Everyone knows this situation with a weather forecast, when the presenter reveals a new Icelandic low on the map. Very soon, they are then often told, the trough of low pressure will reach the mainland and determine the weather for many days in Europe. Small errors often lead to the forecast in Europe being very uncertain for several days, because the system develops vigorously in the 'weather kitchen' over the Atlantic, and that is difficult to capture in weather models. Under the leadership of the Ludwig-Maximilians-Universität (LMU) in Munich and the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), research flights are expected to provide high-resolution data to shed more light on the weather patterns in the remote North Atlantic that are so crucial for Europe. There is even a live data transfer to worldwide meteorological services.
A flapping wing over the coast of Greenland
"The flutter of a butterfly's wing can theoretically affect the weather on the other side of the world, yet most other species can fly without having any effect on the weather," says George Craig of LMU, who heads the international North Atlantic Waveguide and Downstream impact Experiment (NAWDEX) research project. "There are particularly active areas in weather systems, to which the forecasts react sensitively." Europe's weather patterns in the forecast period of up to 14 days depend very strongly on remote regions over the Atlantic Ocean. There are large flows of rapidly ascending hot air there that divert the major wind currents and make their effects felt thousands of kilometres away on the European continent. "The determining factor is the heat of condensation in the clouds, which drives strong winds," continues Craig. "This process is poorly understood and inadequately considered in current weather models."
Hunting for weather systems with HALO and Falcon
With the High Altitude and Long Range (HALO) and Falcon research aircraft, the researchers are flying from 19 September to 16 October to collect high-resolution data on temperature, wind conditions and cloud properties in these weather systems. "To do this, we scan with radar, laser-technology-based LIDAR instruments and measurement probes from a range of 14.5 kilometres altitude down to the surface," explains Andreas Schäfler from the DLR Institute of Atmospheric Physics, who is coordinating the NAWDEX project. "Our two research aircraft act as spatially separated observers, which enables a thorough observation of wind and clouds in regions where few measurements are otherwise available."
Live data for weather forecasting
The measurement probes launched from the HALO research aircraft fall, slowed by small parachutes, to the surface and send their data directly to the aircraft. "In the aircraft, we have built a real-time data link to various meteorological services, so that the readings obtained are incorporated directly into the forecasts," explains Schäfler. "This enables us to find out what influence our measurements have on the forecasts, in particular those for 'high impact' weather events with a large damage potential." During the mission, the German Meteorological Service (Deutscher Wetterdienst; DWD) is also feeding the researchers' data into its forecasts.
Away from normal flight routes
The research mission is based at Keflavik International Airport in Iceland. From there, the scientists can easily reach the weather event areas. "Our research flight planning, of course, depends very much on the regular routes across the Atlantic Ocean," says DLR research pilot Roland Welser. "The planning is easier to perform when the research flights take place in the regions around Iceland. It is more difficult if we operate along the regular Atlantic flight routes and have to fly under or over the commercial aircraft." The HALO research aircraft operated by DLR also has a very long range, which makes the very remote and, until now, almost unreachable regions over the central and eastern Atlantic accessible to the scientists.
Better simulation of the 'weather kitchen'
Together with a number of other measurements from international partners, an unprecedented view is arising of how the weather systems over the North Atlantic develop – a step towards gaining more knowledge that will further improve computer simulations. The detailed data analysis is conducted as part of a large international scientific consortium, the Waves to Weather (W2W) research initiative. "Current weather research in the North Atlantic will make a significant contribution to the World Meteorological Organization's High Impact Weather (HIWeather) project, which has set itself the goal of improving societal, economic and environmental responses to the major damage potentially caused by high impact weather conditions," says George Craig, who is also the spokesperson for the research initiative.
NAWDEX – an international research programme
In total, more than 30 international scientific partners are involved in the NAWDEX project. The measurement programme with the HALO and Falcon research aircraft is a joint project of the DLR Institute of Atmospheric Physics, LMU, the Max Planck Institute for Meteorology in Hamburg and the Universities of Cologne, Hamburg and Leipzig, as well as ETH Zurich. NAWDEX and W2W are research initiatives supported by funding from the German Research Foundation (Deutsche Forschungsgemeinschaft; DFG).
About HALO and Falcon
The HALO research aircraft is a joint initiative involving German environmental and climate research institutions. HALO is supported by grants from the German Federal Ministry for Education and Research (BMBF), DFG, the Helmholtz Association, the Max Planck Society (MPG), the Leibniz Association, the Free State of Bavaria, the Karlsruhe Institute of Technology (KIT), the German Research Centre for Geosciences in Potsdam (GFZ), the Jülich Research Centre and DLR.
The DLR Falcon research aircraft has already been in use for 40 years of atmospheric research.