Coastal and Estuarine Studies

Transcription

1 Coastal and Estuarine Studies Series Editors' Malcolm J. Bowman Christopher N.K.

2 Gyre in Lake Biwa Reproduced with permission from Asahi Shinbun

3 Coastal and Estuarine Studies 48 Setsuo Okuda, JOrg Imberger, and Michio Kumagai (Eds.) Physical Processes in a Large Lake: Lake Biwa, Japan American Geophysical Union Washington,

4 Series Editors Malcolm J. Bowman Marine Sciences Research Center, State University of New York Stony Brook, N.Y , USA Christopher N.K. Mooers Division of Applied Marine Physics RSMAS/University of Miami 4600 Rickenbacker Cswy. Miami, FL , USA Editors Setsuo Okuda Okayama University of Science 1-1 Ridai-cho Okayama, Okayama, 700, Japan Michio Kumagai Lake Biwa Research 1-10 Uchidehama Otsu, Shiga, 520, Japan Institute JOrg Imberger Centre for Water Research University of Western Australia Nedlands, WA 6009, Australia Library of Congress Cataloging-in-Publication Data Physical Processes in a Large Lake: Lake Biwa, Japan / Setsuo Okuda, J6rg Imberger, and Michio Kumagai, editors. p. cm.- (Coastal and estuarine studies; 48) Includes bibliographical references. ISBN Limnology--Japan--Biwa Lake. I. Okuda. Setsuo, II. Imberger, Jorg, Ill. Kumagai, Michio, IV. Series. GB 1752.B58P '2' dc CIP ISSN ISBN Copyright 1995 by the American Geophysical Union, 2000 Florida Avenue, NW, Washington, DC 20009, U.S.A. Figures, tables, and short excerpts may be reprinted in scientific books and journals if the source is properly cited. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by the American Geophysical Union for libraries and other users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, provided that the base fee of $1.00 per copy plus $0.10 per page is paid directly to CCC, 222 Rosewood Dr., Danvers, MA /95/$ This consent does not extend to other kinds of copying, such as copying for creating new collective works or for resale. The reproduction of multiple copies and the use of full articles or the use of extracts, including figures and tables, for commercial purposes requires permission from AGU. Printed in the United States of

5 CONTENTS PREFACE... vii Introduction S. Okuda and M. Kumagai... 1 PART I: GEOSTROPIC GYRES 2 Review of Geostropic Gyres S. Endoh... 7 Field Observation in the North Basin S. Endoh, Y. Okumura, and I. Okamoto PART II: WATER MASS EXCHANGE 4 Water Mass Exchange Between the Main Basin and Shiozu Bay I. Okamoto and S. Endoh Field Observations of the Dense Bottom Current Between the North and South Basins K. Okubo Numerical Simulation of the Density-Induced Currents Between the North and South Basins of Lake Biwa Y. Oonishi PART III: OPTICAL CHARACTERISTICS AND TURBIDITY DYNAMICS 7 Spectral Irradiance and Optical Properties R. Tsuda and M. Nakanishi Turbidity in the North and South Basins R. Tsuda Dynamics of the Turbid Benthic Boundary Layer M. Kumagai, R. Tsuda and K. Fukagae PART IV: INFLOWS INTO LAKE BIWA 10 Distribution and Mixing of the River Seri Water I. Okamoto, S. Endoh and M. Kumagai...

6 11 Sedimentation of Suspended Matter in the Mouth of the Ane River Y. Okumura Inflows Due to Snow Melt M. Kumagai and H. Fushimi PART V: BOTTOM SEDIMENTATION AND PALEO-HYDROLOGY 13 Recent Sedimentation Rates and Sedimentary Anomalies H. Taishi Bottom Sediments and Paleo-Hydrological Processes A. Yamamoto Global Paleo-Hydrological Processes and Lake Biwa K. Kashiwaya and K. Fukuyama PART VI: MODERN SENSING TECHNIQUES IN LAKE BIWA 16 Thermal Infrared Mapping Y. Itakura Laser Sensing of Phytoplankton Size R. Tsuda, Y. Kakui and M. Kumagai New Measurement Techniques and Some Depositional Problems at the Lake Bottom K. Yokoyama and S. Okuda LIST OF CONTRIBUTORS...

7 PREFACE This book arose from a discussion between Michio Kumagai, Setsuo Okuda and myself during a visit to Japan under the auspices of the Japan Society for the Promotion of Science. After hearing of the extensive results of the general research on Lake Biwa, it was suggested that much of the work was not well documented in the open literature and could possibly be summafisexl in book form, complementing the already existing volume "Lake Biwa" by Shoji Horie with a more derailed treatment of the understanding of the physical processes. A further outcome of these discussions was the suggestion of a large interdisciplinary experiment to study the transport processes in Lake B iwa and the impact of these processes on the biogeochemical cycles. This latter suggestion was realised through the Lake Biwa International Transport Experiment (BITEX), the results of which will be published shortly. The work in Lake Biwa was motivated by concerns about the deteriorating quality of the water. The great majority of pollutants are discharged into the smaller South Basin but these are progressively being transported upstream into the North Basin; the source of drinking water for 15 million people. The urgent management problems have been the motivation for research projects with both short and long term implications. This research should be of interesto managers of water supplies throughout the world. The authors of this book give a clear exposition of the various transport mechanisms operating in a large stratified lake. The discussion confined to examples from Lake Biwa, but physical processesuch as basin scale gyre formation, water mass exchange, and the role of the benthic boundary layer are relevant to all large lakes. The material presented on these topics does not find a counterpart in open literature and so should be of great interest to limnologists the world over. The chapter on remote sensing techniques is of general interest since it presents for the first time the laser sensing methodology pioneered in Japan. In this book I have thus attempted to bring together various contributions that detail the advances made in our understanding of the physical processes in Lake Biwa. Also, for the first time, the book provides a coherent overview of the very considerable contributions recently made by Japanese physicalimnologists. I would like to thank the authors for their patience with the long delays in getting the manuscripts into a book form, the three reviewers Greg Ivey, Robert Spigel and Paul Hamblin for their detailed suggestions which led to very considerable improvements in the presentation, and Karen Lane for her very careful preparation of the book as a whole.

8 Her contributions were not confined to the presentation, but also ranged over the scientific consistency of the manuscripts. Without her inputhe book would not have been completed. The collaboration and friendship extended to me by Michio Kumagai and Setsuo Okuda during the editing stage made this undertaking a great pleasure; Michio Kumagai mustake all the credit for interacting with various authors of the book. J6rg Imberger Centre for Water Research University of Western Australia Nedlands, WA 6009,