“…The structures and generation mechanisms of tornadoes have been studied by various methods such as theoretical study, laboratory experiment, numerical experiment, and field observation (recent reviews of the above subjects can be found in Wurman et al, 2012;Bluestein, 2013;Rotunno, 2013;Davies-Jones, 2014). Surface roughness is one factor that has significant impact on the flow structure and intensity of a tornado, which has been investigated by these means (e.g., Church and Snow, 1993;Natarajan and Hangan, 2012).…”