Requests for ECMWF Data David Tan ESA CCI CMUG Integration Meeting #1 ECMWF, Reading a Overview of requests (including common params) b Initial issues (redistribution, common interpolation) c Meeting the requests - providing access options d Next steps

Overview of Requests for ECMWF Data (1/2) “No needs” from Glaciers and Fire Remaining 8 Ecv projects have some needs Reference documents are the Ecv DARDs Email iterations to make requests explicit/complete DARDs for traceability and formal requests Picture is still evolving First requests communicated October 2010 New requests started last week Obstacle to coordination and future CCI phases? Reminder: ERA-Interim is the recommended data stream In many cases, ecv generation is not “business as usual” Long-term consistency of products is a central issue

Overview of Requests for ECMWF Data (2/2) Time periods 1991-present: SST and SeaLevel 2002-present: GHG 2007-2009: Cloud 1997 & 2008: Aerosol 2005: LandCover (potentially 1998-present) Some Round Robin periods are shorter – but not all Requests for ozone fields LandCover & Ozone: Total Column Ozone (2D+time) SST: Ozone mass mixing ratio (3D+time) Requests for temperature and (specific) humidity, 3D+time SST, SeaLevel, GHG, Cloud (mix of Analyses/Forecasts) 1-2 Tbytes, longer-term coordination of requests?

Initial Issues Redistribution policy (especially for Round Robin) Normally no permission to redistribute “raw” fields Data interpolated to satellite locations – ok Agreed by 6 ecvs, 2 pending Common/consistent interpolation Within a single ECV project, one member does all interpolations then redistributes to the other members Approach taken by SST, Cloud and SeaLevel (all using the CDO package) Under consideration by 2 others (technical impact) Yet to respond: 3 Implications for Round Robin and “Operational” system Propose: agree strategy of modularity/consistency implementation dates phased and tbd

Meeting the requests – providing access ECV teams to download from archive Flexibility to download additional data when needed But remember to notify ECMWF and update DARD Via user account or web-based One point of contact per ECV Option to access archive at BADC rather than ECMWF Some teams have faster network links to BADC Strictly speaking, should be a UK-based team member who downloads, interpolates, then redistributes Currently a “short-term” option (next 6 months or so) Is there interest in “long-term” BADC option?

Next steps 2 ecvs to agree redistribution policy No redistribution of “raw” fields Redistribute only data interpolated to satellite locations All ecvs to answer any remaining queries about DARD Liaise with David for starting access (when & which archive) 5 ecvs to propose timeline for more consistent interpolation via the CDO package