Geophysical Monograph Series

Including IUGG Volumes Maurice Ewing Volumes Mineral Physics Volumes Geophysical Monograph Series

137 Earth’s Climate and Orbital Eccentricity: The Marine 157 Seismic Earth: Array Analysis of Broadband Isotope Stage 11 Question André W. Droxler, Richard Seismograms Alan Levander and Guust Nolet (Eds.) Z. Poore, and Lloyd H. Burckle (Eds.) 158 The Nordic Seas: An Integrated Perspective Helge 138 Inside the Subduction Factory John Eiler (Ed.) Drange, Trond Dokken, Tore Furevik, Rüdiger Gerdes, 139 Volcanism and the Earth’s Atmosphere Alan Robock and Wolfgang Berger (Eds.) and Clive Oppenheimer (Eds.) 159 Inner Magnetosphere Interactions: New Perspectives 140 Explosive Subaqueous Volcanism James D. L. White, From Imaging James Burch, Michael Schulz, and Harlan John L. Smellie, and David A. Clague (Eds.) Spence (Eds.) 141 Solar Variability and Its Effects on Climate Judit M. 160 Earth’s Deep Mantle: Structure, Composition, and Pap and Peter Fox (Eds.) Evolution Robert D. van der Hilst, Jay D. Bass, 142 Disturbances in Geospace: The Storm-Substorm Jan Matas, and Jeannot Trampert (Eds.) Relationship A. Surjalal Sharma, Yohsuke Kamide, 161 Circulation in the Gulf of Mexico: Observations and and Gurbax S. Lakhima (Eds.) Models Wilton Sturges and Alexis Lugo-Fernandez (Eds.) 143 Mt. Etna: Volcano Laboratory Alessandro Bonaccorso, 162 Dynamics of Fluids and Transport Through Fractured Sonia Calvari, Mauro Coltelli, Ciro Del Negro, Rock Boris Faybishenko, Paul A. Witherspoon, and John and Susanna Falsaperla (Eds.) Gale (Eds.) 144 The Subseafloor Biosphere at Mid-Ocean Ridges 163 Remote Sensing of Northern Hydrology: Measuring William S. D. Wilcock, Edward F. DeLong, Deborah S. Environmental Change Claude R. Duguay and Alain Kelley, John A. Baross, and S. Craig Cary (Eds.) Pietroniro (Eds.) 145 Timescales of the Paleomagnetic Field James E. T. 164 Archean Geodynamics and Environments Keith Benn, Channell, Dennis V. Kent, William Lowrie, and Joseph Jean-Claude Mareschal, and Kent C. Condie (Eds.) G. Meert (Eds.) 165 Solar Eruptions and Energetic Particles Natchimuthukonar 146 The Extreme Proterozoic: Geology, Geochemistry, Gopalswamy, Richard Mewaldt, and Jarmo Torsti (Eds.) and Climate Gregory S. Jenkins, Mark A. S. McMenamin, 166 Back-Arc Spreading Systems: Geological, Biological, Christopher P. McKay, and Linda Sohl (Eds.) Chemical, and Physical Interactions David M. 147 Earth’s Climate: The Ocean–Atmosphere Interaction Christie, Charles Fisher, Sang-Mook Lee, and Chunzai Wang, Shang-Ping Xie, and James A. Carton (Eds.) Sharon Givens (Eds.) 148 Mid-Ocean Ridges: Hydrothermal Interactions Between 167 Recurrent Magnetic Storms: Corotating Solar the Lithosphere and Oceans Christopher R. German, Wind Streams Bruce Tsurutani, Robert McPherron, Jian Lin, and Lindsay M. Parson (Eds.) Walter Gonzalez, Gang Lu, José H. A. Sobral, and 149 Continent-Ocean Interactions Within East Asian Natchimuthukonar Gopalswamy (Eds.) Marginal Seas Peter Clift, Wolfgang Kuhnt, Pinxian 168 Earth’s Deep Water Cycle Steven D. Jacobsen and Suzan Wang, and Dennis Hayes (Eds.) van der Lee (Eds.) 150 The State of the Planet: Frontiers and Challenges 169 Magnetic ULF Waves: Synthesis and New Directions in‑Geophysics Robert Stephen John Sparks Kazue Takahashi, Peter J. Chi, Richard E. Denton, and and Christopher John Hawkesworth (Eds.) Robert L. Lysak (Eds.) 151 The Cenozoic Southern Ocean: Tectonics, 170 Earthquakes: Radiated Energy and the Physics of Sedimentation, and Climate Change Between Australia Faulting Rachel Abercrombie, Art McGarr, Hiroo and Antarctica Neville Exon, James P. Kennett, Kanamori, and Giulio Di Toro (Eds.) and Mitchell Malone (Eds.) 171 Subsurface Hydrology: Data Integration for 152 Sea Salt Aerosol Production: Mechanisms, Methods, Propertiesand Processes David W. Hyndman, Frederick Measurements, and Models Ernie R. Lewis and Stephen D. Day-Lewis, and Kamini Singha (Eds.) E. Schwartz 172 Volcanism and Subduction: The Kamchatka Region 153 Ecosystems and Land Use Change Ruth S. DeFries, John Eichelberger, Evgenii Gordeev, Pavel Izbekov, Gregory P. Anser, and Richard A. Houghton (Eds.) Minoru Kasahara, Jonathan Lees, (Eds.) 154 The Rocky Mountain Region—An Evolving Lithosphere: 173 Ocean Circulation: Mechanisms and Impacts—Past and Tectonics, Geochemistry, and Geophysics Karl E. Future Changes of Meridional Overturning Andreas Karlstrom and G. Randy Keller (Eds.) Schmittner, John C. H. Chiang, and Sidney R. Hemming 155 The Inner Magnetosphere: Physics and Modeling Tuija (Eds.) I. Pulkkinen, Nikolai A. Tsyganenko, and Reiner H. W. 174 Post-Perovskite: The Last Mantle Phase Transition Kei Friedel (Eds.) Hirose, John Brodholt, Thorne Lay, and David Yuen (Eds.) 156 Particle Acceleration in Astrophysical Plasmas: Geospace 175 A Continental Plate Boundary: Tectonics at South Island, and Beyond Dennis Gallagher, James Horwitz, Joseph New Zealand David Okaya, Tim Stern, and Fred Davey Perez, Robert Preece, and John Quenby (Eds.) (Eds.) Geophysical Monograph 176

Exploring Venus as a Terrestrial Planet

Larry W. Esposito Ellen R. Stofan Thomas E. Cravens Editors

American Geophysical Union Washington, DC Published under the aegis of the AGU Books Board Jean-Louis Bougeret, Chair; Gray E. Bebout, Cassandra G. Fesen, Carl T. Friedrichs, Ralf R. Haese, W. Berry Lyons, Kenneth R. Minschwaner, Andrew Nyblade, Darrell Strobel, and Chunzai Wang, members.

Library of Congress Cataloging-in-Publication Data

Subsurface hydrology : data integration for properties and processes / David W. Hyndman, Frederick D. Day-Lewis, Kamini Singha, editors. p. cm. -- (Geophysical monograph ; 171) ISBN 978-0-87590-437-5 1. Groundwater flow--Mathematical models. I. Hyndman, David W. II. Day-Lewis, Frederick D. III. Singha, Kamini. IV. American Geophysical Union. GB1197.7.S84 2007 551.49--dc22 2007017693

ISBN 978-0-87590-437-5 TKISSN 0065-8448

Front cover image: Spectral analysis of the stream discharge hydrograph (top) for the Muskegon River in central-northern Michigan, USA, reveals a rich time-varying power spectrum (bottom). Direct comparison of the discharge power spectrum to that of precipitation or water table fluctua- tions can provide significant insight into watershed processes. Courtesy of David W. Hyndman.

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 Geophyscial Union for libraries and other users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, provided that the base fee of $1.50 per copy plus $0.35 per page is paid directly to CCC, 222 Rosewood Dr., Danvers, MA 01923. 0065-8448/07/$01.50+0.35.

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 the American Geophysical Union.

Printed in the United States of America. Contents

Preface Larry W. Esposito, Ellen R. Stofan, Thomas E. Cravens...... vii

Exploring Venus: Major Scientific Issues and Directions Larry W. Esposito, Ellen R. Stofan, and Thomas E. Cravens ...... 1

Geochemistry of Venus’ Surface: Current Limitations as Future Opportunities Allan H. Treiman ...... 7

Surface Evolution of Venus Alexander T. Basilevsky and George E. McGill ...... 23

Tectonic and Thermal Evolution of Venus and the Role of Volatiles: Implications for Understanding the Terrestrial Planets Suzanne E. Smrekar, Linda Elkins-Tanton, Johannes J. Leitner, Adrian Lenardic, Steve Mackwell, Louis Moresi, Christophe Sotin, and Ellen R. Stofan...... 45

Atmospheric Composition, Chemistry, and Clouds Franklin P. Mills, Larry W. Esposito, and Yuk L. Yung...... 73

Venus Atmosphere Dynamics: A Continuing Enigma G. Schubert, S. W. Bougher, C. C. Covey, A. D. Del Genio, A. S. Grossman, J. L. Hollingsworth, S. S. Limaye, and R. E. Young...... 101

Radiation in the Atmosphere of Venus Dmitry V. Titov, Mark A. Bullock, David Crisp, Nilton O. Renno, Fredric W. Taylor, and Ljudmilla V. Zasova ...... 121

Venus Upper Atmosphere and Plasma Environment: Critical Issues for Future Exploration C. T. Russell, J. G. Luhmann, T. E. Cravens, A. F. Nagy, and R. J. Strangeway ...... 139

Venus Express and Terrestrial Planet Climatology Fredric W. Taylor, Håkan Svedhem, and Dmitri M. Titov...... 157

Experiencing Venus: Clues to the Origin, Evolution, and Chemistry of Terrestrial Planets via In-Situ Exploration of our Sister World Kevin H. Baines, Sushil K. Atreya, Robert W. Carlson, David Crisp, David Grinspoon, Christopher T. Russell, Gerald Schubert, and Kevin Zahnle...... 171

Astrobiology and Venus Exploration David H. Grinspoon and Mark A. Bullock...... 191

Technology Perspectives in the Future Exploration of Venus James A. Cutts, Tibor S. Balint, Eric Chassefiere, and Elizabeth A. Kolawa...... 207 Preface

Venus has long been recognized as a sister planet to the Steven Saunders, Gerald Schubert, Sue Smrekar, Ellen Stofan, Earth, as one of a triad of terrestrial planets with an atmo- Hakan Svedhem, and Fredric Taylor. This monograph consists sphere (Earth, Venus, Mars), and as a possible analogue for of invited chapters written by the authors of the major review planets circling other stars. Its dense CO2 atmosphere has talks at the Chapman Conference. Financial support for the provided both a lesson and a warning in our understanding conference was provided by NASA, ESA, and the University of the effects of greenhouse gases. of Colorado’s Laboratory for Atmospheric and Space Physics The planet was the first to be visited by spacecraft and was (LASP). More than 120 scientists attended the conference, the target of numerous American and Soviet space missions which emphasizes both the continuing interest in Venus and launched in the 1960s, 1970s, and 1980s. A long, dry spell the importance of Venus to understanding the origin, evolu- in the exploration of this planet was recently broken when tion, and possibly fate, of the terrestrial planets. ESA’s Venus Express went into orbit in 2006 (see the chapter We thank the following reviewers: M. Joan Alexander, by Taylor). Japan’s Venus Climate Orbiter will launch in Sushil K. Atreya, Kevin Baines, Bruno Bezard, Robert 2009. The NASA Messenger spacecraft, en route to Mercury, Carlson, Pierre Drossart, Linda Elkins-Tanton, Richard M. observed Venus closely when it flew by in June 2007. Future Goody, Richard Hartle, Jeffrey Kargel, Walter S. Kiefer, missions are under study by NASA and other space agencies. Vladimir Kranopolsky, Emmanuel Lellouch, Paula Martin, If Venus was the “forgotten planet,” it is now receiving well- Christopher McKay, Roger Phillips, David Stevenson, Jeff deserved close attention! Taylor, and Tielong Zhang. Finally, we are grateful for the With this revived interest, it was timely to hold the AGU- support of the Chapman Conference and this monograph from sponsored Chapman Conference “Exploring Venus as a NASA, ESA and the University of Colorado’s Laboratory for Terrestrial Planet” on 13–17 February 2006 in Key Largo, Atmospheric and Space Physics. Florida. The objectives of that conference were to review the This book is dedicated to all intrepid Venus explorers, past current knowledge of Venus and compare this planet with and future. Earth and Mars; to preview observation plans for Venus Express; and to identify key objectives for future research and space missions. Conference conveners were Larry W. Esposito and Dmitry Titov, and the program committee included Kevin Larry W. Esposito Baines, Alexander Basilevsky, Gordon Chin, David Crisp, Ellen R. Stofan Takeshi Imamura, Masato Nakamura, Christopher Russell, Thomas E. Cravens

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