Damage Analysis of Three Long-Track Tornadoes Using High-Resolution Satellite Imagery

Hannah V Herrero,Kelsey N Ellis,Daniel Burow

doi:10.3390/atmos11060613

Hannah V Herrero, Kelsey N Ellis + Show 1 more

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https://doi.org/10.3390/atmos11060613

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Journal: Atmosphere	Publication Date: Jun 10, 2020
Citations: 6	License type: CC BY 4.0

Affiliation: University of Tennessee at Knoxville

Abstract

Remote sensing of tornado damage can provide valuable observations for post-event surveys and reconstructions. The tornadoes of 3 March 2019 in the southeastern United States are an ideal opportunity to relate high-resolution satellite imagery of damage with estimated wind speeds from post-event surveys, as well as with the Rankine vortex tornado wind field model. Of the spectral metrics tested, the strongest correlations with survey-estimated wind speeds are found using a Normalized Difference Vegetation Index (NDVI, used as a proxy for vegetation health) difference image and a principal components analysis emphasizing differences in red and blue band reflectance. NDVI-differenced values across the width of the EF-4 Beauregard-Smiths Station, Alabama, tornado path resemble the pattern of maximum ground-relative wind speeds across the width of the Rankine vortex model. Maximum damage sampled using these techniques occurred within 130 m of the tornado vortex center. The findings presented herein establish the utility of widely accessible Sentinel imagery, which is shown to have sufficient spatial resolution to make inferences about the intensity and dynamics of violent tornadoes occurring in vegetated areas.

Highlights

Short-term meteorological events such as severe thunderstorms and tornadoes can leave lasting effects on the natural landscape
This study examines damage from three tornadoes using imagery from Sentinel-2 MultiSpectral Instrument (MSI) with a
Pixel values from post-event NDVI, NDVI differences, and eight principal component images are correlated with estimated wind speeds at damage indicators noted in post-event surveys

Summary

Introduction

Short-term meteorological events such as severe thunderstorms and tornadoes can leave lasting effects on the natural landscape. Aerial imagery of tornado damage has been used since the mid-20th century and allows for a “birds-eye” view to identify patterns that may not be discernible at ground-level, or would otherwise be unidentified [8,9] This approach can be useful in rural or remote regions that are difficult to survey after the event because they are inaccessible at ground level [10,11,12,13]. Recent advances in moderate- and high-resolution multispectral imagery have allowed for further study of vegetation damage by tornadoes [12], as well as tornado characteristics that may not be apparent at the ground level, including the extent of tornado path and effects of local topography [14,15,16]. Debris removal and other non-meteorological processes occurring in the weeks after the event can affect NDVI in ways that

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