The GHRSST-PP Regional/Global Task Sharing Framework (R/GTS)
At the core of GHRSST-PP's success is the international collaboration on which it is based. In five years of discussion, debate and planning the main agencies responsible for operating satellite SST sensors and for producing the primary SST datasets have worked with ocean scientists familiar with the processes affecting remote sensing of SST, and with key operational users of SST data, to lay down the rule base for the sharing, indexing, processing, quality control, archiving, analysis and documentation of SST data from diverse sources. This is specified in the GHRSST-PP Data Processing Specification (GDS) document which defines clearly the input and output data specifications, data processing procedures, algorithms and data product file formats that are common to each GHRSST-PP sub-system.
The GHRSST-PP R/GTS implementation framework was first proposed at the Second GHRSST-PP Science Team Meeting held in Tokyo Japan, 2002. In this framework, the data processing and management tasks associated with the application and exchange of large satellite data sets are distributed between international institutions which share the load. This allows regional centres to provide an efficient service to the local/national/regional user community by benefiting directly from the work of other regional and global centre activities. Data processing operations that are necessary to operationally generate and distribute high resolution SST data sets having global coverage are shared by Regional Data Assembly Centres (RDAC). RDAC ingest, quality control and merge existing satellite and in situ SST data sources that are then merged together to generate regional coverage SST data products having the same netCDF format specification (called L2P products), in real-time. RDAC data products are then assembled together at Global Data Analysis Centres (GDAC) where they are merged to provide L4 global coverage data products free of gaps.
In order for the R/GTS framework to function, all GHRSST products, must strictly follow the common GHRSST-PP Data Processing Specification when generating L2P and L4 data. As a result, users with tools to read data from one RDAC can draw data from any of the others and/or the GDAC and should find it is immediately readable by their systems having uniformity within the limits of flexibility permitted by the GHRSST-PP Data Processing Specification. The GHRSST-PP was able to move rapidly from defining the Processing Specification to the present situation in which global L2P and L4 products are being generated in large numbers and beginning to be used operationally, because it established by consensus an implementation framework in which the new data products and services are provided. No attempt was made to impose a top-down structure for commissioning data production. Instead, agreement and commitment to the GHRSST-PP Data Processing Specification facilitated the existing agencies each to contribute a part of the necessary international effort through the Regional/Global Task Sharing system that is illustrated in the figure above. This follows a distributed modular model with a hierarchical distinction between RDAC, GDAC and the Long Term Stewardship and Re-analysis Facility (LTSRF). Follow the links below to learn more about the R/GTS components.
Regional Data Assembly Centres (RDAC)
Global Data Assembly Centres (GDAC)
GHRSST-PP Long Term Stewardship and Reanalysis Facility
Users may access data at any of the GHRSST-PP centres in real time and in delayed mode, using FTP and OPeNDAP protocols. At all levels of the GHRSST international framework, the user community is fully engaged in the development and specification of services and data products. Through the GHRSST-PP R/GTS, observation and analysis SST data sets can be obtained through robust operational data servers, in near real time, in the same generic format and with uncertainty estimates. A large amount of SST data has been made available to the community in this way and the GHRSST-PP may serve as a model for other international projects making a contribution to the Global Earth Observation System of Systems (GEOSS).
(Last Updated: 16-02-2007)