GONG Time distance pipeline status

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GONG Time distance pipeline status

• Shukur Kholikov

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Outline

• Short description
• Some results and examples
• m0 exercise

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• GONG merged velocity images
• 800x800 pix
• 1440 images

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Remaping

• Use 70º in latitude and longitude
• Track relatively noon time of each day
• Apply backward filter (optional)
• Line of sight correction (optional)
• Produce daily acoustic power maps (optional, for
  future use)

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Acoustic powermap example
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Acoustic powermap with one single dead pixel
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SHT computations

• Lmax550 (default)
• Option for any target region or hemispheres
• Mask-out active regions (optional)

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Phase velocity filter

• Predefined 3 depths 7,12,30 Mm
• Option to filter out f-ridge
• Option to keep only f-modes

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Reconstruction

• 57 in latitude and 50 in longitude
• Lat-Long or sin(Lat)-Long
• Corresponding acoustic power map

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Cross-correlations

• Average, north-south, east-west
• Gabor wavelet fitting
• Demodulation and cos-fitting

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Optional output products

• SH time-series
• LNU diagram for individual days
• Phase velocity filtered reconstructed images
• Travel times or differences
• Longitude averaged time series

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North-south travel time differences ( Depth ?
7 Mm )
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North-south travel time differences ( Depth ?
12 Mm )
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North-south travel time differences ( Depth ?
30 Mm )
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Meridional flow profile measurements with
SOHO/MDI U.Mitra-Kraev and M.J.Thompson Astron.Na
chr./ AN 328, 10, 2007
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m0 GONG 150 days
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Travel time differences from longitudinal
averaged images
2006-2007
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2001-2002