Národní shromáždění československé / Poslanecká sněmovna1920 – 1925

ANNEX G.

COLLECTION AND DISSEMINATION OF METEOROLOGICAL INFORMATION.

1. Nature and object of meteorological information to be furnished by Contracting States:

A. "Statistical" is required for the purpose of indicating the degree of safety and convey nience of different routes or aerodromes for different types of aircraft.

It consists of:

a) Analysis and summaries of past meteorological records.

b) Summaries of current observations.

B. "Current" is required for the purpose of:

a) Keeping a current record of the weather.

b) Making forecasts.

It consists of:

1. The result of daily observations,

2. Lists of active stations at which these observations are taken.

C. "Forecasts" are for the purpose of telling all concerned when and where flying is possible and the best conditions for the same. They are statements of conditions anticipated:

a) "Short period" during the next three or four hours.

b) "Normal" during the next 20 to 30 hours.

c) "Long period" during the next two or three days.

d) "Route" for particular region or route during the next six hours.

2. Methods and times of furnishing the different types of information:

A. "Statistical" is furnished by Central Meteorological Offices for general information.

a) Analysis and summaries of past records - by the publication of special handbooks giving averages, frequencies and extremes of the principal meteorological elements, together with charts and diagrams; prominence to be given to meteorological conditions of areas known to have special meteorological peculiarities.

b) Summaries of current observations by the monthly publication of the information obtained each month.

B. "Current" is furnished by meteorological offices to meteorological offices.

a) Results of daily observations - telegraphically by:

1. Regular reports at fixed hours (see Appendix I) and.

2. By special reports at intermediate times when requested (see Appendix II).

b) Lists of stations whenever necessary, to keep other countries informed where observations are being taken, giving also local and topographical details affecting weather conditions at each station.

c) "Forecasts" are furnished by Meteorological Offices for general information by publication in the public Press, telegraphically to other countries if required, or any other, the best, means to bring them to the notice of those requiring them (see Appendix III).

APPENDIX I.

REGULAR REPORTS.

These are of two kinds:

1. Individual station reports.

2. Collective station reports.

1. Individual station reports are the results of observations of individual stations, taken at 0100, 0700, 1300, and (1800 or) 1900 G. M. T. The reports are made as soon as the observation has been taken and are rendered to a central collecting station or office; where reports for only two. of these hours are possible or sufficient, the hours should be separated by an interval of twelve hours. (It is recommended that the standard hours be changed to 0300, 0900, 1500 and 2100 G. M. T. by international agreement.)

Reports will give information on the following, whenever possible:

1. Wind.

2. Pressure.

3. Temperature and humidity.

4. Fog and visibility.

5. Clouds.

6. Precipitation.

7. Thunderstorms, hurricanes, tornadoes, dust-storms.

8. Other weather phenomena.

9. State of sea,

and also on upper air currents and upper air temperature and. humidity, from stations where facilities are available for observation. Reports will be made in the general form and in the codes given in Appendix IV.

2. Collective reports are a collection of the individual reports received by a central station or office and transmitted to other central offices. They are of three classes:

Class 1. The central office in this case is usually the main office of a country; it transmits its reports, within ¹/₂ hours of the time the observations are taken at the individual stations, to all main offices of other countries within a radius of 1.500 kilometres.

Class 2. These are reports made for the purpose of giving countries over 1.500 kilometres distant information essential to making their own forecasts. The central office is that of a selected State which possesses a high-power wireless station capable of world-wide ranges (minimum range 3.000 kilometres). The report is made within three hours of the observations, and is a collection of reports selected from the Class 1 reports and abridged (see Appendix IV). It should include a forecast of conditions in the country of origin.

Class 3. These are local reports made by local centres to other local centres (any within 500 kilometres). the report is a collection of reports, selected from the Class 1 reports from stations in the vicinity and abridged (see Appendix IV). It is made within 30 minutes of the time of observation.

APPENDIX II.

SPECIAL REPORTS.

Special reports give the results of continuous observations at aerodromes having meteorological stations on recognised air routes. They are to be rendered within thirty minutes of a request from a central office on a specified aerodrome on the route. The maximum distance from which these reports will be required is 500 kilometres. The requests may take the form of a demand for hourly reports.

The reports are rendered by telephone or wireless, and may be from one country to another in the case of an international air route. The reports when made by telegram will be in the form and code given in Appendix IV.

APPENDIX III.

FORECASTS.

Short-period forecasts covering three to four hours will give a statement of the anticipated conditions of cloud, weather, surface wind and visibility, together with direction and speed of wind at heights of 1.000 and 2.000 metres, and an estimate of meteorological fitness for different types of aircraft. Normal forecasts for twenty to thirty hours will give similar information, but in more general terms.

Long-period forecasts give a general statement of the prospects for the next two or three days.

Route forecasts are made twice daily by central offices from information received from individual stations and will give a statement of conditions anticipated in the different regions or routes of the country for about six hours ahead.

APPENDIX IV.

GENERAL FORM IN WHICH REPORTS ARE TO BE RENDERED AND CODES FOR THEIR TRANSMISSION.

Individual stations will be allotted station call signs, i. e., an index group of letters of figures which will be used in all reports to indicate the station, and will also serve as the wireless call signs These should be internationally distinct.

The general form is given in meteorological symbols or letters. For purposes of transmission an appropriate figure value is given to each symbol or letter in accordance with the codes given below.

METEOROLOGICAL SYMBOLS OR LETTERS AND THEIR SIGNIFICATION.

Standard symbols.

BBB - barometer reduced to sea level and expressed in millibars and tenths, i. e., corrected for temperature gravity and index error. The initial 9 or 10 is omitted.

DD = direction of wind (true direction as distinguished from magnetic) at a height of 10-15 metres above the surface expressed on scale 1-72 (see Code X).

F = force of wind on Beaufort scale (wind above force 9 to be specially noted at end of telegram).

ww = present weather (Code I).

TT = temperature in degrees A (0⁰ A = - 273⁰ C, 273⁰ A = 0⁰ C), first figure omitted.

A = Form of low cloud (Code III).

L = Amount of low cloud (in tenths of sky covered, amount 10 telegraphed as 0).

B = Form of medium or high cloud (Code III).

M = Amount of medium or high cloud in tenths.

h = Height of base of low! cloud (Code IV) [a].

WW = Past weather (Code II).

V = Visibility (Code V).

H₁ = Relative humidity (Code VI).

S = State of sea (Code VII).

ß = Characteristic of barometric tendency (Code IX).

bb = Amount of barometric tendency in half milibars per 3 hours; 50 added for negative tendencies.

F₁ = Fitness of weather conditions for flying machines (Code VIII) [a.].

F₂ = Fitness of weather conditions for airships (Code VIII) [b].

RR = Rainfall: (i) in day (ii) in night; in milimetres and tenths.

MM = Maximum temperature in the day.

mm = Minimum temperature in the night.

X = Reserve figure.

SPECIAL SYMBOLS FOR UPPER AIR CURRENTS.

H = height (Code IV) [b].

DD = direction on scale J.-72 (i. e., to nearest 5⁰) [see Code X].

VV = speed in kilometres per hour (for speed above 99 K/hr use three figures.

SPECIAL SYMBOLS FOR UPPER AIR TEMPERA TUBE AND HUMIDITY.

p = height or pressure (Code IV) [c].

HH = actual percentage of relative humidity.

SPECIAL SYMBOL FOR COLLECTIVE REPORTS.

CLASSE 2.

BB = barometer in whole millibar s with the initial 9 or 10 omitted.

GENERAL FORMS OF MESSAGES IN METEOROLOGICAL SYMBOLS.

Regular reports.

1. Individual station reports. - Station call sign followed by the following groups: -

BBBDD. FwwTT. ALBMh. wwVHS. ßbbF₁F₂ RRMMX (or RRmmX).

Additional two groups for reports from Stations having facilities for observations of upper air currents; the first of these being:

Alive figure group to indicate that upper air current information is contained in the group which follows and which has the general form HDDVV.

Additional two groups for reports from stations having facilities for observations of upper air temperature and humidity; the first of these being:

A five figure group to indicate that upper air temperature and humidity information is contained in the group which follows and which has the general form TTHH.

(Note. - These indicative five figure groups would be better, from a signalling point of view, as a special Morse signal.)

2. Collective Station Reports, Class 1. - The individual station reports are given in sequence in the same general form as above. Upper air conditions are given at the end for those stations for which available: upper air currents being given only for the following heights, 500, 1000, 2000, 5000 metres (see Code IV. [b]).

Example of general form of collective report (Class 1) giving information from four stations A, B, C, D,: of which, stations B, C, have given upper air currents and stations B, D, upper air temperatures and humidity.

Call sign for "A" - BBBDD - FwwTT - A LBMh - wwVHS - ßbbF₁F₂.

Call sign for "B" - BBBDD - FwwTT - A LBMh - wwVHS - ßbbF₁F₂.

Call sign for "C" - BBBDD - FwwTT - A LBMh - wwVHS - ßbbF₁F₂.

Call sign for "D" - BBBDD - FwwTT - A LBMh - wwVHS - ßbbF₁F₂.

Group or signal indicating that upper air current information follows.

Call sign for "B" - HDDVV.

Call sign for "C" - HDDVV.

Group indicating that upper air temperature and humidity information follows.

Call sign for "B" - TTHH.

Call sign for "D" - TTHH.

3. Collective station, reports, Class 2. The individual station reports are given in sequence in an abridged form as follows: Call sign for station - BBDDF - wwTTh ALßbb.

Upper air currents are given at the end. of the telegram for heights 2000 and 5000 metres for selected stations.

Example of general form of collective report (Class 2) giving information from four stations A, B, C, D, of which stations "B", "C" are selected for upper air current conditions.

Call sign for "A" - BBDDF - wwTTh - ALßbb.

Call sign for "B" - BBDDF - wwTTh - ALßbb.

Call sign for "C" - BBDDF - wwTTh - ALßbb.

Call sign for "D" - BBDDF - wwTTh - ALßbb.

Group indicating that upper air current information follows.

Call sign for "B" - HDDVV.

Call sign for "C" - HDDVV.

Forecast of conditions in country of origin.

4. Collective Station Reports, Class 3. - The individual station reports are given in sequence in an abridged form as follows:

Call sign of station - DDFF₁F₂ - ALBMh - wwWWV.

Note 1. - The general form for transmission "of special reports" and of forecasts has not yet been formulated.

Note 2. - Observations from ships at sea and the transmission of such observations require special arrangements which it has not yet been possible to formulate. Similarly for observation from aircraft and their transmission.

CODES.

Code I. - Present Weather.- ww.

Note. - 00 to 49 weather without precipitation.

50 to 70 and 77 to 97 with precipitation.

In Codes I and II, r = rain, d = drizzle, h = hail, s = snow, rs = sleet, tlr = thunderstorm, e = wet air, f = fog (see Code V).

No Mist or Fog.

00 Absolutely cloudless.

01 Cloud less than ¹/₂.

02 About clouded.

03 About ³/₄, clouded.

04 Overcast, but small amount of blue visible.

05 Absolutely overcast.

Haze, Mist or Fog, but no precipitation.

06 Overcast and 1f.

07 - - 2f.

08 - - 3f.

09 -- - 4f.

10 -- - 5f.

11 - -- 6f.

12 - - 7f.

13 - - 8f.

14 Haze 1f.

15 - 2f.

16 Fog 3f.

17 - 4f.

18 - 5f.

19 - 6f.

20 - 7f.

21 - 8f.

22 Mist 1fe.

23 - 2fe.

24 Fog 3fe.

25 - 4fe.

26 - 5fe.

27 - 6fe.

28 - 7fe.

29 - 8fe.

Special Phenomena without precipitation.

30 a (wet air).

31 Exceptional visibility.

32 Dust Haze.

33 Dew.

34 Hoar Frost.

35 Rime.

36 Glazed Frost.

37 Glazed Roads.

38 Solar Halo.

39 Lunar Halo.

40 Solar Corona.

41 Lunar Corona.

42 Aurora.

43 Squalls.

44 Gale

45 Gloom.

46 Ugly: threatening.

47 Thunder.

48 Lightning.

49 Thunder and Lightning.

Precipitation and Fog (50-58).

50 light r

51 Moderate r - 2f. or 3f.

52 Heavy r

53 Slight r

54 Moderate r - 4f. or 5f.

55 Heavy r

56 Slight r

57 Moderate r - 6f. to 8f.

58 Heavy r

Precipitation grad Squalls of Wind (59-70).

59 Slight r.

60 Moderate r.

61 Heavy r.

62 Slight h.

63 Moderate r. and h.

64 Heavy r and h.

65 Slight rs.

66 Moderate rs.

67 Heavy rs.

68 Slight s.

69 Moderate s.

70 Heavy s.

Snow Covering.

71 s over whole country.

72 s with bare patches.

73 Deep drifts.

74

75 - Reserve figures.

76

Precipitation (77-97).

77 Slight d.

78 Moderate d.

79 Thick d.

80 Slight r.

81 Moderate r.

82 Heavy r.

83 Slight h.

84 Moderate h.

85 Heavy h.

86 Slight rs.

87 Moderate rs.

88 Heavy rs.

89 Slight s.

90 Moderate s.

91 Heavy s.

92 Slight tlr.

93 Moderate tlr - Without hail.

94 Heavy tlr

95 Slight tlr

96 Moderate tlr - With hail.

97 Heavy tlr

98

99 - Reserve Figures.

Code II. - Past Weather. - WW.

Note. - 00-49. Weather without precipitation. 50-97. Weather with precipitation.

No Precipitation or Fog (00-14).

00 equals Cloudless.

01 - b and bc; med. or high cloud.

02 - b and bc; low cloud.

03 - b and c; mixed cloud.

04 - be and e; med. or high cloud.

05 - be and e; low cloud.

06 - be and c; mixed cloud.

07 - c and o; med. or high cloud.

08 - c and o; low cloud.

09 - c and o; mixed cloud.

Overcast with blue patches (10-12).

10 equals med. or high cloud.

11 - low cloud.

12 - mixed cloud.

13 - completely overcast; low or mixed cloud.

14 - b and o; low or mixed cloud.

Fog with Cloud above (15-19).

15 equals overcast and 1f.

16 - overcast and 2f.

17 - overcast and 3f.

18 - overcast and 4f. or 5f.

19 - overcast and 6f. to 8f.

Haze or Fog (20-24).

20 equals Haze 1f.

21 - Haze 2f.

22 equals Fog 3f.

23 - Fog 4f. or 5f.

24 - Fog 6f. to 8f.

Wet Fog or Mist (25-29).

25 equals Mist 1fe.

26 - Mist 2fe.

27 - Fog 3fe.

28 - Fog 4fe. or 5fe.

29 - Fog 6fe to 8fe.

Special Phenomena without Precipitation (30-49).

30 equals a (wet air).

32 - Dust Haze.

33 - Dew.

34 - Hoar Frost.

35 - Rime.

36 - Glazed Frost.

37 - Glazed Roads.

38 - Solar Halo.

39 - Lunar Halo.

40 - Solar corona.

41 - Lunar corona.

42 - Aurora.

43 - Squalls.

44 - Gale.

45 - Gloom.

46 - Ugly; threatening.

47 - Thunder.

48 - Lightning.

49 - Thunder and Lightning.

Precipitation. Passing Showers (50-61).

50 of slight rain.

51 of moderate rain.

52 of heavy rain.

53 of slight hail or r and h.

54 of moderate hail or r and h.

55 of heavy hail or r and h.

56 of slight rs or r and rs.

57 of moderate rs or r and rs.

58 of heavy rs or r and rs.

59 of slight snow.

60 of moderate snow.

61 of heavy snow.

Occasional Precipitation (62-76).

62 occasional slight d.

63 - moderate d.

64 - thick d.

65 - slight r.

66 - moderate r.

67 - heavy r.

68 - slight r and h.

69 - moderate r and h.

70 - heavy r and h.

71 - slight rs or r and rs.

72 - moderate rs or r and rs.

73 - heavy rs or r and rs.

74 - slight s.

75 - moderate s.

76 - heavy s.

Continuous or nearly continuous Precipitation (77-91).

77 slight drizzle.

78 moderate drizzle.

79 thick drizzle.

80 slight rain.

81 moderate rain.

82 heavy rain.

83 slight r and hail.

84 moderate r and hail.

85 heavy r and hail.

86 slight rs or r and rs.

87 moderate rs or r and rs.

88 heavy rs or r and rs.

89 slight snow.

90 moderate snow.

91 heavy. snow.

Thunderstorms (92-97).

92 slight tlr without hail.

93 moderate tlr without hail.

94 heavy tlr without hail.

95 slight tlr with hail.

96 moderate tlr with hail.

97 heavy tlr with hail.

98 Reserve Number.

99 Reserve Number.

Code III. - Form of Cloud. Low Claud. - A.

Medium or High Cloud. - B.

Low Cloud:

1 equals Fracto Cumulus.

2 - Mammato Cumulus.

3 - Low Strato Cumulus (below 1200 m.).

4 - High Strato Cumulus (above 1200 m.).

5 - Nimbus.

6 - Cumulus.

7 - Cumulo Nimbus.

8 - Stratus.

High Cloud:

1 - Cirrus.

2 - Cirro Stratus.

3 - Cirro Cumulus.

4 - False Cirrus.

Medium Cloud:

5 - Thin Alto Stratus - Sun or Moon visible.

6 - Thick Alto Stratus

7 - Alto Cumulus (low) [below 3 km.].

8 - Alto Cumulus (high) [above 3 km.].

C o d e IV (a), (b), (c). - Heights and Pressures of Upper Air Reports.

Code IV (a). - Height of base of Low Cloud. - h.

Code IV (b). - Height of Upper Wind - H.

Code IV (c). - Height or Pressure to which Temperature and Humidity Values refer - p.

Code V. - Surface Visibility and Fog.-V.

Code VI. - Relative Humidity - H.

Code VII. - State of Sea - S.

Code VIII (a) & (b). - Fitness for Flying.

Code VIII (a). Fitness for aeroplane.

Code figure.

0 equals entirely unfit: fog.

1 - entirely unfit: rain and low cloud.

2 - entirely unfit: gales.

3 - very risky: mist.

4 - very risky: wind and weather.

5 - risky: mist.

6 - risky: wind and weather.

7 - fit.

8 - very fit.

9 - perfect.

Code VIII (b) Fitness for Airships.

Code figure.

0 equals entirely unfit: fog.

1 - entirely unfit: rain, wind, and low cloud.

2 - entirely unfit: gales.

3 - very risky: high wind.

4 - very risky: occasional squalls.

5 - risky: strong wind.

6 - risky: slight squalls.

7 - fit.

8 very fit.

9 - perfect.

Code IX. - Characteristic of Barometric Tendency.- ß.

Code figure.

0 equals steady.

1 - unsteady.

2 - rising.

3 - falling.

4 - falling, then rising.

5 - steady, then rising.

6 - steady, then falling.

7 - falling, now steady.

8 - rising, now steady or falling.

9 - line squall; sudden rise with marked change of wind and weather.

Code X. - Direction of wind. - DD.

Direction is specified to the nearest 5 by use of the numbers 1-72. The numbers corresponding with the usual "even" points of the old telegraphic scale are as follows:

04 equals NNE.

09 - NE.

1 - ENE.

18 - East.

22 - ESE.

27 - SE.

31 - SSE.

36 - South.

40 - SSW.

45 - SW.

49 - WSW.

54 - West.

58. WNW.

63 - NW.

67 - NNW.

72 - North.

To express directions calculated in degrees in this scale, divide the number of degrees by 5 (or multiply by 2 and divide by 10).

e. g., 17⁰ equals 03; 53⁰ equals 11; 257⁰ equals 51; 313⁰ equals 63.