Manual of marine weather observations

Summary of the Eighth Edition

Foreword

The "Manual of Marine Weather Observations" (MANMAR) prescribes the legacy information on the procedures, equipment and coding formats used in the observation of marine weather phenomenon and the preparation of marine weather reports. MANMAR is the standard for the legacy manually observed Voluntary Observing Ship (VOS) program. The VOS program has been discontinued within Canada. The Meteorological Service of Canada (MSC) currently supports the Automated Voluntary Observing Ship program (AVOS) and will support visiting VOS ships from other jurisdictions on a "best efforts" basis. Contact your regional Port Meteorological Officer (PMO) for further information.

MANMAR is currently used within MSC as a reference for the SHIP data format and historical VOS program observing procedures.

Amendments to MANMAR will be issued when warranted. All holders of the manual are responsible for keeping their copies current. When amendments have been entered, they are recorded on the page headed "Record of Amendments".

Inquiries on the content of this manual should be directed to the MSC through appropriate channels.

Chapter 1 General Information

This chapter gives general information about the necessity of weather observations at sea, and their use in weather forecasts and bulletins. The "International Convention on Safety of Life at Sea" (SOLAS) is referenced.

The organization of the Canadian weather observing fleet is discussed, and a distinction is made between classes of “selected ships” and “auxiliary ships”.

The World Meteorological Organization’s (WMO) FM 13-XIV Ext. SHIP code form, Report of surface observation from a sea station, is introduced and a table of symbols and their interpretation is given.

Information is given on how observations are recorded in meteorological logs, and procedures for the storage and return of the meteorological logs are also discussed.

Chapter 2 Observational routines

This chapter provides suggestions as to how the observer may complete their observation as quickly and efficiently as possible so that there will be a minimum of interference with other duties. When and where observations should be made is explained.

Chapter 3 Identification information

This chapter provides reference and instructions for recording identification information in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 4 Visibility

This chapter defines the meteorological measure of visibility, explains how visibility is observed at sea, and makes reference to similarities and differences with observing visibility on land. Reference and instructions are given for recording visibility information in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 5 Wind

This chapter defines the meteorological phenomenon “wind” and explains how wind is observed by the appearance of the sea surface, as well as by reference to effects on the observer’s person and shipboard objects. Instructions for obtaining estimates of wind speed observations are given based on the Beaufort wind force scale. Instructions for obtaining estimates of wind direction are given. The distinction between apparent and true wind is explained. Shipboard instruments for measuring wind speed are listed and their operation is explained. Wind shifts and squalls are mentioned as particularly notable wind observations. Reference and instructions are given for recording wind in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 6 Temperatures

This chapter details the four kinds of temperature involved in ships’ weather observations: the dry bulb temperature; the wet bulb temperature; the dew point temperature; and, the sea surface temperature. Instructions for observing and calculating temperature using particular instruments for each of these specific kinds of temperature are given. Instruction for maintenance and replacement of each of the types of thermometers is given. Reference and instructions are given for recording temperature in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 7 Pressure

This chapter defines the meteorological phenomenon “pressure” and explains the measurement of pressure by means of a barometer. The mercury barometer and the aneroid barometer are both detailed. Instructions are given for both types of barometer, including mounting, reading pressure levels, and making corrections for temperature, latitude, sea level, and the index correction. The use of a barograph to measure and provide a continuous record of variations in the atmospheric pressure is detailed. Instructions are given for mounting and operation of the barograph. Reference and instructions are given for recording pressure information in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 8 Present and past weather

This chapter introduces the weather group 7wwW1W2 which is used to code for the various phenomena which are (and/or were) occurring in the atmosphere. Three basic types of reportable meteors are detailed: hydrometeors (any kind of liquid or solid precipitation, fog or mist); lithometeors (haze, smoke, dust, etc.); and, electrometeors (lightning, thunder). Reference and instructions are given for recording present and past weather phenomena in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form. Definitions of terms and descriptions of phenomena are listed at the end of this chapter.

Chapter 9 Clouds

This chapter defines and categorizes clouds, and differentiates them from fog and mist. Cloud types are listed and differentiated by ranges of altitudes. Identifying information is given to aid an observer in differentiating the ten distinctive types of clouds. Further hints on observations are also given. Instructions on determining cloud amounts by estimation are given. Reference and instructions are given for recording cloud information in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 10 Ship’s course and speed

This chapter defines and provides references for calculating a ship’s true course and average speed. Instructions are given for recording a ship’s true course and average speed in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 11 Waves

This chapter introduces sea and swell waves, including the rationale for a continued need for more knowledge of waves, definitions of simple waves, freak waves, sea waves and swell, wave motion at sea, and wave groups. Procedures are given for observing ocean waves. Reference and instructions are given for recording wave information in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 12 Ice accretion on ships

This chapter defines ice accretion on ships and provides information on why this occurrence is such a dangerous hazard for ships at sea. Reference and instructions are given for recording ice accretion information in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 13 Ice

This chapter provides information on sea ice or land ice observed from a ship’s position. Reference and instructions are given for recording ice information in marine weather reports using WMO’s FM 13-XIV Ext. SHIP code form.

Chapter 14 Remarks Column

This chapter provides information and examples of the type of information that is entered in the meteorological log’s remarks column.

Chapter 15 Message transmission

This chapter provides information on the schedule of report transmissions and detailed procedures concerning how to transmit a coded weather report.

Appendices

Appendix A Safety of navigation at sea

This appendix contains a reproduction of "The International Convention on Safety of Life at Sea (SOLAS)", Chapter V, Regulations 1, 5, 6, 31, and 32 (of the 35 total regulations found in Chapter V) for reference purposes.

Appendix B Port Meteorological Officers (PMO)

This appendix contains a list of Canadian and United States of America based port meteorological officers in geographical order from East to West.

Appendix C The Marine Forecast code (MAFOR)

This appendix introduces the code used in the transmission of marine weather forecasts (MAFOR). Environment and Climate Change Canada issues MAFOR coded forecasts as part of their marine weather products for the Great Lakes and the St. Lawrence and Saguenay Rivers. Reference and instructions are given for decoding and interpreting MAFOR forecasts according to the WMO’s FM 61-IV MAFOR code form.

Appendix D Shipboard Environmental Acquisition System(SEAS III)

This appendix provides a description of the purpose and operation of the Shipboard Environmental Acquisition System.

Appendix E State of the sea (Beaufort scale)

This appendix displays 11 photos depicting the effects at sea of Beaufort Forces 0-11.

Appendix F Cloud chart

This appendix displays photographic depictions of clouds for reference when identifying clouds.