1. 1 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

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3. 3 Institute for Meteorology and Climate Research (IMK) Fundamental research on climate, water cycle and trace substances Turbulence, Convection, Cloud formation, Aerosol physics, Precipitation formation, Exchange processes on Earth’s surface Aerosols, Trace Gases and Climate Processes (head of group: B. Vogel) Representation of aerosols and gas phase chemistry on the regional scale (model system COSMO-ART) Particular interest on the interaction of aerosols and clouds in the atmospheric system

4. 4 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale Ext. Parameters = operational weather forecast model (DWD) COSMO–ART (ART = Aerosols and Reactive Trace Gases) Vogel et al., 2009, ACP

5. 5 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale Feedback processes realized in COSMO-ART Aerosol cloud interaction

6. 6 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale Future Applications: Decadal forecasts of the regional climate of Europe Interaction of natural and anthropogenic aerosols with climate Model runs with CCLM-ART (= climate version of COSMO-ART) Computational demand: Based on AIX (16 processors) without speed-up of COSMO-ART: 10 year model run = 112 CPU years 10-20 scenario runs Transported 3-D variables ~60 (gases) + ~ 80 (aerosols) 250x250x40 gridpoints (future applications due to increased resolution ~factor 4)

7. 7 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale Profiling test case Run of 24 h initialized at 22nd June 2007 at 00:00 UTC 193x113x40 grid points, dt=40s, resolution of 0.25° Machine: IBM AIX cluster at KIT 2 nodes with 8 cores each Profiling done with Scalasca

8. 8 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale Total run time: 268.4 CPU hours (2 nodes x 8 cores) cradm2 (31,48%) ISOROPIA (14,72%) ART org (22,72%)

9. 9 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale Further Metrics MetricValueART Computational Imbalance 17,33 CPU hours (6,46 % of total) 85% of imbalance due to ART Synchronizations56,63 CPU hours (21,10 % of total) 47 % ART (anth. Emissions) 52 % organize_data (data output) Communciations9,75e789 % in dynamics and leapfrog Bytes transferred5,75e12 B94 % in dynamics and leapfrog Important imbalance of the code Large need of communications due to more than 150 additional 3D prognotstic fields

10. 10 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale Way forward Model chemistry and physics: Use KPP chemical solver (GPU “version”) Use a simplified version of ISOROPIA Call chemistry and aerosols not at every time-step Try to reduce waiting time for anthropogenic emissions ( call only every 6 hours) Numerics: Code is partly vectorized -> Compiler options for non-vectorized code Lump messages together, to reduce number of communications (but increase their size) Optimize utility routines (unit conversion, string comparision)

11. 11 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

12. 12 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

13. 13 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

14. 14 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

15. 15 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

16. 16 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

17. 17 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale generate animated gif out of visualized states Parallel Visualization HPC-system Desktop-PC Data-Server Visualization -Cluster convert *.grb into *.vts parallel visualization of output data analyze forecast

18. 18 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale Visualization Temperature+Rain

19. 19 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

20. 20 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale

21. 21 The Interactions of Aerosols, Clouds, and Radiation on the Regional Scale