THE SPATIAL AND TEMPORAL PATTERNS OF PRECIPITATION IN TEXAS DISSERTATION Presented to the Graduate Council of Texas State University-San Marcos in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy by Rebecca K. Parylak, B.A., M.A.Geo. San Marcos, Texas May 2010 THE SPATIAL AND TEMPORAL TRENDS IN PRECIPITATION IN TEXAS Committee Members Approved: ____________________________________ Richard W. Dixon, Chair ____________________________________ David R. Butler ____________________________________ Philip W. Suckling ____________________________________ Philip L. Chaney Approved: __________________________________ J. Michael Willoughby Dean of the Graduate College ` COPYRIGHT by Rebecca K. Parylak 2010 ACKNOWLEDGEMENTS I would like to acknowledge the many colleagues, mentors, and friends who have contributed and supported me throughout my time in graduate school. First and foremost, I would like to thank my advisor, Rich Dixon for his unlimited patience, his warm approach to supervision, and supporting me, especially as I struggled with personal challenges during the latter half of my graduate school experience. Thank you for both your personal and academic advice, and for believing in me and in my ability to improve myself through perseverance and hard work. I will continue to persist and work hard as I begin my professional life in academia. I would also like to extend my thanks to the other members of my committee, David Butler, Phil Suckling, and Phil Chaney for their time and feedback throughout my time in graduate school and for this project. I want to thank Allison Glass, Angelika Wahl, Charles Robinson, and Judy Behrens for your assistance, service, and support. A number of friends were extremely encouraging and helpful throughout my graduate school years, and made a lasting impact on my personal and professional life. I want to thank James Vaughan, Dawna Cerney, Carol Sawyer, Fenda Akiwumi, Darlene Occena-Guiterrez, Mindy Conyers, Jamie Zech, David Viertel, Jay Parsons, Brian and Alecia Brettschneider, and many others that I worked with in the department and attended classes with for their support and friendship. It was a privilege to work with you and I am truly blessed to know you and for your continued friendship. Finally, to Emariana Taylor and Melissa Gray, thank you for your friendship, love, and support. The three of iv us have been through quite a journey together during and after our graduate studies. I will always cherish our times, especially those on the Comal River, and also our move from Texas to Ohio. You both have definitely made my life much richer. Thank you. A very special thanks goes to Nicola Harlan, who I can say is my best friend for over a quarter of a century. Nik, as you go through graduate school yourself in the coming years, I only hope to be there for you as you have been for me. I also extend a heartfelt thanks to Dona and Mike Eggenberger, Cari Eggenberger, Sharon Jimenez, Don and Cheri Dancak, Tom and Romy Cisneros, Elena and Richard Luderus, who supported and encouraged me throughout my educational venture. A special thanks goes to Panos Zavos who gave me valuable advice and insight to his graduate studies experience and successful career. I also like to acknowledge and thank my colleagues at Kent State University for their continued support. Mom and Dad, I thank you both for your unconditional love and continued support throughout my time in graduate school. I love you both and I appreciate the sacrifices you have made to help me accomplish my goals while in graduate school and with my move to Ohio. I am proud to be your daughter. To my sister, Debra and husband, Mike, thank you for your continued love and support. Finally, to my son Jonathan, who stood by me all these years and took the journey to Ohio with me to begin new experiences and a new life. I am very proud of you and I am extremely grateful for your love and support. v TABLE OF CONTENTS ACKNOWLEDGEMENTS ........................................................................................ iv LIST OF TABLES ....................................................................................................... x LIST OF FIGURES ................................................................................................... xx ABSTRACT............................................................................................................. xxii CHAPTER 1 ................................................................................................................ 1 INTRODUCTION ................................................................................................ 1 Statement of Research Problem ..................................................................... 1 Research Objectives and Hypotheses ............................................................. 3 Research Hypotheses ...................................................................................... 5 Summary of Work .......................................................................................... 6 CHAPTER 2 ................................................................................................................ 7 LITERATURE REVIEW ..................................................................................... 7 Precipitation Measurement ............................................................................. 7 Measuring Precipitation with Rain Gauges .................................................... 8 Measuring Precipitation using Radar and Satellite Technology .................. 10 Approaches to Precipitation Research .......................................................... 11 Precipitation Studies in Other Countries ...................................................... 11 Precipitation Studies in the United States .................................................... 13 Precipitation Studies in Texas ...................................................................... 17 Summary ...................................................................................................... 18 vi CHAPTER 3 .............................................................................................................. 20 THE STUDY AREA .......................................................................................... 20 Location and Physical Geography of Texas ................................................. 20 Precipitation in Texas ................................................................................... 23 CHAPTER 4 .............................................................................................................. 26 METHODOLOGY AND DATA SOURCES .................................................... 26 Data Preparation ........................................................................................... 27 Missing Data ................................................................................................ 29 Precipitation Variables ................................................................................. 30 Statistical Analysis and GIS Application ..................................................... 31 Descriptives .................................................................................................. 31 Linear Regression ......................................................................................... 31 Probability of Precipitation ........................................................................... 32 GIS ................................................................................................................ 32 CHAPTER 5 .............................................................................................................. 33 RESULTS........................................................................................................... 33 West Texas ................................................................................................... 34 El Paso .......................................................................................................... 35 Balmorhea .................................................................................................... 38 Alpine ........................................................................................................... 42 Pecos............................................................................................................. 46 Ft. Stockton .................................................................................................. 49 McCamey ..................................................................................................... 53 Summary for West Texas ............................................................................. 56 The Panhandle .............................................................................................. 57 Seminole ....................................................................................................... 58 Snyder........................................................................................................... 62 Crosbyton ..................................................................................................... 65 Muleshoe ...................................................................................................... 69 Plainview ...................................................................................................... 73 Miami ..........................................................................................................