EVALUATING AREAL ERRORS IN NORTHERN CASCADE GLACIER INVENTORIES by Sebastian P. Carisio A thesis submitted to the Faculty of the University of Delaware in partial fulfillment of the requirements for the degree of Master of Science in Geography Fall 2012 © 2012 Sebastian P. Carisio All Rights Reserved EVALUATING AREAL ERRORS IN NORTHERN CASCADE GLACIER INVENTORIES by Sebastian P. Carisio Approved: __________________________________________________________ Michael A. O’Neal, Ph.D. Professor in charge of thesis on behalf of the Advisory Committee Approved: __________________________________________________________ Tracy L. DeLiberty, Ph.D. Chair of the Department of Geography Approved: __________________________________________________________ Nancy M. Targett, Ph.D. Dean of the College of Earth, Ocean, and Environment Approved: __________________________________________________________ Charles G. Riordan, Ph.D. Vice Provost for Graduate and Professional Education ACKNOWLEDGMENTS I would like to express my extreme gratitude for the education, support, and experience provided by the faculty of the University of Delaware Department of Geography for both my undergraduate and graduate degrees as well as my graduate certificate. I am forever grateful for the array of opportunities, exposure to the application of numerous geospatial technologies in new environments, and the solid foundation of my technical skillset generously bestowed to me by my advisor, Dr. Michael O’Neal. Without his supervision and knowledge, my academic and professional success would be limited. I would also like to thank my other committee members: my co-advisor Dr. Brian Hanson for his judgment and available experience, as well as Dr. Tracy DeLiberty for her academic guidance since 2005. For this thesis in particular, I need to recognize the immense GIS work and previous analyses of Ashley Satinsky, and the operators from the Fall 2010 GEOG 604 class and Phillip Hendrickson for their participation in the manual digitization error assessment and snowpack variability respectively. I would like to express my gratitude for the assistance of Kevin Brinson with calculating real mean aspect. I must acknowledge the impressive work of Tessa Montini for programming a suite of Python-based software to batch calculate the set of glacier hypsometric statistics that were vital to this study. Also crucial were the raw 2005-2007 DEMs produced by Harvey Greenberg at the University of Washington. Lastly, I offer many thanks to Claire O’Neal for her assistance in editing this thesis. iii I have received so much acceptance and feedback from the close-knit community of Geography graduate students especially my Pearson 207 and 208/211 officemates. I must recognize the constant backing of Renato Kane who has accompanied me on the same path from the literal beginning of our education. I am forever thankful for the absolute love, reinforcement, and prayers of my parents, brother, sister-in-law and all members of the CO and PA Carisio and Majeski families. Ultimately, I owe everything to Alison Hayes. It has been with Alison’s total love, her care, her intellect, and her faith that I have been able to accomplish this part of my education and continue to live and work at my full potential with her unwavering support. iv TABLE OF CONTENTS LIST OF TABLES ........................................................................................................ vi LIST OF FIGURES ...................................................................................................... vii ABSTRACT ................................................................................................................... x Chapter 1 INTRODUCTION .............................................................................................. 1 2 BACKGROUND AND METHODS .................................................................. 3 2.1 Study Area ................................................................................................. 3 2.2 Areal Digital Error Assessments ............................................................... 3 2.2.1 Area Error Estimates ..................................................................... 4 2.3 Digital Elevation Models and Hypsometric Statistics Production ............ 5 2.3.1 Foundational Digital Elevation Models ......................................... 6 2.3.2 Glacier Elevation Preprocessing .................................................... 7 2.3.3 Areal and Surficial Statistics ......................................................... 8 2.3.4 Hypsometric Statistics ................................................................... 9 3 RESULTS ......................................................................................................... 12 3.1 Areal and Surficial Derivatives ............................................................... 12 3.2 Hypsometric Derivatives ......................................................................... 12 3.3 Errors and Areal Change ......................................................................... 14 4 DISCUSSION ................................................................................................... 16 REFERENCES ............................................................................................................. 36 Appendix A COMPOSITE 2006 DEM STATISTICS FOR 742 NORTH CASCADE GLACIER INVENTORY ................................................................................ 38 B PYTHON SCRIPTS FOR HYPSOMETRIC DERIVATIVES ........................ 68 v LIST OF TABLES Table 1 Growing Glacier Correlation Matrix. Correlation matrix for all areal, hypsometric, and surficial derivatives for the 10 growing glaciers. .................................................................................................... 34 Table 2 Shrinking Glacier Correlations. Correlation matrix for all areal, hypsometric, and surficial derivatives for the 240 shrinking glaciers. .... 35 Table A1 Areal and Surficial Statistics for Composite A.D. 2006 DEM. Table is continued through to page 55. ................................................... 38 Table A2 Hypsometric and Surficial Statistics for Composite A.D. 2006 DEM. Table is continued through to page 67. ........................................ 56 vi LIST OF FIGURES Figure 1 Study Area with Glacier Extents. A. Reference map representing the State of Washington with study area boundary. B. Shaded relief map of the North Cascades displaying the relative elevation (i.e., light green = high and dark green = low) and extent of the 742 glaciers (in blue) analyzed in this study. .................................................................... 19 Figure 2 Slope Raster Sample. Sample glacier boundaries (black) displaying 15-meter slope raster values atop composite A.D. 2006 shaded relief and 15-meter DEM. ................................................................................. 20 Figure 3 Aspect Raster Sample. Sample glacier boundaries (black) displaying 15-meter aspect raster values atop composite A.D. 2006 shaded relief and 15 meter DEM. ................................................................................. 21 Figure 4 Glacier Centroids in Study Area. Shaded relief map of the North Cascades displaying the relative elevation (i.e., light green = high and dark green = low) and distribution of centroid point locations (in white) for the 742 glaciers analyzed in this study. .................................. 22 Figure 5 Glacier Geometry. Idealized glacial accumulation and ablation profiles in comparison to generalized, geometric slope profiles. Slope profile types (dark grey) are A. straight B. concave, C. convex, D. concave/convex. White form (outlined in blue) represents the profile of a glacier where thicker upslope sections display accumulation and thinner upslope sections display ablation. ............................................... 23 Figure 6 Glacier Area. Histogram displaying the frequency distribution of A.D. 2006 inventory areas in square kilometers for 742 glaciers. .......... 24 Figure 7 Glacier Perimeter. Histogram displaying the frequency distribution of A.D. 2006 inventory perimeters in meters for 742 glaciers. ............... 25 Figure 8 Glacier Length. Histogram displaying the frequency distribution of A.D. 2006 inventory lengths in meters for 742 glaciers. ........................ 26 vii Figure 9 Real Mean Aspect. Rose diagram showing percentage of the real mean aspect for 742 glaciers based on aspect values obtained from the composite A.D. 2006 DEM. Grey frequency wedges are separated in to 15 degree equal interval classes. The gold line plots the overall mean (20.3 degrees) and the blue arc represents the standard deviation. ................................................................................................. 27 Figure 10 ELA Distribution. Shaded relief map with A.D. 2006 composite DEM ELAs displayed by the glacier centroids within the study area. Legend (bottom left) shows ramped colors corresponding to 10, equal interval ELA classes from 1192 to 2733 meters. .................................... 28 Figure 11 Skewness Sensitivity. Deviation of skewness values, from the original glacier boundary (x-axis), for each glacier within each error level (15m shrink, 15m expand, 30m shrink, 30m expand). ................... 29 Figure 12 Kurtosis Sensitivity. Deviation of kurtosis values, from the original glacier boundary (x-axis), for each glacier within each error level (15m shrink, 15m expand,