Ocean Modeling and Parameterization

Transcription

1 Ocean Modeling and Parameterization

2 NATO Science Series A Series presenting the results of activities sponsored by the NATO Science Committee. The Series is published by los Press and, in conjunction with the NA TO Scientific Affairs Division. General SutrSeries A. Life Sciences B. Physics C. Mathematical and Physical Sciences D. Behavioural and Social Sciences E. Applied Sciences F. Computer and Systems Sciences los Press los Press Partnership SutrSeries 1. Disarmament Technologies 2. Environmental Security 3. High Technology 4. Science and Technology Policy 5. Computer Networking los Press los Press The Partnership SutrSeries incorporates activities undertaken in collaboration with NATO's Partners in the Euro-AUantic Partnership Council- countries of the CIS and Central and Eastern Europe - in Priority Areas of concem to those countries. NAT()'PC()'DATA BASE The NATO Science Series continues the series of books published formerly in the NATO ASI Series. An electronic index to the NATO ASI Series provides full bibliographical references (with keywords and/or abstracts) to more than contributions from international scientists published in all sections of the NATO ASI Series. Access to the NATO-PCO-DATA BASE is possible via CD-ROM "NATO-PCO-DATA BASE" with user-friendly retrieval software in English, French and German (e WTV GmbH and DATAWARE Technologies Inc. 1989). The CD-ROM of the NATO ASI Series can be ordered from: POO, Overijse, Belgium. Series C: Mathematical and Physical Sciences - Vol. 516

3 Ocean Modeling and Parameterization edited by Eric P. Chassignet Department of Meteorology and Physical Oceanography, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, U.S.A. and Jacques Verron Centre National de la Recherche Scientifique, Laboratoire des Ecoulements Geophysiques et Industriels, Grenoble, France Springer Science+Business Media, B.V.

4 Proceedings of the NATO Advanced Study Institute on Ocean Modeling and Parameterization Les Houches, France January 20-30, 1998 A C.I.P. Catalogue record for this book is available from the Library of Congress. ISBN ISBN (ebook) DO I / Printed on acid-free paper AII Rights Reserved 1998 Springer Science+Business Media Dordrecht Originally published by in 1998 Softcover reprint of the hardcover 1 st edition 1998 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

5 TABLE OF CONTENTS Preface vii Chapter 1. Oceanic general circulation models J. McWilliams 1 Chapter 2 Forcing the oceans B. Barnier 45 Chapter 3 Modeling and parameterizing ocean planetary boundary layers W. Large 81 Chapter 4 Parameterization of the fair weather Ekman layer J. Price 121 Chapter 5 The representation of bottom boundary layer processes in numerical ocean circulation models A. Beckmann 135 Chapter 6 Marginal sea overflows for climate simulations J. Price and J. Yang 155 Chapter 7 Turbulent mixing in the ocean J. Toole 171 Chapter 8 Parameterization of processes in deep convection regimes U. Send and R. Kiise 191

6 vi Chapter 9 Double-diffusive convection R. Schmitt 215 Chapter 10 Interleaving at the equator K. Richards 235 Chapter 11 Eddy parameterisation in large scale flow P. Killworth. 253 Chapter 12 Three-dimensional residual-mean theory T. McDougall 269 Chapter 13 Statistical mechanics of potential vorticity for parameterizing mesoscale eddies J. Sommeria 303 Chapter 14 Topographic stress: Importance and parameterization A. Alvarez and J. Tintore 327 Chapter 15 Large-eddy simulations of three-dimensional turbulent flows: Geophysical applications O. Metais 351 Chapter 16 Parameter estimations in dynamical models G. Evensen, D. Dee and J. Schroter 373 Chapter 17 On the large-scale modeling of sea ice and sea ice-ocean interactions T. Fichefet, H. Goose and M. Morales Maqueda 399 Chapter 18 Ocean modeling in isopycnic coordinates R. Bleck 423 Subject Index 449

7 PREFACE The realism of large scale numerical ocean models has improved dramatically in recent years, in part because modern computers permit a more faithful representation of the differential equations by their algebraic analogs. Equally significant, if not more so, has been the improved understanding of physical processes on space and time scales smaller than those that can be represented in such models. Today, some of the most challenging issues remaining in ocean modeling are associated with parameterizing the effects of these high-frequency, small-space scale processes. Accurate parameterizations are especially needed in long term integrations of coarse resolution ocean models that are designed to understand the ocean variability within the climate system on seasonal to decadal time scales. Traditionally, parameterizations of subgrid-scale, high-frequency motions in ocean modeling have been based on simple formulations, such as the Reynolds decomposition with constant diffusivity values. Until recently, modelers were concerned with first order issues such as a correct representation of the basic features of the ocean circulation. As the numerical simulations become better and less dependent on the discretization choices, the focus is turning to the physics of the needed parameterizations and their numerical implementation. At the present time, the success of any large scale numerical simulation is directly dependent upon the choices that are made for the parameterization of various subgrid processes. These choices are often constrained by the overall model architecture and may be more or less natural to the particular model design. The question of this dependence has led to several comparison exercises between various models such as DYNAMO in Europe and DAMEE in the U.S. A good understanding of parameterizations and their impact on the modeled oceanic circulations is crucial to the large international projects presently seeking to achieve global simulations. In parallel, several large observational programs are underway to advance our understanding of the short and long time scales, such as obvii

8 viii servations from space (Topex/Poseidon, Geosat-Follow-On, ERS1, ERS2, ADEOS, ENVISAT, JASON,... ) or in situ (WOCE, CLIVAR, GOOS, GCOS,... ). These observations in turn are leading to improvements in available parameterizations. We therefore considered it timely to bring together leading scientists to summarize our present knowledege of those processes requiring parameterization in ocean models, to fully consider their optimal applications, and to introduce young scientists to the current state of the field. We would like to thank all the speakers for providing a stimulating series of lectures, collected in this volume, and especially Jim McWilliams for his active support before, during, and after the school. We also express our appreciation to the members of the scientific committee (in particular David Anderson and Jiirgen Willebrand), who contributed in numerous ways to the success of this Advanced Study Institute. We thank all the attendees for participating actively in the lecture review process and for creating a most cordial atmosphere. Finally, our thanks also go to Linda Smith, who spent a considerable amount of time proofreading the manuscripts. Primary support for this Advanced Study Institute was provided by the North Atlantic Treaty Organization (NATO) and the European Community (EC/TMR). Additional funding was provided by the National Science Foundation (NSF), the Centre National d'etudes Spatiales (CNES), and the Service Hydrographique et Oceanographique de la Marine (SHOM). This support is gratefully acknowledged. Eric P. Chassignet Jacques Verron April 1998