Brooks H. E., G. W. Carbin, and P. T. Marsh, 2014: Increased variability of tornado occurrence in the United States. Science, 346, 349- 352.10.1126/ or not climate change has had an impact on the occurrence of tornadoes in the United States has become a question of high public and scientific interest, but changes in how tornadoes are reported have made it difficult to answer it convincingly. We show that, excluding the weakest tornadoes, the mean annual number of tornadoes has remained relatively constant, but their variability of occurrence has increased since the 1970s. This is due to a decrease in the number of days per year with tornadoes combined with an increase in days with many tornadoes, leading to greater variability on annual and monthly time scales and changes in the timing of the start of the tornado season.
Fan, W. and X. Yu, 2015: Characteristics of spatial-temporal distribution of tornadoes in China. Meteorology, 41, 793- 805 (in Chinese) on "the Handbook of China Meteorological Disasters" published in 2008 and other relevant documents for period 1961 — 2010,spatial-temporal distribution characteristics of significant tornadoes(EF2 or greater) are analyzed according to the "Enhanced Fujita Scale".And based on "the Annual Report of China Meteorological Disasters" which began to be published from the year 2005,spatial-temporal distribution characteristics of EFl or greater tornadoes are investigated.The main results show there are total 165 significant tornadoes recorded in China during the 50 year period from 1961 to 2010,including 145EF2,16 EF3 and 4 EF4 tornadoes,with average 3.3 significant tornadoes each year.Most of the tornadoes occur in plain area,with higher frequency in Jianghuai Plain,South China,Northeast China Plain and the North China Plain.The highest frequency of tornadoes is during the period 1986 — 1990.Then,it starts to decline.Most of significant tornadoes occur in spring and summer(from April to August) which account for 87% of the total.The peak frequency of tornado genesis in the diurnal variation is from 12:00 to 20:00 local time.The 165 significant tornadoes killed at least 1772 people and wounded more than 31700.During the 10 year period from 2004 — 2013,according to "the Annual Report of China Meteorological Disasters" from 2005 to 2014,there are 121 EFl,19 EF2 and 3 EF3 tornadoes recorded and their spatial distribution is similar to those of the significant tornadoes from 1961 to 2010.Furthermore,at least there are 570 EFO tornadoes during the same period.With the data,we can infer roughly there is about at least 85 tornadoes and 21 EFl or greater tornadoes seen in China on average each year,less than the tenth of the tornado occurring frequency in the United States.
McDonald J. R., K. C. Mehta, 2006: A recommendation for an Enhanced Fujita scale (EF-Scale). Wind Science and Engineering Center, Texas Tech University.
Roberts B., M. Xue, A. D. Schenkman, and I. Daniel T. Dawson, 2016: The role of surface friction in tornadogenesis within an idealized supercell simulation. J. Atmos. Sci., 73, 3371- 3395.10.1175/
Roberts R. D., J. W. Wilson, 1995: The genesis of three non-supercell tornadoes observed with dual-Doppler radar. Mon. Wea. Rev., 123, 3408- 3436.10.1175/1520-0493(1995)1232.0.CO; Dual-Doppler radar analyses of three tornadoes associated with a multicellular line of storms are presented. The F23 intensity tornadoes occurred on 15 June 1988 near Denver, Colorado, during the Terminal Doppler Weather Radar (TDWR) Project. These tornadoes developed from misocyclones of no larger than 2 km in diameter that formed along the collision of two surface outflows. The misocyclones were observed to build in height and intensify with time, coincident with rapid storm growth overhead. All three misocyclones were clearly associated with the maximum storm updrafts. Downdrafts and associated outflows did not play a role in the formation of one of the tornadoes, but may have contributed to the genesis of the other two tornadoes. It is clear that a downdraft is not a necessary condition for the formation of a nonsupercell tornado, but when present, likely plays a role in determining the timing and intensity of the tornado. This is achieved by the downdraft and outflow causing an increase in...
Wakimoto R. M., J. W. Wilson, 1989: Non-supercell tornadoes. Mon. Wea. Rev., 117, 1113- 1140.10.1175/1520-0493(1989)1172.0.CO; Analyses of tornadoes that are not associated with supercells are presented. The database for this study was collected during CINDE (Convention INitiation and Downburst Experiment), a field project operated during the summer of 1987 in Colorado. A total of 27 visual vortices were studied. They appeared to form as shear instabilities along radar detected convergence lines. The circulations initiated at low levels generally in the absence of precipitation echo. Subsequently as these vortices propagated along the convergence line they appeared to strengthen to tornadic intensity when they became colocated with the updraft of a rapidly developing storm. It is hypothesized that vortex stretching is responsible for intensifying the initial rotation. Although these tornadoes were weaker than those accompanied by strong midlevel mesocyclones, estimates of their strength suggest damage capability as high as F2. The implications for operational radars to detect these types of phenomena were identified. The sensitivity of NEXRAD radars to detect motions in clear air, as well as an increased awareness of the radar observations at the lowest elevation angles, were found to be important.
Zhao K., M. Wang, M. Xue, P. Fu, Z. Yang, Y. Zhang, W.-C. Lee, F. Zhang, Q. Lin, and Z. Li, 2016: Doppler radar analysis of a tornadic miniature supercell during the Landfall of Typhoon Mujigae (2015) in South China. Bull. Amer. Meteor. Soc.,conditionally accepted.
Zheng Y., W. Zhu, D. Yao, Z. Meng, M. Xue, K. Zhao, Z. Wu, X. Wang, Y. Zheng.2016: Wind speed scales and rating of tornado in Funing County, Jiangsu Province on 23 June 2016. Meteorological Monthly, accepted. (in Chinese)