Download - Sky Coordinate Image Specs
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Sky Coordinate Image Specs
• Fully processed:– Merged– 10-min cadence– “sky to sky” interpolation– Gaussian temporal filter– Renormalized such that
time is centered– Treatment of poles will be
considered further & tested.
– SolarSoft & WCS compliant headers
• Quick look:– Processed at each site– Full resolution– Bad images removed– 2 consecutive 5-min
averages returned every hour
– Staggered around network by 20 min
– No interpolation (if jitter < 1 pixel)
– Approximate calibration– Evaluate jitter– Provide image geometry (ie
P angle)
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Remapped images
• Full Reduction– Single-site @ 1 min – Merged @ 10 min– Temporal filter same as sky coord images– Spatial resolution to match disk center in longitude & sin lat– Specify heliocentric coordinates with a constant gird, not
heliographic (see next slide)– For 10-min average, no need to correct for differential rotation– Space pixel coordinate definition consistent with temporal
definition– Include specification of CR Time in header
• Quick look– Produced from quick-look sky images
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Definition of heliocentric coordinates
• 0,0 is at central meridian, solar equator
• Longitude coordinate is angular distance from central meridian
• Sin latitude coordinate is measured from equator
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Synoptic maps
• Full processing:– Merged, uniform noise level– Need differential rotation correction– Create usual synoptic map (once every
CR) w. cos4 weights, 1-degree resolution
– Create high-res synoptic map, once per CR, narrow weights, match disk center resolution (or use 0.2 degrees, will test)
– Create “Best” global map:• Cadence: 1 hr goal, 4 hr
requirement • Spatial resolution: matched to disk
center, • Spatial weighting function is broad,
± 60°, temporal weighting is narrow• Consider creation on demand
– Do not match SOLIS cadence, try for compatible data format
– Location of missing data should be identified
– Fill poles like SOLIS– Treat LOS projection like
SOLIS• Quick look:
– Spatial resolution: 1 degree– 1-hr (goal) or 4-hr cadence
updated map– Constructed from quick-look
sky images– Leave hook to include flux
transport for backside fields, but don’t include for now.
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Synoptic map defintions
• Usual synoptic map: covers 1 Carrington rotation, contains all central meridian data available, created once per CR.
• Best global map: created frequently, includes data obtained after target time of map.
• Updated map: like Best global map, but contains only data prior to target time.
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Data distribution
• Maintain access to on-line quick-look jpegs
• Movies
• Separate web page for magnetograms
• Calendar & clock graphical search tools
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Older data
• Make available jpegs of either on-demand or all single site sky images, registered & centered, no ZPC
• How much jpeg compression is acceptable? Jpeg2000?• Evaluate cost of applying current ZPC, either on
demand, or for entire set. Estimate time required for processing & development.
• Work with Yan Li to test ZPC for LCT• Consider constructing a registered merged ZPC’ed
movie for a SHINE interval• Make data limitations clear on the web page, perhaps in
header
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Additional Processing
• Cross-site sensitivity:– Use Harry’s code to see
how big the problem is– Characterize temporal &
site-dependent behavior– Perhaps use global
optimization to remove relative variation in network
– Absolute reference from external source
• Spherical Harmonics:– Yes, on synoptic maps– Adopt Wilcox normalization– Max degree 50
• Potential Field Extrapolation:– Provide “hairy ball” pictures– Provide links to other
sources of results– Provide data to groups with
existing code (e.g. CCMC)
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Additional processing II
• Destretching:– Test effectiveness & cost of correcting RCP &
LCP distortion– Consider adapting Lockheed code, or Harry’s
code.
• Restoration:– Lower priority– Might be useful to smooth noise variations
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Zero Point Correction
• Destretch RCP + LCP of reference magnetograph
• Characterize new modulator response
• Apply existing ZPC to new data, evaluate results.