Ice dynamics and stability analysis of the ice shelf-glacial system on the east Antarctic Peninsula over the past half century: multi-sensor observations and numerical modeling A dissertation submitted to the Graduate School of the University of Cincinnati in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Geography & Geographic Information Science of the College of Arts and Sciences by Shujie Wang B.S., GIS, Sun Yat-sen University, China, 2010 M.A., GIS, Sun Yat-sen University, China, 2012 Committee Chair: Hongxing Liu, Ph.D. March 2018 ABSTRACT The flow dynamics and mass balance of the Antarctic Ice Sheet are intricately linked with the global climate change and sea level rise. The dynamics of the ice shelf – glacial systems are particularly important for dominating the mass balance state of the Antarctic Ice Sheet. The flow velocity fields of outlet glaciers and ice streams dictate the ice discharge rate from the interior ice sheet into the ocean system. One of the vital controls that affect the flow dynamics of the outlet glaciers is the stability of the peripheral ice shelves. It is essential to quantitatively analyze the interconnections between ice shelves and outlet glaciers and the destabilization process of ice shelves in the context of climate warming. This research aims to examine the evolving dynamics and the instability development of the Larsen Ice Shelf – glacial system in the east Antarctic Peninsula, which is a dramatically changing area under the influence of rapid regional warming in recent decades. Previous studies regarding the flow dynamics of the Larsen Ice Shelf – glacial system are limited to some specific sites over a few time periods. This research integrates the multi-sensor remote sensing data acquired by various optical and radar satellites and airborne/satellite altimetry missions to study the spatiotemporal variations in ice velocity, ice front and surface elevation. A half-century ice velocity record has been reconstructed over the Larsen Ice Shelf by processing more than 400 remote sensing images acquired during 1963–2017. Besides, this research implements a physically based ice flow model to investigate the changes in stress conditions prior to the ice-shelf collapse. This integrated perspective of observations and numerical modeling enables to explore the physical processes that lead to the disintegration of an ice shelf. A four-stage development model (unstable condition initiation stage, enhanced weakening stage, destructing stage and catastrophic disintegration stage) is proposed to elucidate the destabilization process of the northern Larsen Ice Shelf. i ii In loving memory of my father, Qiang Wang (1959-2016). iii ACKNOWLEDGMENTS First and foremost, I would like to express my sincere gratitude to my advisor Professor Dr. Hongxing Liu, who has always been a tremendous mentor to me. This work could not have been done without your immense knowledge, support, patience and encouragement. I appreciate all your contributions of time and effort to make my PhD pursuit productive and enjoyable. I am also thankful for the outstanding example Dr. Liu has provided as a successful scientist and professor. The rigor and enthusiasm that you have for research teaches me how excellent research is done, and inspires me to delve deeper into the core of cryosphere science. Your idea, ‘think in conceptual level and frame a big picture’, not only has a profound influence on my research career, but also has been a beacon for me to go through the toughness of life. I would also like to thank Professors Dr. Richard Beck, Dr. Tomasz Stepinski, Dr. Kenneth Hinkel and Dr. Dylan Ward for serving as my committee members and giving me valuable feedbacks and insightful comments. I would particularly like to acknowledge Professor Dr. Kenneth Jezek from the Ohio State University for improving my work from a more ‘science’ perspective, and Professor Dr. Lei Wang from the Louisiana State University for helping me with the algorithm implementation. I am also thankful to Professors Dr. Lin Liu and Dr. Nicholas Dunning for their brilliant comments and suggestions during my defense. Special thanks to the members of the Remote Sensing group. You have contributed enormously to my professional and personal time at UC. The group has been a great source of good advice and collaboration. I am very grateful to Yan Huang, Min Xu, Qiusheng Wu, Bo Yang and Song Shu for their help and support. I would also like to acknowledge Zuoqi Chen, Bin Wu, Yang Liu, Shengan Zhan, Wenbin Sun, Zhaoxia Ye and Yan Liu, who previously worked with me in this group. Thank you all for the wonderful time we have spent together. iv I gratefully acknowledge the funding sources that supported my Ph.D. pursuit. I was funded by the Department of Geography, and was honored to receive the Graduate School Dean’s Fellowship. My work was also supported by the National Aeronautics and Space Administration. Last but not least, I am deeply thankful to my family for all your love, encouragement and sacrifice. I dedicate this dissertation to the memory of my father, whose role in my life was and remains immense. Words cannot express how grateful I am to my parents-in-law and mother for the sacrifices that you’ve made to come to United States to look after me and my daughter. To my beloved daughter Shannon Xiadi Li, thank you for coming to this world and being my little precious. The last word of acknowledgement I have saved for my loving, supportive, encouraging and patient husband Jingfei Li, whose faithful support in the past six years means so much to me and is so appreciated. Thank you. Shujie Wang University of Cincinnati March 2018 v CONTENTS ABSTRACT ..................................................................................................................................... i ACKNOWLEDGMENTS ............................................................................................................. iv CONTENTS ................................................................................................................................... vi LIST OF FIGURES ...................................................................................................................... viii LIST OF TABLES ....................................................................................................................... xiv Chapter 1: Introduction .................................................................................................................... 1 Chapter 2: Revealing the early ice flow patterns with historical Declassified Intelligence Satellite Photographs ..................................................................................................................................... 7 2.1 Introduction ........................................................................................................................... 7 2.2 Data Sets .............................................................................................................................. 10 2.2.1 Declassified ARGON Photographs .............................................................................. 10 2.2.2 WorldView Imagery ..................................................................................................... 11 2.2.3 Other Data..................................................................................................................... 11 2.3 ARGON Image Orthorectification ...................................................................................... 12 2.3.1 Interior Orientation ....................................................................................................... 12 2.3.2 Exterior Orientation ...................................................................................................... 14 2.3.3 Orthorectification Results and Geolocation Accuracy Assessment ............................. 16 2.4 Historical Ice Velocity Fields Over Larsen Ice Shelf ......................................................... 20 2.4.1 Ice Velocity Derivation Results .................................................................................... 21 2.4.2 Ice Flow Pattern During the Baseline Period of 1963–1979 ........................................ 23 2.4.3 Ice Velocity Comparison Between Different Time Periods ......................................... 24 2.5 Discussion ........................................................................................................................... 25 2.6 Conclusions ......................................................................................................................... 27 Chapter 3: Half-century ice velocity records reveal the instability development of Larsen Ice Shelf ....................................................................................................................................................... 28 3.1 Main Text ............................................................................................................................ 28 3.2 Methods ............................................................................................................................... 40 3.3 Supplementary Information ................................................................................................. 42 3.3.1 Data Description ........................................................................................................... 42 3.3.2 Data processing............................................................................................................