1. Report of GDS TAG Working Group

3. GDS finalization There is a need to nominate reviewers for the produced documentation and responsibles to consolidate the GDS specifications documents. It was recommanded that : Samantha Lavender and Leon Majewski will act as reviewers (Oct- Nov 2008) P.Leborgne and JF Piolle are responsible for finalization of L3 specification C.Donlon & H.Roquet is responsible for the finalization of the L2P and L4 specifications and consolidation of final document for review by science team (October 2008) D.Poulter for finalization of the DDS specification JF Piollé for finalization of the MDB specification The process of managing GDS changes may be very long : need new GDS 2.0 quickly => group target 1 st June 2009 for switching the system to GDS 2.0.

4. L2P content to keep the DT_analysis as a required field. Providers are free to use any reference analysis, it was agreed that no unique L4 product should be imposed as reference analysis. For solar surface irradiance, it was noted that the current field is very confusing and not usable : current fields are filled with a mosaic of different sources having various integration time and duration. The DV TAG group is requested to make a recommandation for a definition of the required SSI (integration time,...) and possibly recommand which source(s) should be used. wind speed field is kept as required sea ice fraction is kept as required aeerosols : it was raised that the quality of NAAPS model, currently used to fill this field, is questionable. Better sources or sources adapted to each sensor are required. Hervé Roquet is requested to provide a recommandation for a the « best » source to be used.

5. L2P content Rejection and confidence flags : it was raised that the current flags are quite confusing because they mix together common information with information only meaningful for a specific sensor or wave length (infrared,microwave). It is recommended to redefine these flag, keeping common bits (land, lake,...) and reserving the remaining spare bits to manage the information specific to a given sensor. Recommendation for a new definition of these flags have been requested to SST TAC members (Hervé Roquet) and K.Casey. Lake : need a recommandation from NAVOCEANO and SAF to converge on a common definition of land/lake mask for AVHRR (MODIS and AATSR have a mask). proximity_confidence : the SSES TAG group is requested to provide a recommandation on a precise and unambiguous definition of each confidence level. sst_dtime : it was raised that the current sst_dtime definition hardly manage files with a large time range. Best practices on how to fill this field and the associated reference time (for instance degrading the time resolution or choosing smartly the reference time) have to be recommanded by Gerard Legendre (Meteo-France) in order to be CF 1.3 compliant, a new variable attribute 'standard_name' will be added to the variable for which it exist. The variable names themselves are not changed and stay as they are, only this attribute is added, but users have to be recommanded to use the standard name.

6. L2P Format –NetCDF4 offers great advantages (such as data chunking) but the GDS TAG feels it may be too soon to move to NetCDF4 as long as it is not stable (still in beta version) and that there is not yet a wide range of available tools (Matlab, IDL,...) and libraries natively supporting NetCDF4. –Further testings of NetCDF4 are required. Tests and demonstration of usage will be led by the GDS TAG (David Poulter with his DDS, Jorge Vasquez, Peter Cornillon) which will come with a report at next GHRSST meeting. File naming –the current filenaming convention may not be workable (in particular to guarantee unicity). Recommandations have also been made : –use for the field the ISO time formatting : YYYYMMDDTHHMMSSZ –L3/L3P/L2P/L4 may be simpler and shorter than L3_GHRSST, etc.... –Andy and Ken to fight together and provide final and clear recommandation

7. Metadata It is recommanded that the GDS TAG investigates the existing metadata requirement to interface with the corresponding systems or inventories. Integration within the WMO IGOS will be sought. A Metadata group is set up to perform this task : –Jean-Francois Piollé (chair), –NODC (Ken Casey), –PODAAC (Ed.Armstrong, Thomas Huang) –BoM (Leon Majewski), –WMO (Etienne Carpentier) Identify ISO-19115 metadata requirements for GHRSST; ensure that the GHRSST metadata profile is compatibile with the WMO Core Profile, FGCD profile, and INSPIRE. Liaise with the joint Steering Group for the Ocean Data Portal (ODP) and the WIGOS Pilot Project for WIGOS for submitting GHRSST requirements to the appropriate WIS Expert Teams of the WMO Commission for Basic Systems (CBS). Defines the global attributes to be added within the L2P,L3P,L3 and L4 data files to generate the appropriated metadata records

8. L3 & L3P Two types of L3 have been identified : –L3P : same content and format as L2P but for gridded data (eg NAR, SEVIRI), replace L2P_GRIDDED for AMSRE/TMI. They are produced from native L3 providers. The « P » in L2P/L3P should refer to "Processed". The same processing is applied indifferently to native L2 data to produce L2P, and native L3 data to produce L3P. Therefore the description of L3P content and format goes into the same document as L2P, which should be renamed « L2P and L3P Production Specifications » –L3 (or « collated ») : aggregation over a period of time, with further processing such as adjustement to a reference sensor (such as AATSR). Possible confusion with native L3 was raided. It is requested to Andy Bingham and Ken Casey to provide a recommandation for a possible change to « L3C » (collated) The content and format of L3 (or L3C) product is accepted. Spell checking of the document is needed (P.Leborgne, JF Piollé) for a correct and accurate format description.

9. L4 specification The area code in the file name should be transformed into a free form field it is requested to the GMPE group to define the analysis_error field the sea ice fraction field is set as optional The source_of_data global attribute must provide the full DSD Id for each dataset used as input the specification should be opened to a field with diurnal increments (for instance for skin sst) so the sstskin field is kept as optional : a recommandation is expected from the DV-TAG on the definition and specification of this field.

10. Validation tools (1) DDS System –It is not obvious for GDS TAG that it should provide specifications for datasets which are not part of GHRSST scope. David Poulter is requested to provide a recommandation to conclude if this has to be in the GDS, and if so to define and provide the appropriate format specification. GMPE specification document –It is not obvious to the GDS-TAG that the GMPE specification should be part of the GDS document. It was raised it is mostly a validation tool and a work in progress and there is no real strong need nor user requirement to specify this precisely. –It may be more flexible, open and convenient to keep this as a reference working document of the GMPE-TAG, but not part of GDS. However the effort put on documenting the GMPE validation framework must be encouraged.

11. Validation tools (2) Match-Up Database specification document –The status of the MDB is not clear. Should we have a common specification of the MDB and what should be specified : data model, match-up processing (already there), exchange format between MDBs, software... –The data model should be extended to be capable of adding any additional variable (such as brightness temperature). A recommandation is requested from Jean-François Piollé and Leon Majewski about what should go into the GDS (scope of the specifications) and how to implement that.

12. Support to ocean colour GHRSST science team, sollicited by Samantha Lavender, should recommend and support usage of L2P like format for the delivery of near real time science products of Ocean Color by ESA.