Time--distance inversions for horizontal and vertical flows on supergranular scales applied to MDI and HMI data

Abstract

We study the possibility of consistent extension of MDI full-disc helioseismic campaigns with the growing data set of HMI observations. To do so, we down-sample and filter the HMI Dopplegrams so that the resulting spatial power spectrum is similar to the spatial power spectrum of MDI full-disc Dopplergrams. The set of co-spatial and co-temporal datacube pairs from both instruments containing no missing and no bad frames were processed using the same codes and inverted independently for all three components of the plasma flow in the near surface layers. The results from the two instruments are highly correlated, however systematically larger (by ~20%) flow magnitudes are derived from HMI. We comment that this may be an effect of the different formation depth of the Doppler signal

6 pages, 4 figures, accepted in Journal of Physics: Conference Series

References in corpus (1)

• Linear Sensitivity of Helioseismic Travel Times to Local Flows

Cited by in corpus (3)

• Inversions for Deep Solar Meridional Flow Using Spherical Born Kernels
• Tomography of plasma flows in the upper solar convection zone using time--distance inversion combining ridge and phase-speed filtering
• Comparison of acoustic travel-time measurement of solar meridional circulation from SDO/HMI and SOHO/MDI