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A Strategy for Monitoring Glaciers

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A Strategy for Monitoring Glaciers A STRATEGY FOR MONITORING GLACIERS U.S. Geological Survey Circular 1132 COVER PHOTOGRAPH: Glaciers near Mount Shuksan and Nooksack Cirque, Washington. Photograph 86R1-054, taken on September 5, 1986, by the U.S. Geological Survey. A Strategy for Monitoring Glaciers By Andrew G. Fountain, Robert M. Krimmel, and Dennis C. Trabant U.S. GEOLOGICAL SURVEY CIRCULAR 1132 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Government U.S. GOVERNMENT PRINTING OFFICE : 1997 Free on application to the U.S. Geological Survey Branch of Information Services Box 25286 Denver, CO 80225-0286 Library of Congress Cataloging-in-Publications Data Fountain, Andrew G. A strategy for monitoring glaciers / by Andrew G. Fountain, Robert M. Krimmel, and Dennis C. Trabant. p. cm.--(U.S. Geological Survey circular ; 1132) Includes bibliographical references (p. - ). Supt. of Docs, no.: 119.4/2: 1132 1. Glaciers-United States. I. Krimmel, Robert M. II. Trabant, Dennis. III. Title. IV. Series. GB2415.F68 1997 551.31'2-dc21 96-51837 CIP ISBN 0-607-86638-1 CONTENTS Abstract........................................................................_ 1 Introduction .......................................................................................................................................................................^ 1 Goals..............................................................................................................^ 3 Previous Efforts of the U.S. Geological Survey.................................................................................................................... 3 Methods of Assessing Glacier Mass Balance........................................................................................................................ 6 Monitoring Strategy.....................................................................^ 7 Benchmark Glacier Network................................................................................................................................................. 8 Primary Measurements................................................................................................................................................ 9 Mass Balance..................................................................................................................................................... 9 Geometry........................................................................................................................................................... 11 Meteorology and Streamflow ............................................................................................................................ 12 Supplementary Measurements..................................................................................................................................... 12 Observation Summary................................................................................................................................................. 13 Reports................................................................. 13 Secondary Glacier Network................................................................................................................................................... 14 Primary Measurements................................................................................................................................................ 14 Observation Summary................................................................................................................................................. 15 Reports..........................................................................................................................................^ 15 Remote-Sensing Inventory.................................................................................................................................................... 15 Primary Measurements................................................................................................................................................ 15 Supplementary Data.................................................................................................................................................... 15 Observation Summary................................................................................................................................................. 16 Reports......................................................................................................................................................................... 16 Summary................................................................................................................................................................................ 16 References Cited....................................................................... 16 FIGURES 1-2. Graphs showing: 1. Effect of glacier cover on runoff variability ...................................................................................................... 1 2. Effect of the melting of alpine glaciers worldwide on global sea level............................................................. 2 3. Diagram showing processes that link meteorology with glacier mass balance and their effect on landscape........... 2 4. Map showing major glacierized regions of the United States.................................................................................... 4 5. Diagram showing correspondence between physical processes that determine glacier change and the processes measured by the different surveillance levels............................................................................................. 9 6. Map showing idealized monitoring strategy for a glacierized region ........................................................................ 10 TABLE 1. Frequency of aerial photographic surveys for glacierized mountain regions of the United States......................... 16 Contents CONVERSION FACTORS Multiply By To obtain kilometer (km) 0.6214 mile millimeter (mm) 0.03937 inch square kilometer (km2) 0.3861 square mile Other abbreviations used in this report: millibar (mb) Sea level: In this report "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929) a geodetic datum derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929. IV Contents A Strategy for Monitoring Glaciers By Andrew G. Fountain, Robert M. Krimmel, and Dennis C. Trabant Abstract Glaciers are important features in the EXPLANATION O Washington hydrologic cycle and affect the volume, variability, A Southeast Alaska and water quality of runoff. Assessing and predicting ® Mean Predicted coefficient of variation the effect of glaciers on water resources require a monitoring program to provide basic data for this understanding. The monitoring program of the U.S. Geological Survey employs a nested approach whereby an intensively studied glacier is surrounded by less intensively studied glaciers and those monitored solely by remote sensing. Ideally, each 10 20 30 40 50 60 70 80 90 100 glacierized region of the United States would have PERCENT OF BASIN COVERED BY GLACIERS such a network of glaciers. The intensively studied Figure 1. Effect of glacier cover on runoff variability. ~^he coefficient of variation is the standard deviation dividec1 by glacier provides a detailed understanding of the the mean. physical processes and their temporal changes that control the mass exchange of the glaciers in that contributed to the rise in global sea level (fig. 2) region. The less intensively studied glaciers are used (Meier, 1984; Oerlemans andFortuin, 1992). Glaciers to assess the variability of such processes within the also present special hydrologic hazards, such as floods region. (Post and Mayo, 1971; Driedger and Fountain, 19°9; Mayo, 1989; O'Connor and Costa, 1993) and debris flows (Osterkamp and others, 1986; Walder and INTRODUCTION Driedger, 1994). In addition, glaciers are recognized as sensitive indicators of climate change because their Glaciers are an important water resource of size changes in accordance with variations in mas^ Alaska and a number of Western States because they gain or loss (Johannesson and others, 1989; Meier and are naturally regulated reservoirs that reduce the Roots, 1982; Moss andLins, 1989; Paterson, 1981). runoff variability by increasing flow during hot, dry However, the relation between climate change and periods and by storing water as ice and snow during response of an individual glacier is only generally cool, wet periods (fig. 1) (Meier and Tangborn, 1961; understood and not clearly known for large glacierized Meier, 1962; Krimmel and Tangborn, 1974; Fountain regions. and Tangborn, 1985). The mass wastage of glaciers Understanding the effects of glaciers on ruroff during this century has diminished the volume of requires a long-term program (Benson and others, water stored as ice in the natural reservoirs and has 1986; Fountain and others, 1991) to define the natural reduced the capacity of runoff from the glaciers to variability of the processes that control glacier mass limit annual variations in streamflow. As demands on change (fig. 3). A long-term program also captures water resources continue to increase,
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