Comparison of subsurface flows obtained with acoustic ...
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Comparison of subsurface flows obtained with acoustic holography and ring analysis R. Komm 1 , D. Braun 2 , A. Birch 2 , and the GONG Team 1 NSO, Tucson, AZ 2 NWRA/CoRA, Boulder, CO Introduction y We compare synoptic maps of subsurface flows obtained with acoustic holography and ring analysis. We measure the horizontal flows of Carrington rotation 1988 by analyzing Doppler images from the Michelson Doppler Imager instrument onboard the Solar and Heliospheric Observatory. Meridional Flow Acoustic Holography Map Binned Acoustic Holography Map Ring- Diagram Map focal depth: 0.0043 depth: 0.6 Mm The binned holography map of the meridional flow is very similar to a corresponding ring-diagram map. (Blue/red colors indicate flows to the North/South.) ring-diagram: 0.6 Mm 0.9 Mm 1.2 Mm 1.5 Mm 1.7 Mm 2.0 Mm 3.1 Mm solid: holography squares: binned holography Meridional flow averaged in longitude, as a function of latitude. Latitude 37.5 Deg Latitude 37.5 Deg dashed lines: slope of one Binned acoustic-holography meridional flow values vs. ring- diagram flow values at four depths. The slopes are close to one; both methods lead to similar flows. solid line: all latitudes dashed line 37.5 Deg Correlation of the meridional flows of the binned holography map with the ones of ring-diagram maps at different depths. The largest correlation occurs for ring maps at 0.6 Mm. Acknowledgments This work utilizes data obtained by the Global Oscillation Network Group (GONG) program, managed by the National Solar Observatory, which is operatedby the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperativeagreement with the National Science Foundation.The data were acquired by instrumentsoperated by the Big Bear Solar Observatory, High Altitude Observatory, Learmonth Solar Observatory, Udaipur Solar Observatory, Instituto de Astrof´ ısica de Canarias, and Cerro Tololo Interamerican Observatory. NSO/Kitt Peak data used here are produced cooperativelyby NSF/NSO, NASA/GSFC, and NOAA/SEC. SOLIS VSM data used here are produced cooperatively by NSF/NSO and NASA/GSFC. SOHO is a mission of international cooperation between ESA and NASA. The work of RK was supported by NASA grant NNG 05HL41 to the National Solar Observatory. The research of DCB and ACB is supported by NASA contracts NNH04CC05C, NNH05CC76C, and NNH06CC77C, NSF grant AST-0406225,and a subcontractfrom the NASA-supported HMI Project at Stanford University. The ring-fitting analysis is based on algorithms developed by Haber, Hindman, and Larsen with support from NASA and Stanford University. This poster was prepared with Hardi Peter’s LaTex package. Introduction y For the comparison, we bin the holography maps to a spatial resolution similar to the one of the ring analysis. The holography maps represent averages over layers from the surface to a depth of about 3 Mm, while the ring-diagram maps are derived at different depths to about 16 Mm. Zonal Flow Acoustic Holography Map Binned Acoustic Holography Map Ring- Diagram Map focal depth: 0.0043 depth: 3.1 Mm The binned holography map of the zonal flow is very similar to a corresponding ring-diagram map. (Blue/red colors indicate flows to the North/South.) ring-diagram: 0.6 Mm 0.9 Mm 1.2 Mm 1.5 Mm 1.7 Mm 2.0 Mm 3.1 Mm solid: holography squares: binned holography Zonal flow averaged in longitude, as a function of latitude. Latitude 37.5 Deg Latitude 37.5 Deg dashed lines: slope of one Binned acoustic-holography zonal flow values vs. ring-diagram flow values at four depths. The slopes are close to one; both methods lead to similar flows. solid line: all latitudes dashed line 37.5 Deg Correlation of the zonal flows of the binned holography map with the ones of ring-diagram maps at different depths. The largest correlation occurs for ring maps near 3 Mm (or 5 Mm). Longitudinal-Averaged Holography Inversions Kernels for holography measu- rements of horizontally uniform horizontal flows for five different focus depths. The kernels re- flect the kinetic energy density of the modes which contribute to the measurements at each focus depth. black: averaging kernel and flow at target depth color: constituent kernels and flows Averaging kernels (top panels) and inversion results (bottom panels) for meridional flows (in m/s). At a depth of 3 Mm (left column), the measurement is dominated by the contribution at a focus depth of 3 Mm, while at a depth of 14 Mm (right column), the measurements at several focus depths contribute. A second cell in the northern hemisphere is seen at a depth of 14 Mm. Zonal anti-symmetric phase, Φ A , measured as a function of latitude for five focus depths. Dashed lines: averaging kernel and flow at target depth color: constituent kernels and flows Averaging kernels (top panels) and inversion results (bottom panels) for zonal flow (in m/s) at a depth of 3 Mm (left column) and at 14 Mm (right column). Conclusions y Binned acoustic-holography maps of zonal and meridional flows are very similar to corresponding ring-diagram maps. The longitudinal averages agree quite well. This similarity is apparent in a quantitative comparison leading to regression slopes and correlation coefficients close to one (for ring maps at shallow depths). At great depth, measurements from several depths contribute to holography inversions, while near the surface, only the target depth contributes.
Transcript of Comparison of subsurface flows obtained with acoustic ...
Comparison of subsurface flows obtained with acoustic holography and ring analysisR. Komm1, D. Braun2, A. Birch2, and the GONG Team
1NSO, Tucson, AZ 2 NWRA/CoRA, Boulder, CO
Introduction y
We compare synoptic maps of subsurface flows obtainedwith acoustic holography and ring analysis. We measure thehorizontal flows of Carrington rotation 1988 by analyzingDoppler images from the Michelson Doppler Imager instrumentonboard the Solar and Heliospheric Observatory.
Meridional Flow
AcousticHolographyMap
BinnedAcousticHolographyMap
Ring-DiagramMap
focal depth:0.0043
depth:0.6 Mm
The binned holography map of the meridional flow is verysimilar to a corresponding ring-diagram map. (Blue/red colorsindicate flows to the North/South.)
ring-diagram:0.6 Mm0.9 Mm1.2 Mm1.5 Mm1.7 Mm2.0 Mm3.1 Mm
solid:holography
squares:binnedholography
Meridional flow averaged in longitude, as a function of latitude.
Latitude�37.5 Deg
Latitude� 37.5 Deg
dashed lines:slope of one
Binned acoustic-holography meridional flow values vs. ring-diagram flow values at four depths. The slopes are close toone; both methods lead to similar flows.
solid line:all latitudes
dashed line�37.5 Deg
Correlation of the meridional flows of the binned holographymap with the ones of ring-diagram maps at different depths.The largest correlation occurs for ring maps at 0.6 Mm.
Acknowledgments This work utilizes data obtained by the Global Oscillation Network Group (GONG) program, managed by the National Solar Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National ScienceFoundation. The data were acquired by instruments operated by the Big Bear Solar Observatory, High Altitude Observatory, Learmonth Solar Observatory, Udaipur Solar Observatory, Instituto de Astrofı́sica de Canarias, and Cerro Tololo Interamerican Observatory. NSO/Kitt Peak data used here are producedcooperatively by NSF/NSO, NASA/GSFC, and NOAA/SEC. SOLIS VSM data used here are produced cooperatively by NSF/NSO and NASA/GSFC. SOHO is a mission of international cooperation between ESA and NASA. The work of RK was supported by NASA grant NNG 05HL41 to the National SolarObservatory. The research of DCB and ACB is supported by NASA contracts NNH04CC05C, NNH05CC76C, and NNH06CC77C, NSF grant AST-0406225, and a subcontract from the NASA-supported HMI Project at Stanford University. The ring-fitting analysis is based on algorithms developed by Haber,Hindman, and Larsen with support from NASA and Stanford University. This poster was prepared with Hardi Peter’s LaTex package.
Introduction y
For the comparison, we bin the holography maps to aspatial resolution similar to the one of the ring analysis. Theholography maps represent averages over layers from thesurface to a depth of about 3 Mm, while the ring-diagram mapsare derived at different depths to about 16 Mm.
Zonal Flow
AcousticHolographyMap
BinnedAcousticHolographyMap
Ring-DiagramMap
focal depth:0.0043
depth:3.1 Mm
The binned holography map of the zonal flow is very similarto a corresponding ring-diagram map. (Blue/red colors indicateflows to the North/South.)
ring-diagram:0.6 Mm0.9 Mm1.2 Mm1.5 Mm1.7 Mm2.0 Mm3.1 Mm
solid:holography
squares:binnedholography
Zonal flow averaged in longitude, as a function of latitude.
Latitude�37.5 Deg
Latitude� 37.5 Deg
dashed lines:slope of one
Binned acoustic-holography zonal flow values vs. ring-diagramflow values at four depths. The slopes are close to one; bothmethods lead to similar flows.
solid line:all latitudes
dashed line�37.5 Deg
Correlation of the zonal flows of the binned holography mapwith the ones of ring-diagram maps at different depths. Thelargest correlation occurs for ring maps near 3 Mm (or 5 Mm).
Longitudinal-Averaged Holography Inversions
Kernels for holography measu-rements of horizontally uniformhorizontal flows for five differentfocus depths. The kernels re-flect the kinetic energy densityof the modes which contributeto the measurements at eachfocus depth.
black:averaging kerneland flowat target depth
color:constituentkernelsand flows
Averaging kernels (top panels) and inversion results (bottompanels) for meridional flows (in m/s). At a depth of 3 Mm (leftcolumn), the measurement is dominated by the contributionat a focus depth of 3 Mm, while at a depth of 14 Mm (rightcolumn), the measurements at several focus depths contribute.A second cell in the northern hemisphere is seen at a depth of14 Mm.
Zonal anti-symmetric phase,ΦA, measured as a function oflatitude for five focus depths.
Dashed lines:averaging kerneland flowat target depth
color:constituentkernelsand flows
Averaging kernels (top panels) and inversion results (bottompanels) for zonal flow (in m/s) at a depth of 3 Mm (left column)and at 14 Mm (right column).
Conclusions y
Binned acoustic-holography maps of zonal and meridionalflows are very similar to corresponding ring-diagram maps.The longitudinal averages agree quite well.
This similarity is apparent in a quantitative comparison leadingto regression slopes and correlation coefficients close to one(for ring maps at shallow depths).
At great depth, measurements from several depths contributeto holography inversions, while near the surface, only the targetdepth contributes.
