This project will quantify whether routine military chaff releases influence thunderstorm electrification and lightning behavior at Department of War (DoW) installations. Chaff, fiberglass strands coated in aluminum used as a radar countermeasure, can remain suspended in the atmosphere for hours after release. Decades of research demonstrated that chaff could suppress lightning when ingested into storm updrafts, yet the potential effects of routine chaff releases on regional lightning patterns remain unknown and largely unexamined. By conducting a seven-year reanalysis of existing weather radar, satellite, and lightning detection data combined with microscale electromagnetic modeling, this work will determine whether chaff creates measurable atmospheric feed backs that affect installation operations, safety, and ecosystems. Results will provide the scientific basis needed to incorporate atmospheric impacts into installation planning and airspace management decisions.

The project will be comprised of measurement and modeling components, with a primary focus on a seven-year reanalysis of existing chaff and thunderstorm measurements spanning the full contiguous U.S. The project team will exploit open-access archives of next-generation weather surveillance radar (NEXRAD) and satellite-borne Geostationary Lightning Mapper (GLM) observations, as well as archived measurements from the U.S. National Lightning Detection Network (NLDN). In combination, these three observation systems provide complementary spatial information detailing meso/microscale storm structural characteristics (via NEXRAD) and accompanying lightning flash activity (via GLM and NLDN) to quantify a storm’s electrical attributes. Furthermore, the project team will leverage a chaff detection algorithm that has been recently developed for NEXRAD radar to identify and track chaff plumes originating from routine DoW activities. Conceptually, this analysis approach on historical measurements can be viewed as a retrospective clinical trial in which storms that develop in the presence of chaff plumes are analogous to individuals who have received a treatment that is under evaluation.

Following the analogy of a clinical trial, the project team will test to see if the treatment (chaff exposure) has a statistical effect on a storm’s lightning flash frequency and count when compared to the control (storms with no chaff exposure). This analysis technique will be supplemented by a microscale modeling study on the theoretical effect of chaff on atmospheric electricity. The project team will use an existing electromagnetic modeling framework to investigate how the shape, size, and distribution of chaff particles affect small-scale electrical fields. A second modeling study will quantify the fall rate and dispersal pattern of chaff particles within the atmospheric boundary layer. Chaff fallout estimates will be validated using wind measurements from the Army Research Laboratory’s Meteorological Sensor Array during routine chaff releases over White Sands Missile Range in south-central New Mexico.

This project will provide DoW decision-makers with the first empirical assessment of whether chaff use influences mesoscale and microscale weather dynamics in ways that could affect mission execution, infrastructure, or safety. By clarifying potential links between chaff releases and lightning behavior, the research will reduce uncertainty around an overlooked interaction between training activities and the atmospheric environment. The resulting insights will enable installation managers to evaluate tradeoffs between training requirements and unintended meteorological impacts, supporting more informed decisions about the timing, location, and frequency of chaff use. This includes the potential to reduce risks to personnel, infrastructure, and ecosystems from altered lightning patterns or localized weather effects. (Anticipated Project Completion - 2026)