Aviation Research Aircraft Halo Measures the Dynamics of Weather Systems Using Lidar Remote Sensing Technology

To better understand weather phenomena that lead to extreme weather events, particularly in winter, the research aircraft Halo is being used as part of the NAWDIC measurement campaign. Using lidar measuring instruments from DLR, it studies the dynamics of weather systems over the North Atlantic.

At the beginning of January, storm depression Elli swept through Germany, causing significant traffic chaos with heavy snowfall and icy conditions in certain parts as well as in  Hamburg and Bremen. However, Elli was not an extraordinary event—strong winds, heavy precipitation, and sudden cold spells characterize winters in Europe. Many of these extreme weather events are associated with low-pressure systems that form over the North Atlantic. When these systems move toward Germany, as with Elli, they can lead to train cancellations, road chaos, and school closures. In extreme cases, lives can be at risk, and damages worth millions can occur.

Many of the physical processes that lead to extreme weather in Europe occur over the Atlantic, a region that is inadequately covered by conventional measurements and thus difficult to study scientifically. This is precisely where the international measurement campaign “North Atlantic Waveguide, Dry Intrusion, and Downstream Impact Campaign” (NAWDIC) comes into play, starting on January 13, 2026. Over six weeks, the data situation in the North Atlantic is to be improved through detailed aircraft- and ground-based observations. A key role in this endeavor is played by the research aircraft Halo, operated by the German Aerospace Center (DLR).

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Investigation of insufficiently understood processes

A scientific focus of the investigations is on dry intrusions. These are dry, cool air masses that descend from the high altitude of the stratosphere into the troposphere, thereby influencing the weather. Especially in winter, they can lead to strong winds, turbulence, and intense precipitation. Many of these atmospheric processes are still insufficiently represented in current forecasting models. "Within NAWDIC, we aim to study processes that are not yet adequately understood but cause winter extreme weather events with significant impacts on society and the economy in Europe. We are combining innovative measurement methods with the unique capabilities of the research aircraft Halo," explains Dr. Andreas Schäfler from the DLR Institute of Atmospheric Physics, who is also co-responsible for coordinating the Halo flights within NAWDIC. The goal is to use the measurements to better understand the dynamics in the North Atlantic atmosphere so that forecasts can become more reliable and timely in the future.

Capture vertical profiles between the aircraft and the Earth's surface

The research aircraft is equipped for NAWDIC with Lidar remote sensing technology from the DLR Institute of Atmospheric Physics to capture continuous vertical profiles of wind, ozone, and humidity between the aircraft and the Earth's surface. It operates at flight altitudes of up to 14 kilometers (approx. 9 miles). Onboard are the water vapor Lidar Wales and the wind Lidar Hedwig, used on Halo for the first time. "By deploying these DLR-developed laser remote sensing instruments in remote regions with low observation density, we not only demonstrate the value of Lidar technology in complementing the global observation system but also its suitability for future satellite-based Lidar instruments," emphasizes Dr. Andreas Fix from the DLR Institute of Atmospheric Physics. For the duration of the project, Halo will be stationed at Shannon Airport in Ireland. From there, it can cover a wide area of the North Atlantic, allowing extensive documentation of water vapor transport and interactions between the atmosphere and ocean.

High planning effort

From an operational flight perspective, the measurement flights over the North Atlantic pose increased demands on planning and execution. The airspace is characterized by transatlantic traffic structures, the NAT-Tracks, which are redefined daily, as well as additional traffic outside these routes, and it lacks continuous radar coverage. The DLR Flight Experiments Facility is therefore responsible for close coordination with the relevant air traffic control centers even in advance. During the flights, the pilots ensure the safe and compliant integration of the research missions into air traffic through predominantly data-based communication.

The aircraft measurements are complemented by ground-based observations using KITcube, the mobile atmospheric observation system of KIT. It has been stationed in Brittany, France, since November 2025. It consists of a network of remote sensing instruments capable of capturing atmospheric processes from a few meters up to ten kilometers (approx. 6 miles) in altitude.

Successful interaction of various measurement campaigns

As part of NAWDIC, more than 100 scientists will be involved in the coming weeks to plan and conduct flights from Ireland, manage measuring instruments, and coordinate activities with partners.

Through long-term planning over the past six years in coordination with the World Meteorological Organization (WMO), it was possible to link NAWDIC with additional meteorological measurement campaigns in North America, which observe weather developments upstream. In January and February 2026, up to ten research aircraft, including Halo, will be deployed simultaneously from the Pacific to Europe. (se)

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