NOAA Logo National Centers for Environmental Information

formerly the National Oceanographic Data Center (NODC)...  more on NCEI

NOAA Satellite and Information Service

Sea Level Data (Monthly) (F186)

This format, designed in conjunction with the Joint Archive for Sea Level at the University of Hawaii, is used to report monthly values. The format contains four record types:

1 - HEADER 1, DATE, POSITION, TIME AND LEVEL REFERENCE, AND UNITS
2 - HEADER 2, STATION NAME, COUNTRY, AND CONTRIBUTING AGENCY
3 - STATION INFORMATION, QUALITY ASSESSMENT, AND PROCESSING POLICY
6 - MONTHLY SEA LEVEL VALUES IN MILLIMETERS

Each file contains 80-byte, fixed-length records, which are sorted by unique station, date, and record type. The first nine columns of all records are FILE TYPE (bytes 1-3) and TRACK NUMBER (bytes 4-9), which is used by NODC internally. The file types for sea level will be 184, 185, or 186 for hourly, daily, and monthly values, repectively.

The fields of each record type are described shortly, but first, general characteristics of the data set and important information in the header records are discussed.

The data are linked to fixed bench marks of a sea level station. Data segments from the same site that are not linked to common bench marks are considered two independent time series and are given unique names that are distinguished by suffixing a letter alphabetically, such as Baltra-A and Baltra-B. The REFERENCE LEVEL OFFSET (record 1, bytes 64-68) is a constant that must be added to each value so the data are relative to the tide staff zero or the primary data. It is equal to 00000 in almost all cases. A REFERENCE FLAG, R, (byte 69) is suffixed to the REFERENCE LEVEL OFFSET to denote that the data are linked to a fixed datum.

The time reference of the data is given by a TIME ZONE OFFSET (record 1, bytes 71-74) in hours (to tenths with implied decimal). The data are relative to GMT (TIME ZONE OFFSET = 0000) unless the local time is offset from GMT by a non-integer value, in which case EAST of Greenwich is defined as '+' and WEST as '-'. For example, the data for Colombo, Sri Lanka are relative to a local time zone of GMT plus 5.5 hours; thus, TIME ZONE OFFSET equals 0055.

The NODC station number (records 1 and 2, bytes 11-18) is a 6-digit WMO number, which is unique to a one-degree square, suffixed with a 2-digit random number/character. In some cases, independent time segments may exist for a unique site as noted above; however, the NODC station number is the same for all independent time segments of a unique site.

Next, each field of the four record types is described. Note SC is the starting character or byte position in the record for the given field.

Sea Level Data (Monthly)
ParameterDescriptionSTARTING COLUMN FIELD LENGTH
RECORD TYPE 1:
FILE HEADER RECORD ALWAYS "1" 10 1
NODC ASSIGNED STATION ID UNIQUE CONCATENATION OF WMO TEN+ ONE+ 2 CHARACTERS 11 8
BLANKS 19 1
TIDE STATION ID ORIGINATOR'S STATION IDENTIFIER 20 10
BLANKS 30 1
DATE YYYYMMDD - STARTING DATE (GMT) 31 8
BLANKS 39 1
DATE YYYYMMDD - ENDING DATE (GMT) 40 8
BLANKS 48 1
LATITUDE DDMM PLUS HEMISPHERE 'N' OR 'S' 49 5
BLANKS 54 1
LONGITUDE DDDMM PLUS HEMISPHERE 'E' OR 'W' 55 6
BLANKS 61 1
AVERAGING METHOD ONE-CHARACTER CODE - as follows
1 : filtered
2 : simple average
4 : other or unknown
62 1
BLANKS 63 1
REFERENCE LEVEL OFFSET CONSTANT OFFSET THAT MUST BE ADDED TO EACH DATA VALUE FOR DATA TO BE RELA- TO TIDE STAFF ZERO OR PRIMARY DATUM. (IN SAME UNITS AS SEA LEVEL DATA). 64 5
DATA REFERENCED ONE-CHARACTER CODE - as follows
R : data linked to bench marks
X : data not linked to bench marks
69 1
BLANKS 70 5
SEA LEVEL UNITS XX ALWAYS MM (MILLIMETERS) 76 2
BLANKS 78 4
RECORD TYPE 2:
ParameterDescriptionSTARTING COLUMN FIELD LENGTH
SECOND HEADER RECORD ALWAYS "2" 10 1
NODC ASSIGNED STATION ID UNIQUE CONCATENATION OF WMO TEN+ ONE+ 2 CHARACTERS 11 8
BLANKS 19 1
STATION NAME NAME OF TIDE STATION 20 16
BLANKS 36 1
COUNTRY NAME OR ABREVIATION WHERE TIDE STATION IS LOCATED. 37 16
BLANKS 53 1
AGENCY DATA CONTRIBUTOR 54 27
RECORD TYPE 3:
ParameterDescriptionSTARTING COLUMN FIELD LENGTH
DOCUMENTATION RECORD ALWAYS "3" 10 1
SEQUENCE SEQUENTIAL NUMBER FOR DOCUMENTATION RECORDS 11 4
TEXT DOCUMENTATION TEXT 15 66
RECORD TYPE 6:
ParameterDescriptionSTARTING COLUMN FIELD LENGTH
MONTHLY DATA RECORD ALWAYS "6" 10 1
BLANKS 11 1
DATE YYYY - YEAR OF MONTHLY DATA 12 4
CONTINUATION CODE ONE-CHARACTER CODE
1 = JAN-JUN
2 = JUL-DEC
16 1
BLANKS 17 1
SEA LEVEL MONTHLY SEA LEVEL VALUE 18 5
DAY COUNT NUMBER OF DAYS MISSING IN CALCULATING MONTHLY VALUE - (15 IS MAX, 99 FOR NOT AVAILABLE) 23 2
INTERPOLATION CODE ONE-CHARACTER CODE - as follows
0 : no interpolation
1 : simple interpolation
2 : cubic spline
9 : unknown or missing
25 1
SEA LEVEL MONTHLY SEA LEVEL VALUE 26 5
DAY COUNT NUMBER OF DAYS MISSING IN CALCULATING MONTHLY VALUE - (15 IS MAX, 99 FOR NOT AVAILABLE) 31 2
INTERPOLATION CODE ONE-CHARACTER CODE - as above 33 1
SEA LEVEL MONTHLY SEA LEVEL VALUE 34 5
DAY COUNT NUMBER OF DAYS MISSING IN CALCULATING MONTHLY VALUE - (15 IS MAX, 99 FOR NOT AVAILABLE) 39 2
INTERPOLATION CODE ONE-CHARACTER CODE - as above 41 1
SEA LEVEL MONTHLY SEA LEVEL VALUE 42 5
DAY COUNT NUMBER OF DAYS MISSING IN CALCULATING MONTHLY VALUE - (15 IS MAX, 99 FOR NOT AVAILABLE) 47 2
INTERPOLATION CODE ONE-CHARACTER CODE - as above 49 1
SEA LEVEL MONTHLY SEA LEVEL VALUE 50 5
DAY COUNT NUMBER OF DAYS MISSING IN CALCULATING MONTHLY VALUE - (15 IS MAX, 99 FOR NOT AVAILABLE) 55 2
INTERPOLATION CODE ONE-CHARACTER CODE - as above 57 1
SEA LEVEL MONTHLY SEA LEVEL VALUE 58 2
DAY COUNT NUMBER OF DAYS MISSING IN CALCULATING MONTHLY VALUE - (15 IS MAX, 99 FOR NOT AVAILABLE) 63 2
INTERPOLATION CODE ONE-CHARACTER CODE - as above 65 1
BLANKS 66 15

SIX MONTHLY ENTRIES PER RECORD, TWO RECORDS PER YEAR. MISSING VALUES ARE DENOTED '99999999' (IE SEA LEVEL '99999', COUNT '99', AND CODE '9').

NODC Code Tables Used with this Format:
CODE NUMBER CODE NAME
0505 AVERAGING METHOD
0506 DATA REFERENCE INDICATOR
0507 INTERPOLATION METHOD
  Last modified:    Wed, 10-Oct-2007 20:03 UTC NCEI.info@noaa.gov
 
Dept. of Commerce - NOAA - NESDIS - NCEI
* Offsite Link Notification
USA.gov - The U.S. Government's Web Portal