The GHRSST-PP Data Processing Specification (GDS)

The GHRSST-PP Processing specification (GDS) is a common data processing specification that is implemented at each GHRSST-PP RDAC and GDAC. It represents a consensus opinion of the GHRSST-PP community on how to optimally combine satellite and in situ SST data streams within the globally distributed R/GTS operational system. The GDS documents the minimum data processing that should be completed at each RDAC and GDAC in order that data products generated at different processing centres can be used both individually and together with confidence. The GDS describes in detail the input and output data specifications, data processing procedures, algorithms and data product file formats required in order for the GHRSST-PP shared implementation model to function efficiently. It recognises that RDAC and GDAC must implement specific data processing procedures that account for data streams that are regionally specific (e.g., geostationary imagers). Furthermore, it is expected that RDAC may provide additional data products and services that satisfy regional user requirements (e.g., regionally specific analysed data products or ultra-high resolution data products).

The first version of the GDS to be implemented (GDS v1.0v1.5) was based on the First Report of the GHRSST-PP GDS-TAG (Wick et al, 2002) and subsequent discussions at the GHRSST-PP Workshops. The GDS has been iterated following discussions within the GHRSST-PP Science Team to a version 1.7 This version of the GDS is focused on a data processing model with specific emphasis on implementing:

1. An operational data exchange and delivery system between data providers, RDAC, GDAC and user communities by 2005
2. Definition and operational production of common format L2P SST data files for a number of near real time SST data products,
3. A suite of regional L4 data products based on current best practice/knowledge analysis procedures that can be upgraded and refined based on experience. The analysis procedures should as far as possible capitalise on the synergy benefits of complementary measurements (accuracy, susceptibility to atmospheric clouds and aerosol loading, spatial and temporal resolution etc.)
4. An initial global analysis system providing global coverage data products,
5. An initial implementation of the GHRSST-PP High Resolution Diagnostic Data Set (HR-DDS) system and,
6. A suite of initial test data products to be available to selected users at each RDAC and GDAC by mid 2004.

Much of the GDS is dedicated to issues of data exchange, management and operational considerations. It is a working reference document written primarily for the RDAC and GDAC teams as they physically realise, develop and, refine the GHRSST-PP demonstration system. As such, it may be considered a technical reference manual for the GHRSST-PP. The GDS will evolve throughout this process and a significant scientific upgrade of the processor is foreseen following the successful commission of the GDS at RDAC by regionally funded projects. The GHRSST-PP International Project office continues to work closely with all RDAC projects to refine and upgrade the GDS documentation and specifications as the GHRSST-PP project matures.