APPENDIX E-I

CODE FORM FOR PILOT OBSERVATIONS

E-I.1 CODE FORM: PILOT Parts A, B, C, and D by SECTION NUMBER

Parts A, B, C, and D: SECTION 1 (E-I.2.1)

M_iM_iM_jM_j D....D** YYGGa₄
IIiii*

{ or 99L_aL_aL_a Q_cL_oL_oL_oL_o MMMU_LaU_Lo** h₀h₀h₀h₀i_m***

Parts A and C: SECTION 2 (E-I.2.2)

44nP₁P₁
or
55nP₁P₁

}

ddfff ddfff ..... etc.

Part A and C: SECTION 3 (E-I.2.3)

77P_mP_mP_m
or
66P_mP_mP_m

}

d_md_mf_mf_mf_m (4v_bv_bv_av_a)

or
7H_mH_mH_mH_m
or
6H_mH_mH_mH_m
or
77999

}

d_md_mf_mf_mf_m (4v_bv_bv_av_a)

Parts B and D: SECTION 4 (E-I.2.4)

9
or
8

}

t_nu₁u₂u₃ ddfff ddfff ddfff

...... ...... ...... ...... ......

9
or
8

21212

}

t_nu₁u₂u₃ ddfff ddfff ddfff

n₀n₀P₀P₀P₀   d₀d₀f₀f₀f₀
n₁n₁P₁P₁P₁   d₁d₁f₁f₁f₁
.....                  .....
n_nn_nP_nP_nP_n   d_nd_nf_nf_nf_n

Parts B and D: SECTION 5 (E-I.2.5)

51515 52525 ..... 59595	}	Code groups developed regionally
Parts B and D: SECTION 6 (E-I.2.6)
61616 62626 ..... 69696	}	Code groups developed nationally.

E-I.2 PILOT Upper Wind Report Code Forms. Requirements for international exchange require Parts A, B, C, and D for the Upper Winds.

NOTE: For exchange within Region IV and inclusion in subregional and regional broadcasts, Parts A and B may be transmitted together or separately, as may Parts C and D.

CODE FORM: Parts A and B Up to and including the 100-hPa surface

Parts C and D above the 100-hPa surface

E-I.2.1 SECTION 1 Identification and position data

M_iM_iM_jM_j

{

D....D**
IIiii*
or
99L_aL_aL_a

YYGGa₄

Q_cL_oL_oL_oL_o MMMU_LaU_Lo** h₀h₀h₀h₀i_m***

Symbolic letters and definitions

M_iM_i Type of report
   PP = PILOT (FM 32)
   QQ = PILOT SHIP (FM 33)
   EE = PILOT MOBIL (FM 34)

M_jM_j Part of report transmitted
   AA = Part A
   BB = Part B
   CC = Part C
   DD = Part D

*       Used in FM 32 only.
**     Used in FM 33 and FM 34 only.
***   Used in FM 34 only.

D....D ship or mobile land station--for ship use ships call sign (three or more alphanumeric characters or the identifier SHIP. In the case of mobile land station, the group shall be either the radio call-sign of the station if assigned or an identification group assigned for the duration of the activity which the station is supporting. If possible, the mobile station should maintain the same identification for the duration.

YY Day of the month (UTC), (01 equals the first day, 02 the second day, etc.) on which the actual time of observation falls. YY shall also be used to indicate the unit of wind speed in addition to indicating the day of the month. When wind speeds are given in knots, 50 shall be added to YY. When the speed is given in meters per second, YY shall not be modified.

E-I.2.1 SECTION 1 Identification and position data (Continued)

Symbolic letters and definitions

GG Actual time of observation to the nearest whole hour UTC. In the case of a PIBAL observation, the actual time of observation is the time at which the balloon is actually released.

a₄ Type of measuring equipment used (Code Table 0265)

IIiii WMO index number assigned to a fixed land station

99L_aL_aL_aQ_cL_oL_oL_oL_o MMMU_LaU_Lo replacement group for IIIiii of the report for a sea station, aircraft, a carrier balloon, or a mobile land station.

99 data on position to follow

L_aL_aL_a latitude in tenths of a degree

Q_c quadrant of the globe (Code Table 3333)

L_oL_oL_oL_o longitude in tenths of a degree

MMM Marsden square number in which station is located at observation time. (Code Table 2590)

U_La unit digit of reported latitude

U_Lo unit digit of reported longitude

h₀h₀h₀h₀i_m elevation of mobile land station, units of elevation, and elevation accuracy

h₀h_oh₀h₀ elevation if meters or feet as indicated by i_m

i_m indicator for units of elevation and confidence factor of accuracy (Code Table 1845) assigned or an identification group assigned for the duration of the activity which the station is supporting. If possible, the mobile station should maintain the same identification for the duration.

APPENDIX E-I.2: PILOT Upper Wind Report Code Forms

CODE FORM: Part A Up to and including the 100-hPa surface and C above the 100-hPa surface

E-I.2.2 SECTION 2 Data for standard isobaric surfaces

44nP₁P₁
or
55nP₁P₁

}

ddfff ddfff.....etc.

Regulations:

Symbolic letters and coding remarks

Section 2 shall contain data, in ascending order with respect to altitude, for the standard isobaric surfaces of 850, 700, 500, 400, 300, 250, 200, 150, and 100 hPa in Part A and for the standard isobaric surfaces of 70, 50, 30, 20, and 10 hPa in Part C.

When pressure measurements are not available, wind data shall be reported using geopotential approximations to the standard isobaric surfaces.

All standard isobaric surfaces within the sounding shall be represented in Section 2 of the report by either a data group or a group of solidi (/////).

Indicator figures 44 shall be used when the standard isobaric isobaric surfaces are located by means of pressure equipment. Indicator figures 55 shall be used for the reporting of winds at altitudes approximating the standard isobaric surfaces. If the pressure element failed during the ascent, indicator figures 55 shall replace the indicator figures 44 for the remaining standard isobaric surfaces to be reported.

In the report, no more than three wind groups shall follow a 44nP₁P₁ or 55nP₁P₁ group. The latter groups shall therefore be repeated as often as necessary.

44 Standard isobaric surfaces located by radiosonde.

55 Winds reported at altitudes approximating the standard isobaric surfaces (Code Table 5300).

n Number of consecutive isobaric surfaces for which wind data are reported, starting with the surface specified by P₁P₁.

P₁P₁ Pressure of the lowest standard isobaric surface, with respect to altitude, for which wind data are reported. The pressure of surfaces up to and including the 100-hPa surface shall be reported in tens of hectopascals. Above the 100-hPa surface, pressure shall be reported in whole hectopascals.

dd True direction (rounded off to the nearest 5^O), in tens of degrees, from which wind is blowing.

fff Wind speed in, in meters per second or knots. When encoding wind direction that has been rounded off to the nearest 5^O, the hundreds and tens figures of this rounded direction shall be reported by dd and the units figure shall be added to the hundreds figure of the wind speed. When wind speeds are in knots, 50 shall be added to YY. When speed is given in meters per second, YY shall not be modified.

E-I.2.3 SECTION 3 Data for maximum wind level(s), with altitudes given in pressure units or tens of geopotential meters, and data for vertical wind shear.

77P_mP_mP_m
or
66P_mP_mP_m
or
7H_mH_mH_mH_m
or
6H_mH_mH_mH_m
or
77999

}

}

d_md_mf_mf_mf_m(4v_bv_bv_av_a)

d_md_mf_mf_mf_m (4v_bv_bv_av_a)

Regulations:

Symbolic letters and coding remarks

For coding purposes, a maximum wind level:

(a) Shall be determined by consideration of the list of significant levels for wind speed, as obtained by means of the relevant recommended or equivalent national method and not by consideration of the original wind-speed curve;

(b) Shall be located above the 500-hPa isobaric surface and shall correspond to a speed of more than 30 meters per second.

NOTE: A maximum wind level is defined as a level at which the wind speed is greater than that observed immediately above and below that level.

77 When a maximum wind occurred within the sounding and its level was determined by means of pressure, this indicator shall be used in the first group of Section 3, i.e. 77P _mP_mP_m.

7 When a maximum wind occurred within the sounding and its altitude was expressed in tens of standard geopotential meters, the indicator figure 7 shall be used in the first group of Section 3, i.e. 7H_mH_mH_mH_m.

66 When the greatest wind speed observed throughout the sounding occurred at the top of the sounding and the level of the greatest wind was determined by means of pressure, the indicator figures 66 shall be used in the first group of Section 3, i.e. 66P_mP_mP_m.

6 When the greatest wind speed observed throughout the sounding occurred at the top of the sounding and the altitude of the greatest wind was expressed in tens of standard geopotential meters, the indicator figure 6 shall be used in the first group of Section 3, i.e. 66H_mH_mH_m.

77999 When a maximum wind is not observed or not reported, group 77999 shall be reported in lieu of he maximum wind section, i.e. Section 3.

P_mP_mP_m Pressure at the maximum wind level. (1) The pressure of surfaces up to and including the 100-hPa surface shall be reported in whole hPas. Above the 100-hPa surface, pressure shall be reported in tenths of a hectopascal.

d_md_m True direction (rounded off to the nearest 5^O), in tens of degrees, from which maximum wind is blowing.

APPENDIX E-I.2: PILOT Upper Wind Report Code Forms

CODE FORM: Part A Up to and including the 100-hPa surface and
Part C above the 100-hPa surface(Continued)

E-I.2.3 SECTION 3 Data for maximum wind level(s), with altitudes given in pressure units or tens of geopotential meters, and data for vertical wind shear (Continued)

Symbolic letters and coding remarks (Continued)

Whenever more than one maximum wind level exists, these levels shall be reported as follows:

(a) The level of greatest maximum wind speed shall be transmitted first;

(b) The other levels shall be classified in descending order of speed, and be transmitted only if their speed exceeds those of the two adjacent minimals by at least ten meters per second;

(c) The levels of maximum wind with the same speed shall be encoded successively, beginning with the lowest ones;

(d) Furthermore, the highest level attained by the sounding shall be transmitted, provided:

(i) It satisfies the criteria set forth in the Regulation 32.2.3.1 above;

(ii) It constitutes the level of the greatest speed of the whole sounding.

When more than one level of maximum wind is observed, data for each level shall be reported by repeating Section 3.

f_mf_mf_m Maximum wind speed in meters per second or knots. (1) When encoding wind direction that has been rounded off to the nearest 5^O, the hundreds and tens figures of this rounded direction shall be reported by dd and the units figure shall be added to the hundreds figure of the wind speed. (2) The day of the month (UTC) shall be used to indicate the unit of wind speed in addition to indicating the day of the month. When wind speeds are given in knots, 50 shall be added to YY. When wind speed is given in meters per second, YY shall not be modified.

(4v_bv_bv_av_a) Section containing wind shear. This group shall be included only if data for vertical wind shear are computed and required.

v_bv_b Absolute value of the vector difference between the maximum wind and the wind blowing at 1 km above the level of maximum wind, in units indicated by YY.

v_av_a Absolute value of the vector difference between the maximum wind and the wind blowing at 1 km above the level of maximum wind, in units indicated by YY.

H_mH_mH_mH_m Altitude of the level of maximum wind, in tens of standard geopotential meters.

E-I.2.4 SECTION 4 Data for fixed-additional levels and/or additional levels, with altitudes given either in geopotential units or in pressure units.

9 or 8	}	t_nu₁u₂u₃	ddfff ddfff ddfff
.....		.....	..... ..... .....
9 or 8	}	t_nu₁u₂u₃	ddfff ddfff ddfff
or 21212		n₀n₀P₀P₀P₀ n₁n₁P₁P₁P₁ ..... n_nn_nP_nP_nP_n	d₀d₀f₀f₀f₀ d₁d₁f₁f₁f₁ ..... d_nd_nf_nf_nf_n

Regulations:

Symbolic letters and coding remarks

Additional levels

The reported additional data alone shall make it possible to reconstruct the wind profile with sufficient accuracy for practical use. Care shall be taken that:

(a) The direction and speed curves (in function of the log of pressure or altitude) can be reproduced with their prominent characteristics;

(b) These curves can be reproduced with an accuracy of at least 10^O for direction and five meters per second for speed;

(c) The number of additional levels is kept strictly to a necessary minimum.

NOTE: To satisfy these criteria, the following method of successive approximations is recommended, but other methods of attaining equivalent results may suit some national practices better and may be used:

Indicator figures

9 The indicator figure 9 shall be used when the altitudes of fixed-additional levels and/or additional level are given in units of 300 meters. The figure 9 shall be used in Section 4 up to and including the height of 29 700 meters. Above that level, the indicator figure 1 shall be used to specify that 30 000 meters be added to the heights indicated by t_nu₁u₂u₃

8 The indicator figure 8 shall be used in Section 4 when the altitudes of fixed-additional levels and/or additional levels are given in units of 500 meters.

t_n Tens digit of the altitude, expressed in units of 300 meters or 500 meters, which applies to the following data groups

u₁ Units digit of the altitude, expressed in units of 300 meters or 500 meters, for the first data group following.

u₂ Units digit of the altitude, expressed in units of 300 meters or 500 meters, for the second data group following.

u₃ Units digit of the altitude, expressed in units of 300 meters or 500 meters, for the third data group following.

dd True direction, (rounded off to the nearest 5^O), in tens of degrees, from which wind is blowing.

(1) When encoding wind direction that has been rounded off to the nearest 5^O, the hundreds and tens figures of this rounded direction shall be reported by dd and the units figure shall be added to the hundreds figure of the wind speed.

APPENDIX E-I.2: PILOT Upper Wind Report Code Forms

CODE FORM: Part B up to and including the 100-hPa surface
Part D above the 100-hPa surface

E-I.2.4 SECTION 4 Data for fixed-additional levels and/or additional levels, with altitudes given either in geopotential units or in pressure units (Continued).

(1) The surface level and the highest level attained by the sounding constitute the first and the last mandatory significant levels. The deviation from the linearly interpolated values between these two levels is then considered. If no direction deviates by more than 10^O and no speed by more than five meters per second, no other significant level need be reported. Whenever one parameter deviates by more than the limit specified in paragraph (b) above, the level of greatest deviation becomes a supplementary significant level for both parameters.

(2) The additional levels so introduced divide the sounding into two layers. In each separate layer, the deviation from the linearly interpolated values between the base and the top are then considered. The process used in paragraph (1) above is repeated and yields other significant levels. These additional levels in turn modify the layer distribution, and the method is applied again until any level is approximated to the above-mentioned specified values. For the purpose of computational work, it should be noted that the values derived from a PILOT report present two different resolutions:

(a) Winds at all levels are reported to the resolution of 5^O in direction and one meter per second in speed;

(b) Any interpolated wind at a level between two levels is implicitly reported to the resolution of +10^O in direction and +5 meters per second in speed.

In addition to wind data at other levels, altitudes of which shall be reported in geopotential units, data at the following levels shall be included:

  300 m   1200 m   2400 m   3600 m   7500 m
  600 m   1800 m   2700 m   4800 m   9000 m
  900 m   2100 m   3200 m   6000 m   15000 m

fff Wind speed in meters per second or knots.

(1) YY shall be used to indicate the unit of wind speed in addition to indicating the day of the month. When wind speeds are given in knots, 50 shall be added to YY. When the speed is given in meters per second, YY shall not be modified.

21212      n₀n₀P₀P₀P₁ d₀d₀f₀f₀f₀
                n₁n₁P₁P₁P₁ d₁d₁f₁f₁f₁
                ...      ...
                n_nn_nP_nP_nP_n d_nd_nf_nf_nf_n

21212 Data for significant levels

n₀n₀      Number of level, starting with
n₁n₁      station level. Station level
...          shall be coded n₀n₀.
n_nn_n

P₀P₀P₀      Pressure at specified levels.
P₁P₁P₁      The pressure of the surfaces up
...               to and including the 100-hPa
P_nP_nP_n      surface shall be reported in whole
                  hectopascals. Above the 100-hPa
                  surface, pressure shall be
                  reported in tenths of a hectopascal.

d₀d₀      True direction (rounded off to the
d₁d₁      nearest 5^O), in tens of degrees, from
...          which wind is blowing at specified
d_nd_n      levels starting with surface level. (1)
              When encoding wind direction that
              has been rounded off to the nearest
              5^O, the hundreds and tens figures of
              this rounded direction shall be
              reported by dd and the units figure
              shall be added to the hundreds
              figureof the wind speed.

E-I.2.4 SECTION 4 Data for fixed-additional levels and/or additional levels, with altitudes given either in geopotential units or in pressure units.
(Continued)

Fixed Levels reported in Section 4 shall be determined by regional decision.

In Section 4, the data groups for the fixed- and additional levels within the sounding shall appear in ascending order with respect to altitude.

To indicate that the first wind group refers to station level, u₁ shall be coded/ (solidus), and appropriate values shall be reported for t_n, u₂ and u₃.

Altitudes: The altitudes of fixed- and additional levels shall be reported either in geopotential units or in pressure units. Only one of the units shall be used in a coded report.

In addition to wind data at significant levels, altitudes of which shall be reported in geopotential units, data at the following fixed levels shall be included: 18000, 21000, 24000, 27000, 30000, 33000 m and all successive levels at 3000 m, provided they do not coincide with one of the included significant levels.

The altitudes of 30000 m and above shall be encoded using units of 500 m, i.e. the altitudes 30000 m and 33000 m shall be included as 8606/, at the altitudes 36000 m and 39000 m as 8728/, etc.

Symbolic letters and coding remarks

f₀f₀f₀      Wind speed in meters per second
f₁f₁f₁      or knots, at specified levels
...           starting with station level.
f_nf_nf_n

(1) When encoding wind direction that has been rounded off to the nearest 5^O, the hundreds and tens figures of this rounded direction shall be reported by dd and the units figure shall be added to the hundreds figure of the wind speed. (2) YY shall be used to indicate the unit of wind speed in addition to indicating the day of the month. When wind speeds are given in knots, 50 shall be added to YY. When the speed is given in meters per second, YY shall not be modified.

APPENDIX E-I.2: PILOT Upper Wind Report Code Forms

CODE FORM: Part B Up to and including the 100-hPa surface and

Part D above the 100-hPa surface (Continued)

E-I.2.5 SECTION 5 Code groups developed regionally

51515
52525
.....
59595

}

Code groups developed regionally

E-I.2.6 SECTION 6 Code groups developed nationally

61616
62626
.....
69696

}

Code groups to be developed nationally

Appendix E
Appendix E-II
Table of Contents
Publications List
Home