North Atlantic Waveguide, Dry Intrusion, and Downstream Impact Campaign

• Applicant: Dr. Annika Oertel, since 10/2025
• Subject Area: Atmospheric Science
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 552644175

Accurately forecasting the location, timing, and intensity of mesoscale high impact weather (HIW) events remains a challenge for state-of-the-art numerical weather prediction systems. This is to a large degree due to the cross-scale interactions of physical processes involved in the formation of HIW. These interactions span from near hemispheric-scale Rossby waves with durations of several days to weeks, to momentum transport impacting the planetary boundary layer (PBL), and cloud microphysical processes operating on scales ranging from hundreds of meters to micrometers, with timescales varying from minutes to seconds. To advance our understanding of the synoptic- to micro-scale dynamical and physical processes associated with the triggering of severe wind gusts, heavy precipitation, and cold air outbreaks in the North Atlantic-European region and their representation in NWP models is the overarching goal of the international “North Atlantic Waveguide, Dry Intrusion, and Downstream Impact Campaign” (NAWDIC; https://nawdic.kit.edu) in winter 2025/2026. NAWDIC will specifically focus on the cross-scale dry intrusion (DI) air stream which connects upper-tropospheric Rossby waves to HIW at the surface in a Lagrangian sense. To cover the various scales involved, the international NAWDIC community will deploy airborne and ground-based remote sensing measurement systems. The core element of NAWDIC is the German NAWDIC-HALO component, which will focus on two regions of the DI air stream. First, HALO will sample the structure of the upper troposphere and lower stratosphere in the DI inflow region, which affects the formation of the DI itself and the development downstream. Second, HALO will document the meso-scale processes at the DI outflow-PBL and DI outflow-cold front interfaces which are directly linked to HIW and precondition the atmosphere for subsequent cyclone development. The NAWDIC-HALO consortium, which submits this proposal, consists of several institutions working on topics of mid-latitude atmospheric dynamics. It is led by the Institute of Meteorology and Climate Research, Troposphere Research (IMKTRO) of the Karlsruhe Institute of Technology (KIT), and further consists of the University of Mainz, Ludwig-Maximilians-University of Munich and DLR’s (German Aerospace Center) Institute of Atmospheric Physics. It thus brings together scientists who have already collaborated successfully in the “North Atlantic Waveguide and Downstream Impact Experiment” (NAWDEX, 2016, http://nawdex.ethz.ch/) and the former DFG Transregional Collaborative Research Center (CRC) “Waves to Weather” (SFB/TRR165, 2015-2024, https://www.wavestoweather.de/). At an international level, NAWDIC has matured over the past five years into a large pan-Atlantic consortium with scientific partners from 10 countries involving universities, research institutions and weather services. NAWDIC is endorsed by WMO's World Weather Research Programme.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1294: Atmospheric and Earth System Research with the "High Altitude and Long Range Research Aircraft" (HALO)
• Co-Investigator: Dr. Andreas Schäfler
• Ehemaliger Antragsteller: Professor Dr. Julian Quinting, until 9/2025