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 Meterological Service Service métérologique of Canada du Canada MANOBS Manual of Surface Weather Observations Seventh Edition, Amendment 19 April 2015 Originating Authority: Monitoring and Data Services Directorate ISBN: 978-1-100-25445-6 Cat. No.: En56-238/2-2015E-PDF Unless otherwise specified, you may not reproduce materials in this publication, in whole or in part, for the purposes of commercial redistribution without prior written permission from Environment Canada’s copyright administrator. To obtain permission to reproduce Government of Canada materials for commercial purposes, apply for Crown Copyright Clearance by contacting: Environment Canada Inquiry Centre 10 Wellington Street, 23rd Floor Gatineau QC K1A 0H3 Telephone: 819-997-2800 Toll Free: 1-800-668-6767 (in Canada only) Fax: 819-994-1412 TTY: 819-994-0736 Email: [email protected] Photos: © Environment Canada © Her Majesty the Queen in Right of Canada, represented by the Minister of the Environment, 2015 Disclaimer: Her Majesty is not responsible for the accuracy or completeness of the information contained in the reproduced material. Her Majesty shall at all times be indemnified and held harmless against any and all claims whatsoever arising out of negligence or other fault in the use of the information contained in this publication or product. Aussi disponible en français Seventh Edition, Amendment 19, April 2015 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 Manual of Surface Weather Observations (MANOBS) Working Group. Important note: Amendment 19 will implement the following requirements: A full element SPECI as specified in the WMO Manual on Codes Volume 1.I, International Codes 2011 edition updated in 2012. FM 16-XII requires a full element SPECI. Remove the standard for the reporting of Recent Weather (RE) phenomena in METAR/SPECI to comply with ICAO Annex 3 Eighteenth Edition July 2013, Appendix 3 Section 4.8.1.1 removal of the requirement for Recent Weather (RE) phenomena where METAR/SPECI are issued. Inclusion of Observer Circulars OBS 1-2012, OBS 1-2013 and OBS 2-2013. Update to Appendix "V" for the IFR Approach and Alternate Limits for Canadian Aerodromes. MANOBS – Manual of Surface Weather Observations iii Seventh Edition, Amendment 19, April 2015 This page intentionally left blank MANOBS – Manual of Surface Weather Observations iv Seventh Edition, Amendment 19, April 2015 Record of Revisions – MANOBS Amendment 19 Section Revision description Miscellaneous corrections 1.8.3.1 Added subsection to section 1.8.3: “Data from the Ceilometer shall be correlated with visual observations to determine cloud amount and to ensure that the cloud height is representative of the layer.” 3.9.5 Replaced the term “Visibility” with “Intensity” 5.1.3.1 Updated Maximum Correction Card 5.1.3.2 Revised to match Maximum Correction Card 5.1.3.3 7.7 Updated Beaufort Scale of Wind 10.2.8.8 Removed the wording: “… or when the ceilometer is inoperative” 10.2.10.3 (7) Revised item seven to read: “Additional phenomena and vicinity phenomena” 10.2.10.8 Added paragraph to section: 16.3.8.6.2 “When visibility is 7 SM or more and ice crystals (IC) are observed, IC shall be reported as a remark in the METAR / SPECI.” 10.2.19.8.1 Removed sentence: “It is very important to report CB in remarks when it is observed but it is not the predominant cloud type.” 16.3.8.4 Changed proximity to vicinity in the heading and first sentence 16.4.4.11 Revised fourth point to read: “Immediately upon learning of an aircraft accident, at or in the vicinity of the weather observing station. The observer shall make an Accident Observation unless a complete METAR has been issued subsequent to the accident. The Accident Observation shall be as complete and accurate as possible, with particular care being taken to include in “Remarks” any meteorological facts that might relate to the accident, or which might be of significance to the aircraft accident investigator.” Appendix IV Removed MANOBS – Manual of Surface Weather Observations v Seventh Edition, Amendment 19, April 2015 Section Revision description Full element SPECI 10.3.4 Revised section to read: “An observation shall be taken promptly to report changes which occur between scheduled transmission times. A SPECI observation shall include the following: Sky condition Visibility Weather and obstruction to vision Sea level pressure Temperature Dew point Wind Altimeter setting Clouds Remarks (if required) Runway Visual Range (RVR) (where available)” 10.3.7.1 Revised note to read: “If any of the observed elements warrant a SPECI, as defined in Section 10.3.4 (Criteria for taking a SPECI), a SPECI shall be transmitted and recorded on Form 63-2322.” 10.6 Added full element SPECI for all SP examples on Form 63-2322 Pilot Report (PIREP) 14.3.1(6) Revised to read: “Low-level wind shear 1500 feet AGL and below.” 14.4.4 Changed ICAO documentation reference to “ICAO DOC 8643 – Aircraft Type Designators” 14.4.15 Revised to read: “A pilot report of low-level wind shear 1500 feet AGL and below will be recorded in the Remarks (/RM) field of the PIREP and will be transmitted as an Urgent PIREP.” 14.4.16 Inserted new sub-section: No turbulence or icing encountered MANOBS – Manual of Surface Weather Observations vi Seventh Edition, Amendment 19, April 2015 Section Revision description Wind Shear 10.2.19.6.4 Revised to read: “Wind shear information on the existence of wind shear 1500 feet AGL and below along the take-off path or approach path of runway significant to aircraft operations shall be reported in Column 41 (Remarks) whenever available and local circumstances so warrant. The information will be reported in the following format: When wind shear is reported on take-off or landing on one runway 1500 feet AGL and below it will be reported as: WS RWY DRDR (Official Runway Designation); or, When wind shear is affecting all runways 1500 feet AGL and below, it will be reported as: WS ALL RWY” 16.3.12 Revised to read: “Information on the existence of low-level wind shear along the runway takeoff or approach path 1500 feet AGL and below that is considered significant to aircraft operations shall be reported.” Recent Weather 10.2.10.1 Removed Recent Phenomena from table listing weather and obstruction to vision symbols for Column 32 10.2.10.3 (7) Revised item seven to read: “Additional phenomena and vicinity phenomena” 10.2.10.4 Revised to read: “Record in Column 32 only those phenomena which are occurring at the station, in the vicinity of the station, at the time of observation with the following exceptions:” Removed first part of second paragraph containing recent weather reporting procedures. 10.2.19.4 Removed Remark RERA 10.6 Removed all references to recent weather phenomena from Form 632322 examples 1 and 2. 16.2 Removed reference to Recent Weather code REw’w’ from Symbolic form of the Canadian METAR code. 16.3.12 Removed reference to: Recent Weather (RE) of operational significance Removed reference to: List of Recent Weather (RE) phenomena in 16.3.12.1 Appendix III 16.3.12.2 Removed section 16.3.12.2 Appendix III Removed all references to recent weather (RE) phenomena MANOBS – Manual of Surface Weather Observations vii Seventh Edition, Amendment 19, April 2015 Section Revision description Sky Condition 10.2.18.1 Revised to read: “When a layer consists of two or more types, e.g., SC and CU, the predominating type by amount shall be recorded. If a cloud layer consists of any amount of TCU or CB, the TCU or CB shall be reported as the predominant type. However when an individual layer of cloud is composed of Cumulonimbus (CB) and Towering Cumulus (TCU) with a common cloud base, the type shall be reported as Cumulonimbus only.” 10.2.19 Revised note to read: “Late weather observation shall be recorded first in Column 41 as a general weather remark (See 10.2.19.14.1)” 10.2.19.8.1 Revised to read: “If clouds which indicate unstable conditions (CB, TCU or ACC) are observed and not reported in Column 40, they shall be reported in Remarks” 16.3.13.2.4 Added note to examples of sky condition remarks for convective clouds: “If TCU or CB clouds base are not observed and not reported in the sky condition, they shall be reported in Remarks.” Runway Visual Range RVR 10.2.19.13 Revised to read: “…Stations with the capability to display values for multiple RVR's may record and transmit a maximum of four RVR values and may include RVR data for runway(s) other than the active or most-aligned into-the-wind. ...” 10.6.1 Changed RVR Remarks at given times to read: 0539Z OBS: RVR RWY 15 3500FT 0548Z OBS: RVR RWY 15 3500 FT 10.6.2 Changed RVR Remarks at given times to read: 0700Z OBS: RVR RWY 15 1800FT 0900Z OBS: RVR RWY 15 1600FT 13.8.2 Changed RVR Remark at 0900Z to read: /S08/ RVR RWY15 1600FT 16.3.7 Revised first paragraph to read: “Where RVR data are displayed, they shall be included in the METAR and SPECI observations the active – or most aligned into the wind – runway(s) when the prevailing visibility is 1 SM or less and/or the RVR value for the designated runway(s) is 6000 feet or less.
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]
  • AMOFSG/10-Sod 19/6/13
    AMOFSG/10-SoD 19/6/13 AERODROME METEOROLOGICAL OBSERVATION AND FORECAST STUDY GROUP (AMOFSG) TENTH MEETING Montréal, 17 to 19 June 2013 SUMMARY OF DISCUSSIONS 1. HISTORICAL 1.1 The tenth meeting of the Aerodrome Meteorological Observation and Forecast Study Group (AMOFSG) was held at the Headquarters of the International Civil Aviation Organization (ICAO) in Montréal, Canada, 17 to 19 June 2013. 1.2 The meeting was opened by Mr. Greg Brock, Chief of the Meteorology Section of the Air Navigation Bureau of ICAO, who extended a warm welcome to all the participants. Mr. Brock emphasized that this tenth meeting of the AMOFSG was likely to be the last of the group prior to the convening of an ICAO Meteorology (MET) Divisional Meeting in July 2014, to be held in part conjointly with the Fifteenth Session of the World Meteorological Organization (WMO) Commission for Aeronautical Meteorology (CAeM-XV). For this reason, Mr. Brock underlined the need for the group to work efficiently during its three days of deliberations, with a strong emphasis placed on determining whether proposals arising from each of the topics to be addressed were of sufficient maturity so as to reduce or eliminate entirely the need for significant further work and/or a meeting ahead of the MET Divisional Meeting. 1.3 The names and contact details of the participants are listed in Appendix A . Mr. Bill Maynard was elected Chairman of the meeting. The meeting was served by the Acting Secretary of the AMOFSG, Mr. Greg Brock, Chief, Meteorology Section. 1.4 The meeting considered the following agenda items: Agenda Item 1: Opening of the meeting; Agenda Item 2: Election of Chairman; Agenda Item 3: Adoption of working arrangements; Agenda Item 4: Adoption of the agenda; (41 pages) AMOFSG.10.SoD.en.docx AMOFSG/10-SoD - 2 - Agenda Item 5: Aerodrome observations; Agenda Item 6: Forecasting at the aerodrome and in the terminal area and ATIS requirements; Agenda Item 7: Deliverables; Agenda Item 8: Any other business; and Agenda Item 9: Closure of the meeting.
    [Show full text]
  • Soaring Weather
    Chapter 16 SOARING WEATHER While horse racing may be the "Sport of Kings," of the craft depends on the weather and the skill soaring may be considered the "King of Sports." of the pilot. Forward thrust comes from gliding Soaring bears the relationship to flying that sailing downward relative to the air the same as thrust bears to power boating. Soaring has made notable is developed in a power-off glide by a conven­ contributions to meteorology. For example, soar­ tional aircraft. Therefore, to gain or maintain ing pilots have probed thunderstorms and moun­ altitude, the soaring pilot must rely on upward tain waves with findings that have made flying motion of the air. safer for all pilots. However, soaring is primarily To a sailplane pilot, "lift" means the rate of recreational. climb he can achieve in an up-current, while "sink" A sailplane must have auxiliary power to be­ denotes his rate of descent in a downdraft or in come airborne such as a winch, a ground tow, or neutral air. "Zero sink" means that upward cur­ a tow by a powered aircraft. Once the sailcraft is rents are just strong enough to enable him to hold airborne and the tow cable released, performance altitude but not to climb. Sailplanes are highly 171 r efficient machines; a sink rate of a mere 2 feet per second. There is no point in trying to soar until second provides an airspeed of about 40 knots, and weather conditions favor vertical speeds greater a sink rate of 6 feet per second gives an airspeed than the minimum sink rate of the aircraft.
    [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]
  • Meteorology and Climatology in Normal
    METEOROLOGY AND CLIMATOLOGY IN NORMAL SCHOOLS AND COLLEGE An examination of catalogues from 76 Normal Schools and Teach- ers' Colleges in the United States throws some interesting light on the meteorology and climatology offered in these schools. Under such titles as "Climates of the World," "Meteorology," "The Changing Weather," "Climate and Man," "Weather and Climate or Climatology," 35 courses are listed. As catalogues from 36 states were included, this would seem to be a very small average, but considerably more climatology is taught than appears on the surface, for in 150 courses given on continents or countries, climate is a factor usually considered. Moreover in about 50 courses listed by some such title as "Principles of Geography," "Mathematical Geography," "Human Geography," "Agricultural Ge- ography," or "Elements of Geography," etc., climatology and meteor- ology are taught although the catalogues are not very lucid as to the extent. There is little or no indication of climatological material being included in courses listed under methods, but it is probable that it is not entirely omitted, particularly in the few Normal Schools where no purely contest work is given.—J. M. Shipman. A HANDY BOOKLET ABOUT WEATHER The "Weather" manual in the Merit Badge Series issued by the Boy Scouts of America (200 Fifth Avenue, New York City), has recently appeared. It is a pamphlet of 73 pages, with plenty of instructive pic- tures. There are views of all the cloud types of the International Cloud Classification, optical phenomena, lightning, St. Elmo's fire, aurora, meteorological instruments, etc. The first half of the text is devoted to an explanation, in simple language, of a number of weather phenomena.
    [Show full text]
  • Touching the Clouds Activity Guide
    Touching the Clouds Activity Guide Purpose Provide a mental representation of each cloud type Create a tactile cloud identification chart Overview Individuals will construct and touch a tactile model of common types of clouds to learn how to describe the clouds based on their shape and texture. They will compare their descriptions with the standard classifications using the cloud types identified in the GLOBE Clouds Protocol. Time: 45 minutes to 1 ½ hours, depending on individual’s age Level: All Materials (per person) One large sheet of cardstock (18” x 12”) Tape One set of Braille labels for each cloud type and/or markers One small feather A layered piece of blanket or soft fabric (eight 1’ X 1” pieces) Cotton balls of varied sizes One tissue Organza or a similar material, cut into pieces, one layered 1” x 1” piece Pillow stuffing, one 1” x 1” piece A tsp of sand Three paper clips Liquid glue Scissors Baby Wipes Preparation Use tape to divide the large cardstock sheet in four sections: one for the cloud title at the top and three for the altitudes: using a portrait layout, place three pieces of tape horizontally, from side to side of the sheet. 1. 1” off the upper edge of the sheet 2. 8” off the upper edge of the sheet 1 Steps What to do and how to do it: Making A Tactile Cloud Identification Chart 1. Discuss that clouds come in three basic shapes: cirrus, stratus and cumulus. a. Feel of the 4” feather and describe it; discuss that these wispy clouds are high in the sky and are named cirrus.
    [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]
  • 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]
  • Aerodrome Actual Weather – METAR Decode
    Aerodrome Actual Weather – METAR decode Code element Example Decode Notes 1 Identification METAR — Meteorological Airfield Report, SPECI — selected special (not from UK civil METAR or SPECI METAR METAR aerodromes) Location indicator EGLL London Heathrow Station four-letter indicator 'ten twenty Zulu on the Date/Time 291020Z 29th' AUTO Metars will only be disseminated when an aerodrome is closed or at H24 aerodromes, A fully automated where the accredited met. observer is on duty break overnight. Users are reminded that reports AUTO report with no human of visibility, present weather and cloud from automated systems should be treated with caution intervention due to the limitations of the sensors themselves and the spatial area sampled by the sensors. 2 Wind 'three one zero Wind degrees, fifteen knots, Max only given if >= 10KT greater than the mean. VRB = variable. 00000KT = calm. 31015G27KT direction/speed max twenty seven Wind direction is given in degrees true. knots' 'varying between two Extreme direction 280V350 eight zero and three Variation given in clockwise direction, but only when mean speed is greater than 3 KT. variance five zero degrees' 3 Visibility 'three thousand two Prevailing visibility 3200 0000 = 'less than 50 metres' 9999 = 'ten kilometres or more'. No direction is required. hundred metres' Minimum visibility 'Twelve hundred The minimum visibility is also included alongside the prevailing visibility when the visibility in one (in addition to the 1200SW metres to the south- direction, which is not the prevailing visibility, is less than 1500 metres or less than 50% of the prevailing visibility west' prevailing visibility. A direction is also added as one of the eight points of the compass.
    [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]
  • Ships Observing Marine Climate a Catalogue of the Voluntary
    WORLD METEOROLOGICAL ORGANIZATION INTERGOVERNMENTAL OCEANOGRAPIDC COMMISSION (Of UNESCO) MARINE METEOROLOGY AND RELATED OCEANOGRAPHIC ACTIVITIES REPORT NO. 25 SHIPS OBSERVING MARINE CLIMATE A CATALOGUE OF THE VOLUNTARY OBSERVING SHIPS PARTICIPATING IN THE VSOP-NA WMO/TD-No. 456 1991 NOTE The designations employed and the presentation of material in this publication do not imply the expression ofany opinion whatsoever on the part of the Secretariats of the World Meteorological Organization and the Intergovernmental Oceanographic Commission concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation ofits frontiers or boundaries. Editorial note: This publication is an offset reproduction of a typescript submitted by the authors and has been produced withoutadditional revision by the WMO and IOC Secretariats. SHIPS OBSERVING MARINE CLIMATE A CATALOGUE OF THE VOLUNTARY OBSERVING SHIPS PARTICIPATING IN THE VSOP-NA Elizabeth.C.Kent and Peter.K.Taylor .James .Rennell. centre for Ocean Circulation, Chilworth Research Park. Southampton. UK PREFACE Meteorological observations made onboard merchant vessels of the i'H) vollIDtary observing shipa (ves) scheme, when transmitted to shore in real-time:J are a substantial canponent of the Global Observing System of the World Weather Watch and are essential tc> the pr<>vision of marine lleteorological services ~ as well as tc> ID€:teorol.ogical analyses and forecasts generally. These observations are also recorded in ships r meteorological log1xx>ks:t for later exchange., archival and p:roc-essing -through the i'H) Marine CliJDa.tc>logical StlJllDa'ries Scheme, and as such. they conatitute an equally essential source of data for determining the cliJDa.tc>logy of the marineatlooaphere and ocean surface, and 'for OJIIIPUt.ing a variety of air-sea fluxes.
    [Show full text]