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WG2 Session: Magnetic Data Input into Global Models Chairs: Roussev and Arge Date: Tue AM, July 31. K.D. Leka: “Promises and Reality of Analysis Using Magnetic Field Data” Gave update on present and future magnetic data resources. SOLIS full deployment is coming shortly.
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WG2 Session: Magnetic Data Input into Global ModelsChairs: Roussev and ArgeDate: Tue AM, July 31 • K.D. Leka: “Promises and Reality of Analysis Using Magnetic Field Data” • Gave update on present and future magnetic data resources. • SOLIS full deployment is coming shortly. • SDO/HMI… we are all waiting for this, are not we?! • Summarized the present limitations of magnetic field observations in terms of spatial resolution, cadence, FOV, etc. • Depending on the choice of 180o ambiguity resolution technique you get different magnetic flux balance in ARs. • Different magnetic field inversion techniques yield different results for B. • Need synthetic magnetic magnetograms from numerical models to assess the validity of various inversion techniques. 2. Gordon Petrie & GONG Team: “GONG Magnetograms and Modeling” • GONG is there, and the data are ready to use for global modeling. • Recent hardware improvements reduce the uncertainty in the “0” point to less than 0.1 Gauss! • GONG team now provides synoptic maps updated every 1min (!), 10min, 1hr, 1day, etc. • Neat suite of online tools is available on GONG’s website (gong.nso.edu/data/magmap/index.html).
WG2 Session: Magnetic Data Input into Global Models(Cont.) 3. Peter McNiece: “GONG Magnetograms Impact on CCMC Modeling” • Summary of present state of solar-helio models at CCMC. • MDI and GONG data are presently being tested as input into WSA model. • We need D2MFUs (Data-to-Model Facilitating Units or Teams). • Model developer needs to have the ability to construct global magnetograms with the best available data, on the surface grid of their choice, with the spatial and temporal resolution of their choice. 4. Brian Welsch: “The Use of Vector Magnetogram Data in MHD Models of the Solar Atmosphere and Prospects for an Assimilative Model” • New improved RADMHD model at UCB/SSL is a reality. • RADMHD is driven with photospheric velocities determined from magnetogram sequences. • Data Assimilation model using Kalman filter approach. • This approach is very sound, but its implementation has some issues to be worked out (covariance matrix, etc. Ask Brian!). • There is a long list of requirements to have “reasonably good” data Assimilative model of the solar atmosphere. • Understanding of data errors is good, but understanding of model errors is poor. • Alternative data for application of Kalman approach include radio magnetography, helioseismic measurements, tomographic density reconstruction, chromospheric B measurements (e.g., SOLIS).
WG2 Session: Magnetic Data Input into Global Models(Cont.) 5. Marc DeRosa: “Pros and Cons of Various Magnetic Field Extrapolation Techniques” • PFSS model has its pros and cons (global model, but no currents in the corona). • NLFF models also have their pros and cons (local models, coronal currents are there, but is the reconstructed B in the corona unique?) • MHD models give time-dependent coronal structure, but they are under-constrained by observations. • We need MHD models with magnetic data to set the BC for B at the Sun, and IC to be given by the PFSS model (away from ARs) coupled with a NLFF model (in ARs where the electric currents are strong).
WG2 Session: Magnetic Data Input into Global ModelsChairs: Roussev and ArgeDate: Tue AM, July 31 Keywords & phrases used during the session: data, model, unresolved issues, data massaging, work in progress, ambiguity resolution, inversion techniques, unresolved issues, GONG, D2MFUs, data Assimilation, SDO/HMI, work in progress, model coupling, unresolved issues, CCMC, VSO, work in progress, NASA TR&T Steering Committee, unresolved issues, tools, cadence, work in progress, spatial resolution, insufficient, FOV. • Since work in progress and unresolved issues appear too often here, it looks like we need to continue the discussion at the next SHINE meeting. • Perhaps in two half-day sessions next time? • Action item: compile a list of inquiries about the D2MFUs to be sent to NASA (TR&T Steering Committee) and NSF.