Trend Analysis of U. S. Tornado Activity Frequency

As one of the most severe and high-impact weather phenomena, tornadoes their long-term frequency trends have received lots attention from both scientific community public. Here, we show that over last six decades (1954–2018), U.S. (E)F1 a statistically significant upward trend but (E)F2–E)F4 downward based on solid analyses three independent methods robust verifications reported tornado data using recently developed approach called sample generation by replacement (SGR). Furthermore, develop statistical framework to quantitatively explain two-way interconnections between climate internal variabilities. With support quantile–quantile plots, find large positive results small variability activities. The (E)F2–(E)F4 are also inversely proportional variabilities, as anticipated interconnection theory in this study.