11/10/05 H6: Global Helioseismology Techniques & Data Products Questions for Technique Sessions Chair(s): Hill, Schou, Larsen Status: [draft]

11/10/05 Thompson – inversion –Main task: making the pipeline robust, automate –Subtle feature, how to distinguish noise realization from real signals? –take serious what are the confidence levels? Beat systematics, estimate error magnitude & correlation –Near surface High-l data Incorporate local inversions? 3D models –Test inferences with data from C.Z. simulations –Korzennick: Need to re-evaluate peak-bagging (has stagnated) Need multiple methods that incorporate what we learned from –Larsen: Incorporating a-coeff. correlations makes little difference in inversion and error bar.

11/10/05 Rachel Howe: Peakfinding & inversions –GONG peakfind code. “Rusted in place” very hard to convert. IRAF –Need for HMI Leakage matrix Standard products Standardize mesh, trade-off (on demand with custom parameters) –Post launch: Cross-check between Basu: Inversion parameter choice is a problem. Need scaling with depth. –SOLA (an RLS) vulnerable to bad/sparse data points.

11/10/05 Ed Rhodes: High degree fitting. –Many improvements in ridge fitting technique. –Main holdup for integrating into pipeline: Need to manually check input “seed” values. Discussion: –Sylvain: Asymmetric fits introduce correlated parameters in fit. –Mark Rast: Fitting heuristic asymmetric profile is useless without a consistent model that explains the entire l-nu diagram from proper understanding of source parameters.

11/10/05 Sylvain: Low degree fitting code –Introduce instrumental one at a time to study effects. Gives confidence that error estimates are reliable (the model predicts the right systematics). –V & I comparison –Erro budget: Confidence in correction must be higher than uncertainty of fit. –Hurdles Fix the obvious: plate scale, leakage matrix Need to know: tilt, plate scale, PSF Knowing P0, B0 better –No. 1 priority: pre-launch instrument tests. –Post-launch validation Discussion: Rast: I & V crucial.

11/10/05 Stuart Jeffreys: peak bagging –Leakage matrix & spectral line profile Keep putting effects into leakage matrix - when do you stop? How high I L without ridge fitting? Up to ~ Interpretation of parameters, e.g. re-parameterizaton to reduce number of parameters. How to interpret. –Model all spectrum? –Use high S/N data to improve algorithms Reduce # of params (100 parameters for the whole spectrum) –Ultimate goal: –#1 goal: refine leakage matrix.

11/10/05 GH Implementation: general What do we need to make progress on the science questions in general? – Should a TR&T focused topic be made? Probably not, too technical, unless outside of LWS SR&T instead? – Working groups Probably useful for fitting Inversions with high degree modes Surface treatments, kernel calculation – Schedules, meetings, splinters, etc. +1 month: Status review, plan of attack, priority setting +6 months: Progress review, selection of HMI modules +18 months: CDR of selected modules +24 months: Acceptance testing – Observables, models, codes, resources, people … Observables: V+I time series, phase differences, coherence Models: Near-surface (first 1000 km?), excitation, spectral line profiles Codes: Leaks, ridge fitting, V+I, “Global Global” fitting, direct inversion of spectra Artificial data (gasp!) Resources: CPUs, disk, $$, time People: Hill, Howe, Schou, Rhodes, Korzennik, Jefferies, Burtseva, Salabert, Thompson, JCD, Vorontsov, Tripathy

11/10/05 GH Technique Development Identify hurdles, bottlenecks, uncertainties: – Observables: No HMI proxy data, but plenty of MDI & GONG data – Models: Need near surface treatment – Codes: High-degree ridge fitting is very expensive, can we invert high degree data? – Resources: will need large amounts of compute time – Artificial data is a quagmire – People: Everyone’s busy! Identify best codes and approaches and/or selection criteria – High-degree ridge fitting – Leakage matrix calculations – V+I fitting – “Global Global” fitting Main technique hurdles: – High computational costs – Verification of results – Simulation artifacts Identify standard products and specifications that are needed as input to the technique code (report to D sessions) – Observed parameters – Simulated parameters Identify external (to SDO) data products that should be available – GONG products – MDI products – Simulation products

11/10/05 H6: Global Helioseismology Techniques & Data Products Data Product Development Session Chair(s): Hill, Schou, Larsen Status: [draft]

11/10/05 HMI GH data products What data products must we produce? – Frequencies, amplitudes, widths, excitation parameters, errors for 0 ≤ ℓ ≤ 2000, and 0 ≤ ≤ 10 mHz. – All ms or a-coefficients or ? – Inversions of rotation rate, sound speed differences for 0 ≤ r/R  ≤ 1.1 – Leakage matrices – Inversion kernels Assessment of required resources, etc: – Pipeline software Two major independent fitting codes available, both need work Ridge fitting & global global are major research tasks – Analysis software/studies Inversions & kernels probably well in hand now But surface effects remain – Supporting software/models Leakage matrices are a major task – Computational requirements (run time estimates, system requirements, …) Very large computational tasks, get as much cpu and memory resources as possible – Storage requirements: size, duration, etc. Data set size is small, duration should be indefinite – Access: web, archive, logs, search methods, etc. Make sure processing details are archived, provenance is important here.

11/10/05 GH Implementation What codes do we have now and what codes need to be developed? – Have MDI & GONG fitting codes routinely running, both could use improvements – Need ridge fitting and 3-D global global codes – Have MDI & GONG leakage matrix codes, both could use improvements – Have kernels & RLS, OLA inversion codes for interior – Need inversion technology for near surface regions Who will can implement the required codes? – Ridge Fitting: Rhodes, Reiter, Korzennik, Rabello-Soares – Global Global : Jefferies, Vorontsov – Leakage matrices: Hill, Schou, Burtseva, Howe – Current fitting improvements: Hill, Schou, Burtseva, Howe, Salabert – Inversions: Thompson, Howe, Corbard, Schou, JCD – Surface Kernels: Thompson, JCD, Jefferies, Vorontsov Define key milestones, test procedures, and target dates, … – + 1 year: Current fitting & leakage code improvements completed. Tested with simulated time series – +2 years: Ridge fitting and Global Global codes completed. Tested with simulated power spectra – +2 years: Near surface effects included in models and inversions. Tested with Hare & hounds exercise Communication: define or list meetings, topical sessions, etc., where progress can be presented, discussed, evaluated, … – SPD New Hampshire, June 06 – SOHO/GONG/HELAS, Sheffield UK, Aug 06 – SPD, Hawaii, summer 07 – Set up a “GloHCo” group, with meetings every 3 months until launch X