HIRLAM Use of the Hirlam NWP Model at Met Éireann (Irish Meteorological Service)

1. HIRLAM Use of the Hirlam NWP Model at Met Éireann (Irish Meteorological Service) (James Hamilton -- Met Éireann)

2. COMPUTER SYSTEM and VERSIONS of HIRLAM • IBM RS/6000 SP : 9-nodes each with 4-CPU’s • Operational Hirlam : 438x284 grid pts; 31-levels • Nested Hirlam : 222x210 grid pts; 40-levels • LINUX PC : Twin Xeon Processors [2.0Ghz] • Backup Hirlam : 218x144; 31-levels • LINUX PC : Twin Xeon Processors [500Mhz] • Hourly Hirlam : 97x98 grid pts; 24-levels • LINUX Cluster : Nine Twin Xenon Processors [3.2GHz] • Operational Hirlam : Test mode

3. OPERATIONAL HIRLAM … IBM RS/6000 SP • HIRLAM 5.0.1 with 3DVAR • 3-Hour assimilation cycle with 48-hour forecasts every 6-hours • Rotated lat/long 0.15x0.15 grid with 438x284 grid points • Hybrid [eta] coordinates with 31-levels • CBR vertical diffusion scheme; Sundqvist condensation scheme • STRACO cloud scheme; Savijarvi radiation scheme • Digital filter initialisation • Two time-level Semi-Lagrangian semi-implicit scheme • Use of ‘frame’ boundaries from ECMWF

6. BACKUP HIRLAM … LINUX-PC [Dual 2.0Ghz CPU] • HIRLAM 4.3.5 with OI-Analysis • 3-Hour assimilation cycle with 48-hour forecasts every 6-hours • Rotated lat/long 0.30x0.30 grid with 218x144 grid points • Hybrid [eta] coordinates with 31-levels • SAME AREA AS OPERATIONAL HIRLAM

8. NESTED HIRLAM … IBM RS/6000 SP • HIRLAM 6.0.0 with 3DVAR • 3-Hour assimilation cycle with 24-hour forecasts every 6-hours • Model runs at intermediate hours … 03Z, 09Z, 15Z, 21Z • Rotated lat/long 0.12x0.12 grid with 222x210 grid points • Hybrid [eta] coordinates with 40-levels • Kain-Fritsch/Rasch-Kristjansson convection/condensation scheme • ISBA surface scheme • Output post-processed with MOS

10. HOURLY HIRLAM ... LINUX-PC [Dual 500Mhz CPU] • HIRLAM 4.3 with OI Analysis • Hourly assimilation cycle with hourly analysis and 3-hour forecast • Rotated lat/long 0.15x0.15 grid with 97x98 grid points • Hybrid [eta] coordinates with 24-levels • Analysis shown on public web-site

12. OPERATIONAL USES of HIRLAM • General Forecasting • Forecast guidance out to 48-hours • WAM wave model • Forecast 10-metre winds used to drive model • Roadice Prediction System • Forecast parameters are used as first guess for [human] forecaster • SATREP • Overlay on satellite plots [ZAMG SATREP analysis scheme]

13. RESEARCH ACTIVITIES Better Specification of B.C.’s for NWP models Operational Implementation of Nested System Regional Climate Analysis Modelling & Prediction Centre Community Climate Change Consortium for Ireland [RCAMPC and C4I]

16. EXPERIMENTS with LINUX CLUSTER … • Purchased small experimental Linux-Cluster • Dell PowerEdge 1750 Twin Xeon nodes – rack mounted • 1 x Master node [2.8GHz, 4Gbytes] • 9 x Compute nodes [3.2GHz, 2Gbytes] • Compute nodes in 3x3 2-dimensional torus [Dolphin cards] • RedHat ES-3/WS-3; PGI compilers; Intel compilers • Scali MPI connect, Scali TCP connect, Scali Manage • Original cluster had 6-nodes : upgraded to 9-nodes

17. EXPERIMENTS with LINUX CLUSTER … • Running Operational Hirlam on Cluster [9-node] • Hirlam 5.0.1 with 3DVAR – identical to operational system • Forecast takes 62 mins on IBM/SP; 71 mins on cluster • 3DVAR takes 15 mins on IBM/SP; 9 mins on cluster • Full run takes 77 mins on IBM/SP; 80mins on cluster • Therefore … 9-node cluster is as fast as IBM/SP • Experience with Cluster Generally Positive

18. FUTURE PLANS for CLUSTER …. • Investigate Use of Intel Compilers and Libraries • Should be faster for running Hirlam • Use Cluster as test-bed to implement latest Hirlam 6.4 • Use Cluster to prepare benchmark for new mainframe • Replace Mainframe end of 2006 / start of 2007

19. FUTURE PLANS … Investigate Options to Replace Mainframe in 2006 Get Hirlam 6.4 Running on Cluster Investigate MOS/Neural-Nets for Post-Processing Use Hirlam as input to Point Data-Base

20. Thank You