ASCII Format Description
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
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.
|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.
|1||Station location, time, profile and segment identifiers.|
|2||Up to 1500 repeats of depth-variable information and associated quality control flags.|
For the above example, the organization of a data file would be as follows.