WOCE Science Centers (SC) quality control annual upper ocean thermal data files to identify, flag, and correct errors in the data. During the review process, the following types of changes or additions may have been made:
1. Changes to geographic position fields, date/time fields, or temperature fields.
2. Changes to station overall quality flags for position (Q_POS), date/time, (Q_DATE_TIME), and for the entire station (Q_RECORD).
3. Changes to profile data quality flags set by MEDS or NODC.
4. Added WOCE UOT flags at depths where specific problems are noted.
The data are returned to NODC and the changes and additions are merged into records of the CMD at NODC. In designing this process, NODC chose not to completely replace CMD records with data returned by Science Centers. Rather, those fields which were changed and added are selected from the returned SC files to update existing records in the database.
When SC files are processed at NODC, the following actions are taken:
1. Geographic position fields, date/time fields, or temperature fields: Changed values become the current value of the field, and previous values are stored in History Records which indicate the change by storing the agency, date, and software used to make the change.
2. Station flags (Q_POS, Q_DATE_TIME, or Q_RECORD): Those data base fields are updated with new values, and previous values are stored in History Records.
3. Profile data quality flags set by MEDS or NODC: Flags in profile data base records are updated. All accompanying History Records are added to the data base. If no History Record accompanies the flag changes, one History Record is generated and added to the station. Because of the potentially large number of History Records associated with flag changes, not all History Records are retrieved with the data (unless requested). If flags were changed at many depths, and there is one History Record for each depth, only the flag change History Records from the first and last depths are retrieved with the station.
4. WOCE UOT flags in History Records are recorded with the station in proper sequence with other History Records.