from the airport. If below minimums, the pilot diverted immediately. If at or above minimums, the pilot OPERATIONAL IMPACT ANALYSIS 1. AFOTEC first determined operational outcomes based upon the entire 90-day period. a. The Operational Impact Model was applied to each observation set (i.e., ASOS, CWO, and IWO) as the source of observations received by the pilot to determine the resulting operational outcomes assigned to each minute for each of the three sites and for each of the four user groups. Specifically, for each of the three observation sets, the model was applied to as many minutes as possible of the available assessment hours at each site (i.e., 1,389 hours at Butte, 1,972 hours at Hancock, and 965 hours at Houlton) to assign to each minute an operational outcome (e.g., L--landed mmediately, D--diverted immediately, etc.) for each of the four user groups (i.e., Part 91 VFR arrivals, Part 91 VFR departures, Part 91 IFR arrivals, and Part 135 and 121 operations arrivals). The result was a databe se of operational outcomes for each minute for each observation set for each site. b. Using all available assessment minutes over the 90-day period, AFOTEC then summed the number of occurrences of each possible outcome, broken out by site, observation set, and user group. Each sum was then divided by the total number of available assessment minutes for that site to yield the corresponding percentage of time (i.e., Frequency) each particular outcome occurred. Outcome percentages were calculated broken out by observation set, site, and user group. c. AFOTEC next computed the differences between the outcome percentages for the ASOS observation set and the outcome percentages for the CWO observation set to determine the percent difference (i.e., Delta) for each outcome due to using ASOS rather than CWO observations. Outcome percent differences were generated broken out by site and user group 2. To determine operational outcomes when the weather was considered instrument meteorological conditions, AFOTEC repeated the above three steps using all available assessment minutes in which any of the three observations report IFR (ie., ceilings less than 1000 feet and/or visibility less than 3 miles. 3. To determine operational outcomes during scheduled air carrier (Part 121) operations, AFOTEC repeated the same three steps using all available assessment minutes during periods of scheduled air carrier operations at Butte and Hancock. (Houlton was not included as Houlton has no scheduled air carriers.) 4. Using the resulting operational impact statistics provided by AFOTEC, FAA quantified operational impacts for the three test periods broken out by the four user groups by multiplying the Delta and Frequency of each outcome for each combination of test periods and user groups. Rationale: The operational impact due to nonrepresentativeness of ASOS as compared to CWO is dependent upon (1) the magnitude of the difference (i.e., the Delta) between ASOS and the CWO for a given outcome, and (2) the actual frequency a given outcome occurred as determined by the IWO. Finally, the resulting operational impact measurements were then grouped into the following qualitative assessment categories of ASOS versus the CWO: much better, slightly better, no significant difference, slightly worse, or much worse. APPENDICES Appendix 1: Operational Impact Model Appendix 2: Detailed statistics for the 90-day test Appendix 3: Detailed statistics for the IMC time periods Appendix 4: Detailed statistics for the FAR Part 121 hours of operation Appendix 5: Operational impact analysis summaryImpact Analysis Summary Toward a New National Weather Service Toward a New National Weather Service Future of the National Weather Service Cooperative Observer Network National Weather Service Modernization Committee Commission on Engineering and Technical Systems • NOTICE PANEL COMMITTEE PREFACE ACKNOWLEDGMENTS . CONTENTS EXECUTIVE SUMMARY NATIONAL ACADEMY PRESS NATIONAL ACADEMY PRESS 2101 Constitution Avenue, N.W. • Washington, D.C. 20418 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research This report has been reviewed by a group other than the authors according to procedures approved by a Report Review The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in Toward a New National Weather Service Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad This study was supported by Contract/Grant No. 50-DGNW-5-00004 between the National Academy of Sciences and the Available in limited supply from: Transition Program Office, National Weather Service, NOAA, 1325 East West Highway, Additional copies of this report are available from National Academy Press, 2101 Constitution Avenue, N.W., Lockbox 285, Library of Congress Catalog Card Number 98-86724 International Standard Book Number 0-309-06146-6 Printed in the United States of America Copyright 1998 by the National Academy of Sciences. All rights reserved. PANEL ON CLIMATE RECORD: MODERNIZATION OF THE COOPERATIVE OBSERVER NETWORK WILLIAM D. BONNER (chair), National Center for Atmospheric Research, Boulder, Colorado STANLEY A. CHANGNON, Illinois State Water Survey, Champaign KENNETH C. CRAWFORD, Oklahoma Climatological Survey, Norman NOLAN J. DOESKEN, Colorado State University, Fort Collins THOMAS W. HORST, National Center for Atmospheric Research, Boulder, Colorado ROY L. JENNE, National Center for Atmospheric Research, Boulder, Colorado VERONICA F. NIEVA, WESTAT, Inc., Rockville, Maryland Toward a New National Weather Service DAVID A. ROBINSON, Rutgers University, New Brunswick, New Jersey Advisors CHARLES L. HOSLER, NAE, Pennsylvania State University, University Park THOMAS B. MCKEE, Colorado State University, Fort Collins Staff FLOYD F. HAUTH, study director MERCEDES M. ILAGAN, study associate CARTER W. FORD, project assistant COURTLAND S. LEWIS, technical writer NATIONAL WEATHER SERVICE MODERNIZATION COMMITTEE RICHARD A. ANTHES (chair), University Corporation for Atmospheric Research, Boulder, Colorado WILLIAM E. GORDON (vice chair), NAE, NAS, Rice University (retired), Houston, Texas DAVID ATLAS, NAE, Atlas Concepts, Bethesda, Maryland WILLIAM D. BONNER, National Center for Atmospheric Research, Boulder, Colorado ROBERT BRAMMER, TASC, Reading, Massachusetts KENNETH C. CRAWFORD, Oklahoma Climatological Survey, Norman DARA ENTEKHABI, Massachusetts Institute of Technology, Cambridge GEORGE J. GLEGHORN, NAE, TRW Space and Technology Group (retired), Rancho Palos Verdes, ALBERT J. KAEHN, JR. U.S. Air Force (retired), Burke, Virginia JENANNE L. MURPHY, Hughes Information Technology Corporation, Vienna, Virginia VERONICA F. NIEVA, WESTAT, Inc., Rockville, Maryland DOROTHY C. PERKINS, National Aeronautics and Space Administration, Greenbelt, Maryland PAUL L. SMITH, South Dakota School of Mines and Technology, Rapid City Technical Advisors Toward a New National Weather Service CHARLES L. HOSLER, NAE, Pennsylvania State University, University Park DAVID S. JOHNSON, National Research Council (retired), Annapolis, Maryland ROBERT J. SERAFIN, NAE, National Center for Atmospheric Research, Boulder, Colorado Staf FLOYD F. HAUTH, study director MERCEDES M. ILAGAN, study associate CARTER W. FORD, project assistant Preface As part of its continuing review and evaluation of National Weather Service (NWS) operations and Accordingly, in October 1996 the NWSMC proposed a study of the status and outlook for the Coop Network. The NRC subsequently authorized the study and approved a Panel on Climate Record: Modernization of the Cooperative Observer Network (the Coop Panel). The panel consisted of several members of the NWSMC and other experts with relevant experience in NWS operations, cooperative observing, and private industry. The panel undertook the following tasks: ⚫ to assess the applications of Coop Network data (see Chapter 1) ⚫ to assess the continuation of the Coop Network (see Chapter 2) ⚫ to assess the NWS plans to modernize the network, including the impact of interagency data requirements on NOAA's program responsibility (see Chapter 4) ⚫to identify alternative approaches for improving the effectiveness and efficiency of the network |