Coastal and Estuarine Studies

Transcription

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

2 Solinity: :. W', ter f'-,ß The mean salinity field for winter in the Western Mediterranean Sea, reconstructed from a climatological data set (scattered data), using the GHER Variational Inverse Model (Brasscur and Haus). The colors highlight the intermediate depth intrusion of the progressively modified Levantine Intermediate Water that originates in the Eastern Mediterranean Sea and spreads westward through the Strait of Sicily into the Western Mediterrananean. The winter mean salinity field is presented using volume rendering techniques. The seabed is depicted as semi-transparent, allowing the viewer to visualize the complete salinity field as a single entity. Isobaths (every 300 meters) are drawn onto the semi-transparent seabed to enhance the viewing aspect. In this book the interannual as well as seasonal aspects of the LIW and of other water masses in the Western Mediterranean will be examined to derive their variability as well as their possible forcing. This rendition of the Western Mediterranean winter mean salinity field was made by Jacques Haus and Pierre P. Brasscur (GHER, Sart-Tilman, B5, University of Liege, 4000 Liege, Belgium) with the support of IBM (Winchester Scientific Centre, UK), using IBM Data Explorer

3 Coastal and Estuarine Studies 46 Paul E. La Violette (Ed.) Seasonal and Interannual Variability of the Western Mediterranean Sea ' EARs American Washington, Geophysical Union

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 Editor Paul E. La Violette Mississippi State University Research Center Stennis Space Center, MS 39529, USA Library of Congress Cataloging-in-Publication Data Seasonal and interannual variability of the western Mediterranean Sea / Paul E. La Violette (ed.). p. cm. -- (Coastal and estuarine studies; 46) Includes bibliographical references and index. ISBN X 1. Oceanography--Western Mediterranean. 2. Ocean circulation --Western Mediterranean. I. La Violette, Paul E. II. Series. GC651.S '2--dc CIP ISSN ISBN X Copyright 1994 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 $0.10 per page is paid directly to CCC, 222 Rosewood Dr., Danvers, MA /94/$ 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 1 Overview of the Major Forcings and Water Masses of the Western Mediterranean Sea Paul E. La Violette... 1 PART A. SEASONAL AND INTERANNUAL VARIABILITY IN THE STRAITS 2 An Estimate of the Net Heat Transport Through the Strait of Gibraltar Alison M. Macdonald, Julio Candela, and Harry L. Bryden The Seasonal Variability of the Water Masses and Transport Through the Strait of Sicily Giuseppe M. R. Manzella PART B. SEASONAL AND INTERANNUAL VARIABILITY IN THE REGIONAL BASINS 4 Mesoscale Variability and Q Vector Vertical Motion in the Alboran Sea Joaquœn Tintor, Alvaro Vi dez, Dami& Gomis, Sergio Alonso, and Francisco E. Werner Surface Circulation and Dynamics of the Balearic Sea Emilio Garcia, Joaql in Tintor, Jean Michel Pinot, Jordi Font, and Mario Manriq te The Seasonal and Interannual Variability in the Ligurian-Provenqal Basin Mario Astraldi, Gian Pietro Gasparini, and Stefania Sparnocchia The Seasonal Characteristics of the Circulation in the Tyrrhenian Sea Mario Astraldi and Gian Pietro Gasparini The Surface Characteristics of the Tyrrhenian Sea: Historical Satellite Data Analysis S. Mar tllo, R. Santoleri, and F. Bignami...

6 PART C' SEASONAL AND INTERANNUAL VARIABILITY IN THE SURFACE AND DEEP WATERS 9 The Sea Surface Temperature of the Western Mediterranean Sea' Historical Satellite Thermal Data Rosalia Santoleri, Emanuele B6hm, and Maria Elisabetta Schiano The Interannual and Seasonal Variability of the MAW and LIW Core Properties in the Western Mediterranean Sea Stefania Sparnocchia, Giuseppe M. R. Manzella, and Paul E. La Violette The Temporal and Spatial Variability of Chlorophyll in the Western Mediterranean Robert Arnone The Formation of Western Mediterranean Deep Water Kevin D. Leaman PART D. WESTERN MEDITERRANEAN BASIN DYNAMICS 13 The Dynamics of the Seasonal Variability of the Western Mediterranean Circulation G. W. Heburn Investigation of the Western Mediterranean's Hydrodynamics with the Gher Three-Dimensional Primitive Equation Model J. M. Beckers, P. Brasseur, S. Djenidi, and J. C. J. Nihoul Barotropic Response of the Western Mediterranean to Observed Atmospheric Pressure Forcing Julio Candela and Carlos J. Lozano Topographic Forcing of the Circulation of LIW in the Western Mediterranean Alberto Alvarez, Joaqufn Tintor, Greg Holloway, Michael Eby, and Jean Marie Beckets LIST OF CONTRIBUTORS...

7 Preface This book covers an important period in the study of the Mediterranean Sea. An understanding of the fundamental ocean processes occurring in this important body of water has crucial implications for climatic studies, pollution mitigation, and fisheries management. During the 1980s, severalarge-scale, long-term international experiments were conducted in the Western Mediterranean, providing a wealth of oceanographic information. The current volume is an outgrowth of these field campaigns and the related data analysis. It describes the seasonal and interannual variabilities of the sea and its sub-basins and the forcings related to these variabilities, it examines what is known (and not known) about the western portion of the sea, and it provides in a convenient format a basis on which future investigators can build. The results of the first field campaign, Donde Va? in 1982, raised as many questions as answers. At the coffee tables during a 1983 NATO study meeting in La Spezia, Italy, it was decided that the time and resources were appropriate to study the Western Mediterranean as a single entity. Agreements for pooling resources and setting timetables were made, and the Western Mediterranean Circulation Experiment (WMCE) Consortium was formed. The purpose of the WMCE was to study the circulation of the Western Mediterranean Sea, from the Strait of Sicily to the Strait of Gibraltar, using scales ranging from 1 km to basin size and depths from the surface to the deepest layers. An international consortium of multi-disciplined marine investigators formed its study group, each with programs adapted to achieve the common goal--to derive the spatial and temporal variability of the Western Mediterranean Sea circulation. The field work was conducted during the period August 1985 through March As a result of this field work the major aspects of the circulation and its seasonal variability have been defined. However, there still remains a debate on the relative importance of the various forcings acting on the circulation at any one time and the time scales related to seasonal and interannual variability of these forcings. This volume describes present thinking on the answers to these questions. Paul E. La Violette Editor