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This Manual has been produced within the context of the Global Temperature-Salinity Pilot Project (GTSPP). Because the work- of assuring the quality of data handled by the Project is shared amongst data centres, it is important to have both consistent and well documented procedures. This Manual describes the means by which data quality is assessed and the actions taken as a result of the procedures. The GTSPP handles all temperature and salinity profile data. This includes observations collected using water samplers, continuous profiling instruments such as CTDs, thermistor chain data and observations acquired using thermosalinographs. These data will reach data processing centres of the Project through the real-time channels of the IGOSS program or in delayed mode through the IODE system. The procedures described here are intended to cover only the above-mentioned data types and specifically for data sent through the IGOSS system. However, there are obvious generalizations that can be made to other data types. Because of this, it is expected that this Manual will serve as a base on which to build more extensive procedures for the aforementioned data types and to broaden to other types, as well. Indeed, in sonic cases, tests of data types that are not strictly part of this Project are incorporated into this Manual simply because they are of obvious use and because these data types are often associated with the data of interest to the GTSPP. Updates to this Manual are carried out as new procedures are recommended to the (GTSPP). and as these are accepted by the project Steering Group. Readers are encouraged to make suggestions on both how to improve existing tests, and of new tests that should be considered. In both cases, it is important to explain how the suggestion improves or expands upon the existing suite of tests. Suggestions may be forwarded to any participants of the GTSPP and these will be directed to the Steering Group. As tests are suggested but before incorporation, they will be documented in a section of the Manual. This will provide a means to accumulate suggestions, to disseminate them and solicit comments. This Manual describes procedures that make extensive use of flags to indicate data quality. To make full use of this effort, participants of the (GTSPP). have agreed that data access based on quality flags will be available. That is, (GTSPP). participants will permit the selection of data from their archives based on quality flags as well as other criteria. These flags are always included with any data transfers that take place. Because the flags are always included, and because of the policy regarding changes to data, as described later, a user can expect the participants to disseminate data at any stage of processing. Furthermore, (GTSPP). participants have agreed to retain copies of the data as originally received and to make these available to the user if requested. The implementation of the tests in this Manual requires interactive software to be written. The operator is consulted in the setting of flags or possibly in changing data values. In each case, information is provided to the operator to help them decide what action to take. In the descriptions of the tests, certain specific items of information and data displays are included. So, for example, when a station position fails a test of platform speed, a track chart of the platform is used The amount of information displayed and the presentation technique is dependent upon the hardware and software capabilities at the implementation site. For this reason, the information to be displayed, and the method of presentation should be treated as recommendations.
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