Bo-2 PREPARATION OF CHARTS 
minute. The meridian of the time zone will be entered in the 
space " th Mer.'' In areas where a standard time zone 
has not been established, the meridian that is closest to the 
station and that is evenly divisible by 15 will be entered and 
the date and time entry will pertain to that meridian. The time 
difference between LST and GMT must always agree with the 
meridian time-zone entry, i.e., 75th is 5 hours, 150 is 10 
hours, etc. 
b. A "scheduled observation" is one released within the 45 min- 
utes allotted by International agreement, i.e., between 2315 
and 0000, 0515 and 0600, 1115 and 1200, and 1715 and 1800 
GMT. For all ''scheduled observations,'' the second line will 
show the time to whole hours, i.e., 00,06, 12 or 18 as appro- 
priate. 
c. An observation not released within the 45 minutes allotted by 
international agreement is considered to bea ''delayed sched- 
uled,'' a 'non-scheduled" or a ''special'' observation unless 
granted a waiver by a higher authority. The second line will 
show the time to the nearest whole hour, i.e., 0015 GMT will 
be entered 00, 0047 as 01, 1105as11, 1345 as 14, 2215 as 22, 
etc. 
1.5 Radiosonde Serial Number. The radiosonde serial number can be 
found stamped on the outside of the case in the one-part instrument and 
is identical to the number on the modulator in the two-part instrument. 
Any prefix or suffix will be regardedasa part of the radiosonde number 
which will be entered in the appropriate space on WBAN-31( ). 
1.6 Ascension Numbers. Ascension numbers required on the WBAN- 
31 ( ), the recorder record, and the calibration chart will be numbered 
consecutively throughout the year. No. 1 will be the first raob of each 
year GMT, (the 0000 GMT scheduled raob, or the first raob taken there- 
after). Special raobs, and all raobs that have attained a pressure of 225 
mb or less (AF, N, 60 mb or less), will be given an ascension number 
except that if more than one release is required, only the one which is 
evaluated and used as the official observation willbe assigned an ascen- 
sion number (see §B4-7 and 7.1). If a raob terminates before reaching 
225 mb (AF, N, 60 mb) andbecause of unfavorable weather conditions or 
other reasons, a second release is not made, the first will be given an 
ascension number, evaluated, and the data transmitted. If conditions 
should later improve to such an extent that a second raob is taken, and 
this extends to a higher altitude than the first, which has already been 
transmitted, forms pertaining to both raobs will be forwarded in accord- 
ance with the following instructions. 
LI =) FMH#3 
