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. MAIN EVENTS SINCE LAST MEETING • REPLACEMENT OF COMPUTER SYSTEM • Collaboration agreement with ICHEC • ICHEC : Irish Centre for High-End Computing • CHANGE FROM HIRLAM-5 to HIRLAM-7 • Better model and higher-resolution

3. IRISH CENTRE FOR HIGH-END COMPUTING • ICHEC • www.ichec.ie • 'Bringing Capability Computing to the Irish Research Community' • SFI : Science Foundation Ireland • HEA : Higher Education Authority • HARDWARE • Shared memory system [Bull Novascale NS6320] • Distributed memory system [IBM eServer 1350]

4. IRISH CENTRE FOR HIGH-END COMPUTING • HARDWARE • Distributed memory system [IBM eServer cluster 1350 consisting of 476 IBM e326 compute nodes with 20TB of tightly integrated high-performance SAN based around an IBM DS4500] • SuSe Linux 64-bit operating system • Met Éireann uses 32 dual nodes for main run [out of an allocation of 48] • Special execution queue

5. COMPUTER SYSTEM and VERSIONS of HIRLAM • ICHEC • Operational Hirlam : 438x284 grid pts; 60-levels; 15Km • Nested Hirlam : 438x395 grid pts; 60-level; 5Km • LINUX PC • Hourly Hirlam : 166x163; 40-levels; 15Km; 20-min cutoff • LINUX Cluster : Nine Twin Xenon Processors [3.2GHz] • Backup Hirlam : 438x284 grid pts; 31-levels; 15Km • ALL MODELS are HIRLAM version 7

6. OPERATIONAL HIRLAM … ICHEC • HIRLAM 7 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 60-levels [backup has 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

9. NESTED HIRLAM … ICHEC • HIRLAM 7 with 3DVAR • Runs every 6-hours with 30-hour forecasts [6-hour cycle] • Rotated lat/long 0.05x0.05 grid with 438x395 grid points • Hybrid [eta] coordinates with 60-levels [no backup] • CBR vertical diffusion scheme; Sundqvist condensation scheme • STRACO cloud scheme; Savijarvi radiation scheme • Digital filter initialisation • Two time-level Semi-Lagrangian semi-implicit scheme • Hourly boundaries from Hirlam operational model

11. HOURLY HIRLAM … LINUX PC • HIRLAM 7 with 3DVAR • Runs every hour with 20-minute cutoff • Rotated lat/long 0.15x0.15 grid with 166x163 grid points • Hybrid [eta] coordinates with 40-levels [no backup] • Runs on one hour cycle : 3-hour forecast • Provides hourly analysis and short-range forecast • Used on Met Éireann public internet site [www.met.ie]

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

14. RESEARCH ACTIVITIES Better Specification of B.C.’s for NWP models Operational Implementation of Nested System

15. LINUX CLUSTER … mogall • Small experimental Linux-Cluster used as Backup • 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

16. LINUX CLUSTER … mogall • Used as Backup for Operational Hirlam • Hirlam 7 with 3DVAR – identical to operational system • Both ICHEC and mogall on same 15Km grid • ICHEC has 60 levels; mogall has 31 levels

17. FUTURE PLANS …. Expand area [to North of Greenland] Look at use of higher resolution ECMWF boundary files Investigate 4DVAR Assimilation of satellite data [ATOVS]

18. Thank You