Satellite Altimetry and Earth Sciences

Transcription

1 Satellite Altimetry and Earth Sciences

2 Satellite Altimetry and Earth Sciences

3 This is Volume 69 in the INTERNATIONAL GEOPHYSICS SERIES A series of monographs and textbooks Edited by RENATA DMOWSKA, JAMES R. HOLTON, and H. THOMAS ROSSBY A complete list of books in this series appears on the IGS Website,

4 Satellite Altimetry and Earth Sciences A Handbook of Techniques and Applications Edited by Lee-Lueng Fu Jet Propulsion Laboratory California Institute of Technology Pasadena, California Anny Cazenave Laboratoire d'etudes en Geophysique et Oceanographie Spatiates Centre National d'etudes Spatiates Toulouse, France ACADEM IC PRESS San Diego A Horcourt Science ond Technology Compony San Francisco New York Boston London Sydney Tokyo

5 This book is printed on acid-free paper. Copyright Cc~ 2001 by ACADEMIC PRESS All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt, Inc., 6277 Sea Harbor Drive, Orlando, Florida Explicit permission from Academic Press is not required to reproduce a maximum of two figures or tables from an Academic Press chapter in another scientific or research publication provided that the material has not been credited to another source and that full credit to the Academic Press chapter is given. Academic Press A Harcourt Sctence and Technology Company 525 B Street, Suite 1900, San Diego, California , USA acad emi cpress, com Academic Press Harcourt Place, 32 Jamestown Road, London NW1 7BY, UK academi cpres s. com Library of Congress Catalog Card Number: International Standard Book Number: PRINTED IN THE UNITED STATES OF AMERICA EB

6 Contents Contributors Preface xi ix 1 Satellite Altimetry DUDLEY B. CHELTON, JOHN C. RIES, BRUCE J. HAINES, LEE-LUENG FU, AND PHILIP S. CALLAHAN 1. Introduction 1 2. Radar Measurement Principles Normalized Radar Cross Section Ocean Surface Reflectivity Atmospheric Attenuation Two-Way Travel Time Range Estimation Atmospheric Refraction Sea-State Effects Precision Orbit Determination The Orbit Determination Concept Precision Satellite Tracking Systems Orbit Estimation Performance Assessment Future Prospects Geophysical Effects on the Sea Surface Topography GeoidUndulations Dynamic Sea-Surface Height Ocean Tides Atmospheric Pressure Loading Aliased BarotropicMotion Significant Wave Height Estimation Significant Wave-Height Algorithms Significant Wave Height Measurement Accuracy Wind-Speed Estimation Wind-Speed ModelFunctions Wind Speed Measurement Accuracy TOPEX/POSEIDON Mission Design and Performance Orbit Considerations and Altimeter Sampling Patterns Calibration and Validation Measurement Performance Outlook for Future Altimeter Missions 119 Acknowledgments 121 References Large-Scale Ocean Circulation LEE-LUENG FU AND DUDLEY B. CHELTON 1. Introduction The Ocean General Circulation The Temporal Variability Buoyancy-Forcing and the Heat Budget of the Ocean Atmospheric Pressure Forcing Wind Forcing Baroclinic Rossby Waves The Relation Between Sea Level and Subsurface Variability The Annual Cycle InterannualVariability Conclusions 163 Acknowledgments 165 References 165

7 vi CONTENTS 3 Ocean Currents and Eddies P. Y. LE TRAON AND R. MORROW 1. Introduction Altimeter Data Processing for Mesoscale Studies Ocean Signal Extraction Mapping and Merging of Multiple Altimeter Missions Surface Geostrophic Velocity Calculations Sampling Issues Ocean Currents Estimating the Absolute Velocities and Transports from Altimetry Western Boundary Currents Eastern Boundary Currents Open Ocean Currents Semi-Enclosed Seas Mesoscale Eddies Global Statistical Description Seasonal Variations of Mesoscale Variability Intensity Space and Time Scales of Mesoscale Variability Frequency/Wavenumber Spectral Analysis Comparison with Eddy-Resolving Models Eddy Dynamics Conclusions 209 Acknowledgments 210 References Data Assimilation by Models ICHIRO FUKUMORI 1. Introduction Examples and Merits of Data Assimilation Data Assimilation as an Inverse Problem Assimilation Methodologies Inverse Methods Overview of Assimilation Methods Adjoint Method Representer Method Kalman Filter and Optimal Smoother Model Green's Function Optimal Interpolation Three-Dimensional Variation Method Direct Insertion Nudging Summary and Recommendation Practical Issues of Assimilation Weights, A Priori Uncertainties, and Extrapolation Verification and the Goodness of Estimates 5.3. Observability Mean Sea Level Summary and Outlook 261 Acknowledgments 262 References Tropical Ocean Variability JOEL PICAUT AND ANTONIO J. BUSALACCHI 1. Introduction Tropical Pacific Sea-level Validation Altimetry-derived Surface Current Evidence of Equatorial Waves Testing Theories of ENSO, Improving Its Prediction Changes of Mass, Heat and Salt of the Upper Ocean High-frequency Oscillations Indian Ocean Tropical Atlantic Conclusion 232 Acknowledgments 233 References Ocean Tides C. LE PROVOST 1. Introduction Mathematical Representation of Ocean Tides The Harmonic Expansion The Response Formalism The Orthotide Formalism Status Before High-Precision Satellite Altimetry In Situ Observations Hydrodynamic Numerical Modeling Modeling With Data Assimilation Methodologies for Extracting Ocean Tides from Altimetry Tidal Aliasing in Altimeter Data Methods for Estimating Ocean Tides from Satellite Altimetry 275

8 CONTENTS vii 5. The Semi-Diurnal and Diurnal Tides over the Deep Ocean Characteristics of the Ocean Tides at the Global Scale Coherency and Accuracy Assessment The Long Period Ocean Tides Internal Tides Methodology for Internal Tide Extraction from Satellite Data Recent Results on Internal Tides from Satellite Altimetry The Tides over Shallow Waters Nonlinear Constituents Solutions from Altimetry Improving Shallow-water Tide Solution Through Assimilation Tidal Energetics and Satellite Altimetry Dissipation Through Bottom Friction Tidal Fluxes Internal Tide Dissipation Applications Earth Rotation Tidal Loading Tidal Currents Tides and Coastal Engineering Conclusions 300 Acknowledgments 301 References Ocean Surface Waves J.-M. LEFI~VRE AND P. D. COTTON 1. Introduction Wave Modeling and Altimetry NumericalWave Prediction AltimetricApplications Operational Data Assimilation Use of Model Data to Improve Altimetry Wave Climate Studies with Altimeter Data Introduction The Data Global Ocean Wave Field Climate Variability Summary Conclusions Glossary 327 Acknowledgments 327 References Introduction Sea Level Change R. S. NEREM AND G. T. MITCHUM 2. The Tide Gauge Record and its Limitations Satellite Altimeter Measurements of Sea-Level Change Calibration of Satellite Altimeter Measurements Using Tide Gauge Data Detecting Changes in the Rate of Sea-Level Rise Global Mean Changes in Sea Level, Sea-Surface Temperature, and Precipitable Water Spatial Variations of Sea-Level Change and Sea-Surface Temperature Linking Together Different Satellite Altimeter Missions Conclusions 347 Acknowledgments 347 References Ice Sheet Dynamics and Mass Balance H. JAY ZWALLY AND ANITA C. BRENNER 1. Introduction Radar Altimeter Measurement of Ice Sheet Surface Elevations The Effect of Surface Slope and Undulations The Effect of Penetration and Sub-surface Volume Scattering Waveform Shape Fitting and Retracking Summary of Radar Altimetry Missions Used for Ice Sheet Elevation Studies Greenland and Antarctica Ice Sheet Topography Data Preparation Gridding Procedure Accuracy Analysis of Digital Elevation Models Ice Surface Slopes and Driving Stresses Measurement of Ice Margins Surface Elevation Changes and Mass Balance 363 Acknowledgments 367 References 367

9 viii CONTENTS 10 Applications to Geodesy BYRON D. TAPLEY AND MYUNG-CHAN KIM 1. Introduction Mean Sea Surface Mapping Historical Review Repeat-Track Averaging Crossover Adjustment Weighted Least-Squares Objective Analysis Gravity Recovery Geoid Undulation and Gravity Anomaly Short-Wavelength Marine Gravity Field Global Gravity Recovery Marine GeoidError New Frontiers Time-Varying Gravity Field Variations in the Geocenter and Earth Rotation Parameters Roles of Satellite Gravity Data Concluding Remarks 403 Acknowledgments 403 References Applications to Marine Geophysics ANNY CAZENAVE AND JEAN YVES ROYER 1. Introduction Filtering the Long-Wavelength Geoid Signal Geoid Anomalies and Isostatic Compensation Local Compensation in the Long-Wavelength Approximation Regional Compensation Admittance Approach Mechanical Behavior of Oceanic Plates: Flexure under Seamount Loading Thermal Evolution of the Oceanic Lithosphere Oceanic Hotspot Swells Short and Medium Wavelength Lineations in the Marine Geoid Mapping the Seafloor Tectonic Fabric Fracture Zones Seamounts Spreading Ridges Conclusions 434 Acknowledgments 435 References Bathymetric Estimation DAVID T. SANDWELL AND WALTER H. E SMITH 1. Introduction Gravity Anomaly and Sea Surface Slopes Geoid Height, Vertical Deflection, Gravity Gradient, and Gravity Anomaly Limitations of Radar Alitmetry for Gravity Field Recovery Forward Models Inverse Approaches Data Availability and Case Study: Bathymetric Estimation Results, Verification, and Hypsometry Effects on Ocean Currents Prospects for the Future Appendix: Interaction of the Radar Pulse with the Rough Ocean Surface Beam-Limited Footprint Pulse-limited Footprint Significant Wave Height Modeling the Return Waveform 456 References 456 Index 459