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Consortium Meeting Feb 3, 2011

Consortium Meeting Feb 3, 2011. Hit Rates. Finally, a clear reduction in Canadian traffic and other mega-users not part of the consortium Some may have switched to Comcast or alternative avenues of access. Major Hardware Changes. Eight new Nehalem (dual-quad core) nodes for SAGE.

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Consortium Meeting Feb 3, 2011

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  1. Consortium Meeting Feb 3, 2011

  2. Hit Rates • Finally, a clear reduction in Canadian traffic and other mega-users not part of the consortium • Some may have switched to Comcast or alternative avenues of access.

  3. Major Hardware Changes • Eight new Nehalem (dual-quad core) nodes for SAGE. • Added Infiniband communication between these nodes (40 Gbit per sec) • Two new uninterruptable power supplies (old ones failed) • Replace RAID server for the EnkF analysis and forecasting system. • Innumerable disk replacements. • Replaced UPS in SAGE. • Moved all SAGE processors to our ensemble system (allow switch to WRF).

  4. Impacts • Now only were our main nodes refreshed, each node is twice as fast, AND WRF scales far better (can use all the nodes simultaneously effectively). • Major resource increase which made possible substantial changes to be described later.

  5. Scalability • The combination of the new chips (much better memory bandwidth) and the fast backplane, has given us something we always wanted…almost unlimited scalability….adding more processors speed things up.

  6. Major Changes Since the Last Meeting • Not only installed a wide range of new hardware, but made radical changes to the modeling systems. • Very large changes in our modeling approaches.

  7. Major Change 1 • Greatly expanded the 4/3 km run to include the Gorge and all of Washington State. • Run twice a day. • Initially extended to 48 hr both cycle.

  8. No more nestdown and different use of machines • The old way was to run 36-12 km first to 72h, saving the grids. • THEN, we would use nestdown to run 4-km completely separately from 36-12 km • THEN, would run 1.3 km separately from 4-km. • 36-12 km would run out to 180 h on the slower Blade server.

  9. Better approach • We now have the computer power to do this better. • All runs are nested interactively in lower resolution run. • Found that this substantially improved moisture fields coming in on boundaries, which are not updated in nestdown runs. • Less boundary issues, better simulations. • Extended 4-km to 84 hr.

  10. How we do it now. • As first grids come in, the Blade Cluster starts 36-12 km and stays with it until 180h. Finishes by 10:15 AM • The new Sage cluster also starts and does 36-12-4km immediately. Finishes by 9:45 AM. • It then starts 36-12-4-1.3 km. Finishes by 2:40 PM through 48 hr. Can go further in time.

  11. Issues and Problems • Huge impact on all the controlling scripts and graphics generation. Most conquered. • Some stability problems at 1.3 km…losing 1 in 15-20 runs at some point. • Traced it to CFL errors over the steepest terrain…Mt. Rainier. Testing fixing and think we have one (vertical velocity damping or smoothing Mt. Rainier).

  12. Need Better Snow Fields! • Think we got one that is available daily:

  13. One More Change • New consortium member, Iberdrola, has requested a small domain increase to the south (roughly to Salem). 9% increase in domain, 30 minute longer runtime. • Will result in excellent coverage of Portland area and inclusion of important terrain draining into Gorge.

  14. Added Terrain

  15. Further Expansion to Missoula?

  16. This domain is current size: 448x334 • Both westward and southward expansion:616x 364= 49.9% increase • Would need seven more nodes to do this, we no impact on availability. • Cost for hardware (including more disks) around 50K.

  17. EnKF System Goes Truly Operational with 3-h Cycling • The system now does 36-4 km analyses every three hours, followed by 3 hr forecast. • Converted to DART system—now the national system—lots of flexibility. • Remember this is an ensemble of 64 members. • Proved itself during Nov 22 snowstorm

  18. Next Stage • Make improvements in system (bias of obs, vertical localization, and others) • Add forecasts (e.g, 24h, every say 6 hr) • One hour cycling • better web page

  19. 12-km domain tests • Our northern boundary is relatively close—is this a problem?

  20. Northern Boundary • 95% of the time this is no concern….most of our weather comes from the west or southwest…particularly when there are strong winds. • But what about the rare case when there is strong flow from the north with important weather features (like November 22). • Got concerned about this when we didn’t do as well as the NAM for this event.

  21. Tests • Did a series of tests for this and some other cases…expanding the 12-km domain northward in steps, including making the 12-km as big as the 36-km. • Bottom line: no real improvement. NAM was better in this one case due to better initialization than GFS (which is relatively rare)

  22. SnowWatch • The City of Seattle is concerned about snow/ice situations. • A major issue is having the best real-time information—issues demonstrated on Nov 22. • Proposed to build a system for them—SnowWatch that makes use of our high resolution modeling and data assets…and the infrastructure of RainWatch. • Funding looks good---Jeff Baars will build it.

  23. NW Weather Workshop • Delayed until May 13-14th.

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