The Pavement Precipitation Accumulation Estimation System— Further Development http://aurora-program.org Aurora Project 2009-05 Final Report May 2013 About Aurora Aurora is an international program of collaborative research, development and deployment in the field of road and weather information systems (RWIS), serving the interests and needs of public agencies. The Aurora vision is to deploy RWIS to integrate state-of-the-art road and weather forecasting technologies with coordinated, multi-agency weather monitoring infrastructures. It is hoped this will facilitate advanced road condition and weather monitoring and forecasting capabilities for efficient highway maintenance, and the provision of real-time information to travelers. Disclaimer Notice The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. 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The opinions, findings, and conclusions expressed in this publication are those of the authors and not necessarily those of the Iowa Department of Transportation or the U.S. Department of Transportation Federal Highway Administration. Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. Aurora Project 2009-05 4. Title and Subtitle 5. Report Date The Pavement Precipitation Accumulation Estimation System—Further May 2013 Development 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Mark Askelson, Jeff Tilley, Ed Townsend, and Christopher Theisen Aurora Project 2009-05 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) John D. Odegard School of Aerospace Sciences University of North Dakota 11. Contract or Grant No. 3890 Campus Road, Stop 9007 Grand Forks, ND 58202-9007 12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered Aurora Program Federal Highway Administration Final Report Iowa Department of Transportation U.S. Department of Transportation 14. Sponsoring Agency Code 800 Lincoln Way 1200 New Jersey Avenue SE Pooled Fund SPR 72-00-0003-042 Ames, Iowa 50010 Washington, DC 20590 15. Supplementary Notes Visit www.intrans.iastate.edu for color pdfs of this and other research reports. 16. Abstract Wintertime precipitation has profound impacts on surface transportation. Surface transportation ramifications include decreased public safety, compromised traveler mobility, diminished productivity of roadway users, and adverse environmental effects due to the need to chemically treat icy roads. The winter road maintenance community can benefit from having more information about wintertime precipitation, including where precipitation is occurring and precipitation rate, leading to improvements of safety and greater cost effectiveness. Determining wintertime precipitation occurrence and intensity is challenging. The Pavement Precipitation Accumulation Estimation System (PPAES) was designed such that precipitation field analyses could be produced using individual sources of information and multiple sources of information. When multiple sources are utilized, PPAES algorithms are designed to take advantage of data strengths and mitigate data weaknesses to maximize analysis quality. This study, in addition to providing new techniques for fusing information from multiple sources to produce enhanced wintertime precipitation analyses, identifies future research areas that may lead to even more advanced techniques that will serve the road weather community. 17. Key Words 18. Distribution Statement algorithm performance—precipitation analyses—wintertime precipitation No restrictions. 19. Security Classification (of this 20. Security Classification (of this page) 21. No. of 22. Price report) Pages Unclassified. Unclassified. 169 NA Form DOT F 1700.7 (8-72) Reproduction of completed page authorized THE PAVEMENT PRECIPITATION ACCUMULATION ESTIMATION SYSTEM—FURTHER DEVELOPMENT Final Report May 2013 Authors Mark Askelson, Associate Professor, Atmospheric Sciences John D. Odegard School of Aerospace Sciences, University of North Dakota Jeffrey Tilley, Research Faculty Regional Weather Information Center, John D. Odegard School of Aerospace Sciences Ed Townsend, Graduate Research Assistant Atmospheric Sciences John D. Odegard School of Aerospace Sciences, University of North Dakota Christopher Theisen, Radar Research Meteorologist, Regional Weather Information Center, John D. Odegard School of Aerospace Sciences Sponsored by Aurora Program, Iowa Department of Transportation, And Federal Highway Administration (FHWA) FHWA Pooled Fund Study SPR-3(042): AK, IA, IL, IN, KS, MI, MN, ND, NV, NY, OH, Ontario MOT, PA, Quebec MOT, SD, Sweden NRA, TN, UT, VA, WI Preparation of this report was financed in part through funds provided by the Iowa Department of Transportation through its Research Management Agreement with the Institute for Transportation (Aurora Project 2009-05) A report from Aurora Program Institute for Transportation Iowa State University 2711 South Loop Drive, Suite 4700 Ames, IA 50010-8664 Phone: 515-294-8103 Fax: 515-294-0467 www.intrans.iastate.edu TABLE OF CONTENTS ACKNOWLEDGMENTS ........................................................................................................... xiii EXECUTIVE SUMMARY ...........................................................................................................xv 1 INTRODUCTION ...............................................................................................................1 1.1 Motivation ................................................................................................................1 2 BACKGROUND .................................................................................................................5 2.1 PPAESv1..................................................................................................................5 2.2 Previous Studies .......................................................................................................5 2.3 Objective Analysis ...................................................................................................7 2.4 Snowfall Rate and Size Distribution Variability ...................................................11 3 DATA ................................................................................................................................15 3.1 MADIS Surface Observation Data ........................................................................15 3.2 Clarus Surface Observation Data ...........................................................................16 3.3 NEXRAD Level II Radar Data ..............................................................................18 3.4 GOES Satellite Data ..............................................................................................19 3.5 Rapid Refresh Model Data.....................................................................................20 4 METHODOLOGY ............................................................................................................21 4.1 Surface Observation Data Quality Checking .........................................................21 4.2 Surface Observation Density Analysis ..................................................................23 4.3 MADIS Surface Observation Climatology ............................................................28 4.4 Deriving Surface Precipitation Occurrence ...........................................................29 4.5 Estimating Instantaneous Surface Precipitation Rate ............................................31 4.6 Complex Terrain Algorithm for Radar Analysis ...................................................35 4.7 Fusion of Radar Measurements with