Atmospheric and Insect Responses to a Total Solar Eclipse

Abstract How do the atmosphere and airborne insects respond to the abrupt cessation and restoration of sunlight during a total eclipse? The Flexible Array of Radars and Mesonets (FARM), including three mobile Doppler on Wheels (DOW) radars, mobile mesonets, Pod weather stations, and an upper-air sounding system, was deployed as an unprecedentedly dense observing network in the path of totality of the 21 August 2017 eclipse that spanned the United States from its Pacific to Atlantic coasts. This was the first targeted dual-polarization radar, multiple-Doppler, and micronet study of the impacts of totality on meteorology and insect behavior. The study area was chosen to be completely sunny, nearly devoid of trees, with homogeneous, nonforested land use, and very flat. This resulted in as near an ideal observational environment as realistically attainable to observe the effects of a total solar eclipse absent the confounding effects of variable cloud shading, terrain, and land use. Rapid and substantial changes in the boundary layer and propagation of a prominent radar fine line associated with a posttotality wind shift mechanism different than previously hypothesized were observed. Profound and rapid changes in airborne insect behavior were documented, including descent and then reascent during the minutes immediately surrounding totality, with implications related to solar-related insect navigational mechanisms and behavior. Significance Statement We document, for the first time, the fine-temporal and spatial-scale evolution of the atmosphere, and detail, for the first time, the rapid response of insects to complete totality during a solar eclipse. Targeted high-spatiotemporal-frequency observations during totality across a small observational domain, chosen specifically for clear skies, flat terrain, and nonforested land use, permit the first fine-scale quantification of kinematic/entomological responses to totality nearly absent confounding nonsolar factors. A posttotality radar fine line causing a wind shift is observed. Insect behavior during totality is qualitatively different than during near-, even 98%-, totality, with cross-disciplinary implications related to insect navigation and migratory behavior.