Heft 50/1997

Schriftenreihe
des Instituts für Geodäsie


 
Heft 50/1997

WELSCH, Walter M. /
LANG, Martin /
MILLER, Maynard M.
[Herausgeber]

Geodetic Activities Juneau Icefield, Alaska, 1981 - 1996

268 S.

Auflage:  350

ISSN:  0172-1009

Inhaltverzeichnis

Vorwort 1

Vorwort 2

 


Inhaltsverzeichnis

Preface 1 7
Preface 2 11
Maynard M. Miller
     Alaska

15
Maynard M. Miller
     The Juneau Icefield Research Program and its
     Surveying Mission


27
Robert P. Sharp
     The Flow of Glaciers

51
Arne Friedmann
     The Ice Flux and Dynamics of Taku Glacier,
     Juneau Icefield, Alaska


61
Walter M. Welsch
     Description of Homogeneous Horizontal Strains and
     some Remarks to their Analysis


73
Martin Lang and Walter M. Welsch
     Movement Vector and Strain Rate Determination
     for the Taku Glacier System


91
Keith K. Daellenbach and Walter M. Welsch
     Determination of Surface Velocities, Strain and Mass
     Flow Rates of the Taku Glacier, Juneau Icefield, Alaska


117
Scott R. McGee
     Using GPS to Determine Local Surface Mass
     Balance: A Case Study on the Taku Glacier


127
Martin Lang
     Geodetic Contributions to Glaciology  -
     A Review of various JIRP Survey Projects


137
Hermann Rentsch
     Terrestrial Photogrammetry on the Juneau Icefield

167
Hermann Rentsch, Walter M. Welsch, Christian Heipke and Maynard M. Miller
     Digital Terrain Models as a Tool for Glacier Studies


171
Melvin G. Marcus, Fred B. Chambers, Maynard M. Miller and Martin Lang
     Recent Trends in Lemon Creek Glacier, Alaska


185
 
Appendices  
     Appendix A  -  Observation Timetables 201
     Appendix B  -  Movement Vectors 205
     Appendix C  -  Short Term Height Changes 237
     Appendix D  -  Long Term Height Changes 251
     Appendix E  -  Strain Rates 255
     Appendix F  -  Coordinate Lisiting JIRP Benchmarks 263
 

 
Preface 1

The Juneau Icefield Research Program (JIRP) was organized in 1946 to purpose long-term research on interrelationships of scientific disciplines necessary to understand the total environment of arctic and mountain regions. The Summer Institute of Glaciological 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.

In a two months period (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 Bundeswehr University Munich, Germany
Institute of Geodesy
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 glaciers 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 the 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 glaciers' surfaces.

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 indivudual, 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 ina two or three weeks period, now up to or even more 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 ca 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 enjoayable 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 theoratical 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 periodocals, some others are especially prepared for this booklet. The reader may consider that most of the observations were carried out by students not eoo 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.
 

 

The editors
 



Preface 2

The motto of the Juneau Icefield Research Program is „Books - Nature - Action”. It describes completely how the founder and promoter on this unique project, Prof. Dr. Maynard M. Miller, thinks geo-sciences should be performed. The combination of the three elements is the precious way of learning and teaching. It is perfected on the Icefield. We are grateful to Prof. Miller that he has provided the opportunity for us to participate in this valuable kind of academic education.
 


 

We feel also indebted to his wife, Mrs. Joan Miller, who has supported us in many invaluable ways over all the years. But not only us - she has supported Mal and the whole programm, too. „We couldn't do without Joan. She is our official greeter, front office, purchasing agent, secretary-administrator, diplomatic liaison with the Air National Guard and the Governor's office, and a host of other things”, Mal says. Joan is the „soul” of the program.

Martin Lang,
Walter M. Welsch

 


 
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