Why We Study the Physics of the Ocean Why We Study the Physics of the Ocean: What Physical Oceanographers Really Do By William J. Emery Why We Study the Physics of the Ocean: What Physical Oceanographers Really Do By William J. Emery This book first published 2021 Cambridge Scholars Publishing Lady Stephenson Library, Newcastle upon Tyne, NE6 2PA, UK British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Copyright © 2021 by William J. Emery All rights for this book reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright owner. ISBN (10): 1-5275-6791-5 ISBN (13): 978-1-5275-6791-7 This book is dedicated to Henry Stommel who provided an early inspiration for me to write this book. It is also dedicated to my wife Dora and son Micah who have tolerated me writing it. TABLE OF CONTENTS 1.0 Introduction .......................................................................................... 1 1.1 Physical Oceanography as a Science .............................................. 3 2.0 Historical Development ........................................................................ 8 2.1 Benjamin Franklin .......................................................................... 8 2.2 Naturalists at Sea............................................................................. 9 2.2.1 Naturalist Observers ............................................................. 10 2.3 Organized Expeditions .................................................................. 11 2.3.1 U.S. Exploring Expedition ................................................... 11 2.3.2 The Challenger Expedition ................................................... 13 2.3.3 Fridtjof Nansen and the Fram Expedition ............................ 21 2.3.3.1 Vagn Walfrid Ekman ................................................... 26 2.3.3.2 The Dynamic Method .................................................. 28 2.4 Matthew Fountaine Maury ............................................................ 29 2.5 The Meteor Expedition (1925-27) ................................................ 32 2.6 Oceanographic Institutions ........................................................... 43 2.7 Two Leading Physical Oceanographers ........................................ 44 2.7.1 Henry Melson Stommel ........................................................ 45 2.7.2 Walter H. Munk .................................................................... 50 2.7.2.1 Munk's Evolution of Physical Oceanography .............. 52 3.0 Where Physical Oceanographers Work .............................................. 57 4.0 What are the Sub-disciplines of Physical Oceanography ................... 60 5.0 The Role of Funding in Ocean Research ............................................ 69 5.1 Funding of Research Vessels and the U.S. Research Fleet ........... 70 5.1.1 The Academic Research Fleet (ARF) ................................... 75 5.1.2 NOAA’s Research Fleet ....................................................... 78 5.1.3 UNOLS Operations .............................................................. 81 5.1.4 Research Fleet Capacity and Use ......................................... 82 5.1.5 Scientists at Sea-The Importance of Being There ................ 86 5.1.6 Telepresence at Sea .............................................................. 88 5.1.7 Research Fleet Renewal and Retirement .............................. 89 5.1.8 The Cost of Fleet Renewal ................................................... 94 viii Table of Contents 5.1.9 Fleet Support, Utilization and Operational Costs ................. 96 5.1.10 Ship Concept Designs ........................................................ 98 5.1.11 German Research Vessel Fleet ........................................... 99 5.1.12 The French Research Fleet ............................................... 103 5.1.13 Research Vessels of the United Kingdom ........................ 105 5.1.14 Research Vessel Summary ............................................... 109 6.0 Evolution of Measurements in Physical Oceanography ................... 111 6.1 Traditional Hydrographic Profiling............................................. 112 6.2 Electronic Methods ..................................................................... 116 6.2.1 Underway Upper Ocean Temperature Profiling ................. 124 6.2.1.1 The Mechanical Bathythermograph ........................... 124 6.2.1.2 The Expendable Bathythermograph .......................... 127 6.3 Deep-Sea Moorings .................................................................... 132 6.3.1 The Acoustic Release ......................................................... 132 6.3.2 Current Meter Moorings ..................................................... 135 6.3.3 Eulerian Current Meters ..................................................... 140 6.3.4 Non-mechanical Current Meters ........................................ 148 6.3.4.1 Acoustic Current Meters ............................................ 148 6.3.4.2 Electromagnetic Current Meters ................................ 150 6.3.5 Profiling instruments on moorings ..................................... 154 6.3.6 Lagrangian current measurements ...................................... 155 6.3.6.1 Surface Drifters .......................................................... 155 6.3.6.2 Subsurface Drifters .................................................... 170 6.4 Surface Buoys ............................................................................. 187 6.5 New Measurement Platforms ...................................................... 190 6.5.1 Gliders ................................................................................ 190 6.5.2 Wave Gliders ...................................................................... 194 6.5.3 Saildrones ........................................................................... 198 6.6 New Applications of Old Measurements .................................... 202 6.7 Coastal Surface Currents from High Frequency Radar ............... 203 6.8 Satellite Oceanography ............................................................... 206 6.8.1 Satellite Sea Surface Temperature (SST) ........................... 206 6.8.2 The JPSS and VIIRS .......................................................... 210 6.8.3 Low Light Sensing ............................................................. 214 6.8.4 The Special Sensor Microwave Imager (SSM/I) ................ 216 6.8.5 The Coastal Zone Color Scanner (CZCS) and SeaWIFS ... 220 6.8.6 SEASAT ............................................................................. 237 6.8.7 Satellite Altimetry .............................................................. 240 6.8.8 Ocean Wind Speed and Direction: Radar Scatterometry.... 247 Why We Study the Physics of the Ocean: ix What Physical Oceanographers Really Do 6.8.9 Directional Wave Spectra from Synthetic Aperture Radar (SAR) ..................................................................................... 251 6.8.10 Rainfall Over the Ocean ................................................... 253 6.8.11 Tracking Surface Features ................................................ 255 7.0 The Evolution of Major Challenges in Physical Oceanography ....... 261 7.1 Early Problems in Physical Oceanography ................................. 261 7.1.1 Salt in the Sea ..................................................................... 261 7.1.2 Tides in the Ocean .............................................................. 265 7.1.3 Waves in the Ocean ............................................................ 266 7.1.4 Establishing the Mean State of the Ocean .......................... 266 7.2 Modern Challenges in Physical Oceanography .......................... 267 7.2.1 Understanding Turbulent Diffusion and Dissipation .......... 267 7.2.2 The Discovery of Mesoscale Eddies; the Weather of the Ocean ........................................................................... 272 7.2.2.1 The Mid-Ocean Dynamics Experiment (MODE) ...... 274 7.2.2.2 Mesoscale Eddies from Satellite Altimetry ............... 282 7.2.2.3 Biological Consequences of Mesoscale and Submesoscale Eddies ....................................................... 293 7.2.3 El Nino and the Southern Oscillation (ENSO) ................... 296 7.2.4 The Submesoscale Circulation ........................................... 309 7.2.4.1 Observing the Submesoscale ..................................... 313 7.2.4.2 Relationships between Submesoscale Circulations and Biological Productivity.............................................. 322 7.2.5 The Ocean and the Climate ................................................ 328 7.2.5.1 Changing Ocean Heat-Content; the Warming of the Ocean ..................................................................... 329 7.2.5.2 Global Ocean Sea Level Rise .................................... 334 7.2.5.3 Coupled Climate System ........................................... 340 8.0 Conferences and Meetings in Physical Oceanography ..................... 343 8.1 Review Panels ............................................................................. 344 9.0 Writing Research Proposals and Research Papers ............................ 346 9.1 The Research Proposal ...............................................................