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A New Technique for Bridging the Gap Between Global and Local Helioseismology
Edward Rhodes, Sarbani Basu, Rick Bogart, Sasha Kosovichev, Johann
Reiter, Thad Szabo, and Jesper Schou
HMI Science Team Meeting Monterey, CA 2/14/06
Red Kernels and Sound-Speed Inversion Show Importance ofInclusion of High-Degree P-Mode Frequencies for Degrees upto 1467
Green Kernels and Sound-Speed Inversion Were Computed UsingOnly Intermediate-Degree P-Mode Frequencies
Basu, Antia, and Bogart (2004) Compared Active and Quiet Sets of Ring-Diagram Frequencies Using 5.7-Day MDI Time Series
Quiet Region NOAA AR9901
Set of Global-fitFrequencies from 5.7-DayMDI Time Series UsingNigam and KosovichevAsymmetric Profile forApril 7-12, 2002
Corresponding Set ofRing-fit FrequenciesComputed from Same 5.7-DayTime Series Centered onAR9901
Differences BetweenGlobal-fit and Ring-fitFrequencies for April 7-12, 2002
Error Magnification ofRing-fit FrequenciesRelative to Global-fitFrequencies for April7-12, 2002
Comparison of Global-fitFrequencies with TheoreticalFrequencies
Comparison of Ring-fitFrequencies with TheoreticalFrequencies
Differences Between ActiveAnd Quiet Global-fit Frequencies
Differences Between ActiveAnd Quiet Ring-fit Frequencies
Two Examples of Regions of Tighter-Apodization Applied to Same Pair of Active and Quiet Regions
Quiet Region NOAA AR9901
Differences in Two Sets ofFrequencies Computed Using0.5 Solar Radius Inner ApodizationRegion and 4-day Time Series Instead of 5.7-day Time Series
Differences in TwoSets of Original 5.7-day Ring-fit Frequencies(regression line slope is14 times larger than at left)
Comparison of Error MagnificationsOf Ring-fit (Upper Curve) and Tighter-Apodization (Lower Curves)Methods of Frequency Computation
Comparison of Ratios ofActive-Quiet FrequencyDifferences Divided byTheir Errors for Ring-fits(Upper Curve) and Tighter-Apodization (LowerCurves)
Comparison ofRadial Profiles ofSound-Speedand AdiabaticExponent StructuralInversions UsingActive-QuietFrequency Differences From Ring-fits For AR9901 andTighter-ApodizationMethod
Rotational Inversion of High-Degree P-Mode Splitting Coefficients forDegrees up to 500 ComputedUsing Multiple-Peak Tesseral-Spectrum Fitting Method
Inner Turning-Point RadiusDependence of Newer SetOf P-Mode Splitting CoefficientsComputed Using Multiple-PeakTesseral-Spectrum Method forDegrees up to 1000
Planned Extension of Tighter-Apodization for Increased Sensitivity
Elliptical Region Surrounding NOAAAR9901 for 4-Day Time Interval
Conclusions Use of Spherical Harmonic Decompositions with Tighter-
Apodization Can Result in Substantial Increases in Sensitivity of P-Mode Frequencies to Local Conditions Without the Increases in Formal Frequency Errors and Mode-to-Mode Scatter that is Associated with the Ring-Diagram Method
Further Tightening of Apodization Regions Beyond Those Tried Thus Far Are Still Required to Approach Current Sensitivity of Ring-fit Frequencies to Local Conditions
Both Structural and Rotational Inversions Are Possible with the Tighter-Apodization Technique