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>> ASCII Format
The ASCII (character) format used for the delivery of the data is moderately complex since it provides information in addition to the actual observations. The data format was originated by Canadian Marine Environment Data Service. It makes use of a number of international codes to describe the data and how they were collected. International vessel call sign tables and ship platform names are also provided.
ASCII Format Description
The data are organized in the
following manner. A 'Station' record always appears first followed by
one or more 'Profile' records. All records are of variable length, with
the exact number of fields to be found being provided in the record.
The complete description of the
fields of the format is provided below.
The 'Station' Record
The 'Station' record is built
of a number of components. The first component always has a fixed number
of fields and is always present. This component provides information about
the location and time of the station, information about how the data were
received and the number of repeats of other components found in the 'Station'
record.
The second component provides
information about the number of profiles measured at the station, whether
or not a profile is a duplicate of another, higher resolution copy, and
some information about the accuracy and precision of the variables measured.
The deepest depth of each profile is recorded here. Because of limitations
of records lengths on some computers, profiles are broken into a number
of segments. Each segment has up to 1500 depth-variable pairs. There are
as many repeats of this component as required to describe all profiles
present. The actual number of profile records associated with a station
is the sum of the number of segments of each profile.
The third component carries
information about other variables measured at the station, such as winds,
air temperature, and so on. The measurements are expressed as numeric
values. A code table is used to indicate the variable measured. There
are as many repeats of this component as required to describe all numeric
variables present.
The fourth component carries
information about other variables measured at the station but which are
recorded as alphanumerics. Such measurements as Beaufort winds, QC tests
executed, etc. are to be found here. There are as many repeats of this
component as required to describe all alphanumeric variables present.
The last component records
the processing history of the station. It provides information about who
carried out which actions against what variable and when. If values have
been changed, the original value is stored in this component. There are
as many repeats of this component as required to describe all the processing
that has taken place on the station.
Suppose that a temperature
and a salinity profile were collected at a station. Suppose also that
there were observations every meter to 3500 m depth. Suppose also that
wind speed and direction were measured, that the Beaufort wind speed was
recorded and that the station had 5 different actions taken against it.
The layout of the station record is then as follows.
| Component |
Contents |
| 1 |
Station location, time
and other information. |
| 2 |
Two repeats of profile
information, one for temperature and one for salinity. |
| 3 |
Two repeats, one for each
of wind speed and direction. |
| 4 |
One repeat for the Beaufort
code. |
| 5 |
Five repeats of the history
information, one to describe each action taken against the record. |
The 'Profile' Record
There may be one or more 'Profile'
records associated with each station record. The associated 'Profile'
records always follow immediately after the station record to which they
are linked.
There are two components to
a 'Profile' record. The first always has a fixed number of fields and
is always present. This component provides a repeat of the station location
and time. It identifies the profile type and segment of that profile.
It indicates if depths or pressures are recorded and how many depth-variable
pairs are to be found.
The second component records
the depth and measured variable as well as quality control flags that
have been applied at each depth. There are as many repeats of this component
as required to describe all depths (pressures) measured in the profile.
For the example data collection
described above, the layout of the profile records is as follows.
| Component |
Contents |
| 1 |
Station location, time,
profile and segment identifiers. |
| 2 |
Up to 1500 repeats of
depth-variable information and associated quality control flags. |
File Organization
For the above example, the
organization of a data file would be as follows.
Format Description
|
Field
Name
|
Field
Size
|
Starting
Position
|
Justify
(L / R)
|
Field
Description
|
| ---------------------- |
----------- |
--------------
|
---------
|
----------------------------------------------------------------------- |
| MKey |
char*08 |
01
|
L
|
Sort Key |
| One_Deg_sq |
char*08 |
09
|
R
|
MEDS geographic 1 degree
square |
| Cruise_ID |
char*10 |
17
|
L
|
Radio callisgn + year
for real time data, or NODC reference number for delayed mode data. |
| Obs_Year |
char*04 |
27
|
L
|
Century and year of Observation |
| Obs_Month |
char*02 |
31
|
L
|
Month of Observation |
| Obs_Day |
char*02 |
33
|
L
|
Day of Observation 01-31 |
| Obs_Time |
char*04 |
35
|
L
|
Time of Observation |
| Data_Type |
char*02 |
39
|
L
|
Instrument type or type
of IGOSS radio message |
| Iumsgno |
char*12 |
41
|
R
|
A unique identifier used
by MEDS in their processing |
| Stream_Source |
char*01 |
53
|
L
|
A field used by MEDS to
track if the data are new or have been retrieved from its archives. |
| Uflag |
char*01 |
54
|
L
|
Record update action |
| Stn_Number |
char*08 |
55
|
R
|
MEDS Station Number for
real-time data, or cruise consec number for delayed mode data. |
| Latitude |
char*08 |
63
|
R
|
Decimal degrees (+ = north,
- = south) |
| Logitude |
char*09 |
71
|
R
|
Decimal degrees (+ = west,
- = east) |
| Q_Pos |
char*01 |
80
|
L
|
Station Position Quality |
| Q_Date_Time |
char*01 |
81
|
L
|
Date-Time Quality |
| Q_Record |
char*01 |
82
|
L
|
Worst Quality flag in
the station |
| Up_Date |
char*08 |
83
|
L
|
Date of last action on
record |
| Bul_Time |
char*12 |
91
|
L
|
Time bulletin was placed
on GTS |
| Bul_Header |
char*06 |
103
|
L
|
GTS bulletin header |
| Source_ID |
char*04 |
109
|
L
|
GTS node which placed
message on the GTS. |
| Stream_Ident |
char*04 |
113
|
L
|
Source and type of data |
| QC_Version |
char*04 |
117
|
L
|
Version of the QC program
used. |
| Data_Avail |
char*01 |
121
|
L
|
Data Availability |
| No_Prof |
char*02 |
122
|
R
|
Number of Parameter profiles
in station |
| Nparms |
char*02 |
124
|
R
|
Number of Surface Parameter
groups |
| Nsurfc |
char*02 |
126
|
R
|
Number of Surface Codes
groups |
| Num_Hists |
char*03 |
128
|
R
|
Number of History groups |
| |
|
Profile
Information; repeats No_prof (1-30) times
|
| |
| No_Seg |
char*02 |
01
|
R
|
Number of Profile Records
in the profile |
| Prof_Type |
char*04 |
03
|
L
|
Type of data in profile |
| Dup_flag |
char*01 |
07
|
L
|
'Y' indicates this station
duplicates another higher quality. |
| Digit_Code |
char*01 |
08
|
L
|
Data Digitization method |
| Standard |
char*01 |
09
|
L
|
Standards to which the
observations were made |
| Deep_Depth |
char*05 |
10
|
R
|
Depth (m) of the deepest
observation in the profile. |
| |
| Surface Parameter
Group; repeats Nparms (0-30) times |
| |
| Pcode |
char*04 |
01
|
L
|
Parameter - GF3 or User
code. |
| Parm |
char*10 |
05
|
R
|
Measured surface parameter
value. |
| Q_Parm |
char*01 |
15
|
L
|
Parameter Quality |
| |
|
Surface
Codes Group; repeats Nsurfc (0-30) times
|
| |
| SRFC_Code |
char*04 |
01
|
L
|
Parameter - GF3 or User
code. |
| SRFC_Parm |
char*10 |
05
|
L
|
Surface code |
| SRC_Q_Parm |
char*01 |
15
|
L
|
Parameter Quality |
| |
|
History
Group; repeats Num_Hists (0-100) times
|
| |
| Ident_Code |
char*02 |
01
|
L
|
Organization which created
the record |
| PRC_Code |
char*04 |
03
|
L
|
Computer program which
modified the station and created a history group |
| Version |
char*04 |
07
|
L
|
Version of the above program |
| PRC_Date |
cahr*08 |
11
|
R
|
Date of action (YYYYMM) |
| Act_Code |
cahr*02 |
19
|
L
|
Action performed on parameter |
| Act_Parm |
char*04 |
21
|
L
|
Parameter code of changed
parameter |
| Aux_ID |
char*08 |
25
|
R
|
Locator (e.g. depth) of
changed parameter |
| Previous_Val |
char*10 |
33
|
R
|
Value of parameter before
change |
| |
|
Profile
Record
|
| |
| MKey |
char*08 |
01
|
L
|
Sort Key |
| One_Deg_sq |
char*08 |
09
|
R
|
MEDS geographic 1 degree
square |
| Cruise_ID |
char*10 |
17
|
L
|
Radio callisgn + year
for real time data or NODC reference number for delayed mode data. |
| Obs_Year |
char*04 |
27
|
L
|
Century and year of Observation |
| Obs_Month |
char*02 |
31
|
L
|
Month of Observation |
| Obs_Day |
char*02 |
33
|
L
|
Day of Observation 01-31 |
| Obs_Time |
char*04 |
35
|
L
|
Time of Observation |
| Data_Type |
char*02 |
39
|
L
|
Instrument type or type
of IGOSS radio message |
| Iumsgno |
char*12 |
41
|
R
|
MEDS field - not used |
| Profile_Type |
char*04 |
53
|
L
|
Type of data in the profile |
| Profile_Seg |
char*02 |
57
|
L
|
Profile segment number
of this record |
| No_Depths |
cahr*04 |
59
|
R
|
Number of Depth/Pressure
values in this record |
| D_P_Code |
char*01 |
63
|
L
|
Depth/Pressure code |
| |
|
Paramter
Group; occurs No_Depth (1-1500) times
|
| |
| Depth_Press |
char*06 |
01
|
R
|
Depth or Pressure value |
| Depres_Q |
char*01 |
07
|
L
|
Depth/Pressure quality |
| Prof_Parm |
char*09 |
08
|
R
|
Measured parameter value |
| Prof_Q_Parm |
char*01 |
17
|
L
|
Data Quality |
|