms will be.
Traditionally nowcasting and numerical modelling were done by separate groups; we have been bringing them together in a new integrated system. This combines ensembles of both into a single probabilistic forecast, from minutes up to around 12 hours ahead, so that we can say not just that there may be severe weather, but where it's most likely to develop, how likely it is to intensify and what the strongest impacts will be.
Just before an event hits, it's very much the judgement of our forecasters that plays a strong role, both in preparing and issuing the warnings and in directly advising emergency responders, the people who actually have to make decisions on the ground.
What have the new generation Meteosat and Metop satellites changed so far, and what are you most looking forward to?
I have been delighted to see the successful launches of the new generation satellites, the culmination of a huge amount of hard work and planning over many years.
I first started working at DWD in 2011, just as we had specified what these satellites needed to deliver, and it's quite a forecast to make to say what we would need in 2026. Thanks to the foresight between EUMETSAT and the national services in its Member States, the satellites are delivering what we need, which is something for us as a community to be proud of.
The new programmes bring higher spatial and temporal resolution, more variables and many new ways to use them.
On Meteosat Third Generation, the Lightning Imager complements ground-based lightning detection, especially over the ocean and for cloud-to-cloud lightning that's hard to detect from the surface. The Flexible Combined Imager is already improving our global forecasts with extra information on water vapour and cloud, and will continue climate records that have been building for more than 40 years.
And we are very, very keen on the infrared sounding data from the MTG Sounder 1 satellite, which will give us observations of temperature and humidity through the full daily cycle, with specific benefits for the high-resolution regional modelling behind our national forecasts and warnings.
The same is true of the polar-orbiting Metop Second Generation satellites, which continue the core observations we rely on for numerical weather prediction, combined with better accuracy and a whole range of new instruments.
To give just two examples, we are really excited about the microwave imager data, which will improve our observations of ice clouds, important for climate modelling and for observing the upper troposphere, which will help improve aviation safety. New aerosol data on aspects such as atmospheric dust from Metop Second Generation's multi-viewing imager will also be very important for the renewable energy sector, helping to make operational dust forecasts and predicting the impact of dust clouds on the solar radiation available for solar power.
Another component that will have huge benefits for weather prediction is EPS-Sterna, a constellation of small satellites that will measure temperature and humidity through the atmosphere more frequently. There's always a lot of work involved in getting observations into models, and we are already preparing for EPS-Sterna data ahead of the first launches in 2029.
Europe has had a succession of heatwaves this year, with national records broken in several countries. What has the summer been like for you and your teams?
It's been a very challenging period, with repeated spells of extreme heat and very dry conditions across the country, and I would like to thank all the people at DWD who have been working during this time to provide the information that's needed to decision makers and the general public.
Extreme heat is a serious risk to health, and during such events there's a high demand for information from the national weather services, especially when many people have not experienced such extremes before, or are not used to dealing with extreme heat over longer periods.
Our Naturgefahrenportal, the national natural hazards portal, and our WarnWetter app both include heatwave warnings with specific information on potential health impacts. In an extended period of very hot weather, our agricultural advisory services, such as soil moisture information, are also particularly important, as are the warning indices we develop together with the federal states for grassland and forest fire risk.
"Satellite observations feed into all of these products, from the cloud and solar radiation information behind the soil moisture and fire risk indices to the observations we use to monitor heat over cities. This really helps support emergency response teams and authorities at every level, helping people assess their risks, prepare and respond effectively."
Extended heat with lower-than-average rainfall leads to very dry conditions that can be interrupted by extreme thunderstorms, bringing localized, very severe rainfall. Authorities increasingly need to balance the multi-hazard challenges of dealing with the heat and the potential for flash flooding at the same time, with more heatwaves, more unevenly distributed rainfall and more extreme weather events becoming a ‘new normal’.
It's really important to recognize the need for commitment to climate change mitigation, and to build long-term resilience to such extreme events. Our role is to support that with scientifically based data and expertise. Standing still is really not an option.
How have events such as the catastrophic Ahr Valley floods of July 2021 shaped the way DWD gets information to people?
What we provide as the German Weather Service, the meteorological and climatological information and the warnings of an approaching severe weather event, is not the end of the process but really the beginning of a chain of actors and activities that then need to lead to informed action.
How has the relationship between EUMETSAT and DWD developed during the past 40 years?
Looking back at how DWD used satellite observations when EUMETSAT first launched, it was really about receiving the observations from EUMETSAT and applying them directly in our own weather predictions and warning systems. Over time, a much deeper operational partnership has evolved. A colleague of mine summed this up:
"EUMETSAT provides the European eyes in space, and we integrate those observations with many other sources so we can deliver forecasts, warnings and climate services for Germany."
We work together at various levels: scientific, technical, operational and also at the level of management and governance. Because so much of the data we use comes from satellites, a lot of our experts are actively engaged in EUMETSAT's technical and scientific working groups, to ensure we use the information efficiently and to give input into planning future satellite generations that reflects the needs of organizations in Germany.
We also work together in the generation and distribution of products through the Satellite Application Facilities (SAFs), which provide a crucial link between the operational satellites and how those data are actually used. SAFs provide both the brainpower and the knowledge of users' needs to translate the data the satellites are producing into products and services.
DWD is the lead centre of the Satellite Application Facility for Climate Monitoring (CM SAF), working with European partners to provide long-term information on climate and climate change, and a contributing partner in the SAFs for numerical weather prediction and atmospheric composition monitoring.
It is great to have the EUMETSAT conference in this 40th anniversary year in Darmstadt, the home of EUMETSAT and a very important centre in Europe for meteorological and satellite expertise. It is a fantastic platform for exchange between the international satellite community, meteorological services, researchers and users of satellite data such as forecasters and emergency responders.
I think it also really highlights the relationship between EUMETSAT and national meteorological services, which is really a European success story: EUMETSAT provides common infrastructure, technological innovations and long-term continuity that no individual country could support on its own.
Such a severe flooding event is a very interdisciplinary process: it goes from the meteorology through to the hydrology and the flood forecasts, into the decision-making processes and communication. A key lesson learned from the Ahr Valley flooding was the need to strengthen the transport of actionable information.
After the event, there were a lot of meetings and discussions between all the players along this decision-making chain, and one of the actions we agreed together was to develop the Naturgefahrenportal as a central access point for information on natural hazards. It brings together warnings with information about risk and the steps people can take to protect themselves, both ahead of an event and during one.
One of the focus points of the EUMETSAT conference is the Early Career Scientists Initiative: What is your advice for young people wanting to get into meteorology?
It's a really exciting area to work in, and there's a big spectrum of possibilities, from working on new satellite programmes at EUMETSAT to working on weather prediction and climate change at a national weather service.
It's a very interdisciplinary field, where you can bring an aptitude for natural science, computing, mathematics, engineering and combine that with doing something that is really relevant and needed in our society.
What inspired you to become a researcher and what do you regard as the most important steps along the way?
I started sailing as a kid, and my motivation to work in meteorology stems from wanting to understand how the weather works and connect that to something useful for everyday life. I enjoyed science and maths at school, did a bachelor's in physics in the UK and moved into meteorology.
A postdoctoral position took me to the University of Munich to research tropical cyclones and that led naturally to the Deutscher Wetterdienst, where I managed the research there for a number of years before moving into my current position. It has been more of a journey than a single moment: you take opportunities, you take new steps, you increase your skill set, and it has been a real privilege.
It is exciting and rewarding to have responsibility for an organisation of which I am immensely proud, and to work with partners such as EUMETSAT so that, as a community, we deliver what societies need. The challenge is making sure it all fits together, from the advances of science and technology through to the daily business of forecasts and warnings.
"The international collaboration that EUMETSAT exemplifies is a very personal commitment for me too and it has been a privilege to follow this path and be amongst the community I work in."