A new code for Fourier-Legendre analysis of large datasets: first results and a comparison with ring-diagram analysis

TL;DR

This paper introduces a new Fourier-Legendre decomposition code for analyzing large helioseismic datasets to estimate deep solar meridional flow, showing promising initial results compared to ring-diagram analysis.

Contribution

The paper presents a novel, scalable Fourier-Legendre analysis code for helioseismic data, enabling improved probing of deep solar flows.

Findings

Qualitative agreement with ring-diagram analysis results

Effective for large-scale helioseismic datasets

Potential to probe deep solar meridional flow

Abstract

Fourier-Legendre decomposition (FLD) of solar Doppler imaging data is a promising method to estimate the sub-surface solar meridional flow. FLD is sensible to low-degree oscillation modes and thus has the potential to probe the deep meridional flow. We present a newly developed code to be used for large scale FLD analysis of helioseismic data as provided by the Global Oscillation Network Group (GONG), the Michelson Doppler Imager (MDI) instrument, and the upcoming Helioseismic and Magnetic Imager (HMI) instrument. First results obtained with the new code are qualitatively comparable to those obtained from ring-diagram analyis of the same time series.