Comparison of large-scale flows on the Sun measured by time-distance helioseismology and local correlation tracking technique

Abstract

We present a direct comparison between two different techniques time-distance helioseismology and a local correlation tracking method for measuring mass flows in the solar photosphere and in a near-surface layer: We applied both methods to the same dataset (MDI high-cadence Dopplergrams covering almost the entire Carrington rotation 1974) and compared the results. We found that after necessary corrections, the vector flow fields obtained by these techniques are very similar. The median difference between directions of corresponding vectors is 24 degrees, and the correlation coefficients of the results for mean zonal and meridional flows are 0.98 and 0.88 respectively. The largest discrepancies are found in areas of small velocities where the inaccuracies of the computed vectors play a significant role. The good agreement of these two methods increases confidence in the reliability of large-scale synoptic maps obtained by them.

14 pages, 6 figures, just before acceptance in Solar Physics

References in corpus (2)

• Local helioseismology and correlation tracking analysis of surface structures in realistic simulations of solar convection
• Large-scale horizontal flows in the solar photosphere I: Method and tests on synthetic data

Cited by in corpus (10)

• A Comprehensive Method to Measure Solar Meridional Circulation and Center-to-Limb Effect Using Time-Distance Helioseismology
• An exploration of heating mechanisms in a supra-arcade plasma sheet formed after a coronal mass ejection
• Measuring solar active region inflows with local correlation tracking of granulation
• Large-scale horizontal flows in the solar photosphere III: Effects on filament destabilization
• Large-scale horizontal flows in the solar photosphere II: Long-term behaviour and magnetic activity response
• Issues with time--distance inversions for supergranular flows
• Reconstruction of Solar Subsurfaces by Local Helioseismology
• Average solar active region: I. Intensities, velocities, and the photospheric magnetic field
• Observational characterisation of large-scale transport and horizontal turbulent diffusivity in the quiet Sun
• Evolution of solar surface inflows around emerging active regions