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Observations and Laboratory Simulations of Tornadoes in Complex Topographical Regions Christopher D Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2012 Observations and Laboratory Simulations of Tornadoes in Complex Topographical Regions Christopher D. Karstens Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Atmospheric Sciences Commons, and the Meteorology Commons Recommended Citation Karstens, Christopher D., "Observations and Laboratory Simulations of Tornadoes in Complex Topographical Regions" (2012). Graduate Theses and Dissertations. 12778. https://lib.dr.iastate.edu/etd/12778 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Observations and laboratory simulations of tornadoes in complex topographical regions by Christopher Daniel Karstens A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Meteorology Program of Study Committee: William A. Gallus, Jr., Major Professor Partha P. Sarkar Bruce D. Lee Catherine A. Finley Raymond W. Arritt Xiaoqing Wu Iowa State University Ames, Iowa 2012 Copyright © Christopher Daniel Karstens, 2012. All rights reserved. ii TABLE OF CONTENTS LIST OF FIGURES ............................................................................................... iv LIST OF TABLES ................................................................................................. ix CHAPTER 1. GENERAL INTRODUCTION ...................................................... 1 Introduction ......................................................................................................................... 1 Research Background ......................................................................................................... 2 Research Hypothesis ........................................................................................................... 9 Dissertation Organization ................................................................................................. 10 CHAPTER 2. ANALYSIS OF TORNADO-INDUCED TREE-FALL USING AERIAL PHOTOGRAPHY FROM THE JOPLIN, MO, AND TUSCALOOSA-BIRMINGHAM, AL, TORNADOES OF 2011 ......................19 Abstract .............................................................................................................................. 19 1. Introduction .................................................................................................................. 20 2. Methodology ................................................................................................................. 23 3. Results ........................................................................................................................... 31 4. Conclusions ................................................................................................................... 42 5. Acknowledgements ....................................................................................................... 45 CHAPTER 3. LABORATORY INVESTIGATION OF TOPOGRAPHICAL INFLUENCES ON A SIMULATED TORNADO-LIKE VORTEX ................60 Abstract .............................................................................................................................. 60 1. Introduction .................................................................................................................. 61 2. Methodology ................................................................................................................. 63 3. Results ........................................................................................................................... 67 4. Conclusions ................................................................................................................... 78 5. Acknowledgements ....................................................................................................... 80 6. Appendix ....................................................................................................................... 81 CHAPTER 4. ON THE USE OF NON-STANDARD EF-SCALE DAMAGE INDICATORS TO CATAGORIZE TORNADOES ..........................................95 Abstract .............................................................................................................................. 95 1. Introduction .................................................................................................................. 96 2. Analyses of Non-Standard Damage Indicators ......................................................... 97 3. Discussion .................................................................................................................... 104 iii 4. Acknowledgements ..................................................................................................... 105 CHAPTER 5. GENERAL CONCLUSIONS .....................................................115 General Discussion .......................................................................................................... 115 Recommendations for Future Research ........................................................................ 118 REFERENCES CITED .......................................................................................120 APPENDIX A. DATA ACQUISITION SOFTWARE .....................................130 APPENDIX B. OMNIPROBE EXPERIMENTAL SETUP ............................133 1. Introduction ................................................................................................................ 133 2. Setup ............................................................................................................................ 133 3. Data Acquisition ......................................................................................................... 134 4. Post-Processing ........................................................................................................... 136 5. Example Data .............................................................................................................. 138 ACKNOWLEDGEMENTS ................................................................................144 VITA ......................................................................................................................145 iv LIST OF FIGURES Figure 1.1. Non-dimensional ratios representative of peak near-surface vortex intensity as a function of the local corner flow swirl ratio (Sc) using (a) the average maximum tangential wind and minimum surface pressure relative to their respective values at rc and (b) the ratio of the average maximum and minimum vertical velocities to the average maximum tangential wind speed. Peak intensity occurs when Sc is near 1.2. Figures are from Lewellen et al. (2000). ..........................................................................................................12 Figure 1.2. (a) Digital Elevation Model (DEM; 2.5 degree horizontal resolution) for the contiguous U.S. (meters), and (b) terrain slope values (degrees) derived from the DEM. Hatched areas indicate regions with a 1 tornado per 100 km2 density, based on 1950-2009 tornado starting points. Note: slope values are lower than perhaps anticipated, due to the coarse horizontal resolution of the DEM. ......................................................................................13 Figure 1.3. Contours of amplification factor (Az) in a y-z cross-section for (a) a cliff, (b) 1:1 escarpement, (c) 2:1 escarpment, and (d) 4:1 escarpment. Figure is from Bowen and Lindley (1977). ..............................................................................................................................14 Figure 1.4. (a) Schematic of an idealized two-dimensional escarpment and the dimensions used to calculate (b) non-dimensionalized maximum speed-up ratio versus normalized height. Figure is from Bitsuamlak et al. (2004). ........................................................15 Figure 1.5. As in Fig. 1.3, except for an idealized two-dimensional ridge. Figure is from Bitsuamlak et al. (2004). ................................................................................................................16 Figure 1.6. Aerial depiction of the mesocyclone track (yellow line, yellow x denote positions) and the tornado damage path (orange filled areas) from a storm that crossed the Hudson River Valley. The direction of surmised channeled flow is depicted. Figure is from Bosart et al. (2006). ...............................................................................................................17 Figure 1.7. Ground tracks historical tornadoes occurring in the Upper Rhine valley. Numbers at tracks correspond to dates of occurrence: 1.) 4 Jul 1885, 2.) 7 Jun 1952, 3.) 27 Apr 1960, 4. a, b) 10 Jul 1968, 5.) 8 May 1985, 6.) 23 Jul 1986, 7.) 21 Jul 1992, 8. a– d) 9 Sep 1995. Cities denoted with black squares as follows: N = Nußbach, Pf = Pforzheim, Stg = Stuttgart, Str = Strasbourg. Figure is from Hannesen et al. (1998). .................18 Figure 2.1. Digitized tree-fall from the (a) Joplin and (b) Tuscaloosa-Birmingham tornadoes. The arrow colors denote track-relative tree-fall direction that has utility in identifying locations of converging
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