Comparing the Hinode and SOHO/MDI Data to the Simulated Large Scale Solar Convection

Large-scale simulations of solar turbulent convection produce realistic data and provide a unique opportunity to study solar oscillations and test various techniques commonly used for the analysis of solar observations. We applied helioseismic methods to the sets of simulated as well as observed data and find remarkable similarities. Power spectra, k − ν diagrams, timedistance diagrams exhibit similar details, although sometimes subtle differences are present. 1. Numerical Simulations and Observational Data The upper part of solar convection zone is simulated using a 3D, compressible, radiative-hydrodynamic code (Stein and Nordlund 2000). It performs LTE, nongray radiation transfer calculations and employs realistic equation of state and opacities. The computational domain spans 96 Mm by 96 Mm horizontally and 20 Mm vertically, with 96 km horizontal grid resolution and 12 to 75 km vertical resolution. We used a 512-min sequence of the three velocity components from the simulation, measured at 200 km above the photospheric base. This height corresponds to the average height of formation for the Ni I line used for MDI observations. To compare with Hinode observations, we also used the vertical velocity component sampled at 75 km and 250 km above the photospheric base. According to the model of Carlsson et al. (2007), these heights correspond to the average heights of formation for the G-band and Ca H signals. The velocities are sampled every minute. The high-resolution MDI Doppler velocity observations (Scherrer et al. 1995) are 512 min long (1 minute cadence) and cover an area of 211.5 Mm by 211.5 Mm (512 by 512 pixels, 413 km pixel size). The Hinode data (Tsuneta et al. 2008) are 512-min long series (1 minute cadence) of 79 Mm by 79 Mm patches of intensity in both Ca H and G-band, on a spatial grid 1024 by 1024 pixels (either half of the original images; resolution 77 km). Michigan State University, East Lansing, MI 48824-2320, USA HEPL, Stanford University, Stanford, CA 94305, USA Kettering University, Flint, MI 48504, USA Niels Bohr Institute, Copenhagen, DK-2100, Denmark