Estimating Spatial Characteristics of Precipitation Associated with Tropical Cyclones Originating Over the North Atlantic Ocean
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ESTIMATING SPATIAL CHARACTERISTICS OF PRECIPITATION ASSOCIATED WITH TROPICAL CYCLONES ORIGINATING OVER THE NORTH ATLANTIC OCEAN By YAO ZHOU A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2018 © 2018 Yao Zhou To my family ACKNOWLEDGMENTS I would like to thank my advisor, Dr. Corene Matyas, for her encouragement and commitment to help me to reach my goal. I would also like to thank my other committee members, Drs. Joann Mossa, Peter Waylen, and Stefan Gerber, for their invaluable insight and expertise. Thanks to all faculty members, staff, Hurricane research group, and graduate students of the Department of Geography at the University of Florida who were always willing to help me. This dissertation research was funded by National Science Foundation (NSF) CAREER Award BCS-1053864. I would also like to extend my sincere appreciation to all my family members, for their unending love, support, and reliance. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 9 LIST OF ABBREVIATIONS ........................................................................................... 11 ABSTRACT ................................................................................................................... 13 CHAPTER 1 INTRODUCTION .................................................................................................... 15 Research Background ............................................................................................ 15 Spatial Characteristics of TC Precipitation and Contributing Factors ...................... 17 Research Objectives ............................................................................................... 20 2 SPATIAL CHARACTERISTICS OF STORM-TOTAL RAINFALL SWATHS ASSOCIATED WITH TROPICAL CYCLONES OVER THE EASTERN UNITED STATES .................................................................................................................. 25 Background ............................................................................................................. 25 Data and Methodology ............................................................................................ 29 Data .................................................................................................................. 29 Methodology ..................................................................................................... 30 Spatial Characteristics of TCP Regions over Land ................................................. 33 Change of Left Width of TCP Swath along Tracks .................................................. 36 Return Intervals of TC Rainfall and Wind Events .................................................... 40 Concluding Remarks............................................................................................... 43 3 CONDITIONS ASSOCIATED WITH RAIN FIELD SIZE FOR TROPICAL CYCLONES LANDFALLING EASTERN U.S. ......................................................... 53 Background ............................................................................................................. 53 Data and Methodology ............................................................................................ 56 Data .................................................................................................................. 56 Methodology ..................................................................................................... 59 Area and Extent of TC Rain Field ........................................................................... 62 Statistical Modeling of TC Rainfall Size .................................................................. 66 General Connections between TCP Size and Environmental Conditions ........ 67 Results of Generalized Regression Models...................................................... 69 Conclusions and Discussions ................................................................................. 75 5 4 SPATIAL CHARACTERISTICS OF RAIN FIELDS ASSOCIATED WITH TROPICAL CYCLONES LANDFALLING OVER THE WESTERN GULF OF MEXICO AND CARIBBEAN SEA ........................................................................... 84 Background ............................................................................................................. 84 Data and Methodology ............................................................................................ 87 Overview of Rain Field Metrics and Environmental Conditions ............................... 94 Regional Variations of Rain Rates and Corresponding Environmental Conditions ............................................................................................................ 99 Overall Variations of Rain Rates and Corresponding Environmental Conditions .. 102 Rainfall Start Time and Average Duration ............................................................. 106 Conclusions and Future Research ........................................................................ 108 5 CONCLUSIONS ................................................................................................... 119 Summary .............................................................................................................. 119 Future Directions .................................................................................................. 124 LIST OF REFERENCES ............................................................................................. 127 BIOGRAPHICAL SKETCH .......................................................................................... 140 6 LIST OF TABLES Table page 2-1 Averages of the wind radii for 17-m/s wind (unit: km) . ....................................... 47 2-2 Spatial characteristics of TCP swaths in Gulf Coast group (area unit:105 sq. km, width unit: km). ............................................................................................. 49 2-3 Spatial characteristics of TCP swaths in Florida group (area unit:105 sq. km, width unit: km). ................................................................................................... 49 2-4 Spatial characteristics of TCP swaths in East Coast group (area unit:105 sq. km, width unit: km). ............................................................................................. 50 2-5 Change in distance of left width in each group (unit: km). .................................. 51 2-6 Chi-square test results. ....................................................................................... 51 3-1 Variables’ descriptions. ....................................................................................... 79 3-2 Area and extent of rainfall fields of TCs (area unit:104 sq. km, width unit: km). .. 80 3-3 The correlation coefficients between area and extent of TC rain fields and predictors (Correlation coefficients greater than 0.30 and significant at 0.01). ... 82 3-4 Coefficients and model estimation of regression model to predict rainfall area over land and ocean (Variables significant at 0.1). ............................................. 82 3-5 Coefficients and model estimation of extent regression models over land (Variables significant at 0.1). .............................................................................. 83 3-6 Coefficients and model estimation of extent regression models over ocean (Variables significant at 0.1). .............................................................................. 83 4-1 Abbreviations, units, source, and spatial range of TC attributes and environmental conditions. ................................................................................. 112 4-2 Number of features and statistics of metrics for all observations, hot spots, and cold spots of light rainfall (area unit:104 sq km, width unit: km) ................. 113 4-3 Name, unit and statistics of variables over entire region. Different number of observations is due to the missing data in SHIPS. ........................................... 113 4-4 Mann-Whitney U Tests results of conditions related to hot and cold spots of area, dispersion and displacement of light rainfall. ........................................... 116 7 4-5 Spearman’s rank correlation coefficients, time lags and spatial range between area, shape metrics and environmental conditions (Correlation coefficients greater than 0.3 and significant at 0.01). ....................................... 116 8 LIST OF FIGURES Figure page 1-1 Tracks of all tropical cyclones making landfall over U.S. coast in 1948-2015 and making landfall in 1998–2015 over the western Caribbean and/or Gulf coasts that examined in this dissertation. Elevation data were obtained from USGS. ................................................................................................................ 24 2-1 Extracting TCP from daily precipitation data. ...................................................... 47 2-2 Example of data from Hurricane Frances (2004). ............................................... 48 2-3 Shaded areas depicting total rainfall extent for all TCs in each group