Depending on geographical location, ships 

 at sea report marine weather to designated 

 receiving stations. North Pacific Ocean data 

 for the region west of the 180th meridian are 

 received by "Observer Tokyo." Data for the 

 region east of the 180th meridian are received 

 by "Observer San Francisco" and are relayed 

 to the U.S. Weather Bureau Forecast Center 

 at San Francisco International Airport, San 

 Bruno, Calif. This center transmits both 

 Observer San Francisco and Tokyo reports to 

 other agencies via teletype circuits. The BCF 

 Biological Laboratory, San Diego, maintains 

 a drop on Service "O", Circuit 8274 to receive 

 ship surface weather information 24 hours 

 daily. 



The ship weather report code adheres to 

 the following symbolic 5-digit word group 

 format: 



Table 1. — Elements of the ship's surface 

 synoptic code, FM 21. A 1 



Symbols 



Definitions of symbols 



YQL a L a L a 

 PPPTT 



OT T T,T, 

 s s d d 



L L L GG 



o o o 



Nddff WwwW 



N,C T hC. ,C__ 

 h L M H 



Id d P H 



WWWW 



D s v s app 



ICE c,KD.re 

 2 i 



Additional groups are coded when required; 

 supplementary information following the ICE 

 word group is usually transmitted in plain 

 language. Definitions of symbols are given in 

 table 1. 



Since a large percentage of the incoming 

 marine weather observations emanates from 

 vessels having observers with limited meteor- 

 ological experience, the question arises as 

 to the validity of certain portions of the stand- 

 ard weather message. It is recognized that 

 certain observational errors maybe introduced 

 by equipment in poor condition or through 

 faulty operation. The problem of variability of 

 ship's injection system thermometer readings, 

 as an example, has been reviewed by Saur 

 (1963). From his studies aboard U.S. Navy 

 radar picket vessels, Military Sea Transport 

 Service ships, and oil tankers, Saur found that 

 the average injection temperature bias from 

 that of a bucket temperature taken at the 

 surface was about + 1.2° F. In addition to 

 instrument error, one complicating factor is 

 that sea temperatures are not reported directly 

 but, rather must be derived from air tempera- 

 tures and air-sea temperature differences. In 

 the near future the Commission on Maritime 

 Meteorology of the WMO plans to discuss the 

 possibility of changing the marine weather 

 coding instructions so that sea temperature will 

 be reported directly. Another complicating 

 factor is the problem of communication 

 errors. A study by Gibson (1962) for the 

 Atlantic Ocean showed that 19 percent of 

 the sea temperatures received on 1 day 

 were incorrect; these errors were due to 

 improper coding procedures, to communica- 

 tion transmission errors, and to faulty in- 

 struments. 



Y 

 Q 

 L a L a L a 



GG 



N 

 dd 



ff 



W 



WW 



W 

 PPP 



TT 



«h 



C L 

 h 



C„ 



PP 



Vs 



Vd 



1 



<Vw 



p w 



«w 



ICE 



c 2 

 K 



Di 



r 



e 



Day of week 



Octant of globe 



Latitude in degrees and tenths 



Longitude in degrees and tenths 

 Greenwich civil time of observa- 

 tions, to nearest hour 



Fraction of celestial dome covered 



by clouds 

 Direction from which the wind is 



blowing (tens of degrees) 

 Wind speed in knots 



Visibility (in code) 

 Present weather (in code) 

 Past weather (in code) 



Sea-level pressure (tens, units, 



tenths) millibars (mb). 

 Temperature of the air (whole 



degrees Centigrade) 



Fraction of celestial dome covered 

 C L or ^U clou d 



Clouds of types stratocumulus , stra- 

 tus, cumulus, cumulonimbus (in code) 



Height of base of lowest C^ or Cjj 

 cloud above sea 



Clouds of types altocumulus, alto- 

 stratus, nimbostratus (in code) 



Clouds of types cirrus, cirrostratus, 

 cirrocumulus (in code) 



Ship's course (in code) 

 Speed of ship in knots (in code) 

 Characteristic of barometric tend- 

 ency (in code) 

 Amount of barometric change (units 

 and tenths) millibars (mb.) 



Group designator 



Difference between air and sea tem- 

 perature (half degrees Centigrade) 



Temperature of dew point (whole 

 degrees Centigrade) 



Group designator 



Direction from which waves are 



coming (tens of degrees) 

 Period of waves (in code) 

 I* an height of waves (in code) 



Group designator for ice group 

 Description of kind of ice (in code) 

 Effect of ice on navigation (.'.a code) 

 Bearing of ice limit (in code) 

 Distance of ice from ship (in code) 

 Orientation of ice field (in code) 



1 Adapted from U.S. Weather Bureau Manual of 

 Marine Meteorological Observations, Circular M 



[11th ed.), January 1963, p. 8. 



