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Buoy (F291) Format

Meteorology, Oceanography, and Wave Spectra from Buoys (F291)

  ------------------------------------------------------------------------
          FILE TYPE 291 - METEOROLOGY OCEANOGRAPHY AND WAVE SPECTRA

THIS FORMAT IS USED TO REPORT METEOROLOGICAL, OCEANOGRAPHIC, AND WAVE
SPECTRA DATA FROM NDBC MOORED BUOYS AND FIXED LAND STATIONS. THE FORMAT
CONTAINS TEN 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.

****NOTE****

THIS FORMAT REPLACES FILE TYPE 191 WHICH IN TURN REPLACED 091.

03/30/81 - ADDED WIND SPEED AND DIRECTION TO RECORD TYPE '2'
12/28/81 - ADDED RECORD TYPES '6' AND '7'
11/04/85 - ADDED RECORD TYPE '8'
01/01/88 - ADDED RECORD TYPE '9'
01/30/91 - 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.

05/01/92 - 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."

01/01/95 - 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.

RECORD FORMAT DESCRIPTION
RECORD NAME: Meteorology Oceanography & Wave Spectra (File Type "291")
                    DESCRIPTIVE HEADER RECORD (RECORD A)

     PARAMETER       STARTING      FIELD             DESCRIPTION
                     POSITION      LENGTH
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)
                                           HHMM (UTC) - End of met. data
OBSERVED TIME           23           4     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                                   XXXX - Whole degrees from true
VARIATION               47           4     North (signed value)

BUOY HEADING            51           3     XXX - Whole degrees from true
                                           North
SAMPLING RATE                              XXXX - Original measurements per
(WAVES)                 54           4     minute to tenths
                                           XXXX - Minutes to hundredths If
                                           equal to 40 minutes, the actual
SAMPLING DURATION                          duration for all wave
(WAVES)*                58           4     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                            XXX - Number of frequency
(WAVES)                 62           3     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     FIELD            DESCRIPTION
                        POSITION    LENGTH
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)
                                            HHMM (UTC) - End of met. data
OBSERVED TIME             23          4     acquisition, rounded to
                                            beginning of nearest whole
                                            minute

ANEMOMETER HEIGHT         27          3     XXX - Height above water level
                                            or ground (meters to tenths)
                                            XXXX - Negative temperatures
AIR TEMPERATURE           30          4     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 weather code
VISIBILITY                52          3     XXX - Nautical miles to tenths

PRECIPITATION             55          4     XXXX - Accumulation in
                                            millimeters

SOLAR RADIATION                             xxx - Langleys/min to
(ATMOSPHERIC              59          3     hundredths, wave length less
                                            than 3.6 microns

SOLAR RADIATION                             XXX - Langleys/min to
(ATMOSPHERIC)             62          3     hundredths, wave length from
                                            4.0 to 50 microns

SIGNIFICANT WAVE                            XXX - Corrected for low
HEIGHT*                   65          3     frequency noise, etc. (meters
                                            to tenths)
AVERAGE WAVE PERIOD*      68          3     XXX - Seconds to tenths
                                            XXX - Mean direction at the
                                            dominant wave period (spectral
                                            peak period) in whole degrees
MEAN WAVE DIRECTION       71          3     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
                                            XXXX - Sea surface - Negative
TEMPERATURE (SEA                            temperatures are preceded by a
SURFACE)                  80          4     minus sign adjacent to
                                            temperature value-Deg C to
                                            hundredths
PRACTICAL SALINITY
(SEA SURFACE)             84          5     XXXXX - To thousandths
CONDUCTIVITY (SEA                           XXXXX - Millisiemens/cm to
SURFACE)                  89          5     thousandths
DOMINANT WAVE                               XXX - Spectral peak period-
PERIOD*                   94          3     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     FIELD             DESCRIPTION
                      POSITION    LENGTH
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)
                                           HHMM (UTC) - End of met. data
OBSERVED TIME           23          4      acquisition, rounded to beginning
                                           of nearest whole minute
END OF WAVE DATA                           HHMM (UTC) - Rounded to beginning
ACQUISITION             27          4      of nearest whole minute
BLANKS                  31          3
                                           X - Number of frequencies on this
COUNT DATA              34          1      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     FIELD             DESCRIPTION
                      POSITION    LENGTH
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)
                                           HHMM (UTC) - End of met. data
OBSERVED TIME           23          4      acquisition, rounded to beginning
                                           of nearest whole minute

DEPTH                   27          5      XXXXX - Meters from the surface
                                           to tenths
                                           XXXX - Negative temperatures are
TEMPERATURE             32          4      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,       5      Repeated in descending order
                       81,99

TEMPERATURE         50, 68, 86, 4          Repeated in descending order
                        104

PRACTICAL SALINITY  54, 72, 90,     5      Repeated in descending order
                        108

CONDUCTIVITY        59, 77, 95,     4      Repeated in descending order
                        113
BLANK                   117         1
DURATION OF
SAMPLING PERIOD         118         3      XXX - Minutes to tenths
  ------------------------------------------------------------------------
                 SUBSURFACE CURRENT DATA RECORD (RECORD E)

    PARAMETER       STARTING      FIELD              DESCRIPTION
                    POSITION     LENGTH
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)
                                          HHMM (UTC) - End of met. data
OBSERVED TIME         23           4      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
                                          XXXXX - East component from true
U COMPONENT           36           5      North (cm/sec) to tenths. Minus
                                          sign indi- cates westward
                                          component
                                          XXXXX - True North component in
V COMPONENT           41           5      cm/sec to tenths. Minus sign
                                          indicates southward component
                                          XXX - Vertical component in cm/sec
W COMPONENT           46           3      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     FIELD            DESCRIPTION
                        POSITION     LENGTH
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)
                                             HHMM (UTC) - End of met. data
OBSERVED TIME              23          4     acquisition, rounded to
                                             beginning of nearest whole
                                             minute
                                             XXXX - From the surface in
DEPTH                      27          4     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      FIELD              DESCRIPTION
                    POSITION     LENGTH
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)
                                          HHMM (UTC) - End of met. data
OBSERVED TIME          23          4      acquisition, rounded to beginning
                                          of nearest whole minute

FREQUENCY              27          4      XXXX - Center frequency of
                                          interval in Hz to thousandths
                                          XXXXX - Spectral resolution of
RESOLUTION             31          5      this frequency band to Hz to
                                          ten-thousandths
                                          XXXXXX - Signed uncorrected
                                          spectral density of CO spectra in
CO-SPECTRA (C11)       36          6      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      FIELD             DESCRIPTION
                     POSITION      LENGTH
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)
                                           HHMM (UTC) - End of met. data
OBSERVED TIME           23           4     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                                  XXX - ARCTAN b1/a1 in whole
DIRECTION              108           3     degrees from true North
BLANKS                 111          10
  ------------------------------------------------------------------------
             DIRECTIONAL WAVE PARAMETER DATA RECORD (RECORD I)

    PARAMETER       STARTING     FIELD              DESCRIPTION
                    POSITION     LENGTH
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)
                                         HHMM (UTC) - End of met. data
OBSERVED TIME         23           4     acquisition, rounded to beginning
                                         of nearest whole minute

COUNT                 27           1     X - Number of frequencies on this
                                         record (1 to 3)
                                         XXXX - Center of frequency
FREQUENCY             28           4     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                           XXXX - Direction in degrees to the
ALPHA1                44           4     tenth
WAVE DIRECTION                           XXXX - Direction in degrees to the
ALPHA2                48           4     tenth
WAVE ESTIMATE                            XXXXXX - Spectral value in m2/Hz
C11                   52           6     to the thousandth
                                         XXXX - Center of frequency
FREQUENCY             58           4     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                           XXXX - Direction in degrees to the
ALHPA1                74           4     tenth

WAVE DIRECTION        78           4     XXXX - Direction in degrees to the
                                         tenth
WAVE C11                                 XXXXXX - Spectral value in m2/Hz
ESTIMATE              82           6     to the thousandth
                                         XXXX - Center of frequency
FREQUENCY             88           4     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                           XXXX - Direction in degrees to the
ALPHA1                104          4     tenth
WAVE DIRECTION                           XXXX - Direction in degrees to the
ALPHA2                108          4     tenth
WAVE C11                                 XXXXXX - Spectral value in m2/Hz
ESTIMATE              112          6     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      FIELD            DESCRIPTION
                        POSITION     LENGTH
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)
                                             HHMM (UTC) - End of met. data
REPORT TIME                23          4     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 (high-
                                             est 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
BLANKS                     83          38
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     FIELD             DESCRIPTION
                      POSITION    LENGTH
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)
                                           HHMM (UTC) - End of met. data
OBSERVED TIME           23          4      acquisition, rounded to beginning
                                           of nearest whole minute
END OF WAVE DATA                           HHMM (UTC) - Rounded to beginning
ACQUISITION             27          4      of nearest whole minute
BLANKS                  31          3

COUNT                   34          1      X - Number of frequencies on this
                                           record
                                           Up to 5 frequency, resolu- tion,
DATA                                       and density fields. Null fields
                                           are zero or blank
                                           XXXX- Center frequency of
FREQUENCY               35          4      interval in Hertz to ten-
                                           thousandths

RESOLUTION              39          4      XXXX - Interval width in Hertz to
                                           ten-thousandths
                                           XXXXXXXXX - Spectral Density,
DENSITY                 43          9      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      FIELD              DESCRIPTION
                    POSITION     LENGTH
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)
                                          HHMM (UTC) - End of met. data
OBSERVED TIME          23          4      acquisition, rounded to beginning
                                          of nearest whole minute
                                          XXXX - Center frequency of
FREQUENCY              27          4      interval in Hz to ten-
                                          thousandths

RESOLUTION             31          5      XXXXX - Interval width in Hertz
                                          to ten-thousandths
                                          XXXXXX - Signed uncorrected
                                          spectral density. Decimal assumed
CO-SPECTRA C11)**      36          6      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. ** For displacement: C11 in m2/Hz, C22 in 1/Hz, C33 in 1/Hz,
C12 in m/Hz, C13 in m/Hz, Q12 in m/Hz, Q13 in m/Hz, C23 in 1/Hz, Q23 in
1/Hz. For acceleration: C11, C12, C13, Q12, Q13 in [m/s2]2/Hz, C22, C33,
Q23,
  ------------------------------------------------------------------------
                             COMMENT (RECORD M)

   PARAMETER        STARTING        FIELD             DESCRIPTION
                    POSITION       LENGTH
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
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