Uncertainty Management in Remote Sensing of Climate Data: Summary of a Workshop (2009)

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Uncertainty Management in Remote Sensing of Climate Data SUMMARY OF A WORKSHOP Martha McConnell and Scott Weidman, Rapporteurs Board on Atmospheric Sciences and Climate Climate Research Committee Board on Mathematical Sciences and Their Applications Committee on Applied and Theoretical Statistics Space Studies Board Committee on Earth Studies Division on Earth and Life Studies Division on Engineering and Physical Sciences 

THE NATIONAL ACADEMIES PRESS  500 Fifth Street, N.W.  Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Gov- erning Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engi- neering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This study was supported by the National Aeronautics and Space Administra- tion contract number NNH07CC37B for the Climate Research Committee and NNH06CE15B for the Committee on Earth Studies, and National Science Founda- tion contract number DMS-0456571 for the Committee on Applied and Theoretical Statistics. Any opinions expressed in this material are those of the author(s) and do not necessarily reflect the views of NASA, NSF, or any of its sub agencies. International Standard Book Number-13:  978-0-309-13958-8 International Standard Book Number-10:  0-309-13958-9 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu. Copyright 2009 by the National Academy of Sciences. All rights reserved. Printed in the United States of America 

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PLANNING COMMITTEE FOR A WORKSHOP ON UNCERTAINTY MANGEMENT IN REMOTE SENSING OF CLIMATE DATA AMY BRAVERMAN (Chair), Jet Propulsion Laboratory, Pasadena, California PHILIP E. ARDANUY, Raytheon Information Solutions, Reston, Virginia JOHN J. BATES, National Oceanic and Atmospheric Administration, Asheville, North Carolina JAMES A. COAKLEY, JR., Oregon State University, Corvallis KAREN KAFADAR, Indiana University, Bloomington DOUGLAS NYCHKA, National Center for Atmospheric Research, Boulder, Colorado JOYCE E. PENNER, University of Michigan, Ann Arbor STEVEN PLATNICK, National Aeronautics and Space Administration, Greenbelt, Maryland NRC Staff MARTHA MCCONNELL, Associate Program Officer SCOTT WEIDMAN, Study Director IAN KRAUCUNAS, Senior Program Officer ART CHARO, Senior Program Officer LAUREN BROWN, Christine Mirzayan Fellow KATIE WELLER, Research Associate SHELLY-ANN FREELAND, Senior Program Assistant  

CLIMATE RESEARCH COMMITTEE GERALD MEEHL (Chair), National Center for Atmospheric Research, Boulder, Colorado ANA P. BARROS, Duke University, Durham, North Carolina CECILIA BITZ, University of Washington, Seattle JAMES COAKLEY JR., Oregon State University, Corvallis GABRIELE HEGERL, University of Edinburgh, Scotland HENRY D. JACOBY, Massachusetts Institute of Technology, Cambridge ANTHONY C. JANETOS, Pacific Northwest National Laboratory/University of Maryland, College Park ROBERT LEMPERT, RAND Corporation, Santa Monica, California ROGER B. LUKAS, University of Hawaii, Honolulu LINDA MEARNS, National Center for Atmospheric Research, Boulder, Colorado SUMANT NIGAM, University of Maryland, College Park JOYCE E. PENNER, University of Michigan, Ann Arbor RICHARD RICHELS, Electric Power Research Institute, Washington, D.C. TARO TAKAHASHI, Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York LONNIE G. THOMPSON, Ohio State University, Columbus COMMITTEE ON APPLIED AND THEORETICAL STATISTICS KAREN KAFADAR (Chair), Indiana University, Bloomington AMY BRAVERMAN, Jet Propulsion Laboratory, Pasadena, California CONSTANTINE GATSONIS, Brown University, Providence, Rhode Island MICHAEL F. GOODCHILD, University of California, Santa Barbara MICHAEL A. NEWTON, University of Wisconsin, Madison MICHAEL STEIN, University of Chicago, Illinois COMMITTEE ON EARTH STUDIES BERRIEN MOORE III (Chair), Climate Central, Princeton, New Jersey RUTH S. DeFRIES (Vice Chair), Columbia University, New York MARK R. ABBOTT, Oregon State University, Corvallis RICHARD A. ANTHES, University Corporation for Atmospheric Research, Boulder, Colorado PHILIP E. ARDANUY, Raytheon Information Solutions, Reston, Virginia STEVEN J. BATTEL, Battel Engineering, Scottsdale, Arizona ANTONIO J. BUSALACCHI, JR., University of Maryland, College Park HEIDI M. DIERSSEN, University of Connecticut, Storrs THOMAS H. VONDER HAAR, Colorado State University, Fort Collins HUNG-LUNG ALLEN HUANG, University of Wisconsin, Madison ANNE W. NOLIN, Oregon State University, Corvallis JAY S. PEARLMAN, Boeing Company, Kent, Washington vi 

Preface T he National Academies’ Climate Research Committee (CRC), orga- nized under the Board on Atmospheric Sciences and Climate, is charged to foster atmospheric, oceanic, and related research aimed at advancing knowledge and understanding of climate and climate change. The Committee on Applied and Theoretical Statistics (CATS), which is organized under the Board on Mathematical Sciences and Their Applications, is charged to provide a locus of activity and concern for the statistical sciences, statistical education, use of statistics, and issues affect- ing the field. The Committee on Earth Studies (CES), organized under the Space Studies Board, provides oversight on civil earth observation space activities in the general areas of earth sciences and other remote sensing applications, including both applicable technology and all earth science disciplines that can be addressed from space. All three committees have expertise and a longstanding interest in the use of statistics in climate research and applications. Satellites provide a unique vantage point for studying the earth’s climate and associated systems, but obtaining climate-relevant data from remotely sensed platforms is a demanding task requiring careful analysis and expertise from numerous disciplines. Many of the techniques cur- rently used to process and analyze remotely sensed climate data could potentially be improved using modern statistical techniques. This is par- ticularly true because the amount of data involved has increased so dra- matically. To address these issues, and stimulate additional opportunities for beneficial collaboration between statisticians, climate scientists, and vii 

viii PREFACE experts in remote sensing, a workshop was convened December 4, 2008, in Washington, D.C., under the auspices of the CRC, CATS, and CES to explore uncertainty management in remote sensing, with an emphasis on remotely sensed climate information. This workshop brought together the statistics and geoscience communities from academia, government, and industry. Through invited presentations and discussion, participants investi- gated the sources of uncertainty throughout satellite and other remote data collection systems, described the statistical methods currently used to quantify sources of uncertainty, and discussed how modern statistical methods might be used to provide a more useful framework for char- acterizing and propagating these uncertainties. The primary objectives were to examine sources of uncertainty in remote sensing data collection systems that include, among other things, issues of sampling, scale, pro- cessing, and validation. Other topics covered at the workshop included the challenge of communicating uncertainties to the end-user and build- ing institutional capacity to address problems that require expertise from both statisticians and earth scientists. Under the National Academies’ policy, workshops do not produce findings and recommendations. Thus, the goal of this workshop report is to summarize the major discussion items that arose and to synthesize key points from the presentations on uncertainty management in remote sens- ing. This report was written by rapporteurs and we hope that the broad topics covered in this report will stimulate additional opportunities for collaborations betweens statisticians and earth scientists. We thank the planning team, the presenters, and other participants at the workshop. Martha McConnell Scott Weidman Rapporteurs 

Acknowledgments T his workshop report was written by National Academies staff based on the presentations and discussion at the workshop. It does not necessarily represent the views of the workshop planning com- mittee, which was not involved in its production. This report has been reviewed in draft form by individuals chosen for their diverse perspec- tives and technical expertise, in accordance with procedures approved by the National Research Council’s (NRC’s) Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional stan- dards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this summary: Amy Braverman, Jet Propulsion Laboratory, Pasadena, California John J. Bates, National Oceanic and Atmospheric Administration, Asheville, North Carolina Anna Michalak, University of Michigan, Ann Arbor Ivanka Stajner, Noblis, Inc., Falls Church, Virginia Although the reviewers listed above have provided many construc- tive comments and suggestions, they were not asked to endorse the con- clusions and recommendations from the speakers nor did they see the ix 

 ACKNOWLEDGMENT final draft of the summary before its release. Lee Branscombe, Clima- tological Consulting Corporation, oversaw the review of this summary. Appointed by the NRC, he was responsible for making certain that an independent examination of this summary was carried out in accordance with institutional procedures and that all review comments were care- fully considered. Responsibility for the final content of this summary rests entirely with the authors and the institution. 

Contents 1 INTRODUCTION 1 Why Worry About Statistical Structure: An Example from Modeling Snow Depth, 6 2 CROSS-CUTTING ISSUES 11 Validation of Remotely Sensed Climate Data, 11 The Need to Stay Focused on the End-User, 17 Cross-Disciplinary Collaborations between Climate Scientists and Statisticians, 19 3 CONCLUDING THOUGHTS 24 REFERENCES 26 APPENDIXES A Workshop Agenda 29 B Summaries of Workshop Presentations 32 C Planning Committee and Rapporteur Biographies 48 xi