Marc L. DeRosa’s research while affiliated with Laboratory of Astrophysics of Bordeaux and other places

What is this page?


This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.

Publications (109)


Ensemble Kalman Filter Data Assimilation into the Surface Flux Transport Model to Infer Surface Flows: An Observing System Simulation Experiment
  • Article
  • Full-text available

November 2024

·

10 Reads

·

2 Citations

The Astrophysical Journal

·

Marc L. DeRosa

·

Mausumi Dikpati

·

[...]

·

Knowledge of the global magnetic field distribution and its evolution on the Sun’s surface is crucial for modeling the coronal magnetic field, understanding the solar wind dynamics, computing the heliospheric open flux distribution, and predicting the solar cycle strength. As the far side of the Sun cannot be observed directly and high-latitude observations always suffer from projection effects, we often rely on surface flux transport (SFT) simulations to model the long-term global magnetic field distribution. Meridional circulation, the large-scale north–south component of the surface flow profile, is one of the key components of the SFT simulation that requires further constraints near high latitudes. Prediction of the photospheric magnetic field distribution requires knowledge of the flow profile in the future, which demands reconstruction of that same flow at the current time so that it can be estimated at a later time. By performing Observing System Simulation Experiments, we demonstrate how the ensemble Kalman filter technique, when used with an SFT model, can be utilized to make “posterior” estimates of flow profiles into the future that can be used to drive the model forward to forecast the photospheric magnetic field distribution.

Download

Ensemble Kalman Filter Data Assimilation Into Surface Flux Transport Model To Infer Surface Flows: An Observing System Simulation Experiment

September 2024

·

13 Reads

Knowledge of the global magnetic field distribution and its evolution on the Sun's surface is crucial for modeling the coronal magnetic field, understanding solar wind dynamics, computing the heliospheric open flux distribution and predicting solar cycle strength. As the far side of the Sun cannot be observed directly and high-latitude observations always suffer from projection effects, we often rely on surface flux transport simulations (SFT) to model long-term global magnetic field distribution. Meridional circulation, the large-scale north-south component of the surface flow profile, is one of the key components of the SFT simulation that requires further constraints near high latitudes. Prediction of the photospheric magnetic field distribution requires knowledge of the flow profile in the future, which demands reconstruction of that same flow at the current time so that it can be estimated at a later time. By performing Observing System Simulation Experiments, we demonstrate how the Ensemble Kalman Filter technique, when used with a SFT model, can be utilized to make ``posterior'' estimates of flow profiles into the future that can be used to drive the model forward to forecast photospheric magnetic field distribution.


Solar rotation for small short-lived (SSGs, filled black and gray squares, upside open triangles) and large long-lived sunspot groups (LLGs, filled circles, and open triangles). Adapted from Nagovitsyn, Pevtsov, and Osipova (2018). Dashed curves correspond to Equations 2 and 3.
Torsional oscillation for the period 1983 to 2012, derived using Direct Doppler measurements from MWO.
Mean differential rotation measured 22 Apr 2010 to 20 Jan 2011 (CR 2096 – 2105) obtained from measurements within 1 Mm of the surface using different techniques described in the text. (GT data is only available 16 Aug – 14 Sep 2010). Even though magnetic pattern tracking methods (MPT1 and MPT2) use surface magnetograms, their rotation profiles do not match other near-photosphere results.
Angular rotation rates during the overlap period showing the depth at which differential rotation inferred from magnetic pattern tracking matches helioseismic inversions. For global helioseismology (HMI data), a match is found around 28 Mm whereas for ring diagram local helioseismology (GONG data) a match is found near 25 Mm.
Torsional oscillation measurements (in ms⁻¹) in order from top to bottom: GHS1, GHS2, GHS3, RD2, TD, DD, MPT1, and MPT2 (refer to Table 2 for the acronyms). The solid black lines mark the sunspot belt derived from the RGO/NOAA database.

+1

The Sun’s Large-Scale Flows I: Measurements of Differential Rotation & Torsional Oscillation

March 2024

·

81 Reads

·

3 Citations

Solar Physics

We have developed a comprehensive catalog of the variable differential rotation measured near the solar photosphere. This catalog includes measurements of these flows obtained using several techniques: direct Doppler, granule tracking, magnetic pattern tracking, global helioseismology, as well as both time-distance and ring-diagram methods of local helioseismology. We highlight historical differential rotation measurements to provide context, and thereafter provide a detailed comparison of the MDI-HMI-GONG-Mt. Wilson overlap period (April 2010 – Jan 2011) and investigate the differences between velocities obtained from different techniques and attempt to explain discrepancies. A comparison of the rotation rate obtained by magnetic pattern tracking with the rotation rates obtained using local and global helioseismic techniques shows that magnetic pattern tracking measurements correspond to helioseismic flows located at a depth of 25 to 28 Mm. In addition, we show the torsional oscillation from Sunspot Cycles 23 and 24 and discuss properties that are consistent across measurement techniques. We find that acceleration derived from torsional oscillation is a better indicator of long-term trends in torsional oscillation compared to the residual velocity magnitude. Finally, this analysis will pave the way toward understanding systematic effects associated with various flow measurement techniques and enable more accurate determination of the global patterns of flows and their regular and irregular variations.


Figure 1. (a) Left: forward-modeled emission image for the AIA 211 Å channel at time step 488. Right: the corresponding full-Sun map of AIA 211 Å emission, integrated along the radial direction. The region highlighted in blue is the subregion considered in the second half of this Letter. (b) Plots of B r and AIA 211 Å differenced emission; the latter color table highlights where the TDC simulation emission is higher (purple) and where the SS simulations' emission is higher (orange).
Figure 2. (a) Percent of global total open flux for SS and TDC during the selected time period. Except for time step 440, immediately before the emergence of the active region, the SS has uniformly less open flux than the TDC simulation. (b) The global magnetic energy for both the TDC and SS simulations.
Figure 5. Left: difference maps showing agreement and disagreement between the steady-state (SS) and time-dependent runs. Black corresponds to locations where the SS is open (negative-polarity CH) but the TDC is closed, medium gray is where both are open (negative polarity), light gray is where the TDC is open (negative polarity) but the SS is closed, white is where both are closed, pink is where TDC is open (positive polarity) but the SS is closed, red is where both are open (positive polarity), and maroon is where the TDC is closed but the SS is open (positive polarity). The blue rectangle on each map shows the region integrated over for Figure 3. Right: 3D visualizations of the same maps at the same times, with the SS field lines in red/orange and the TDC field lines in shades of blue. The seed locations of the field lines are the same for both models, and black lines are open for both SS and TDC.
Time-dependent Dynamics of the Corona

December 2023

·

48 Reads

·

6 Citations

The Astrophysical Journal Letters

We present in this Letter the first global comparison between traditional line-tied steady-state magnetohydrodynamic models and a new, fully time-dependent thermodynamic magnetohydrodynamic simulation of the global corona. To approximate surface magnetic field distributions and magnitudes around solar minimum, we use the Lockheed Evolving Surface-Flux Assimilation Model to obtain input maps that incorporate flux emergence and surface flows over a full solar rotation, including differential rotation and meridional flows. Each time step evolves the previous state of the plasma with a new magnetic field input boundary condition, mimicking photospheric driving on the Sun. We find that this method produces a qualitatively different corona compared to steady-state models. The magnetic energy levels are higher in the time-dependent model, and coronal holes evolve more along the following edge than they do in steady-state models. Coronal changes, as illustrated with forward-modeled emission maps, evolve on longer timescales with time-dependent driving. We discuss implications for active and quiet Sun scenarios, solar wind formation, and widely used steady-state assumptions like potential field source surface calculations.


Figure 3. Evolution of the photospheric magnetic field and the open flux boundaries over 1 month in the time-evolving MHD model. The left panels show B r , derived from the ESFAM flux transport model, as a latitude−longitude map. These are the boundary maps for the calculation. The right panels show open/closed boundaries (coronal holes) in the same format, with dark red indicating outward (positive) polarity, dark blue showing inward (negative) polarity, and white indicating closed-field regions. Five time instances are shown, from top to bottom: t = 0, t ; 180 hr, t ; 360 hr, t ; 540 hr, and t ; 720 hr. The box in every panel (black on the left, gold on the right for visibility) highlights a persistent open-field region, while the magenta circle near the center of each panel indicates a bipole that undergoes decay. Other rectangles and circles denote more transient open-field and flux emergence regions, respectively. A 7 s animation of this figure is available online (www.predsci.com/ corona/tdc/animations/RL_2023_Fig3.mp4) showing both maps for the duration of the simulation time. (An animation of this figure is available.)
Figure 4. The emission in the AIA 171 Å channel over 1 month in the time-evolving MHD model. The left panels show the Sun from the point of view of an observer on Earth, as the star completes a full rotation around its axis. The right panels show a projection of the emission as a latitude−longitude map; the annotations are analogous to those from the previous figure. Five time instances are shown, corresponding to those of Figure 3: (a) t = 0; (b) t ; 180 hr; (c) t ; 360 hr; (d) t ; 540 hr; (e) t ; 720 hr. A 7 s animation of this figure is available online (www.predsci.com/corona/tdc/animations/RL_2023_Fig4.mp4), showing both visualization styles for the duration of the simulation time. (An animation of this figure is available.)
Global MHD Simulations of the Time-dependent Corona

December 2023

·

68 Reads

·

7 Citations

The Astrophysical Journal

We describe, test, and apply a technique to incorporate full-Sun, surface flux evolution into an MHD model of the global solar corona. Requiring only maps of the evolving surface flux, our method is similar to that of Lionello et al., but we introduce two ways to correct the electric field at the lower boundary to mitigate spurious currents. We verify the accuracy of our procedures by comparing to a reference simulation, driven with known flows and electric fields. We then present a thermodynamic MHD calculation lasting one solar rotation driven by maps from the magnetic flux evolution model of Schrijver & DeRosa. The dynamic, time-dependent nature of the model corona is illustrated by examining the evolution of the open flux boundaries and forward-modeled EUV emission, which evolve in response to surface flows and the emergence and cancellation flux. Although our main goal is to present the method, we briefly investigate the relevance of this evolution to properties of the slow solar wind, examining the mapping of dipped field lines to the topological signatures of the “S-Web” and comparing charge state ratios computed in the time-dependently driven run to a steady-state equivalent. Interestingly, we find that driving on its own does not significantly improve the charge state ratios, at least in this modest resolution run that injects minimal helicity. Still, many aspects of the time-dependently driven model cannot be captured with traditional steady-state methods, and such a technique may be particularly relevant for the next generation of solar wind and coronal mass ejection models.



Figure 2. Torsional Oscillation for the period 1983 to 2012 derived using Direct Doppler measurements from MWO.
Rotational A coefficient averages over single Carrington rotations during the year 2010. Shown are the year value at the center of the average, the corresponding Carrington rotation number, the average of A, the number of observations, the rms of the A values and the error of the mean for A. These are obtained with the direct Doppler technique from MWO observations.
The Sun’s Large-Scale Flows I: Measurements of Differential Rotation & Torsional Oscillation Solar Physics

October 2023

·

97 Reads

·

1 Citation

We have developed a comprehensive catalog of the variable differential rotation measured near the solar photosphere. This catalog includes measurements of these flows obtained using several techniques: direct Doppler, granule tracking, magnetic pattern tracking, global helioseismology as well as both time-distance and ring-diagram methods of local helioseismology. We highlight historical differential rotation measurements to provide context and thereafter provide a detailed comparison of the MDI-HMI-GONG-Mt. Wilson overlap period (April 2010-Jan 2011) and investigate the differences between velocities obtained from different techniques and attempt to explain discrepancies. A comparison of the rotation rate obtained by magnetic pattern tracking with the rotation rates obtained using local and global helioseismic techniques shows that magnetic pattern tracking measurements correspond to helioseismic flows located at a depth of 25 to 28 Mm. In addition, we show the torsional oscillation from sunspot cycles 23 and 24 and discuss properties that are consistent across measurement techniques. We find that acceleration derived from torsional oscillation is a better indicator of long-term trends in torsional oscillation compared to the residual velocity magnitude. Finally, this analysis will pave the way toward nderstanding systematic effects associated with various flow measurement techniques and enable more accurate determination of the global patterns of flows and their regular and irregular variations.


Figure 3. Results of a flight dynamics analysis for a separation angle of 15⁰ per year between the upper and lower constellations. (a) early after launch, (b) 10 months into the mission, and (c) when the initial configuration of all the spacecraft is established. MOST1-4 arrive in their respective locations at 3.88, 4.67, 4.84, and 5.72 years, respectively.
MOST Science Traceability Matrix.
Science instruments and their purpose
High-level specifications of the science instruments
Estimated Mission Cost
The Multiview Observatory for Solar Terrestrial Science (MOST)

July 2023

·

91 Reads

·

5 Citations

Understanding the emergence of magnetic flux from the solar interior through thephotosphere and its global impact on the inner heliosphere is a key scientific goal of theheliophysics community. This white paper outlines the concept of the Multiview Observatory forSolar Terrestrial Science (MOST) mission, which will make measurements of solar variabilityfrom the solar interior, atmosphere, and the interplanetary (IP) medium. MOST will be a 4-spacecraft mission with one each at L4 (MOST1) and L5 (MOST2) and the other two (MOST3and MOST4) at variable locations along Earth orbit. MOST1 and MOST2 will each carry sevenremote-sensing and 3 in-situ instruments. All four spacecraft will carry elements of a novel radiopackage known as the Faraday Effect Tracker of Coronal and Heliospheric structures (FETCH).FETCH will systematically probe the magnetic content of transient IP structures includingcoronal mass ejections (CMEs) and stream interaction regions (SIRs). The Faraday rotationmeasurements will provide magnetic information of these structures at various heliocentricdistances from the outer corona to Earth’s vicinity. Photospheric and chromosphericmagnetograms will cover >70% of the solar surface providing synchronic maps needed foraccurately modeling the corona and solar wind. EUV, coronagraph, radio spectrograph, andheliospheric imager (HI) observations from multiple viewpoints provide 3-d information onCMEs/CME-driven shocks, SIRs, and other solar wind structures. The Hard X-ray imagers willprovide the flare aspects of solar eruptions to complement the CME aspects. MOST, a 10-yearmission, is well aligned with NASA’s Heliophysics objectives and will provide anunprecedented opportunity to achieve these objectives with broad participation from theheliophysics community. (2) (PDF) The Multiview Observatory for Solar Terrestrial Science (MOST). Available from: https://www.researchgate.net/publication/373623519_The_Multiview_Observatory_for_Solar_Terrestrial_Science_MOST [accessed Sep 12 2023].




Citations (63)


... Data assimilation refers to ingesting available observational data into the model over time and is a key component for SFT models being used to generate synchronic full-Sun magnetic maps. Sophisticated methods of accounting for data uncertainty in the assimilation (such as Kalman filtering) have been utilized in SFT models (Hickmann et al. 2015;Dash et al. 2024). The data assimilation in the present version of HipFT uses a custom weighting between the observed and model data. ...

Reference:

Open-source Flux Transport (OFT). I. HipFT -- High-performance Flux Transport
Ensemble Kalman Filter Data Assimilation into the Surface Flux Transport Model to Infer Surface Flows: An Observing System Simulation Experiment

The Astrophysical Journal

... The subsurface zonal and meridional flow in the NSSL are known to vary with the solar cycle (Choudhuri 2021;Hanasoge 2022;Upton et al. 2023;Mahajan et al. 2024, for recent reviews). For the zonal flow, bands of faster-than-average flows move from mid-latitude toward the equator during a solar cycle alternating with bands of slower-than-average zonal flows (Komm, Howe, and Hill 2018;Getling, Kosovichev, and Zhao 2021;Mahajan et al. 2024, for example). ...

The Sun’s Large-Scale Flows I: Measurements of Differential Rotation & Torsional Oscillation

Solar Physics

... There will be additional data in the following years that might be considered somewhat similar to Vigil. They will be provided by missions JUICE (Grasset et al., 2013), SWFO-L1 (Pacini et al., 2023), Punch (Kolinski et al., 2022), IMAP (McComas et al., 2018) and MOST (Gopalswamy et al., 2024). Although most of the missions mentioned above are scientific missions without requirements to provide data for operational purposes, they operate in continuous data acquisition regimes. ...

The multiview observatory for solar terrestrial science (MOST)

Journal of Atmospheric and Solar-Terrestrial Physics

... One of the key features of the MAS model is its Wave-Turbulence-Driven (WTD) heating capabilities, which have been instrumental in improving the realism of coronal simulations (Mikić et al. 2018;Lionello et al. 2023;Mason et al. 2023). As described by Mikić et al. (2018) heating the corona and accelerating the solar wind. ...

Time-dependent Dynamics of the Corona

The Astrophysical Journal Letters

... However, it is too computationally expensive to perform time-evolving MHD coronal simulations (Yeates et al. 2018). One of the main reasons is that most state-of-the-art time-evolving coronal models (Hayashi et al. 2021;Hoeksema et al. 2020;Linker et al. 2024;Lionello et al. 2023;Mason et al. 2023;Yang et al. 2012) still rely on explicit or semi-implicit approaches, where only certain source terms are treated implicitly while the time step remains constrained by the explicitly treated terms, leading to extremely low efficiency. As a result, real-time explicit or semi-implicit MHD coronal simulations typically require thousands of compute cores. ...

Global MHD Simulations of the Time-dependent Corona

The Astrophysical Journal

... The elliptic torus shape of HCs (Figure 8) inspired by theoretical MFR models (Chen 1989;Titov & Démoulin 1999) is highly beneficial to the calculations of volume, mass, thermal energy, and kinetic energy in statistical analysis. Multi-point observations of HCs in EUV and SXR passbands, especially from the Sun-Earth Lagrange point L5, are expected in next-generation solar telescopes (Liu et al. 2010b;Gopalswamy et al. 2023) to facilitate 3D reconstructions of HCs. ...

The Multiview Observatory for Solar Terrestrial Science (MOST)

... In this work, we use a new electric field derived from the observed normal magnetic field B r and vertical electric current J r evolution from the SDO/HMI vector magnetograms for the lower boundary driving of an MHD simulation of the eruptive flare and CME developed from AR 11158 on Feb. 15, 2011. The preliminary results of the simulation were reported in a NASA Living With a Star focused science team joint paper (section 4 of Linton et al. 2023). Here we present a more detailed description of the simulation and the results, and expand on the analysis of the erupting magnetic field and comparison with the observations by the STEREO-B EUVI and the SDO/AIA. ...

Recent progress on understanding coronal mass ejection/flare onset by a NASA living with a star focused science team

Advances in Space Research

... As a result, users of maps must rely on the assumptions and parameter choices of the model developers, which may have been tailored for specific purposes. The ADAPT model has pioneered the use of multiple realizations to characterize possible variability, but Barnes et al. (2023) found that greater differences were present between maps generated by different SFTs than amongst the ADAPT ensembles. The consequences of different SFT map properties for coronal/heliospheric models have not been investigated extensively, although Knizhnik et al. (2024) demonstrated similar performance of solar wind models using ADAPT and AFT for a single Carrington rotation. ...

Implications of Different Solar Photospheric Flux-transport Models for Global Coronal and Heliospheric Modeling

The Astrophysical Journal

... Magnetographs and instruments with a lower spatial or spectral resolution usually give systematically lower field strengths than those with a higher resolution because of the effect of the magnetic fill factor inside the resolution element for unresolved magnetic fields (Plowman & Berger 2020). Fouhey et al. (2023) found that even mismatches in spatial scaling can lead to different results from comparing measurements by the Helioseismic and Magnetic Imager (HMI; Scherrer et al. 2012) tropolarimeter (SP; Kosugi et al. 2007;Ichimoto et al. 2008;Tsuneta et al. 2008). ...

Large-scale Spatial Cross-calibration of Hinode/SOT-SP and SDO/HMI

The Astrophysical Journal Supplement Series

... Some activity on the far side can either be observed from near the L5 Lagrange point (Vourlidas 2015;Weinzierl et al. 2016) or inferred from machine learning (Broock et al. 2021) or helioseismic techniques (Liewer et al. 2017;Lindsey & Braun 2017;Zhao et al. 2019;Chen et al. 2022;Yang et al. 2023), leading to convincing evidence of a relationship . Synchronic maps from the baseline AFT (left) and AFT-304 (right) models for CR2098. ...

Inferring Maps of the Sun’s Far-side Unsigned Magnetic Flux from Far-side Helioseismic Images Using Machine Learning Techniques

The Astrophysical Journal