Contributed by Andrey Stejko. Posted on October 28, 2022
Forward modeling is applied to numerous global hydrodynamic solar models, and helioseismic measurements on the meridional circulation are made using the forward modeling results. Comparison against the observational measurements shows significant differences, indicating our insufficient knowledge on either the global hydrodynamic modeling or the helioseismic inversions.
Contributed by Junwei Zhao. Posted on September 10, 2021
A new website is developed to host HMI’s time-distance pipeline products, including far-side images, subsurface flows, evolution of near-surface zonal and meridional flows.
Contributed by Andrey M. Stejko. Posted on May 24, 2021
Helioseismic wavefields are simulated using different meridional-circulation models. Time-distance helioseismic measurements applied on the simulated data indicate that it may be difficult to distinguish between single- or double-cell meridional circulation profiles.
Contributed by Junwei Zhao. Posted on March 28, 2021
A new method to derive the helioseismic sensitivity kernels for the Sun’s large-scale internal flows is developed. The new method is based on the idea of placing a small-volume flow perturbation inside the Sun’s model, simulating the wavefield in the photosphere, and then measuring the phase shifts caused by this internal perturbation.
Contributed by Doug Braun. Posted on March 16, 2021
Fourier Legendre decomposition is applied on HMI’s long-term Doppler-velocity observations to derive the Sun’s internal meridional circulation. In addition to the well-known center-to-limb effect, a non-axisymmetric component in the northern- and southern-hemisphere is identified as another systematic effect that complicates the derivation of the internal meridional circulation.
Contributed by Ruizhu Chen. Posted on November 29, 2017
A more comprehensive time-distance helioseismic method is developed to derive the Sun’s meridional circulation, and a 3-layer flow structure is found through the convection zone.
Contributed by Bidya Binay Karak. Posted on May 27, 2014
Motivated by recent observations we have explored whether the flux-transport dynamo model can work with multi-cell meridional flow. We find that it can work when certain conditions are fulfilled.
Contributed by Mausumi Dikpati. Posted on February 11, 2014
Solar meridional circulation, if mechanically driven and thermally
braked, contains two cells in latitude; generating two cells in depth,
recently observed by SDO/HMI, is a new challenge to theory.