HIRLAM Use of the Hirlam NWP Model at

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

COMPUTER SYSTEM and VERSIONS of HIRLAM IBM RS/6000 SP : 9 -nodes each with 4 -CPU’s • Operational Hirlam : 438 x 284 grid pts; 31 -levels • Nested Hirlam : 222 x 210 grid pts; 40 -levels LINUX PC : Twin Xeon Processors [2. 0 Ghz] • Backup Hirlam : 218 x 144; 31 -levels LINUX PC : Twin Xeon Processors [500 Mhz] • Hourly Hirlam : 97 x 98 grid pts; 24 -levels

OPERATIONAL HIRLAM … IBM RS/6000 SP HIRLAM 5. 0. 1 with 3 DVAR • 3 -Hour assimilation cycle with 48 -hour forecasts every 6 -hours • Rotated lat/long 0. 15 x 0. 15 grid with 438 x 284 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

BACKUP HIRLAM … LINUX-PC [Dual 2. 0 Ghz CPU] HIRLAM 4. 3. 5 with OI-Analysis • 3 -Hour assimilation cycle with 48 -hour forecasts every 6 -hours • Rotated lat/long 0. 30 x 0. 30 grid with 218 x 144 grid points • Hybrid [eta] coordinates with 31 -levels SAME AREA AS OPERATIONAL HIRLAM

NESTED HIRLAM … IBM RS/6000 SP HIRLAM 6. 0. 0 with 3 DVAR • 3 -Hour assimilation cycle with 24 -hour forecasts every 6 -hours • Model runs at intermediate hours … 03 Z, 09 Z, 15 Z, 21 Z • Rotated lat/long 0. 12 x 0. 12 grid with 222 x 210 grid points • Hybrid [eta] coordinates with 40 -levels • Kain-Fritsch/Rasch-Kristjansson convection/condensation scheme • ISBA surface scheme • Output post-processed with MOS

HOURLY HIRLAM. . . LINUX-PC [Dual 500 Mhz CPU] HIRLAM 4. 3 with OI Analysis • Hourly assimilation cycle with hourly analysis and 3 -hour forecast • Rotated lat/long 0. 15 x 0. 15 grid with 97 x 98 grid points • Hybrid [eta] coordinates with 24 -levels • Analysis shown on public web-site

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]

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 C 4 I]

FUTURE PLANS … Purchase small experimental Linux-Cluster • Budget of approx Euro 50 k • Use as backup for main computer [Operational Hirlam] • Gain experience with Linux clusters Investigate MOS/Neural-Nets for Post-Processing Use Hirlam as input to Point Data-Base

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