Heft 50

Schriftenreihe des Studiengangs Geodäsie und Geoinformation
der Universität der Bundeswehr München

 


 

 

  • Contents
  • Preface
  • Order

 


 

 

Heft 50

Geodetic Activites
Juneau Icefield, Alaska
1981 - 1996

Editors: Walter M. Welsch, Martin Lang and Maynard M. Miller

Universität der Bundeswehr München, Neubiberg, 1997
268 Seiten

 


 

 

Contents

Preface 1

Preface 2

Miller, M. M.:
The Juneau Icefield Research Program and its Surveying Mission

Sharp, R. P.:
The Flow of Glaciers

Friedmann, A.:
The Ice Flux and Dynamics of Taku Glacier, Juneau Icefield, Alaska

Welsch, W. M.:
Description of Homogeneous Horizontal Strains and some Remarks to their Analysis

Lang, M. and Welsch, W. M.:
Movement Vector and Strain Rate Determination for the Taku Glacier System

Daellenbach, K. K. and Welsch, W. M.:
Determination of Surface Velocities, Strain and Mass Flow Rates of the Taku Glacier, Juneau Icefield, Alaska

McGee, S. R.:
Using GPS to Determine Local Surface Mass Balance: a Case Study on the Taku Glacier

Lang, M.:
Geodetic Contributions to Glaciology - a Review of various JIRP Survey Projects

Rentsch, H.:
Terrestrial Photogrammetry on the Juneau Icefield

Rentsch, H., Welsch, W. M., Heipke, C. and Miller, M. M.:
Digital Terrain Models as a Tool for Glacier Studies

Marcus, M. G., Chambers, F. B., Miller, M. M. and Lang, M.:
Recent Trends in Lemon Creek Glacier, Alaska

Appendices

  • Appendix A: Observation Timetables
  • Appendix B: Movement Vectors
  • Appendix C: Short Term Height Changes
  • Appendix D: Long Term Hight Changes
  • Appendix E: Strain Rates
  • Appendix F: Coordinate Listing JIRP Benchmarks

 


 

 

Preface 1

The Juneau Icefield Program (JIRP) was organized in 1946 to pursue long-term research on interrelationships of scientific disciplines necessary to understand the total environment of arctic and mountain regions. The Summer Institute of Glaciology and Arctic Sciences was organized in 1959 to provide combined academic and field training, both at the graduate and undergraduate level, so essential to the solution of these multivaried problems. The aim is total systems competence in potential polar and mountain scientists and practical field training for geologists, hydrologists, geophysicists, atmospheric scientists, resource planners, ecologists, and - last but not least - surveyors. The program is in cooperation between the University of Idaho's Glaciological and Arctic Sciences Institute and the Foundation for Glacial and Environmental Research, Juneau, Alaska. The environmental science aspect is cooperative with the University of Alaska and the University of Idaho.

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In a two months oeriod (July and August) students have the opportunity to observe and study dynamic geo-processes in a region of existing glaciers and rugged mountain terrain, and to appreciate the inter-science investigational approach in the field studies applicable not only to pristine wilderness regions but to scientific assessments of environmental problems even in rural and urban areas. Participants attend lectures at pertinent field sites, participate in demonstrations with instruments and materials in the field, and take and record scientific measurements under supervision or via their own scientific competence as part of long-range research from high-elevation and continental periglacial areas to low-level temperate and maritime regions.

The Institute of Geodesy of the Bundeswehr University in Munich, Germany, joined the Juneau Icefield Research Program in 1981. Since then members of this institute and of other co-operative institutions have taken care of the scientific and practical field training in geodesy and surveying. The scientists and field instructors participated in the program are listed in Table 1.

Table 1: Scientists and field instructors participated in the Juneau Icefield Research Program

Year
Name
Institution
1981 Prof. Dr.-Ing. W. M. Welsch Bundeswehr University, Munich, Germany
Institute of Geodesy
1982 Dipl.-Ing. H. Rentsch Bavarian Academy of Sciences, Munich, Germany
Commission for Glaciology
1983 Prof. Dr.-Ing. H. Rüther University of Cape Town, Rondebosch, South Africa
Prof. Dr.-Ing. W. M. Welsch Bundeswehr University, Munich, Germany
Institute of Geodesy
1985 Dr.-Ing. H. Heister
Prof. Dr.-Ing. W. M. Welsch
Dipl.-Ing. H. Rentsch Bavarian Academy of Sciences, Munich, Germany
Commission for Glaciology
M. Welsch  
1986
Dipl.-Ing. N. Kersting Bundeswehr University, Munich, Germany
Institute of Geodesy
1987
Dipl.-Ing. K. Blachnitzky Bavarian Ordnance Survey, Munich, Germany
1988
Dipl.-Ing. K. Blachnitzky (†)
Prof. Dr.-Ing. W. M. Welsch Bundeswehr University, Munich, Germany
Institute of Geodesy
1989
Dipl.-Ing. M. Lang
1990
Dr.-Ing. H. Heister
Prof. Dr.-Ing. W. M. Welsch
Prof. Dr. H. Papo Israel Institute of Technology, Haifa, Israel
1991
Dipl.-Ing. M. Lang Bundeswehr University, Munich, Germany
Institute of Geodesy
1992
Prof. Dr.-Ing. W. M. Welsch
1993
Dr.-Ing. C. Heipke Technical University Munich, Germany
Institute of Photogrammetry
Dipl.-Ing. M. Lang Bundeswehr University, Munich, Germany
Institute of Geodesy
1994
Dipl.-Ing. D. Beineke Bundeswehr University, Munich, Germany
Institute of Photogrammetry and Cartography
1995
Dipl.-Ing. M. Lang Bundeswehr University, Munich, Germany
Institute of Geodesy
Prof. Dr. H. Papo Israel Institute of Technology, Haifa, Israel
1996 Prof. Dr.-Ing. W. M. Welsch Bundeswehr University, Munich, Germany
Institute of Geodesy
1997 Dipl.-Ing. M. Lang

From 1988 on (with the exception of 1995) Scott McGee, US Fish and Wildlife Service and Foundation for Glacial and Environmental Research, has supported the surveying work and the students' field training. The surveying program conducted by these scientists and the students interested in surveying work has covered a variety of subjects. The yearly repeated main task has been monitoring the surface velocities of some of the major galciers of the Taku-Llewellyn glacier system at distinguished cross-glacier profiles mainly in the vicinity of Camp 10 and Camp 18. Glacier flow velocities can be used for different purposes. It is interesting to study the flow rates as such, to compare the velocity profiles of different glaciers, to draw conclusions from their diversity, and to find clues from the alterations of the flow patterns over the years as to the reaction of glaciers due to climatic changes. The velocity profiles were also applied to support and to calibrate a dynamic glacier model of Taku Glacier. Based on the flow law of glaciers developed by glaciologists and glaciophysicists mass flow rates were calculated as a contribution to the mass balance of the profiles; from principal strain rates stresses were derived and correlated with the crevasse patterns of the glacier's surfaces.

Alaska.gif 

The Juneau Icefield, Alaska

The technique applied was polar point positioning and intersection by theodolite and electronic distance measurements. As reference frames local networks were established around the camps. Attemps were made to interconnect these individual, isolated networks with each other. However, in the circumstances given the trials were not successful. The whole situation changed drastically when the surveying work was supported by satellite aided measurements. From 1992 on the radio signals of the Global Positioning System (GPS) were used for all kinds of surveying tasks. Surveying, observations as well as calculations, became much more enjoyable, no longer so tedious for the students (and the supervisors), the work was pushed ahead, weather was no longer an obstacle. If with terrestrial means half a dozen of profiles, consisting of some 80 points or so, could be observed and evaluated in a two or three weeks period, now up to or even mor than 300 points were measured within ten days. The progress is more than amazing, it's fascinating! Especially real time applications speed up the operations. Apart from the new momentum, real time GPS has still more advantages to offer. It is now possible to find exactly the point positions of the last year's survey poles in no time, one can place a GPS receiver on the glacier's surface and literally watch the glacier moving - and even prove whether the glacier moves smoothly or by jerks. With the help of a helicopter the badly broken ice of the Taku terminus can be stepped on and recorded in much shorter time and much more accurately than it could before by terrestrial means. It has been easy to interconnect the local survey points around the camps to an overall network covering the whole icefield and even to integrate this network to the global network system of the International Geodynamic Service (IGS) making use of the Internet to get hold of the observations of permanent GPS-station as remote as Yellow Knife (Northwest Territories, Canada), Fairbanks (Alaska, USA), and Penticton (British Columbia, Canada). The new possibilities this high-tech surveying has to offer contribute much to an enjoyable and successful work for everybody involved.

A specific problem has always been to record the high-rate velocity of the inaccessible Vaughan-Lewis Icefall near Camp 18. The only reasonable solution could be achieved by applying terrestrial photogrammetry. This technique was also used for other unique tasks like monitoring the loss of volume of Lake Linda which uses to drain off all the sudden every year, or to sketch the pattern of the crevasses of Gilkey Glacier.

The publication in hand contains contributions about Alaska and the Juneau Icefield Program as an introductory information in general as well as some basic treatises on the phenomenon and the geodetic analysis of glacier flow for a better understanding of specific theoretical aspects. The main part documents essential results of the geodetic measurements carried out over the years as a source for further investigations by other disciplines involved in glaciological research. Some of the articles are reprints of former publications in scientific periodicals, some others are especially prepared for this booklet. The reader may consider that most of the observations were carried out by students not too familiar with geodesy and surveying but always eager to learn and ready for fieldwork and action. The work could not have been carried out without them.

We wish to dedicate this publication to our friend and colleague Dipl.-Ing. Klaus Blachnitzky who lost his live on the Icefield in fulfillment of his dedication to science and education.

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