GENERAL HEADQUARTERS
SUPREME COMMANDER FOR THE ALLIED POWERS

APO 500
28 August 1946

AG 000.93 (28 Aug 46) GB
(SCAPIN-1163)

MEMORANDUM FOR	IMPERIAL JAPANESE GOVERNMENT.
THROUGH	Central Liaison Office, Tokyo.
SUBJECT	Operations of Japanese Weather Service.

1. It is directed that per. 5 of SCAPIN 308, 19 November 1945 be deleted and the following substituted therefor:
"5. Atmospheric soundings taken by means of radiosonde will be prepared and transmitted daily to the Central Meteorological Observatory.
a. Sounding will be taken at the following points:
Tokyo 662
Kagoshima 652
Siomisaki 656
Yonago 236
Wajima 676
Akita 679
Urakawa 682
Wakkanai 321
Aomori 680
Sendai 665
Hukuoka 210
Sapporo 686
b. Code form for the transmission of radiosonde data will be as follows:
(1) Standard or Basic Section:
IIIGG P0 P'0 P' 0 T 0 T 0 U0U0X1X2X3 (Oddvv) P1P1h1h1h1
T1 T1U1u'1u'1 (Oddvv) P2P2h2h2h2 T2TsU2u'u' (oddvv)
..... ...... .....
(2) Significant Point Section:
11199 hhPP'P'' TTUu'u' hhPP'P'' TTUu'u' .....
..... ...... (101AA) 101 DD
c. An explanation of the symbols used in the radiosonde code follows:
(1) Standard or Basic Section:
III - International Index number of station.
GG - Time of beginning of ascent, nearest whole hour GMT.
POP'OP'O' o' - Pressure at surface, whole millibars.
Note: The convention of writing P for hundreds place, P prime (P') for tens place and P double prime (P'') for units place has been adopted.
TOTO - Temperature at surface, whole degree C
UOUO - Relative humidity at surface, whole percent.
x1x2x3 - Indicator figures to show units used and inclusion of wind groups: x1 for heights and temperatures, x2 for wind and x3 for moisture (u'u'). Tables are in paragraph d. below.
O - Indicator figure for wind group (radio or radar wind). Data in the wind group always refers to the level immediately preceding.
dd - Wind direction, tens of degrees.
vv - Wind speed. (See paragraph f (8) for wind speed over 99 knots)
P1P1, P2P2 - Pressure in 10's of millibars of the first (lowest) second, etc, pressure levels. 00▰ 1000mb., 90▰ 900 mb., 85 ▰ 850 mb., etc.
h1h1h1 h2h2h2 - Height of P1P1, P2P2, etc. in tens of feet
T1T1, T1T1 - Temperature of P1P1, P2P2, etc. in whole degrees C.
U1U2, etc. - Relative humidity at P1P1, P2P2, etc.
u'1u'1, u2u'2 - Moisture values at P1P1, P2P'2, etc.
(2) Significant point Section:
11199 - Indicator, additional levels follow.
hh - Height of the level in hundreds of feet.
PP'P'' - Pressure at selected point in whole millibars.
TT - Temperature at selected point in whole degrees C.
U - Relative humidity at 10's of percent.
u'u' - Moisture values at selected points in units according to x3.
(101AA) - Supplementary group giving reason for failure to reach 100 mb. Level in ascent, as indicated in paragraph e. below.
101DD - Indicator and group (DD) giving the day of month GMT of the ascent. 01- first day, 02- second day, etc.
c. Code table for x1, x2, and x3 Symbols follow:
(1) x1 - Indicator for units of height and temperature.
0 - Feet - degrees C.
2 - Feet - degrees F.
4 - Meters - degrees C.
6 - Meters - degrees F.
7 - Heights not reported - degrees C.
8 - Heights nor reported - degree F.
(2) x2 - Indicator for wind group
0 - Winds not reported.
2 - Winds reported in miles per hour.
4 - Winds reported in knots.
6 - Winds reported in kilometers per hour.
8 - Winds reported in meters per second.
(3) X3 - Indicator for u'u'.
0 - mrmr - Mixing ratio, grams and tenths, tens figure omitted.
2 - TwTw - Temperature of wet bulb, whole degrees C or F.
4 - TsTs - Temperature of dewpoint, whole degrees C or F.
6 -tntn - Depression of wet bulb in half degrees C or F.
・Code table 101 - Reason No Report files or Incomplete Report.
40 ‐Report not filed.
41 - Airplane observation equipment failure.
42 -Radiosonde equipment failure.
43 -Observation delayed.
45 - Unfavorable weather conditions.
46 - Low maximum altitude (less than 500 meters about ground).
47 - Leaking balloon.
48 - Ascent not authorized for this period
50 - Ascent did not extend above 400 mb. level
51 -Balloon forced down by icing condition
52 -Balloon forced down by precipitation
53 -Atmospheric interference
54 -Local Interference
55 -Fading Signal
56 - Weak Signal
59 - Any reason not listed above
f. The following practices and conventions in the use of the above code will be followed:
(1) The mandatory levels (basic section) transmitted will be the 1000, 850, 700, 500, 300, 200, and 100 millibar levels.
(2) Transmission of the data will be in two parts. First transmission will include all data to the 400 mb. Level. Second transmission will include all the available data above 400 mb. Fifty will be added to Greenwich Time of ascent in the second transmission to designate it as such.
(3) The temperature, moisture group, and wind group for any pressure level will be omitted when the level is below the surface of the station. Omission of these groups will be clearly indicated by the negative value for height when the surface is below sea level (see paragraph (4)), by the value for surface pressure, and by the first two figures of the next group.
(4) To report heights below sea level the convention of adding 500 to the code figures (5000 to the actual values in fact) will be used. Example: If the height of the 1000 mb, surface is 1280 feet below sea level, 5000 is added and the figures 628 are coded for hhh.
(5) Temperature will be reported in whole degree Centigrade with code 0 being used for x1 (paragraph d (1) above). The convention of adding 50 for negative values will apply. Example: 15{C is coded as 65.
(6) Moisture content (u'u') will be reported as indicated by O in code table d(3) above.
(7) When combination rawin and radiosonde flights are made, code number 4 will be used for x2(paragraph d(2)above) and wind data will be included for mandatory constant pressure levels in the basic section of the radiosonde transmission. This wind data will not tale the place of the regular transmission, but complete transmission will be sent. Wind data taken by other methods (Pabal, etc.) will not be included in the radiosonde report.
(8) The following convention will be used for reporting wind speeds over 99 knots:
(a) In the range 100 to 199, 50 is added to dd, and vv gives the actual speed 100. Example: a speed of 135 from the west (370 degrees) is coded 07755.
(b) In the range 200 to 299, the group 00200 is insorted immediately Following the Oddvv group. dd gives the actual 10's of degrees and vv gives the actual speed mines 200. Example: a speed of 235 from the west (270 degrees) is coded 02735 00200.
(c) In the range 300 to 399, the group 00200 is inserted immediately following the Oddvv group, 50 is added to dd, and vv gives the actual speed minus 300. Example: a speed of 335 from the most (270 degrees) is coded 07755 00300.
(9) The figures 9, 99 and 999 will be used for missing data, in all positions except surface pressure. It is assumed that surface pressure will always be available.
(10) Additional information such as icing data, cloud data, special phenomena, etc., will be included in supplemental group as required.
(11) The group 101DD (paragraph 3b) giving the day of the month, will be the last group in both first and second transmissions.
(12) The group 101AA will be the next to last group in second transmission when ascent faile to reach 100 millibar level.
g. Reports prepared for transmission will be in the hands of the radio operator at least five minuites before transmission time.
h. Observation time of radiosonde reports will be 0400 GNT and 1600 GNT.
i. When , for various reasons, observations cannot be obtained in time for transmission on weather net, a report will be filled utilizing code table 101, paragraph c. above."

FOR THE SUPREME COMMANDER:

JOHN B. COOLEY,
Colonel, AGD,
Adjutant General.