| Description |
Observations of the solar surface reveal the presence of flows with length scales of around 35 Mm, commonly referred to as supergranules. Inferring the sub-surface flow profile of supergranules from measurements of the surface and photospheric wavefield is
an important challenge faced by helioseismology. Traditionally, the inverse problem has been approached by studying the linear response of seismic waves in a horizontally translationally invariant background to the presence of the supergranule. Following an iterative approach that does not depend on horizontal translational invariance might perform better, since the misfit can be analyzed post iterations. In this work, we construct
synthetic observations using a reference supergranule, and invert for the flow profile using surface measurements of travel-times of acoustic and surface-gravity waves. We study the extent to which individual modes and their combinations contribute to infer the
flow. We show that this method of non-linear iterative inversion tends to underestimate the flow velocities as well as inferring a shallower flow profile, with significant deviations from the reference supergranule near the surface of the Sun. We show that similar deviations persist for sound-speed perturbations. We conclude that the present approach
is insufficient to infer supergranular flows accurately, and more reliable inversion strategies need to be sought.
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