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Accurate inference of solar meridional flow is of crucial importance for the understanding of solar dynamo process. Wave travel times, as measured on the surface, will change if the waves encounter perturbations e.g. in the sound speed or…

Solar and Stellar Astrophysics · Physics 2018-08-15 K. Mandal , S. M. Hanasoge , S. P. Rajaguru , H. M. Antia

We propose a useful method for mapping large-scale velocity fields in the solar photosphere. It is based on the local correlation tracking algorithm when tracing supergranules in full-disc dopplergrams. The method was developed using…

Astrophysics · Physics 2007-05-23 M. Svanda , M. Klvana , M. Sobotka

Context. In local helioseismology, the travel times of acoustic waves propagating in opposite directions along the same meridian inform us about horizontal flows in the north-south direction. The longitudinal averages of the north-south…

Solar and Stellar Astrophysics · Physics 2022-08-31 Paul-Louis Poulier , Zhi-Chao Liang , Damien Fournier , Laurent Gizon

We present a 3-dimensional (3D) numerical solver of the linearized compressible Euler equations (GALE -- Global Acoustic Linearized Euler), used to model acoustic oscillations throughout the solar interior. The governing equations are…

Solar and Stellar Astrophysics · Physics 2021-03-01 Andrey M. Stejko , Alexander G. Kosovichev , Nagi N. Mansour

Hierarchical land cover and land use (LCLU) classification aims to assign pixel-wise labels with multiple levels of semantic granularity to remote sensing (RS) imagery. However, existing deep learning-based methods face two major…

Computer Vision and Pattern Recognition · Computer Science 2026-03-17 Tianlong Ai , Tianzhu Liu , Haochen Jiang , Yanfeng Gu

High-resolution remote sensing images (RSIs) are crucial for Earth observation applications, yet acquiring them is often limited by sensor constraints and costs. In recent years, generative super-resolution (SR) methods, particularly…

Computer Vision and Pattern Recognition · Computer Science 2026-05-22 Jiangwei Mo , Xi Lu , Hanlin Wu

We produce a 10-day series of simulated Doppler images at a 15-minute cadence that reproduces the spatial and temporal characteristics seen in the SOHO/MDI Doppler data. Our simulated data contains a spectrum of cellular flows with but two…

Solar and Stellar Astrophysics · Physics 2010-03-23 David H. Hathaway , Peter E. Williams , Manfred Cuntz

Inferences of sub-surface flow velocities using local domain ring-diagram helioseismology depend on measuring the frequency splittings of oscillation modes seen in acoustic power spectra. Current methods for making these measurements…

Solar and Stellar Astrophysics · Physics 2014-03-10 Benjamin J. Greer , Bradley W. Hindman , Juri Toomre

Large-scale plasma flows in the Sun's convection zone likely play a major role in solar dynamics on decadal timescales. In particular, quantifying meridional motions is a critical ingredient for understanding the solar cycle and the…

Solar and Stellar Astrophysics · Physics 2015-06-19 Shukur Kholikov , Alexander Serebryanskiy , Jason Jackiewicz

We compared the results from the JSOC pipeline for horizontal flow components and the perturbations of the speed of sound at set of depths with equivalent results from an independently implemented pipeline using a different time-distance…

Solar and Stellar Astrophysics · Physics 2019-09-04 David Korda , Michal Švanda , Junwei Zhao

The subsurface structure of an "average" supergranule is derived from existing HMI pipeline time-distance data products and compared to the best helioseismic flow model detailed in Duvall and Hanasoge (2013). We find that significant…

Solar and Stellar Astrophysics · Physics 2015-06-03 K. DeGrave , J. Jackiewicz

We have developed and implemented an iterative algorithm of flux calibration for the LAMOST Spectroscopic Survey of the Galactic anti-center (LSS-GAC). For a given LSS-GAC plate, the spectra are first processed with a set of nominal…

Solar granules are bright patterns surrounded by dark channels called intergranular lanes in the solar photosphere and are a manifestation of overshooting convection. Observational studies generally find stronger upflows in granules and…

Solar and Stellar Astrophysics · Physics 2017-11-01 T. Oba , T. L. Riethmüller , S. K. Solanki , Y. Iida , C. Quintero Noda , T. Shimizu

The dynamics in the photosphere is governed by the multi-scale turbulent convection termed as granulation and supergranulation. It is important to derive 3-dimensional velocity vectors to understand the nature of the turbulent convection.…

Solar and Stellar Astrophysics · Physics 2022-03-14 Ryohtaroh T. Ishikawa , Motoki Nakata , Yukio Katsukawa , Youhei Masada , Tino L. Riethmüller

The global scales of solar convection are studied through three-dimensional simulations of compressible convection carried out in spherical shells of rotating fluid which extend from the base of the convection zone to within 15 Mm of the…

Astrophysics · Physics 2009-11-13 Mark S. Miesch , Allan Sacha Brun , Marc L. Derosa , Juri Toomre

We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from…

Solar and Stellar Astrophysics · Physics 2015-06-23 H. Hotta , M. Rempel , T. Yokoyama

Supergranulation is a fluid-dynamical phenomenon taking place in the solar photosphere, primarily detected in the form of a vigorous cellular flow pattern with a typical horizontal scale of approximately 30--35~megameters, a dynamical…

Solar and Stellar Astrophysics · Physics 2018-07-05 Francois Rincon , Michel Rieutord

We investigate how rotationally-constrained, deep convection might give rise to supergranulation, the largest distinct spatial scale of convection observed in the solar photosphere. While supergranulation is only weakly influenced by…

Solar and Stellar Astrophysics · Physics 2016-10-19 Nicholas A. Featherstone , Bradley W. Hindman

Wave propagation through sunspots involves conversion between waves of acoustic and magnetic character. In addition, the thermal structure of sunspots is very different than that of the quiet Sun. As a consequence, the interpretation of…

Solar and Stellar Astrophysics · Physics 2016-10-05 T. Felipe , D. C. Braun , A. D. Crouch , A. C. Birch

The Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) filtergrams, taken at six wavelengths around the Fe I 6173.3 {\AA} line, contain information about the line-of-sight velocity over a range of heights in the solar…

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