An Eclipse-Ballooning Study of Shadow Bands During the April 2024 Total Eclipse

TL;DR

This study used high-altitude balloons and aircraft to investigate shadow bands during the April 2024 solar eclipse, aiming to determine their origin and improve understanding of their atmospheric or diffraction-based nature.

Contribution

It deployed advanced sensors on balloons and aircraft to test theories about shadow band origins, providing new observational data during a major eclipse.

Findings

No shadow bands detected above the planetary boundary layer in Texas or Vermont

Cloud cover limited ground-based measurements and conclusions

Results suggest shadow bands may be linked to atmospheric turbulence or may not always be present

Abstract

In this study we searched for shadow bands associated with the total solar eclipse of April 8, 2024. Our aim was to improve our understanding of their origin. Shadow bands are debated to arise either from atmospheric turbulence within Earth's planetary boundary layer (PBL) or from a diffraction-interference effect occurring above the atmosphere. To test these theories, high altitude balloons (HABs) equipped with light sensors, similar ground light sensors, radiosondes launched with weather balloons, and an aircraft-mounted light sensor were deployed. Our team was located in Concan, TX, except for the plane which flew to NE Vermont to find clear weather. Unlike Pitt's 2017 HAB study, which detected a 4.5 Hz signal attributed to shadow bands above the PBL and on the ground, no shadow bands were detected above the PBL in Texas or in northeast Vermont, despite the use of improved instrumentation. Cloud cover prevented useful ground based measurements in Texas, limiting our conclusions about the nature of shadow bands. These findings suggest that shadow bands may not always be present or, if they are, may be primarily due to atmospheric turbulence. The results of this study and Pitt's 2017 study emphasize the need for future work.