Atmospheric circulation model SAMIL3 of the Institute of Atmosphere completed ten thousand nuclear test test
Recently, the high-resolution atmospheric circulation model SAMIL3 developed by the State Key Laboratory of Numerical Simulation of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) of the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences has been launched at the National Supercomputing (Tianjin) Center "Tianhe-1" On the supercomputer, we successfully carried out the performance test of 10,000-core computing scale with a resolution of 12.5 kilometers and 6 kilometers in the world. The results show that SAMIL3 has superior parallel computing performance and parallel I / O performance. This is the first 10,000-nuclear test successfully conducted in China using the three-dimensional atmospheric circulation model AGCM.
SAMIL3 is the latest high-resolution atmospheric circulation model developed by the IAP / LASG Earth System Model R & D team. SAMIL3 dynamic framework can choose spectral method (Wu et al., 1996) and finite volume method (Lin, 1996). Both methods use the same set of physical process parameterization schemes. The SAMIL3 mode can flexibly use 200km, 100km, 50km, 25km, 12.5km, 6.25km horizontal resolution, and 26 layers in the vertical direction. Through a large number of standard power frame ideal tests and standard water ball tests, SAMIL3 has good stability and simulation effects at different resolutions. In order to further test the computing performance and I / O performance of the model, the SAMIL3 R & D team transplanted the SAMIL3 water ball test version to the "Tianhe-1" supercomputer for large-scale high-resolution performance testing.
The water polo test refers to an ideal experiment conducted by applying the complete atmospheric circulation model to the earth completely covered by the ocean. There is no land or sea ice in the design of the water polo experiment. The global sea temperature is given, an ideal distribution that decreases from the equator to the poles. The solar constant is 1365W / m2, and there is no seasonal variation in solar radiation. Ozone has no latitudinal changes and is symmetrical about north and south of the equator. CO2, CH4, N2O and other gases take constants, and there is no aerosol that affects the radiation effect.
The results of the pattern calculation performance test (Figure 1) show that at the parallel computing scale below a thousand cores, SAMIL3 has very superior calculation performance, and the relative parallel algorithm efficiency is between 1.0-1.12. When the scale of parallel computing increases to more than a thousand cores, the superior computing performance of SAMIL3 can still be maintained, and the relative parallel algorithm efficiency is greater than 1.0. Above 3456 cores (12.5 kilometers) and 6144 cores (6.25 kilometers), the computing performance of SAMIL3 began to decline. At 6144 cores (12.5 kilometers) and 13824 cores (6.25 kilometers), the relative parallel algorithm efficiency of SAMIL3 is only 0.66 and 0.52, respectively. This shows that SAMIL3 is below 3456 cores (12.5 kilometers) and 6144 cores (6.25 kilometers), the model can maintain superior parallel computing performance, and the mode can run up to 1.5 years (12.5 kilometers resolution) and 3.5 months (6.25 kilometers) Resolution) One day per wall clock.
In the mode I / O performance test, each mode integration time step outputs u, v, q, t, ps five variable fields at a global resolution of 12.5 km, where u, v, q, t are three-dimensional variables, ps Is a two-dimensional variable. The test result is shown in Figure 2. When there is no I / O node, the I / O module does not occupy any calculation time, so the mode I / O efficiency reaches 100%. When there are only 6 I / O nodes, the mode I / O efficiency can reach more than 80%. As the number of I / O nodes increases, the efficiency of mode I / O gradually increases. When each core has participating I / O (1536 cores), the mode I / O efficiency is close to 100%, that is, the I / O process does not affect the mode calculation speed. The large-scale parallel I / O test results on "Tianhe" show that the SAMIL3 parallel I / O module has superior performance.
The development of high-resolution climate models is at the forefront of international competition in climate simulation research. The high-resolution SAMIL3 model was successfully tested on the "Tianhe" supercomputer, indicating that the climate model developed by the Chinese Academy of Sciences has the ability to participate in international competition in the research and development of high-resolution models. The success of the SAMIL 30 thousand nuclear test test, together with the previous IAP / LASG ocean circulation model LICOM successfully carried out a 10-km resolution thousand-core test test on the "Tianhe" computer, laid a solid foundation for the development of ultra-high resolution Chinese Academy of Sciences climate system model .
Figure 1 The speed of the model obtained by SAMIL3 on the "Tianhe-1" supercomputer, unit: model year (month) / wall clock day (a) 12.5 km resolution, blue dot marks corresponding to 216, 4, 864, 1536, 3456, 6144 cores from left to right; (b) 6.25 km resolution, blue dot marks respectively from left to right Correspond to 1536, 3456, 6144, 13824 core. The solid blue line is the actual mode time, and the red dotted line is the ideal mode time. The dot mark value indicates the relative parallel algorithm efficiency (speedup ratio = serial execution time / parallel execution time, parallel algorithm efficiency = speedup ratio / core number, nth point relative parallel algorithm efficiency = nth point parallel algorithm efficiency / first Parallel algorithm efficiency).
Figure 2 The SAMIL3 12.5 km resolution mode I / O efficiency obtained by using the 1536 core test on the "Tianhe-1" supercomputer Mode time), unit:%.
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