VAISALA Oy PC-CORA File Structure - Met Systems Division 1991-02-05



PC-CORA SOUNDING DATA FILE STRUCTURE

1. GENERAL

PC-CORA file format is designed to be used in PC-CORA sounding data files. All raw data files and edited files have this format.

1.1. PC-CORA File Structure

PC-CORA file has four sections:

1. Header Section (50 bytes)

2. Identification Data Section (196 bytes)

3. SYSPAR Section (8087 bytes)

4. Sounding Data Records (record length * number of records)

Sections 1, 2 and 3 have the same structure for all data files. Section 4 is specific for each file type. Currently supported file types are: Raw PTU, Edited data, Raw Radar data, Omega derivative data, Omega local phase data, Omega remote phase data, Loran-C derivative data, Loran-C phase data, Raw special sensor data.

1.2. Header Section

The header defines general details about the file like the type of file, length of blocks, number of record.

BYTE

DATA

TYPE

COMMENTS

1-20
(C) Valsala 1.01 left justified, null terminated Char

21-22
Length of Identification block in bytes Int 196

23-24
Length of SYSPAR in bytes Int 8087

25-26
Number of data records Int

27-28
Number of standard levels (Type EDT) Int

29-30
Type of Data Int 1 = Raw PTU
2 = EDT
3 = Raw radar
4 = Omega derivative
5 = Omega local
6 = Omega remote
7 = Loran C derivative
8 = Loran C phases
9 = Raw special sensor

31-32
Length of data record in bytes Int

33
"File ready" flag Byte 1 = Ready

0 = Not Ready

34-50
Reserved

The length of header is constant for all file types and is 50 bytes.

1.3. Identification Data Section

BYTE

DATA
UNIT TYPE

COMMENTS

1-2
Station type Int 0=Land, 1=Ship

3-4
Region number Int

5-6
WMO block number Int

7-8
WMO station number Int

9-10
Station latitude 0.01 deg Int

11-12
Station longitude 0.01 deg Int

13-14
Station altitude

m
Int

15-16
Wind speed unit in message Int 0 = m/s, 1 = knots

17-18
Use of telecommunication headings Int 0 = No, 1 = Yes

19-20
Res Int

21-22
Sounding type Int 0 = PTU

1 = Only pressure
2 = No PTU (Radar)

23-24
Start mode Int 0 = Auto, 1 =Manual

25-26
Time elapsed at the start of ascent

s
Int

27-28
PTU rate

s
Int

29-32
SPU card serial number Long

33-34
Year Int

35-36
Month Int

37-38
Day Int

39-40
Julian date Int

41-42
Hour Int

43-44
Minute Int

45-46
Message year Int

47-48
Message month Int

49-50
Message day Int

51-52
Message hour Int

53-58
Cloud group Char

59-64
Weather group Char

65-70
Napp Char

71-72
Surface pressure 0.1 hPa Int

73-74
Surface temperature 0.1 K Int

75-76
Surface humidity % RH Int

77-78
Surface wind direction Deg Int

79-80
Surface wind speed 0.1 m/s Int

81-90
Radiosonde number Char

91-100
Sounding number Char

101-102
Pressure correction Int

103-104
Temperature correction Int

105-106
Humidity correction Int

107-108
Succ. Of signal Int

109-110
Pressure accept level Int

111-112
Pressure replace level Int

113-114
Pressure reject level Int

115-116
Temperature accept level Int

117-118
Temperature replace level Int

119-120
Temperature reject level Int

121-122
Humidity accept level Int

123-124
Humidity replace level Int

125-126
Humidity reject level Int

127-128
Total omega count Int

129-130
Reason of termination Int

131-152
Omega count Int

153-154
Wind computing mode Int 0 = Remote

1 = Local
2 = Differential

155-156
Wind mode Int 0 = Omega

1 = Loran-C
2 = Radar
255 = Only PTU

157-158
Loran/Omega stations used Int One bit for each station

1 = Used, 0 = Not used

159
Number of Loran-C chains in use Byte

160-161
GRI of chain 1 10 µs Int

162-163
GRI of chain 2 10 µs Int

164-165
Excluded Loran-C transmitters Int One bit for each in the

chain; and chain 2
transmitted

166
Unit to control change of phase

integration time
Byte 0 = time (s)
1 = Altitude (m/MSI)

167-168
Phase Integration time 1 s Int

169-170
Phase Integration time 2 s Int

171-172
Phase Integration time 3 s Int

173-174
Phase Integration time 4 s Int

175-176
Phase Integration time 5 s Int

177-178
Phase Integration time 6 s Int

179-180
Phase Integration change level 1 Int

181-182
Phase Integration change level 2 Int

183-184
Phase Integration change level 3 Int

185-186
Phase Integration change level 4 Int

187-188
Phase Integration change level 6 Int

189-190
Phase Integration change level 6 Int

191-192
Reference pressure Int

193-194
Reference temperature Int

195-196
Reference Humidity Int

1.4. SYSPAR Data

Array of 8087 bytes. Contains the SYSPAR as specified by SYSGEN data description. The data values as they were when sounding was processed.

2. Sounding Data Records

All data records for one file type have the same format. The records are repeated sequentially following the time elapsed during the sounding. The missing data value for a parameter is -32768 unless otherwise stated.

2.1. Raw PTU Data

BYTE

DATA
UNIT TYPE

COMMENTS

1-2
Time Second Int

3-4
Scaled logarithmic pressure 4096*ln(P)hPa Int

5-6
Temperature 0.1 K Int

7-8
Humidity % RH Int

2.2. Edited Data

BYTE

DATA
UNIT TYPE

COMMENTS

1-4
Elapsed time since sonde release Second Float

5-6
Scaled logarithmic pressure 4096*ln(P)hPa Int

7-8
Temperature 0.1 K Int

9-10
Humidity % RH Int

11-12
North component of wind 0.01 m/s Int

13-14
East component of wind 0.01 m/s Int

15-16
Altitude above mean sea level m Int 30000m subtracted

17-18
Pressure 0.1 hPa Int

19-20
Dew point temperature 0.1 K Int

21-22
Mixing ratio 0.1 g/Kg Int

23-24
Wind direction deg Int

25-26
Wind speed 0.1 m/s Int

27-28
Azimuth to the sonde deg Int

29-30
Horizontal distance to the sonde 100m Int

31-32
Sonde position longitude 0.01 deg Int

33-34
Sonde position latitude 0.01 deg Int

35-36
SOND calculated significance key Bit pattern

37-38
User edited/recalculated significance key Bit pattern

39-40
Radar height m Int 30000m subtracted

Significance key bit pattern:

Flag Ts Us Tr ITr Pi Ti Ui x x x x x Mw V Ds Fs
Bit 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

When bit is 1 the data level had the following level type:

    BIT

LEVEL TYPE FLAG

0

Ts
Level type flag

1

Us
Significance level of humidity

2

Tr
Tropopause

3

ITr
Incompletely defined tropopause

4

Pi
Pressure Interpolated

5

Ti
Temperature Interpolated

6

Ui
Humidity Interpolated

7-11

x
Don't Care

12

Mw
Maximum wind

13

V
Significance level of wind using vector criteria

14

Ds
Significance level of wind direction

15

Fs
Significance level of wind speed

The first 25 data records in an EDT file are always reserved for standard level data. The standard levels are sorted according to ascending height. The 26th data record contains ground level data. The rest of the levels are sorted according to ascending height.

2.3. Radar Raw Data


BYTE

DATA
UNIT TYPE

COMMENTS

1-2
Time Second Int

3-4
Azimuth 0.01 deg Int

5-6
Elevation 0.01 deg Int

7-10
Range m Float 0 = Track On

11
Radar track flag Byte 1 = Track Off

Missing data for azimuth is given as 32768.

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