RESEARCH ARTICLE


Detection of Tornado Frequency Trend Over Ontario, Canada



Zuohao Cao*, 1, Huaqing Cai2
1 Cloud Physics and Severe Weather Research Section, Science and Technology Branch, Environment Canada, Toronto, Ontario, Canada
2 National Center for Atmospheric Research, Boulder, Colorado, USA


© 2011 Cao and Cai.;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario, M3H 5T4, Canada; Tel: 416-739-4551; Fax: 416-739-4721; E-mail: zuohao.cao@ec.gc.ca


Abstract

An upward trend in Ontario tornado frequency (about 1.6 tornadoes/decade with the statistically significant level at least at 95%) is identified using three independent approaches. The first method is the conventional linear regression method that had no disturbance to the original tornado time series. The second approach is to employ the Mann-Kendall test with consideration of removing a lag one autoregressive process. The trend is further firmed up using the Monte Carlo simulation. The robustness of the detected tornado frequency trend presented in this work offers an example for tornado frequency trend analysis over other regions of the world. It is shown in this study that the Ontario tornado frequency is linked to ENSO (El Niño/Southern Oscillation) signals with a statistically significant level at 99%.

Keywords: Tornado, Tornado Frequency Trend Detection, Mann-Kendall Test, Monte Carlo Simulation, Regional Climate Change.