Articles

Tornado outbreak variability follows Taylor’s power law of fluctuation scaling and increases dramatically with severity

Tippett, Michael K.; Cohen, Joel E.

Tornadoes cause loss of life and damage to property each year in the United States and around the world. The largest impacts come from ‘outbreaks’ consisting of multiple tornadoes closely spaced in time. Here we find an upward trend in the annual mean number of tornadoes per US tornado outbreak for the period 1954–2014. Moreover, the variance of this quantity is increasing more than four times as fast as the mean. The mean and variance of the number of tornadoes per outbreak vary according to Taylor’s power law of fluctuation scaling (TL), with parameters that are consistent with multiplicative growth. Tornado-related atmospheric proxies show similar power-law scaling and multiplicative growth. Path-length-integrated tornado outbreak intensity also follows TL, but with parameters consistent with sampling variability. The observed TL power-law scaling of outbreak severity means that extreme outbreaks are more frequent than would be expected if mean and variance were independent or linearly related.

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Also Published In

Title
Nature Communications
DOI
https://doi.org/10.1038/ncomms10668

More About This Work

Academic Units
Applied Physics and Applied Mathematics
Publisher
Nature Publishing Group
Published Here
March 8, 2016

Notes

Supplementary information associated with this article is available on the journal website at http://dx.doi.org/10.1038/ncomms10668 and in Academic Commons at http://dx.doi.org/10.7916/D8TX3F8W.