DOCSLIB.ORG

MANOBS Manual of Surface Weather Observations

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
MANOBS Manual of Surface Weather Observations Seventh Edition, Amendment 18, January 2013 MANOBS Manual of Surface Weather Observations Seventh Edition, Amendment 18 January 2013 MANOBS– Manual of Surface Weather Observations i Seventh Edition, Amendment 18, January 2013 Originating Authority: Weather and Environmental Monitoring Directorate Issued under the authority of the Assistant Deputy Minister, Meteorological Service of Canada ISBN: 978-1-100-20937-1 Cat. No.: En56-238/2-2012E-PDF Information contained in this publication or product may be reproduced, in part or in whole, and by any means, for personal or public non-commercial purposes, without charge or further permission, unless otherwise specified. You are asked to: • exercise due diligence in ensuring the accuracy of the materials reproduced; • indicate both the complete title of the materials reproduced, as well as the author organization; and • indicate that the reproduction is a copy of an official work that is published by the Government of Canada and that the reproduction has not been produced in affiliation with or with the endorsement of the Government of Canada. Commercial reproduction and distribution is prohibited except with written permission from the Government of Canada’s copyright administrator, Public Works and Government Services of Canada (PWGSC). For more information, please contact PWGSC at 613-996- 6886 or at [email protected]. Photographs: © Environment Canada © Her Majesty the Queen in Right of Canada, represented by the Minister of the Environment, 2013. Aussi disponible en français MANOBS– Manual of Surface Weather Observations ii Seventh Edition, Amendment 18, January 2013 Foreword This manual prescribes the standard procedures of the Meteorological Service of Canada for observing, recording and reporting weather conditions. It has been prepared in accordance with internationally recommended procedures as established by the World Meteorological Organization (WMO). Amendments will be issued when warranted. All holders of the manual are responsible for keeping their copies current. When amendments have been entered, this fact should be recorded on the page headed Record of amendments. Inquiries on the content of this manual should be directed to the Meteorological Service of Canada through appropriate channels. This supplement contains the amendments adopted by the MANOBS Working Group. Important note: This amendment will affect the observing standards for SPECI, see 10.3.5.7 and 16.4.4.7. This amendment is to enhance the observing and reporting weather observations practices for Aviation. MANOBS– Manual of Surface Weather Observations iii Seventh Edition, Amendment 18, January 2013 Record of Revisions – MANOBS (Amendment 18) S ection R evision description SPECI criteria SPECI shall be reported for the starting and stopping of freezing Section 10.3.5.3 fog SPECI shall be taken to report the change in intensity from Section 10.3.5.7 moderate to heavy Observer Circulars incorporated in MANOBS Section 3.7.6 OBS 1 – 2001 Weaverboard OBS 1 – 2004 Additional SPECI Observations Criteria at Section 10.3.5.4 Designated Aerodromes (IFR Approach and Alternate Limits) OBS 1 – 2007 List of NC designated sites required to issue Appendix II SPECI for Criteria Temperature Section 12.3.2.1 OBS 1 – 2008 Correction to WMO Code Table 2700 Section 2.15 OBS 2 – 2008 Correction to French MANOBS Section 4.5.2 OBS 4 – 2009 AWOS Pressure Comparison Reading Deletions The content of this chapter has been removed due to the decommissioning of this program. Information about the program Chapter 15, “Pilot-Balloon is still available in the following manuals: Pilot-Balloon Observations” Observations, instrument manual # 60; Pilot-Balloon tables, # 63- 2342; Approximate Altitude of Standard Isobaric Levels for Canadian Pibal Stations, SPC. The content of this chapter has been removed. All information Chapter 16, “Decoding about decoding Autostation reports is available in the following autostation reports” manual: Reference Guide to the Automated Weather Observation System. MANOBS– Manual of Surface Weather Observations iv Seventh Edition, Amendment 18, January 2013 S ection R evision description Chapter 17, “Abstracting The content of this chapter has been removed since this chapter and recording references old practices which are no longer used. Refer to supplementary data, MANOBS Amendment 17 to view this chapter. monthly climatological summary – Form 63- 2320” The content of this chapter has been removed since this chapter Chapter 18, “Abstract of references old practices which are no longer used. Refer to wind” MANOBS Amendment 17 to view this chapter. MANOBS– Manual of Surface Weather Observations v Seventh Edition, Amendment 18, January 2013 Record of Amendments AMD No. E ffective date Entered by Date of entry MANOBS– Manual of Surface Weather Observations vii Seventh Edition, Amendment 18, January 2013 Table of Contents Page Foreword .............................................................................................................................. iii Record of Revisions – MANOBS (Amendment 18) ........................................................... iv Record of Amendments ..................................................................................................... vii Table of Contents ................................................................................................................ ix Introduction ........................................................................................................................... 1 Part A Observing Procedures – General ..................................................... 13 Chapter 1 Sky .............................................................................................................. 1–15 1.1 Celestial dome .................................................................................................... 1–15 1.2 Layer determination ............................................................................................ 1–15 1.3 Layer identification ............................................................................................. 1–16 1.4 Layer amount and opacity .................................................................................. 1–17 1.5 Direction of motion of layers ............................................................................... 1–19 1.6 Height ................................................................................................................. 1–20 1.7 Ceiling ................................................................................................................ 1–22 1.8 Method of determining heights of layers ............................................................. 1–22 Chapter 2 Visibility ..................................................................................................... 2–33 2.1 General ............................................................................................................... 2–33 2.2 Prevailing visibility .............................................................................................. 2–33 2.3 Determination of prevailing visibility ................................................................... 2–33 2.4 Units of measure ................................................................................................ 2–36 2.5 Variable visibility ................................................................................................. 2–36 2.6 Guides in determining visibility ........................................................................... 2–36 Chapter 3 Atmospheric phenomena ......................................................................... 3–41 3.1 General ............................................................................................................... 3–41 3.2 Tornadoes and Waterspouts (+FC) .................................................................... 3–41 3.3 Thunderstorm (TS) definition .............................................................................. 3–43 3.4 Precipitation ........................................................................................................ 3–43 3.5 Obstructions to vision ......................................................................................... 3–48 3.6 Visibility reduced below eye level ....................................................................... 3–53 3.7 Measurement of precipitation amounts............................................................... 3–53 3.8 Depth of snow on the ground ............................................................................. 3–58 3.9 Intensity of precipitation ...................................................................................... 3–58 3.10 Intensity of precipitation with an obstruction to vision ......................................... 3–62 3.11 Character of precipitation ................................................................................... 3–62 3.12 Notes on unusual weather .................................................................................. 3–63 MANOBS– Manual of Surface Weather Observations ix Seventh Edition, Amendment 18, January 2013 Chapter 4 Atmospheric pressure .............................................................................. 4–65 4.1 General ............................................................................................................... 4–65 4.2 Barometric pressure computations ....................................................................
Load more

Recommended publications
  • Lesson 6 Weather: Collecting Data GRADE 3-5 BACKGROUND Meteorologists Collect Weather Data Daily to Make Forecasts
    Lesson 6 Weather: Collecting Data GRADE 3-5 BACKGROUND Meteorologists collect weather data daily to make forecasts. With the aid of high altitude weather balloons, weather equipment and gauges, satellites, and computers, accurate daily forecasts can be made. Collecting weather data in just one location and making a forecast requires a great deal of skill. Since air travels from one location to another, it is helpful to know what the approaching weather will be. In this investigation, the students will collect data for two weeks. At this time they will start seeing patterns in each of the areas. They can predict what the weather will be like the next day and for the next few days. They will also write if their predictions were correct from the previous day. Collecting the data for this lesson can be done instead of collecting the data separately in lesson 1-4. BASIC LESSON Objective(s) Students will be able to… Collect data for two weeks and use the information to detect patterns and predict weather around their location. State Science Content Standard(s) Standard 4. Students through the inquiry process, demonstrate knowledge of the composition, structures, processes and interactions of Earth's systems and other objects in space. A. 4.4 Observe and describe the water cycle and the local weather and demonstrate how weather conditions are measured. A. Record temperature B. Display data on a graph C. Interpret trends and patterns of data D. Identify and explain the use of a barometer, weather vane, and anemometer E. Collect, record and chart data from each weather instrument F.
    [Show full text]
  • Snow Nowcasting Using a Real-Time Correlation of Radar Reflectivity
    20 JOURNAL OF APPLIED METEOROLOGY VOLUME 42 Snow Nowcasting Using a Real-Time Correlation of Radar Re¯ectivity with Snow Gauge Accumulation ROY RASMUSSEN AND MICHAEL DIXON National Center for Atmospheric Research, Boulder, Colorado STEVE VASILOFF National Severe Storms Laboratory, Norman, Oklahoma FRANK HAGE,SHELLY KNIGHT,J.VIVEKANANDAN, AND MEI XU National Center for Atmospheric Research, Boulder, Colorado (Manuscript received 21 November 2001, in ®nal form 13 June 2002) ABSTRACT This paper describes and evaluates an algorithm for nowcasting snow water equivalent (SWE) at a point on the surface based on a real-time correlation of equivalent radar re¯ectivity (Ze) with snow gauge rate (S). It is shown from both theory and previous results that Ze±S relationships vary signi®cantly during a storm and from storm to storm, requiring a real-time correlation of Ze and S. A key element of the algorithm is taking into account snow drift and distance of the radar volume from the snow gauge. The algorithm was applied to a number of New York City snowstorms and was shown to have skill in nowcasting SWE out to at least 1 h when compared with persistence. The algorithm is currently being used in a real-time winter weather nowcasting system, called Weather Support to Deicing Decision Making (WSDDM), to improve decision making regarding the deicing of aircraft and runway clearing. The algorithm can also be used to provide a real-time Z±S relationship for Weather Surveillance Radar-1988 Doppler (WSR-88D) if a well-shielded snow gauge is available to measure real-time SWE rate and appropriate range corrections are made.
    [Show full text]
  • Radar Derived Rainfall and Rain Gauge Measurements at SRS
    Radar Derived Rainfall and Rain Gauge Measurements at SRS A. M. Rivera-Giboyeaux February 2020 SRNL-STI-2019-00644, Revision 0 SRNL-STI-2019-00644 Revision 0 DISCLAIMER This work was prepared under an agreement with and funded by the U.S. Government. Neither the U.S. Government or its employees, nor any of its contractors, subcontractors or their employees, makes any express or implied: 1. warranty or assumes any legal liability for the accuracy, completeness, or for the use or results of such use of any information, product, or process disclosed; or 2. representation that such use or results of such use would not infringe privately owned rights; or 3. endorsement or recommendation of any specifically identified commercial product, process, or service. Any views and opinions of authors expressed in this work do not necessarily state or reflect those of the United States Government, or its contractors, or subcontractors. Printed in the United States of America Prepared for U.S. Department of Energy ii SRNL-STI-2019-00644 Revision 0 Keywords: Rainfall, Radar, Rain Gauge, Measurements Retention: Permanent Radar Derived Rainfall and Rain Gauge Measurements at SRS A. M. Rivera-Giboyeaux February 2020 Prepared for the U.S. Department of Energy under contract number DE-AC09-08SR22470. iii SRNL-STI-2019-00644 Revision 0 REVIEWS AND APPROVALS AUTHORS: ______________________________________________________________________________ A. M. Rivera-Giboyeaux, Atmospheric Technologies Group, SRNL Date TECHNICAL REVIEW: ______________________________________________________________________________ S. Weinbeck, Atmospheric Technologies Group, SRNL. Reviewed per E7 2.60 Date APPROVAL: ______________________________________________________________________________ C.H. Hunter, Manager Date Atmospheric Technologies Group iv SRNL-STI-2019-00644 Revision 0 EXECUTIVE SUMMARY Over the years rainfall data for the Savannah River Site has been obtained from ground level measurements made by rain gauges.
    [Show full text]
  • FAA Advisory Circular AC 91-74B
    U.S. Department Advisory of Transportation Federal Aviation Administration Circular Subject: Pilot Guide: Flight in Icing Conditions Date:10/8/15 AC No: 91-74B Initiated by: AFS-800 Change: This advisory circular (AC) contains updated and additional information for the pilots of airplanes under Title 14 of the Code of Federal Regulations (14 CFR) parts 91, 121, 125, and 135. The purpose of this AC is to provide pilots with a convenient reference guide on the principal factors related to flight in icing conditions and the location of additional information in related publications. As a result of these updates and consolidating of information, AC 91-74A, Pilot Guide: Flight in Icing Conditions, dated December 31, 2007, and AC 91-51A, Effect of Icing on Aircraft Control and Airplane Deice and Anti-Ice Systems, dated July 19, 1996, are cancelled. This AC does not authorize deviations from established company procedures or regulatory requirements. John Barbagallo Deputy Director, Flight Standards Service 10/8/15 AC 91-74B CONTENTS Paragraph Page CHAPTER 1. INTRODUCTION 1-1. Purpose ..............................................................................................................................1 1-2. Cancellation ......................................................................................................................1 1-3. Definitions.........................................................................................................................1 1-4. Discussion .........................................................................................................................6
    [Show full text]
  • COOP Observer Manual (1).Pdf
    National Weather Service WFO Mount Holly, NJ Cooperative Observation Program Observer Manual Updated: October 3, 2020 Table of Contents 1. Taking Observations a. Rainfall/Liquid Equivalent Precipitation i. Rainfall 1. Standard 8” Rain Gauge 2. Plastic 4” Rain Gauge ii. Snowfall/Frozen Precipitation Liquid Equivalent 1. Standard 8” Rain Gauge 2. Plastic 4” Rain Gauge b. Snowfall c. Snow Depth d. Maximum and Minimum Temperatures (if equipped) i. Digital Maximum/Minimum Sensor with Nimbus Display ii. Cotton Region Shelter with Liquid-in-Glass Thermometers 2. Reporting Observations a. WxCoder b. Things to Remember 1 1. Taking Observations Measuring precipitation is one of the most basic and useful forms of weather observations. It is important to note that observations will vary based on the type of precipitation that is expected to occur. If any frozen precipitation is forecast, it is important to remove the ​ funnel top and inner tube from your gauge before precipitation begins. This will prevent ​ ​ ​ damage to the equipment and ensure the most accurate measurements possible. Note that the inner tube of the rain gauge only holds a certain amount of precipitation until it begins to overflow into the outer can. If rain falls, but is not measurable inside of the gauge, this should be reported as a Trace (T) of rainfall. This includes sprinkles/drizzle and occurrences where there is some liquid in the inner tube, but it is not measurable on the measuring stick. During the cold season (generally November through early April), we recommend that observers leave their snowboards outside at all times, if possible.
    [Show full text]
  • Imet-4 Radiosonde 403 Mhz GPS Synoptic
    iMet-4 Radiosonde 403 MHz GPS Synoptic Technical Data Sheet Temperature and Humidity Radiosonde Data Transmission The iMet-4 measures air temperature with a The iMet-4 radiosonde can transmit to an small glass bead thermistor. Its small size effective range of over 250 km*. minimizes effects caused by long and short- wave radiation and ensures fast response times. A 6 kHz peak-to-peak FM transmission maximizes efficiency and makes more channels The humidity sensor is a thin-film capacitive available for operational use. Seven frequency polymer that responds directly to relative selections are pre-programmed - with custom humidity. The sensor incorporates a temperature programming available. sensor to minimize errors caused by solar heating. Calibration Pressure and Height The iMet-4’s temperature and humidity sensors are calibrated using NIST traceable references to As recommended by GRUAN3, the iMet-4 is yield the highest data quality. equipped with a pressure sensor to calculate height at lower levels in the atmosphere. Once Benefits the radiosonde reaches the optimal height, pressure is derived using GPS altitude combined • Superior PTU performance with temperature and humidity data. • Lightweight, compact design • No assembly or recalibration required The pressure sensor facilitates the use of the • GRUAN3 qualified (pending) sonde in field campaigns where a calibrated • Status LED indicates transmit frequency barometer is not available to establish an selection and 3-D GPS solution accurate ground observation for GPS-derived • Simple one-button user interface pressure. For synoptic use, the sensor is bias adjusted at ground level. Winds Data from the radiosonde's GPS receiver is used to calculate wind speed and direction.
    [Show full text]
  • Lecture Notes on Marine Meteorology
    Lecture notes on Marine Meteorology By Shri S. P. Joshi Assistant. Meteorologist Office of DDGM (WF) India Meteorological Department Pune-5 Preface The aim of these lecture notes is to provide training to the marine observers in handling and maintenance of meteorological instruments and collect meteorological observations in the form of logbooks. The chapters included in these lecture notes are from the Basic and Intermediate training courses of the department. The present lecture notes are merely a collection of information available on Internet and are compiled from various WMO sites, freely available, keeping in view the up-and-coming trends and new technological advancements. This collection is for private circulation for trainees of Basic and Intermediate training courses of the department and the author do not intend to violate copyrights of anybody what so ever. Port Meteorological Officers in the immediate future have to deal with the modernization of the marine equipments and automation of Marine Data collection, its transmission and archival by observing minimum quality control through the in-built software like TURBOWIN. These lecture notes will also be useful to Port Meteorological Officers in understanding the nature of work of PMOs and will provide them the useful guidelines. A separate chapter on installation of Turbowin is also included in these notes. S. P. Joshi. 9th April 2005. Gudhi Padva Table of contents Chapter no Contents Page no. 1 WMO Voluntary Observing Ships’ Scheme 1 2 Meteorological Instrumentation on board ships 8 3 Port Meteorological Office ( PMO ) 15 4 The Ship Weather Code 19 5 Broadcast of weather bulletins for Merchant shipping 24 6 Broadcast of weather bulletins for Indian navy 28 7 Warnings to Ports and Storm Warning Signals 30 8 Broadcast of weather warnings for fishermen through 34 All India Radio.
    [Show full text]
  • GPS-Based Measurement of Height and Pressure with Vaisala Radiosonde RS41
    GPS-Based Measurement of Height and Pressure with Vaisala Radiosonde RS41 WHITE PAPER Table of Contents CHAPTER 1 Introduction ................................................................................................................................................. 4 Executive Summary of Measurement Performance ............................................................................. 5 CHAPTER 2 GPS Technology in the Vaisala Radiosonde RS41 ........................................................................................... 6 Radiosonde GPS Receiver .................................................................................................................. 6 Local GPS Receiver .......................................................................................................................... 6 Calculation Algorithms ..................................................................................................................... 6 CHAPTER 3 GPS-Based Measurement Methods ............................................................................................................... 7 Height Measurement ......................................................................................................................... 7 Pressure Measurement ..................................................................................................................... 7 Measurement Accuracy..................................................................................................................... 8 CHAPTER
    [Show full text]
  • A Study on Snow Density Variations at Different Elevations
    Brian Miretzky 1 A Study on Snow Density Variations at Different Elevations and the Related Consequences; Especially to Forecasting. Brian J. Miretzky Senior Undergrad at the University of Wisconsin- Madison ABSTRACT With observations becoming more common and forecasting becoming more accurate snow density research has increased. These new observations can be correlated with current knowledge to develop reasons for snow density variations. Currently there is still no specific consensus on what are the important characteristics in snow density variations. There are many points of general agreement such as that temperature and relative humidity are key factors. How to incorporate these into snowfall prediction is the key. Once there is more substantiated knowledge, more accurate forecasts can be made. Finally, the last in the chain of events is that society can plan accordingly to this new data. Better prediction means less work, less time, and less money spent. This study attempts to determine if elevation is an important characteristic in snow density variations. It also looks at computer models and how snow density is used in conjunction with these models to make snowfall projections. The results seem to show elevation is not an important characteristic. The results also show that model accuracy is more important than snow density variations when using models to make snowfall projections. 1. Introduction volume of the sample. Snow densities are typically on an order of 70 to 150 kg The density of snow is a m-3, but can be lower or higher in some very important topic in winter weather. cases. This is because the density of snow The fact that snow densities can helps determine characteristics of a vary makes them one of the most given snowfall.
    [Show full text]
  • METAR/SPECI Reporting Changes for Snow Pellets (GS) and Hail (GR)
    U.S. DEPARTMENT OF TRANSPORTATION N JO 7900.11 NOTICE FEDERAL AVIATION ADMINISTRATION Effective Date: Air Traffic Organization Policy September 1, 2018 Cancellation Date: September 1, 2019 SUBJ: METAR/SPECI Reporting Changes for Snow Pellets (GS) and Hail (GR) 1. Purpose of this Notice. This Notice coincides with a revision to the Federal Meteorological Handbook (FMH-1) that was effective on November 30, 2017. The Office of the Federal Coordinator for Meteorological Services and Supporting Research (OFCM) approved the changes to the reporting requirements of small hail and snow pellets in weather observations (METAR/SPECI) to assist commercial operators in deicing operations. 2. Audience. This order applies to all FAA and FAA-contract weather observers, Limited Aviation Weather Reporting Stations (LAWRS) personnel, and Non-Federal Observation (NF- OBS) Program personnel. 3. Where can I Find This Notice? This order is available on the FAA Web site at http://faa.gov/air_traffic/publications and http://employees.faa.gov/tools_resources/orders_notices/. 4. Cancellation. This notice will be cancelled with the publication of the next available change to FAA Order 7900.5D. 5. Procedures/Responsibilities/Action. This Notice amends the following paragraphs and tables in FAA Order 7900.5. Table 3-2: Remarks Section of Observation Remarks Section of Observation Element Paragraph Brief Description METAR SPECI Volcanic eruptions must be reported whenever first noted. Pre-eruption activity must not be reported. (Use Volcanic Eruptions 14.20 X X PIREPs to report pre-eruption activity.) Encode volcanic eruptions as described in Chapter 14. Distribution: Electronic 1 Initiated By: AJT-2 09/01/2018 N JO 7900.11 Remarks Section of Observation Element Paragraph Brief Description METAR SPECI Whenever tornadoes, funnel clouds, or waterspouts begin, are in progress, end, or disappear from sight, the event should be described directly after the "RMK" element.
    [Show full text]
  • ESSENTIALS of METEOROLOGY (7Th Ed.) GLOSSARY
    ESSENTIALS OF METEOROLOGY (7th ed.) GLOSSARY Chapter 1 Aerosols Tiny suspended solid particles (dust, smoke, etc.) or liquid droplets that enter the atmosphere from either natural or human (anthropogenic) sources, such as the burning of fossil fuels. Sulfur-containing fossil fuels, such as coal, produce sulfate aerosols. Air density The ratio of the mass of a substance to the volume occupied by it. Air density is usually expressed as g/cm3 or kg/m3. Also See Density. Air pressure The pressure exerted by the mass of air above a given point, usually expressed in millibars (mb), inches of (atmospheric mercury (Hg) or in hectopascals (hPa). pressure) Atmosphere The envelope of gases that surround a planet and are held to it by the planet's gravitational attraction. The earth's atmosphere is mainly nitrogen and oxygen. Carbon dioxide (CO2) A colorless, odorless gas whose concentration is about 0.039 percent (390 ppm) in a volume of air near sea level. It is a selective absorber of infrared radiation and, consequently, it is important in the earth's atmospheric greenhouse effect. Solid CO2 is called dry ice. Climate The accumulation of daily and seasonal weather events over a long period of time. Front The transition zone between two distinct air masses. Hurricane A tropical cyclone having winds in excess of 64 knots (74 mi/hr). Ionosphere An electrified region of the upper atmosphere where fairly large concentrations of ions and free electrons exist. Lapse rate The rate at which an atmospheric variable (usually temperature) decreases with height. (See Environmental lapse rate.) Mesosphere The atmospheric layer between the stratosphere and the thermosphere.
    [Show full text]
  • Evaluation of the Hotplate Snow Gauge
    Evaluation of the Hotplate Snow Gauge http://aurora-program.org Aurora Project 2004-01 Final Report July 2005 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. Aurora Project 2004-01 4. Title and Subtitle 5. Report Date Evaluation of the Hotplate Snow Gauge July 2005 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Jack Stickel, Bill Maloney, Curt Pape, Dennis Burkheimer 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Center for Transportation Research and Education Iowa State University 11. Contract or Grant No. 2711 South Loop Drive, Suite 4700 Ames, IA 50010-8664 12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered Aurora Program Iowa State University 14. Sponsoring Agency Code 2711 South Loop Drive, Suite 4700 Ames, IA 50010-8664 15. Supplementary Notes Visit www.ctre.iastate.edu for color PDF files of this and other research reports. 16. Abstract Winter precipitation (e.g., snow, ice, freezing rain) is poorly measured by current National Weather Service (NWS), Federal Aviation Administration (FAA), and State Departments of Transportation (SDOT) automated weather observation systems. The lack of accurate winter precipitation measurements, particularly snow, negatively impacts the ability of winter maintenance personnel to conduct snow and ice control operations. The inability to accurately measure winter precipitation is an ongoing problem that is well recognized by the meteorological community as well as organizations and industries dependent on accurate quantitative precipitation information. The FAA recognized this limitation and its impact on the ability to conduct aircraft deicing operations, and began a research program in the 1990s to improve decision support for aircraft deicing.
    [Show full text]