1. 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

2. 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
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

3. Overview of Requests for ECMWF Data (2/2)
Time periods
1991-present: SST and SeaLevel
2002-present: GHG
: 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?

4. 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

5. 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?

6. 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