File format description for meteorology, oceanography, and wave spectra data from buoys (National Oceanographic Data Center F291 format)
Format last changed: September 1, 2006
Document last edited: May 30, 2008 by Steven Rutz, National Oceanographic Data Center
THIS FORMAT IS USED TO REPORT METEOROLOGICAL, OCEANOGRAPHIC, AND WAVE SPECTRA
DATA FROM MOORED BUOYS, PRIMARILY FROM THE NATIONAL DATA BUOY CENTER, AND FIXED
LAND STATIONS. THE FORMAT CONTAINS THIRTEEN DATA RECORD TYPES TO:
- IDENTIFY THE BUOY POSITION AND OTHER DESCRIPTIVE INFORMATION;
- REPORT THE METEOROLOGICAL MEASUREMENTS;
- REPORT WAVE ENERGY SPECTRA AND WAVE DIRECTION;
- REPORT SUBSURFACE PHYSICAL, BIOLOGICAL AND CHEMICAL OCEANOGRAPHIC
MEASUREMENTS; AND
- REPORT DETAILED INFORMATION ON CONTINUOUSLY MEASURED WIND SPEED AND
DIRECTION.
NOTES ON UPDATES TO FILE FORMAT
- F291 FORMAT, ALSO KNOWN AS FILE TYPE 291, REPLACED FILE TYPE 191, WHICH REPLACED FILE TYPE 091.
03/30/1981 - ADDED WIND SPEED AND DIRECTION TO RECORD TYPE '2'
12/28/1981 - ADDED RECORD TYPES '6' AND '7'
11/04/1985 - ADDED RECORD TYPE '8'
01/01/1988 - ADDED RECORD TYPE '9'
01/30/1991 - DESIGNED F291 TO:
- RELABEL RECORD TYPES - RECORD TYPES 1 THROUGH 5 BECOMING A THROUGH E; ADD
NEW RECORD TYPE F; AND RELABEL 6 THROUGH 9 AS G THROUGH J;
- ADD A PRESENCE OF A RECORD INDICATOR IN RECORD TYPE 'A';
- REDEFINE RECORD TYPE B BY DELETING "HIGHEST CREST" AND "DEEPEST TROUGH"
AND INSERTING "WATER LEVEL";
- IDENTIFY RECORD TYPE C AS "NON-DIRECTIONAL WAVE SPECTRA DATA RECORD";
- DELETE DEFINITION OF COLUMNS 27 THROUGH 33 IN RECORD C AND REPLACE WITH 7
BLANKS;
- ADD A DURATION OF SAMPLING FIELD AT THE END OF RECORD D;
- DEFINE RECORD TYPE E TO PROVIDE ONLY SUBSURFACE CURRENT INFORMATION; AND
- DEFINE NEW RECORD TYPE F TO PROVIDE SUBSURFACE PHOTOSYNTHETIC ACTIVE
RADIATION.
05/01/1992 - REFINED DEFINITION OF OBSERVED TIME IN RECORDS A THROUGH J TO BE
"END OF MET. DATA ACQUISITION, ROUNDED TO THE BEGINNING OF THE NEAREST WHOLE
MINUTE." TIME TAG OF DATA ARCHIVED PRIOR TO THIS DATE REFLECTS NEAREST WHOLE
HOUR OF MET. DATA ACQUISITION. ALSO, FOR RECORD C, BLANK SPACES 27-30 ARE
DEFINED AS "END OF WAVE DATA ACQUISITION, ROUNDED TO THE BEGINNING OF THE
NEAREST WHOLE MINUTE."
01/01/1995 - ADDED TWO NEW RECORDS TO 291 TO HANDLE WPM DATA:
- DEFINED RECORD TYPE K TO PROVIDE EXPANDED RESOLUTION FOR
NONDIRECTIONAL CENTER FREQUENCY AND WAVE SPECTRA DATA; AND
- DEFINED RECORD TYPE L TO PROVIDE EXPANDED RESOLUTION FOR
CENTER FREQUENCY OF THE CO AND QUAD SPECTRA. THE "SENSOR
OUTPUT" FIELD WAS ALSO ADDED TO INDICATE THE TYPE OF SENSOR.
03/17/2000 - FOUR DIGIT YEAR
-
TO ACCOMMODATE FOUR DIGIT YEARS, THE FORMER FILE DATE
FIELD COL 4-9 (THAT WAS USED FOR YEARS FOR THE NODC REFERENCE
NUMBER) IS NOW USED TO HOLD THE YYYYMM OF OBSERVATION AND IS
CALLED OBS YEAR/MONTH.
04/21/2000 - ADDED NEW COMMENT RECORD M
-
ADDED NEW M RECORD FOR COMMENTS. IT CAN OCCUR AT ANY PLACE IN THE FILE.
09/01/2006 - ADDED NEW PARAMETERS TO RECORD J, COLUMNS 83 THROUGH 101 (THESE COLUMNS WERE BLANK SPACES).
-
HOURLY LOW ATMOSPHERIC PRESSURE
-
TIME OF HOURLY LOW ATMOSPHERIC PRESSURE
-
HOURLY PEAK WIND SPEED
-
DIRECTION OF HOURLY PEAK WIND SPEED
-
TIME OF HOURLY PEAK WIND SPEED
DESCRIPTIVE HEADER RECORD (RECORD A)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | "291" (constant)
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'A'
|
STATION | 11 | 6 | Six-character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
LATITUDE | 27 | 7 | DDMMSS plus hemisphere 'N' or 'S'
|
LONGITUDE | 34 | 8 | DDDMMSS plus hemisphere 'E' or 'W'
|
BOTTOM DEPTH | 42 | 5 | XXXXX - Meters to tenths
|
MAGNETIC VARIATION | 47 | 4 | XXXX - Whole degrees from true North (signed value)
|
BUOY HEADING | 51 | 3 | XXX - Whole degrees from true North
|
SAMPLING RATE (WAVES) | 54 | 4 | XXXX - Original measurements per minute to tenths
|
SAMPLING DURATION (WAVES)* | 58 | 4 | XXXX
- Minutes to hundredths If equal to 40 minutes, the actual duration for
all wave calculations varies by frequency range: .02 to .925 Hz - 40
min .1 to .35 Hz - last 20 min .365 to .485 Hz- last 10 min
|
TOTAL INTERVALS (WAVES) | 62 | 3 | XXX - Number of frequency intervals
|
CHIEF SCIENTIST | 65 | 20 | 20-Character field for scientist name
|
INSTITUTION | 85 | 20 | 20-Character field for data source
|
WIND SAMPLING DURATION | 105 | 3 | XXX - Minutes to tenths
|
PRESENCE OF RECORD 'B' | 108 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'C' | 109 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'D' | 110 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'E' | 111 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'F' | 112 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'G' | 113 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'H' | 114 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'I' | 115 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'J' | 116 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'K' | 117 | 1 | X - Y=YES; N=NO
|
PRESENCE OF RECORD 'L' | 118 | 1 | X - Y=YES; N=NO
|
BLANKS | 119 | 2 |
|
ENVIRONMENTAL DATA RECORD (RECORD B)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | "291" (constant)
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'B'
|
STATION | 11 | 6 | Six-character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
ANEMOMETER HEIGHT | 27 | 3 | XXX - Height above water level or ground (meters to tenths)
|
AIR TEMPERATURE | 30 | 4 | XXXX - Negative temperatures are preceded by a minus sign adjacent to tempera- ture value Deg C to tenths
|
DEW POINT | 34 | 4 | XXXX - Degrees C to tenths
|
BAROMETER | 38 | 5 | XXXXX - Reduced to sea level (MB to tenths)
|
WIND SPEED (AVG) | 43 | 4 | XXXX - m/sec to hundredths
|
WIND DIRECTION (AVG) | 47 | 4 | XXXX - Degrees from true North to tenths
|
WEATHER | 51 | 1 | One-character code from NODC code table 0108 (WMO 4501)
|
VISIBILITY | 52 | 3 | XXX - Nautical miles to tenths
|
PRECIPITATION | 55 | 4 | XXXX - Accumulation in millimeters
|
SOLAR RADIATION (ATMOSPHERIC | 59 | 3 | xxx - Langleys/min to hundredths, wave length less than 3.6 microns
|
SOLAR RADIATION (ATMOSPHERIC) | 62 | 3 | XXX - Langleys/min to hundredths, wave length from 4.0 to 50 microns
|
SIGNIFICANT WAVE HEIGHT* | 65 | 3 | XXX - Corrected for low frequency noise, etc. (meters to tenths)
|
AVERAGE WAVE PERIOD* | 68 | 3 | XXX - Seconds to tenths
|
MEAN WAVE DIRECTION | 71 | 3 | XXX
- Mean direction at the dominant wave period (spectral peak period) in
whole degrees clockwise from true North to the direction from which the
waves are coming. level; minus sign indicates below MLLW (meters to
tenths)
|
BLANKS | 78 | 2 |
|
TEMPERATURE (SEA SURFACE) | 80 | 4 | XXXX - Sea surface - Negative temperatures are preceded by a minus sign adjacent to temperature value-Deg C to hundredths
|
PRACTICAL SALINITY (SEA SURFACE) | 84 | 5 | XXXXX - To thousandths
|
CONDUCTIVITY (SEA SURFACE) | 89 | 5 | XXXXX - Millisiemens/cm to thousandths
|
DOMINANT WAVE PERIOD* | 94 | 3 | XXX - Spectral peak period- Seconds to tenths
|
MAXIMUM WAVE HEIGHT | 97 | 3 | XXX - Meters to tenths
|
MAXIMUM WAVE STEEPNESS | 100 | 3 | XXX
|
WIND GUST | 103 | 4 | XXXX - Meters/sec to hundredths
|
WIND GUST AVERAGING PERIOD | 107 | 2 | XX - Seconds
|
WIND GUST | 109 | 4 | XXXX - Meters/sec to hundredths
|
WIND GUST AVERAGING PERIOD | 113 | 2 | XX - Seconds
|
WIND SPEED (58 MIN AVG) | 115 | 3 | XXX - Meters/sec to tenths
|
WIND DIRECTION (58 MIN AVG) | 118 | 3 | XXX - Whole degrees
|
* Significant wave height, average wave period, and dominant wave period are set
to zero when significant wave height is less than 0.15 meters.
NONDIRECTIONAL WAVE SPECTRA DATA RECORD (RECORD C)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | "291" (constant)
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'C'
|
STATION | 11 | 6 | Six-character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
END OF WAVE DATA ACQUISITION | 27 | 4 | HHMM (UTC) - Rounded to beginning of nearest whole minute
|
BLANKS | 31 | 3 |
|
COUNT DATA | 34 | 1 | X - Number of frequencies on this record Up to 5 frequency, resolu- tion, and density fields. Null fields are zero or blank
|
FREQUENCY | 35 | 4 | XXXX - Center frequency of interval in Hertz to thousandths
|
RESOLUTION | 39 | 4 | XXXX - Interval width in Hertz to ten-thousandths
|
DENSITY | 43 | 6 | XXXXXX - Spectral Density, C11, in m2/Hz to thousandths
|
FREQUENCY | 49 | 4 | XXXX - See above
|
RESOLUTION | 53 | 4 | XXXX - See above
|
DENSITY | 57 | 6 | XXXXXX - See above
|
FREQUENCY | 63 | 4 | XXXX - See above
|
RESOLUTION | 67 | 4 | XXXX - See above
|
DENSITY | 71 | 6 | XXXXXX - See above
|
FREQUENCY | 77 | 4 | XXXX - See above
|
RESOLUTION | 81 | 4 | XXXX - See above
|
DENSITY | 85 | 6 | XXXXXX - See above
|
FREQUENCY | 91 | 4 | XXXX - See above
|
RESOLUTION | 95 | 4 | XXXX - See above
|
DENSITY | 99 | 6 | XXXXXX - See above
|
BLANKS | 105 | 16 |
|
SUBSURFACE TEMPERATURE/SALINITY DATA RECORD (RECORD D)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | "291" (constant)
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'D'
|
STATION | 11 | 6 | Six character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
DEPTH | 27 | 5 | XXXXX - Meters from the surface to tenths
|
TEMPERATURE | 32 | 4 | XXXX - Negative temperatures are preceded by a minus sign adjacent to temper- ature value-Deg C to hundredths
|
PRACTICAL SALINITY | 36 | 5 | XXXXX - Parts per thousands reported to thousands
|
CONDUCTIVITY | 41 | 4 | XXXX - Millisiemens/cm to hundredths
|
DEPTH | 45, 63, 81,99 | 5 | Repeated in descending order
|
TEMPERATURE | 50, 68, 86, 104 | 4 | Repeated in descending order
|
PRACTICAL SALINITY | 54, 72, 90, 108 | 5 | Repeated in descending order
|
CONDUCTIVITY | 59, 77, 95, 113 | 4 | Repeated in descending order
|
BLANK | 117 | 1 |
|
DURATION OF SAMPLING PERIOD | 118 | 3 | XXX - Minutes to tenths
|
SUBSURFACE CURRENT DATA RECORD (RECORD E)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | Always "291"
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'E'
|
STATION | 11 | 6 | Six character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
DEPTH | 27 | 4 | XXXX - From the surface in meters
|
PRESSURE | 31 | 5 | XXXXX - Hydrostatic pressure (kg/cm2) to hundredths
|
U COMPONENT | 36 | 5 | XXXXX - East component from true North (cm/sec) to tenths. Minus sign indi- cates westward component
|
V COMPONENT | 41 | 5 | XXXXX - True North component in cm/sec to tenths. Minus sign indicates southward component
|
W COMPONENT | 46 | 3 | XXX - Vertical component in cm/sec to tenths. Minus sign indicates downward component
|
DEPTH | 49, 71, 93 | 4 | Repeated in descending order
|
PRESSURE | 53, 75, 97 | 5 | Repeated in descending order
|
U COMPONENT | 58, 80, 102 | 5 | Repeated in descending order
|
V COMPONENT | 63, 85, 107 | 5 | Repeated in descending order
|
W COMPONENT | 68, 90, 112 | 3 | Repeated in descending order
|
BIN WIDTH | 115 | 2 | XX - Width of each depth bin whole meters
|
SAMPLING INTERVAL | 117 | 3 | XXX - Minutes to tenths
|
BLANK | 120 | 1 |
|
SUBSURFACE DATA PROFILE (RECORD F)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | Always "291"
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'F'
|
STATION | 11 | 6 | Six-character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
DEPTH | 27 | 4 | XXXX - From the surface in meters. Negative value indicates height in meters above water surface
|
PHOTOSYNTHETIC ACTIVE RADIATION (PAR) | 31 | 4 | XXXX - Micromol/sec/m2
|
BLANKS | 35 | 15 | 15 Blanks reserved for future parameters
|
DEPTH | 50, 73, 96 | 4 | Repeated in descending order
|
PAR | 54, 77, 100 | 4 | Repeated in descending order
|
BLANKS | 58, 81, 104 | 15 | Reserved for future parameters
|
BLANKS | 119 | 2 |
|
CO AND QUAD SPECTRA FOR DIRECTIONAL WAVES DATA RECORD (RECORD G)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | Always "291"
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'G'
|
STATION | 11 | 6 | Six character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
FREQUENCY | 27 | 4 | XXXX - Center frequency of interval in Hz to thousandths
|
RESOLUTION | 31 | 5 | XXXXX - Spectral resolution of this frequency band to Hz to ten-thousandths
|
CO-SPECTRA (C11) | 36 | 6 | XXXXXX
- Signed uncorrected spectral density of co-spectra in m2/Hz. Decimal
assumed to be left of first digit. Subscripts are: 1=Heave, 2=E-W
slope, 3=N-S slope
|
EXPONENT* | 42 | 2 | XX - First space is the sign
|
CO-SPECTRA (C22) | 44 | 6 | XXXXXX - See above
|
EXPONENT* | 50 | 2 | XX - See above
|
CO-SPECTRA (C33) | 52 | 6 | XXXXXX - See above
|
EXPONENT* | 58 | 2 | XX - See above
|
CO-SPECTRA (C12) | 60 | 6 | XXXXXX - See above
|
EXPONENT* | 66 | 2 | XX - See above
|
QUAD-SPECTRA (Q12) | 68 | 6 | XXXXXX - See above
|
EXPONENT* | 74 | 2 | XX - See above
|
CO-SPECTRA (C13) | 76 | 6 | XXXXXX - See above
|
EXPONENT* | 82 | 2 | XX - See above
|
QUAD-SPECTRA (Q13) | 84 | 6 | XXXXXX - See above
|
EXPONENT* | 90 | 2 | XX - See above
|
CO-SPECTRA (C23) | 92 | 6 | XXXXXX - See Above
|
EXPONENT* | 98 | 2 | XX - See above
|
QUAD-SPECTRA (Q23) | 100 | 6 | XXXXXX - See above
|
EXPONENT* | 106 | 2 | XX - See above
|
SPECTRA (C22-C33) | 108 | 6 | XXXXXX - See Above
|
EXPONENT* | 114 | 2 | XX - See above
|
BLANKS | 116 | 5 |
|
* If this exponent is less than -9, the exponent and its associated spectra will
be zero.
DIRECTIONAL WAVE FOURIER COEFFICIENT DATA RECORD (RECORD H)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | Always "291"
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'H'
|
STATION | 11 | 6 | Six character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
FREQUENCY | 27 | 4 | XXXX - Hz to thousandths
|
RESOLUTION | 31 | 5 | XXXXX - Hz to ten- thousandths
|
ANGULAR FOURIER COEFF (a0) | 36 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 42 | 2 | XX
|
ANGULAR FOURIER COEFF (a1) | 44 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 50 | 2 | XX
|
ANGULAR FOURIER COEFF (b1) | 52 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 58 | 2 | XX
|
ANGULAR FOURIER COEFF (a2) | 60 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 66 | 2 | XX
|
ANGULAR FOURIER COEFF (b2) | 68 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 74 | 2 | XX
|
ANGULAR FOURIER COEFF (a3) | 76 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 82 | 2 | XX
|
ANGULAR FOURIER COEFF (b3) | 84 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 90 | 2 | XX
|
ANGULAR FOURIER COEFF (a4) | 92 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 98 | 2 | XX
|
ANGULAR FOURIER COEFF (b4) | 100 | 6 | XXXXXX - m2/Hz
|
EXPONENT | 106 | 2 | XX
|
MEAN WAVE DIRECTION | 108 | 3 | XXX - ARCTAN b1/a1 in whole degrees from true North
|
BLANKS | 111 | 10 |
|
DIRECTIONAL WAVE PARAMETER DATA RECORD (RECORD I)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | Always "291"
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'I'
|
STATION | 11 | 6 | Six character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
COUNT | 27 | 1 | X - Number of frequencies on this record (1 to 3)
|
FREQUENCY | 28 | 4 | XXXX - Center of frequency interval in Hz to the ten- thousandth
|
RESOLUTION | 32 | 4 | XXXX - Resolution of interval in Hz to the ten-thousandth
|
R1 | 36 | 4 | XXXX - Nondimensional. Given to nearest hundredth
|
R2 | 40 | 4 | XXXX - Nondimensional. Given to nearest hundredth
|
WAVE DIRECTION ALPHA1 | 44 | 4 | XXXX - Direction in degrees to the tenth
|
WAVE DIRECTION ALPHA2 | 48 | 4 | XXXX - Direction in degrees to the tenth
|
WAVE ESTIMATE C11 | 52 | 6 | XXXXXX - Spectral value in m2/Hz to the thousandth
|
FREQUENCY | 58 | 4 | XXXX - Center of frequency interval in Hz to the ten- thousandth
|
RESOLUTION | 62 | 4 | XXXX - Resolution of interval in Hz to the ten-thousandth
|
R1 | 66 | 4 | XXXX - Nondimensional. Given to nearest hundredth
|
R2 | 70 | 4 | XXXX - Nondimensional. Given to nearest hundredth
|
WAVE DIRECTION ALHPA1 | 74 | 4 | XXXX - Direction in degrees to the tenth
|
WAVE DIRECTION | 78 | 4 | XXXX - Direction in degrees to the tenth
|
WAVE C11 ESTIMATE | 82 | 6 | XXXXXX - Spectral value in m2/Hz to the thousandth
|
FREQUENCY | 88 | 4 | XXXX - Center of frequency interval in Hz to the ten-thousandth
|
RESOLUTION | 92 | 4 | XXXX - Resolution of interval in Hz to the ten-thousandth
|
R1 | 96 | 4 | XXXX - Nondimemsional. Given to nearest hundredth
|
R2 | 100 | 4 | XXXX - Nondimensional. Given to nearest hundredth
|
WAVE DIRECTION ALPHA1 | 104 | 4 | XXXX - Direction in degrees to the tenth
|
WAVE DIRECTION ALPHA2 | 108 | 4 | XXXX - Direction in degrees to the tenth
|
WAVE C11 ESTIMATE | 112 | 6 | XXXXXX - Spectral value in m2/Hz to the thousandth
|
BLANKS | 118 | 3 |
|
NOTE: DIRECTIONAL WAVE SPECTRUM = C11(f)*D(f,A), f=frequency (Hz), A=Azimuth
angle measured clockwise from North to the direction wave is from.
D(f,A)=(1/PI)*(0.5+R1*COS(A-ALPHA1)+R2*COS(2*(A-ALPHA2))), in which R1 and R2
are dimensionless and ALPHA1 and ALPHA2 are respectively mean and principal
wave directions. In terms of Longuet-Higgins Fourier Coefficients
R1=(SQRT(a1*a1+b1*b1))/a0, R2=SQRT(a2*a2+b2*b2))/a0, ALPHA1=270.0-ARCTAN(b1,a1),
ALPHA2=270.0-(0.5*ARCTAN(b2,a2)+{0. or 180.}), C11(f) is the nondirectional wave
spectra data from RECORD C or RECORD K.
CONTINUOUS WIND MEASUREMENT DATA RECORD (RECORD J)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | Always "291"
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'J'
|
STATION | 11 | 6 | Six character unique name of observation point
|
REPORT DATE | 17 | 6 | YYMMDD (UTC)
|
REPORT TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
SPEED AVERAGING METHOD | 27 | 1 | X - 1=VECTOR, 2=SCALER
|
STANDARD DEVIATION OF HOURLY SPEED | 28 | 3 | XXX - m/sec to tenths
|
STANDARD DEVIATION OF HOURLY DIRECTION | 31 | 4 | XXXX - Whole degrees
|
HOURLY PEAK WIND | 35 | 3 | XXX - m/sec to tenths (highest 5 sec wind)
|
DIRECTION OF HOURLY PEAK | 38 | 3 | XXX - Whole degrees
|
MINUTE OF HOURLY PEAK | 41 | 2 | XX - Minutes
|
END OF ACQUISITION TIME | 43 | 4 | XXXX - HHMM (UTC)
|
FIRST AVERAGE DIRECTION | 47 | 3 | XXX - Whole degrees
|
FIRST AVERAGE SPEED | 50 | 3 | XXX - m/sec to tenths
|
SECOND AVERAGE DIRECTION | 53 | 3 | XXX - Whole degrees
|
SECOND AVERAGE SPEED | 56 | 3 | XXX - m/sec to tenths
|
THIRD AVERAGE DIRECTION | 59 | 3 | XXX - Whole degrees
|
THIRD AVERAGE SPEED | 62 | 3 | XXX - m/sec to tenths
|
FOURTH AVERAGE DIRECTION | 65 | 3 | XXX - Whole degrees
|
FOURTH AVERAGE SPEED | 68 | 3 | XXX - m/sec to tenths
|
FIFTH AVERAGE DIRECTION | 71 | 3 | XXX - Whole degrees
|
FIFTH AVERAGE SPEED | 74 | 3 | XXX - m/sec to tenths
|
SIXTH AVERAGE DIRECTION | 77 | 3 | XXX - Whole degrees
|
SIXTH AVERAGE SPEED | 80 | 3 | XXX - m/sec to tenths
|
HOURLY LOW ATMOSPHERIC PRESSURE | 83 | 5 | XXXXX - hPa to tenths (lowest 1 min. avg.)
|
TIME OF HOURLY LOW ATMOSPHERIC PRESSURE | 88 | 4 | HHMM (UTC)
|
HOURLY PEAK WIND SPEED | 92 | 3 | XXX - m/sec to tenths (highest 1 min. avg.)
|
DIRECTION OF HOURLY PEAK WIND SPEED | 95 | 3 | XXX - Whole degrees
|
TIME OF HOURLY PEAK WIND SPEED | 98 | 4 | HHMM (UTC)
|
BLANKS | 102 | 19 |
|
Ten minute average winds are measured for minutes 0-9, 10-19, 20-29, 30-39,
40-49, and 50-59. The first set is for the ten minute time period ending
immediately before the end of acquisition time. The remaining sets go back in
time. For example, if the end of acquisition time is 1025, then the first
average is 1010 to 1019, the second, 1000 to 1009, etc. If the end of
acquisition time is 1030, then the first period will be 1020 to 1029.
EXPANDED RESOLUTION NONDIRECTIONAL WAVE SPECTRA DATA RECORD (RECORD K)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | "291" (constant)
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'K'
|
STATION | 11 | 6 | Six-character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
END OF WAVE DATA ACQUISITION | 27 | 4 | HHMM (UTC) - Rounded to beginning of nearest whole minute
|
BLANKS | 31 | 3 |
|
COUNT | 34 | 1 | X - Number of frequencies on this record
|
DATA |
|
| Up to 5 frequency, resolu- tion, and density fields. Null fields are zero or blank
|
FREQUENCY | 35 | 4 | XXXX- Center frequency of interval in Hertz to ten- thousandths
|
RESOLUTION | 39 | 4 | XXXX - Interval width in Hertz to ten-thousandths
|
DENSITY | 43 | 9 | XXXXXXXXX - Spectral Density, C11, in m2/Hz to hundred thousandths
|
FREQUENCY | 52 | 4 | XXXX - See above
|
RESOLUTION | 56 | 4 | XXXX - See above
|
DENSITY | 60 | 9 | XXXXXXXXX - See above
|
FREQUENCY | 69 | 4 | XXXX - See above
|
RESOLUTION | 73 | 4 | XXXX - See above
|
DENSITY | 77 | 9 | XXXXXXXXX - See above
|
FREQUENCY | 86 | 4 | XXXX - See above
|
RESOLUTION | 90 | 4 | XXXX - See above
|
DENSITY | 94 | 9 | XXXXXXXXX - See above
|
FREQUENCY | 103 | 4 | XXXX - See above
|
RESOLUTION | 107 | 4 | XXXX - See above
|
DENSITY | 111 | 9 | XXXXXXXXX - See above
|
BLANKS | 120 | 1 |
|
EXPANDED RESOLUTION CO AND QUAD SPECTRA FOR DIRECTIONAL WAVES DATA RECORD (RECORD L)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | Always "291"
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always 'L'
|
STATION | 11 | 6 | Six character unique name of observation point
|
OBSERVED DATE | 17 | 6 | YYMMDD (UTC)
|
OBSERVED TIME | 23 | 4 | HHMM (UTC) - End of met. data acquisition, rounded to beginning of nearest whole minute
|
FREQUENCY | 27 | 4 | XXXX - Center frequency of interval in Hz to ten- thousandths
|
RESOLUTION | 31 | 5 | XXXXX - Interval width in Hertz to ten-thousandths
|
CO-SPECTRA (C11)** | 36 | 6 | XXXXXX
- Signed uncorrected spectral density. Decimal assumed to be left of
first digit. Subscripts are: 1=Heave, 2=E-W slope, 3=N-S slope
|
EXPONENT* | 42 | 2 | XX - First space is the sign
|
CO-SPECTRA (C22)** | 44 | 6 | XXXXXX - See above
|
EXPONENT* | 50 | 2 | XX - See above
|
CO-SPECTRA (C33)** | 52 | 6 | XXXXXX - See above
|
EXPONENT* | 58 | 2 | XX - See above
|
CO-SPECTRA (C12)** | 60 | 6 | XXXXXX - See above
|
EXPONENT* | 66 | 2 | XX - See above
|
QUAD-SPECTRA (Q12)** | 68 | 6 | XXXXXX - See above
|
EXPONENT* | 74 | 2 | XX - See above
|
CO-SPECTRA (C13)** | 76 | 6 | XXXXXX - See above
|
EXPONENT* | 82 | 2 | XX - See above
|
QUAD-SPECTRA (Q13)** | 84 | 6 | XXXXXX - See above
|
EXPONENT* | 90 | 2 | XX - See above
|
CO-SPECTRA (C23)** | 92 | 6 | XXXXXX - See Above
|
EXPONENT* | 98 | 2 | XX - See above
|
QUAD-SPECTRA (Q23)** | 100 | 6 | XXXXXX - See above
|
EXPONENT* | 106 | 2 | XX - See above
|
SPECTRA (C22-C33)** | 108 | 6 | XXXXXX - See Above
|
EXPONENT* | 114 | 2 | XX - See above
|
SENSOR OUTPUT | 116 | 1 | X - 1=Displacement; 2=Acceleration
|
BLANKS | 117 | 4 |
|
* If this exponent is less than -9, the exponent and its associated
spectra will be zero.
** If the sensor output is displacement, the units of the cross-spectral parameters are:
m2/Hz for C11, m/Hz for C12, Q12, C13, and Q13, and 1/Hz for C22, C33, C23, and Q23.
If the sensor output is acceleration, the units of the cross-spectral parameters are:
(m/s2)2/Hz for C11, (m/s2)/Hz for C12, Q12, C13, and Q13, and 1/Hz for C22, C33, C23, and Q23.
COMMENT (RECORD M)
PARAMETER | STARTING POSITION | FIELD LENGTH | DESCRIPTION
|
FILE TYPE | 1 | 3 | Always "291"
|
OBS YEAR/MONTH | 4 | 6 | YYYYMM of Observation
|
RECORD TYPE | 10 | 1 | Always "M"
|
STATION | 11 | 6 | Six character unique name of observation point
|
BLANK | 17 | 1 | Always blank
|
COMMENT | 18 | 103 | Free form comments
|
NODC CODE TABLE 0108 (WMO 4501)
CODE WEATHER
---- --------------------
0 CLEAR (NO CLOUD AT ANY LEVEL)
1 PARTLY CLOUDY (SCATTERED OR BROKEN)
2 CONTINUOUS LAYER(S) OF CLOUD(S)
3 SANDSTORM, DUSTSTORM, OR BLOWING SNOW
4 FOG, THICK DUST OR HAZE
5 DRIZZLE
6 RAIN
7 SNOW, OR RAIN AND SNOW MIXED
8 SHOWER(S)
9 THUNDERSTORM(S)