Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Atmospheric Muon Measurements Near Tornadic and Non-Tornadic Storms in the US Central Plains

William Luszczak, Jana Houser, Matt Kauer, Leigh Orf

TL;DR

This study investigates whether atmospheric muons can image density perturbations inside and around tornadic and non-tornadic storms. Using a mobile, bidirectional muon detector (≈1 m^2 effective area) deployed near several storms in the US Central Plains, the authors compare muon flux from directions toward and away from storm systems to infer density changes via muography concepts. Results show a ~0.5% muon excess near a forming tornado (p ≈ 0.023) and a highly significant muon deficit near a non-tornadic line (p ≈ 3.6e-6), corresponding to low-density and high-density perturbations, respectively, with inferred density changes in the ranges of roughly 1.5–11% for tornadic cases and 3–11.5% for non-tornadic lines. The work demonstrates logistical feasibility and lays the groundwork for larger, tracking detectors and electric-field measurements to robustly map storm-density structures and advance understanding of tornadogenesis, while highlighting systematic uncertainties and the need for improved instrumentation.

Abstract

Tornadoes and other severe weather hazards affect thousands of people every year. Despite this, the details surrounding tornadic processes including formation, decay, and longevity are not well understood, partially due to limitations of available instrumentation. Measurements of atmospheric pressure within tornadic systems currently rely almost entirely on in-situ instrumentation, and no existing techniques can provide two-dimensional spatial information of the atmospheric density field. Atmospheric muons may hold a solution to this problem: muons are attenuated by matter, and tornadic storms are large regions of low atmospheric density, suggesting that tornadic storms induce a directional perturbation on the atmospheric muon flux. Measurements of this perturbation could then be used to infer the density field associated with severe weather. Simulations of these systems indicate that a robust measurement of the atmospheric density field would require a relatively large muon detector, however smaller detectors may be able to detect ambient muon flux perturbations if the storm is large and intense enough. This paper presents results from a pilot field study that measured the atmospheric muon flux near tornadic storms during May 2025, including directional measurements of the muon flux near tornadic mesocyclones and a measurement of the muon flux near the base of a forming tornado.

Atmospheric Muon Measurements Near Tornadic and Non-Tornadic Storms in the US Central Plains

TL;DR

This study investigates whether atmospheric muons can image density perturbations inside and around tornadic and non-tornadic storms. Using a mobile, bidirectional muon detector (≈1 m^2 effective area) deployed near several storms in the US Central Plains, the authors compare muon flux from directions toward and away from storm systems to infer density changes via muography concepts. Results show a ~0.5% muon excess near a forming tornado (p ≈ 0.023) and a highly significant muon deficit near a non-tornadic line (p ≈ 3.6e-6), corresponding to low-density and high-density perturbations, respectively, with inferred density changes in the ranges of roughly 1.5–11% for tornadic cases and 3–11.5% for non-tornadic lines. The work demonstrates logistical feasibility and lays the groundwork for larger, tracking detectors and electric-field measurements to robustly map storm-density structures and advance understanding of tornadogenesis, while highlighting systematic uncertainties and the need for improved instrumentation.

Abstract

Tornadoes and other severe weather hazards affect thousands of people every year. Despite this, the details surrounding tornadic processes including formation, decay, and longevity are not well understood, partially due to limitations of available instrumentation. Measurements of atmospheric pressure within tornadic systems currently rely almost entirely on in-situ instrumentation, and no existing techniques can provide two-dimensional spatial information of the atmospheric density field. Atmospheric muons may hold a solution to this problem: muons are attenuated by matter, and tornadic storms are large regions of low atmospheric density, suggesting that tornadic storms induce a directional perturbation on the atmospheric muon flux. Measurements of this perturbation could then be used to infer the density field associated with severe weather. Simulations of these systems indicate that a robust measurement of the atmospheric density field would require a relatively large muon detector, however smaller detectors may be able to detect ambient muon flux perturbations if the storm is large and intense enough. This paper presents results from a pilot field study that measured the atmospheric muon flux near tornadic storms during May 2025, including directional measurements of the muon flux near tornadic mesocyclones and a measurement of the muon flux near the base of a forming tornado.
Paper Structure (18 sections, 2 equations, 10 figures, 2 tables)

This paper contains 18 sections, 2 equations, 10 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Mesocyclones and Tornadoes
  3. Cosmic Rays and Atmospheric Muons
  4. Atmospheric Density Measurement with Atmospheric Muons
  5. Instrument Description
  6. Overview
  7. Observations
  8. Tornado near Blodgett, MO (5/16/25, 3:44 CDT)
  9. Meteorological State
  10. Muon Observations
  11. Mesocyclone near MO 301 (5/16/25, 4:52 CDT)
  12. Meteorological State
  13. Muon Observations
  14. Non-Tornadic Line of Storms near Gideon MO (5/16/25, 8:04 CDT)
  15. Meteorological State
  16. ...and 3 more sections

Figures (10)

  • Figure 1: Top: A cartoon showing the ideal setup for this study. A muon detector is placed some distance away from a mesocyclone of interest, and the atmospheric muon flux from that direction is measured. The muon flux from the opposite direction (ideally without any severe weather) can then be used as a control measurement. Bottom: An alternative setup in which the muon detector is placed close to the severe weather system of interest. In contrast with the ideal setup, this setup boasts improved sensitivity to local density perturbations, however separate control measurements must be obtained after the detector has been moved away from the severe weather system.
  • Figure 2: Photos of the muon detector used in this project, showing the three detection planes (denoted A, B, and C) mounted into a triangular configuration (top). Muon direction can be roughly reconstructed by examining coincidences between pairs of panels. A coincident detection between A and C corresponds to a muon originating from the left in the figure, and a coincidence between B and C corresponds to a muon originating from the right. Coincidences between A and B are not recorded.The entire device was mounted on a trailer and covered with protective plywood (bottom).
  • Figure 3: Calibration measurements used to account for detector roll angle when observing storms. "Chan 11" corresponds to the rate observed by the pair of panels B and C, while "Chan 13" corresponds to the rate observed by the pair of panels A and C.
  • Figure 4: Storm reports from the NOAA Storm Prediction Center for 5/15/25, when the muon detector was located in SE Missouri. The area of muon deployments is circled in orange and pointed to with the arrow.
  • Figure 5: Multi-panel radar imagery from the 3 storm deployments on 5/16/25. Images in the left column are radar reflectivity factor (precipitation distribution and intensity, reds = heavy, blue = light); Right column images are radial velocity (kts) indicating motion towards (green, blue, purple) the radar and away (yellow, pink). The pink pixels in the top images are aliased velocities. These were not corrected because the automatic unfolding algorithm deleted relevant data when dealiasing was applied. The black stars indicate muon detector locations. Scale is equivalent in all 3 images. The circles in the top image indicate the location of the developing tornado .
  • ...and 5 more figures