Herausgeber: Prof. Dr. Wilfried Haeberli, Prof. Dr. Max Maisch Dieser Beitrag basiert auf einer Arbeit, die von der Mathematisch-naturwissenschaftlichen Fakultät der Universität Zürich im Sommersemester 2004 aufgrund der Gutachten von Prof. Dr. W. Haeberli (Universität Zürich), Prof. Dr. M. Bishop (Universität von Nebraska in Omaha), Prof. Dr. R. Dikau (Universität Bonn), und Dr. B. Bindschadler (NASA, Goddard Space Flight Center, Maryland) als Habilitation angenommen wurde. Für den Inhalt des Textes und der Illustrationen ist der Autor/die Autorin allein verantwortlich. Die Herausgeber. ISBN 3 85543 244 9 © Geographisches Institut der Universität Zürich, 2005 Bezugsadresse: Geographisches Institut der Universität Zürich Winterthurerstrasse 190 CH-8057 Zürich Fax: +41 (0)1 635 68 48 E-mail: [email protected] Druck: Stiftung Zentralstelle der Studentenschaft der Universität Zürich Titelbild: Section of the Bhutanese Himalayas taken from the Advanced Thermal Emission and Reflection Radiometer (ASTER) onboard the TERRA satellite. Image courtesy of EROS data center, NASA/ GSFC/METI/ERSDAC/JAROS, and the US/Japan ASTER science team. Summary At present, monitoring of mountain glaciers and permafrost creep is being confronted with new challenges. High-mountain natural systems that involve surface and sub-surface ice change with rates which are with no historical precedences. Monitoring and decision strategies have to respond to this rapid evolution. New earth observation technologies in combination with geoinformatics have to be adapted or to be developed for glacier and rockglacier monitoring. Permafrost monitoring has to become an integrated part of the global terrestrial observation networks, like glacier monitoring is since many decades. In this work, an overview is provided of, for the most part, optical air- and spaceborne remote sensing methods, which are suitable for the investigation of mountain glaciers and permafrost creep. The topics covered range from the generation of digital terrain models, to the detection and quantiÞcation of terrain changes, to multispectral analyses. It is shown, how geoinformatics and visualization can be used to exploit these data. In a second main part of this volume, case studies are employed in order to exemplify and discus the methods presented. On the basis of repeat satellite imagery, the ßow of a number of glaciers in the Bhutan Himalaya is examined for the Þrst time. A similar study revealed the surface velocity Þeld of the fast-ßowing Kronebreen in Svalbard, and Tasman Glacier, New Zealand. Furthermore, the surge-type movement of Belvedere Glacier, a glacier instability which is exceptional in the European Alps, is analyzed using repeated aerial photography. A further chapter of case studies discusses and models spatio-temporal high- resolution data on rockglacier deformation in the Swiss Alps. For the Þrst time, rockglacier advance and the evolution of micro-topography on creeping permafrost is investigated in great detail. The sensitivity of rockglacier creep to temperature changes is discussed. Techniques similar to those developed here for rockglaciers are applied to paraglacial rock mass movements also. In this way, it is possible to gain insight into the dynamics and internal structure of such slope instabilities. Application schemes that combine and exemplify the techniques presented in this volume are compiled for the assessment of glacier- and permafrost-related hazards, and for glacier inventorying based on multispectral imagery. Research perspectives rising from the methodology shown and from the test studies conducted conclude the individual sections, and the end of this work. Among these perspectives, the global availability of medium- to high-resolution digital terrain models plays a prominent role. The increasing temporal and spatial resolution of earth observation sensors bears a great potential for multidimensional examination and time series analyses of mountain glaciers and rockglaciers. 3 4 Acknowledgements This work would not have been possible without the help of numerous people. I would like to sincerely thank them all. Wilfried Haeberli enabled this volume with his continuous support and his thoughtful feedback. Frank Paul and Christian Huggel shared fruitful discussions with me and gave mindful comments on the manuscript. Robert Bindschadler, Michael Bishop and Richard Dikau reviewed an earlier version of this work. My special thanks go to Regula Frauenfelder for her invaluable help during all the years in which the studies of this volume developed. In addition, I gratefully acknowledge the support that I received in various ways from the following colleagues: Kurt Brassel Hugh Kieffer Demian Schneider Marta Chiarle Bernhard Lefauconnier Oliver Stebler Luke Copland Kjetil Melvold Tazio Strozzi Trond Eiken Philippe Meuret Markus Vollmer Hans Elsasser Gianni Mortara Bjørn Wangensteen Luzia Fischer Ulrike Müller-Böker Monika Weber Mirjam Friedli Daniel Nüesch Bruno Weber Thomas Geist Bruce Raup Röbi Weibel Samuel Guex Thekla Reichmuth Yvo Weidmann Karen Hammes Andrés Rivera Rick Wessels Klaus Itten Isabelle Roer Othmar Wigger Martin Hoelzle Nadine Salzmann Daniel Wirz Jeffrey Kargel Stefan Schläfli Tobias Kellenberger Kostia Schmutz Many other colleagues and friends helped me to finish this work, and numerous students assisted with the fieldwork in all types of weather conditions. Susan Braun-Clarke carefully corrected and improved the language of this volume. The Swisstopo flight service provided valuable aerial photography, and the NASA/ASTER science team/US Geological Survey likewise provided important satellite data for this work. The studies were supported by the Swiss National Science Foundation under contracts no. 21-54073.98 and no. 21-59045.99 and by the Swiss Federal Office for Education and Science. The work presented here is based, for the most part, on the author’s own research, but also involves students’ papers and diploma or doctoral theses under the author’s supervision. For this reason, more references to these unpublished works are given as might be common for an international publication. Furthermore, some of the presented case studies were conducted in collaboration with other scientists and institutions. The respective references are given at the beginning of the individual sections in Part III. 5 Abbreviations ASL Above sea level ASTER Advanced thermal emission and reßection radiometer BRDF Bidirectional reßectance distribution function BTS Base (or basal, bottom) temperature of snow CCD Charge-coupled device DEM Digital elevation model DHM Digital height model DInSAR Differential interferometric synthetic aperture RADAR DN Digital number DSM Digital surface model DTM Digital terrain model ETM+ Enhanced Thematic Mapper plus FCC False colour composite GIFOV Ground-projected instantaneous Þeld of view GLIMS Global land ice measurements from space GNSS Global navigation satellite system GPS Global positioning system IHS Intensity-hue-saturation INS Inertial navigation system InSAR Interferometric synthetic aperture RADAR IR Infrared IRS Indian remote sensing satellite LIA Little ice age LIDAR Light detection and ranging MIR Middle infrared MSS Multi-spectral scanner RADAR Radio detection and ranging RGBRed-green-blue RMS Root mean square error SAR Synthetic aperture RADAR SIRAL SAR interferometric RADAR altimeter SPOT Systeme probatoire pour l’observation de la terre SRTM Shuttle RADAR topography mission SWIR Short-wave infrared TIN Triangular irregular network TIR Thermal infrared TM Thematic mapper UTM Universal transversal Mercator projection UV Ultraviolet VIS Visible VNIR Visible and near infrared WGMS World glacier monitoring service 6 Table of Contents SUMMARY ACKNOWLEDGEMENTS ABBREVIATIONS TABLE OF CONTENTS I. INTRODUCTION 1. ABOUT THIS WORK 13 Introduction 13 Structure 14 II. THEORY AND METHODS 2. TERRAIN DIMENSIONS, DATA DOMAINS AND OTHER DEFINITIONS 21 2.1 Geometry, kinetics and dynamics 21 2.2 Kinematic boundary condition at the surface 21 2.3 Data domains, resolution, scale and time 22 Data domains 22 Resolution 24 Time, scale and space-time concepts 24 2.4 Accuracy 25 3. TERRAIN GEOMETRY 27 3.1 Geometry data 27 3.2 Terrestrial methods 27 3.3 Airborne DTM acquisition 28 3.3.1 Digital photogrammetry of frame imagery 29 Principle 29 Application 30 Accuracy 31 3.3.2 Digital photogrammetry of airborne pushbroom imagery 35 Principle 35 Application and accuracy 35 3.3.3 Airborne laserscanning (LIDAR) 36 Principle 36 Application and accuracy 37 3.3.4 Airborne interferometric synthetic aperture radar (InSAR) 38 Principle 38 Application and accuracy 41 3.3.5 Analogue and analytical photogrammetry 41 3.4 Spaceborne DTM acquisition 41 3.4.1 Satellite stereo imagery 42 Principle 42 Application 44 Accuracy 44 3.4.2 Spaceborne InSAR 48 Principle 48 Application and accuracy 50 Shuttle Radar Topography Mission (SRTM) 50 3.4.3 Other methods 53 3.5 DTM evaluation and reÞnement by orthoimage overlay 55 3.6 Digital terrain modelling 55 3.7 Conclusions and perspectives for DTM acquisition 58 Terrestrial methods 58 Airborne methods 58 Spaceborne methods 60 Sensor-specific problems for high-mountain applications 61 DTM processing 62 4. CHANGES IN TERRAIN GEOMETRY 63 4.1 Displacements and elevation changes 63 4.2 Vertical DTM differences 63 7 4.2.1 Filtering 64 4.2.2 DTM matching 65 DTM shift from cross-correlation 65 DTM shift from statistical adjustment 66 Numerical correction of DTM differences 69 4.3 Qualitative analysis of terrain movement 70 4.4