Comparison between Tornadic and Nontornadic Mesocyclones Using the Vorticity (Pseudovorticity) Line Technique

Comparisons between tornadic and nontornadic mesocyclones using the concept of fractal geometry are presented. Both the maximum vertical vorticity (ζmax) and pseudovorticity (ζpv) associated with a mesocyclone at low levels are found to be scaling with the horizontal grid spacing (e) according to a power-law relationship. The linear least square best fitting of ln (ζmax) or ln (ζpv) versus ln (e) for different scales can be obtained for each mesocyclone at a certain time, and it is named the vorticity (pseudovorticity) line of a mesocyclone. Different mesocyclones have different vorticity (pseudovorticity) line slopes that are closely related to the fractal dimension of vorticity (pseudovorticity) of a mesocyclone as a possible fractal structure. Various factors that may affect the accurate estimate of the vorticity (pseudovorticity) line of a mesocyclone are also discussed in detail. Differences between tornadic and nontornadic mesocyclones are found in terms of the slope of vorticity (pseudovor...