Aerosol Pollution Impact on Precipitation
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Aerosol Pollution Impact on Precipitation Zev Levin l William R. Cotton Editors Aerosol Pollution Impact on Precipitation A Scientific Review 13 Editors Zev Levin William R. Cotton 69978 Tel Aviv Ft.Collins CO 80523 Dept. of Geophysics Colorado State University Tel Aviv University USA Israel [email protected] [email protected] ISBN: 978-1-4020-8689-2 e-ISBN: 978-1-4020-8690-8 Library of Congress Control Number: 2008933938 # Springer ScienceþBusiness Media B.V. 2009 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Printed on acid-free paper 987654321 springer.com Lead Authors Name Affiliation Country Andreae, Meinrat Max Planck Institute for Chemistry, Mainz Germany O. Artaxo, Paulo University of Sao Paulo, Sao Paulo Brazil Barrie, Leonard. A. WMO, Geneva Switzerland Brenguier, Jean- Meteo France, Paris France Louis Cotton, William R. Colorado State University, Fort Collins, CO USA Feingold, Graham NOAA, Earth System Research Laboratory, Boulder, USA CO Gong, Sunling L. Environment Canada, Dufferin St., Toronto, Canada Canada Hegg, Dean A. University of Washington, Seattle, WA USA Kaufman,Yoram NASA, Goddard, Greenbelt, MD USA (deceased) Levin, Zev Tel Aviv University, Tel Aviv Israel Lohmann, Ulrike ETH, Zurich Switzerland Tanre´, Didier CNRS, University of Lille, Lille France Yuter, Sandra North Carolina State University, Raleigh, NC USA Liaisons L.A. Barrie (WMO) R. List (IUGG) Co-authors and Contributor Authors Co-authors and Contributors Chapters Arimoto, R. 4 Baltensperger, U. 5 Barrie, L. A. 3 Brenguier, J. L. 2 Bruintjes, R. T. 8 Cotton, W. R. 6 Feichter, J. 3 Feingold, G. 2, 5, 6, 7 Guibert, S. 4 Hallett, J. 2, 6 Hobbs, P. V. (deceased) 2, 8 Kinne, S. 4 Kloster, S. 3 Kreidenweis, S. M. 3, 4 Levin, Z. 2, 3, 5, 8 Li, S.M. 4 Liousse, C. 3 Lohmann, U. 2 Radke, L. F. 5 Schulz, M. 4 Shepherd, J. M. 5 Stier, P. 3 Strawbridge, K. 4 Sugimoto, N. 4 Terblanche, D. 8 Textor, C. 3, 4 Zhang, L.M. 4 Scientific Reviewers Chairperson: Dr. George Isaac, Environment Canada Name Affiliation Country Ayers, Greg CSIRO Marine and Atmospheric Research Australia Barth, Mary National Center of Atmospheric Research USA Bormann, Stephan Johannes-Gutenberg-University Germany Choularton, Thomas University of Manchester UK DeMott, Paul Colorado State University USA Laboratoire de Me´te´orologie Physique/OPGC Flossmann, Andrea Universite´Blaise Pascal/CNRS France Kahn, Ralph Jet Propulsion Laboratory USA Khain, Alexander The Hebrew University of Jerusalem Israel Leaitch, Richard Environment Canada Canada Pandis, Spyros University of Patras Greece Rosenfeld, Daniel The Hebrew University of Jerusalem Israel Ryan, Brian CSIRO Marine and Atmospheric Research Australia Twohy, Cynthia Oregon State University USA Vali, Gabor University of Wyoming USA Yau, Peter McGill University Canada Zipser, Ed University of Utah USA Contents Foreword .................................................. xi Preface ................................................... xiii Executive Summary .......................................... xv 1 Introduction ............................................. 1 Leonard A. Barrie, Ulrike Lohmann and Sandra Yuter 2 Principles of Cloud and Precipitation Formation ................. 13 William R. Cotton and Sandra Yuter 3 Sources and Nature of Atmospheric Aerosols.................... 45 Meinrat O. Andreae, Dean A. Hegg and Urs Baltensperger 4 The Distribution of Atmospheric Aerosols: Transport, Transformation and Removal ................................ 91 Sunling Gong and Leonard A. Barrie 5 In Situ and Remote Sensing Techniques for Measuring Aerosols, Clouds and Precipitation ................................... 143 Didier Tanre´, Paulo Artaxo, Sandra Yuter and Yoram Kaufman 6 Effects of Pollution and Biomass Aerosols on Clouds and Precipitation: Observational Studies ....................... 205 Zev Levin and Jean-Louis Brenguier 7 Effects of Pollution Aerosol and Biomass Burning on Clouds and Precipitation: Numerical Modeling Studies.......... 243 Graham Feingold, William Cotton, Ulrike Lohmann and Zev Levin ix x Contents 8 Parallels and Contrasts Between Deliberate Cloud Seeding and Aerosol Pollution Effects ............................... 277 William R. Cotton 9 Summary ............................................... 295 10 Recommendations ........................................ 301 Appendix A: List of Acronyms Used in the Report .................. 307 References ................................................. 313 Index ..................................................... 383 Foreword In 2003, the World Meteorological Organization (WMO) and the International Union for Geodesy and Geophysics (IUGG) agreed to conduct jointly a scien- tific review of the current state of knowledge on the impacts of aerosol pollution on rain, snow and hail. The review is concerned with a critical societal resource: water. Problems are frequently encountered in relation to too little water, such as those caused by droughts, or to too much water causing flooding and landslides. Under a changing climate and a growing global population, the availability of enough water to sustain life ranks amongst the highest priorities in many communities, especially in developing countries. Considerable evi- dence was presented in the recent Intergovernmental Panel for Climate Change (IPCC) Fourth Assessment Report in the sense that pollution aerosols can affect climate by altering the Earth’s energy budget. These aerosols do so by absorbing or reflecting radiation in clear skies or by affecting clouds that in turn interact with solar and terrestrial radiation. However, less well understood are the effects of aerosols on precipitation in the form of rain, snow and hail. Atmospheric suspended particulate matter, commonly known as aerosols, can originate from many types of human activity in the form of wind-blown sand and dust, biomass-burning particles and smog particles from fossil fuel combustion and industrial activities. The hydrological cycle is potentially very vulnerable to changes in climate and to associated changes in aerosol pollution, so a key question would be: How far have we progressed in quantifying the impacts on the amount of water reaching the ground from the atmosphere and its temporal or spatial distributions? It has been noted that even relatively small changes in the spatial distribution of rain might cause significant shortages in one country and abundance or even flooding in another. WMO and the IUGG opportunely requested a review of the state of scientific knowledge on this subject as well as recommendations on the issues to be studied in order to advance the decision-making capabilities of those responsible for managing water supply problems. A group of experts under the leadership of Professors Zev Levin and William Cotton produced an assess- ment of the subject that was subsequently reviewed independently by a team of scientists led by Dr. George Isaac. The late Professor Peter Hobbs is also acknowledged for beginning this initiative. WMO and IUGG wish to thank xi xii Foreword all those who volunteered their time and efforts to contribute to this scientific review, which sets a benchmark in our current understanding of this complex phenomenon and provides a valuable introduction to the subject for the next generation of scientists. The review also makes specific recommendations for collective international actions that can be deemed essential in advancing our knowledge in this critical field. A number of internationally coordinated projects have been proposed that, if carefully designed and implemented, could considerably contribute to unraveling the complex interactions occurring among aerosols, clouds and precipitation. It has been suggested that WMO and IUGG should take the lead in such projects, together with other organizations of the UN System. This is indeed a challenge that our respective organizations are particularly suited to address and one that they would be prepared to consider. In this respect, WMO has a long history in organizing research assessments like the IPCC which it co-sponsors with UNEP and others that have led to highly successful environmental conventions, such as the Vienna Convention on the Protection of the Ozone Layer, and has also contributed to the global coordination of atmospheric and marine observations. Moreover, WMO has coordinated the international provision of weather and climate warnings for over a century. IUGG complements these capabilities with a broad programme of research in Earth systems undertaken by a global community organized under its scientific associations, two of which, the International Association of Meteorology and Atmospheric Science (IAMAS) and the International Association of Hydrological Sciences (IAHS), are particularly involved in these issues. It is therefore our sincere wish that the full strength of early 21st Century science and technology can be focused on international projects to enhance our understanding of aerosol impacts on precipitation and thereby contribute to reduce the societal impacts of hydrometeorological disasters. (M. Jarraud) (T. Beer) Secretary-General President World Meteorological Organization