Towards Estimating the Solar Meridional Flow and Predicting the 11-yr Cycle Using Advanced Variational Data Assimilation Techniques

Ching Pui Hung; Allan Sacha Brun; Alexandre Fournier; Laurène Jouve; Olivier Talagrand; Mustapha Zakari

doi:10.1017/S1743921317010754

Conference papers

Towards Estimating the Solar Meridional Flow and Predicting the 11-yr Cycle Using Advanced Variational Data Assimilation Techniques

Ching Pui Hung ^{1, 2} Allan Sacha Brun ² Alexandre Fournier ¹ Laurène Jouve ^{3, 2} Olivier Talagrand ⁴ Mustapha Zakari ¹

1 IPGP - Institut de Physique du Globe de Paris

2 AIM (UMR_7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation

3 IRAP - Institut de recherche en astrophysique et planétologie

4 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)

Abstract : We present in this work the development of a solar data assimilation method based on an axisymmetric mean field dynamo model and magnetic surface data. Our mid-term goal is to predict the solar quasi cyclic activity. We focus on the ability of our variational data assimilation algorithm to constrain the deep meridional circulation of the Sun based on solar magnetic observations. Within a given assimilation window, the assimilation procedure minimizes the differences between data and the forecast from the model, by finding an optimal meridional circulation in the convection zone, and an optimal initial magnetic field, via a quasi-Newton algorithm. We demonstrate the capability of the technique to estimate the meridional flow by a closed-loop experiment involving 40 years of synthetic, solar-like data. We show that the method is robust in estimating a (stochastic) time-varying flow fluctuating 30% about the average, and that the horizon of predictability of the method is ~ 1 cycle length.

Keywords : Dynamo meridional circulation data assimilation numerical

Document type :

Conference papers

Domain :

Sciences of the Universe [physics]

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https://hal-insu.archives-ouvertes.fr/insu-03589340
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Submitted on : Friday, February 25, 2022 - 3:27:55 PM
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Towards Estimating the Solar Meridional Flow and Predicting the 11-yr Cycle Using Advanced Variational Data Assimilation Techniques

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Towards Estimating the Solar Meridional Flow and Predicting the 11-yr Cycle Using Advanced Variational Data Assimilation Techniques

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