VAISALA Oy PC-CORA File Structure - Met Systems Division 1991-02-05
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 sensor31-32 Length of data record in bytes Int 33 "File ready" flag Byte 1 = Ready
0 = Not Ready34-50 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 = Differential155-156 Wind mode Int 0 = Omega
1 = Loran-C
2 = Radar
255 = Only PTU157-158 Loran/Omega stations used Int One bit for each station
1 = Used, 0 = Not used159 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
transmitted166 Unit to control change of phase
integration timeByte 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.
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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