Comparing the best ADAPT realizations from WSA, AWSoM and AWSoM-R

Abstract:

Solar corona models are typically driven by global photospheric magnetic field maps assembled from magnetograms. Magnetic field maps derived from different magnetogram sources (e.g. MDI, GONG, etc) can produce different results when used as boundary conditions. One of the commonly used synchronic maps is provided by the ADAPT (Air Force Data Assimilative Photospheric Flux Transport) model, which makes use of a flux transport model to evolve the regions where there are no observations. The ADAPT model uses the ensemble least-squares data assimilation method that account for model and observational uncertainties and provides 12 different realizations for a given moment in time. Previous studies have shown the same solar corona model running with 12 different realizations also provide different predicted solar wind values at 1 AU. In this presentation, we will use the ADAPT maps to drive the WSA (Wang-Sheeley-Arge) model, the AWSoM (Alfven-Wave driven Solar atmosphere Model) and the AWSoM-R (Alfven-Wave driven Solar atmosphere Model - Realtime) model. The coronal portion of the WSA model makes use of the coupled potential field source surface and Schatten current sheet models to derive the global coronal magnetic field from global maps of the photospheric field. The model then applies empirical formulas to specify the solar wind at the outer coronal boundary and a 1D kinematic model to predict solar wind speed and interplanetary magnetic polarity anywhere in the inner heliosphere. AWSoM is a physics-based model solving the MHD equations together with radiative cooling, heat conduction and a phenomenological Alfven wave turbulence and dissipation model including wave reflection (proportional to the Alfvén speed gradients) and turbulent dissipation from the chromosphere to the heliosphere. The AWSoM-R model uses 1-D field line threads to simulate the region in the lower chromosphere to speed up the simulations. We will compare the predicted solar wind values at 1 AU with observations and use the WSA Prediction Metric developed at NASA Goddard Space Flight Center to select the best ADAPT map realization(s) for the three models. We will investigate whether we can improve the prediction capability of the complex physics-based models like AWSoM and AWSoM-R using the insight gained from the inexpensive empirical WSA model.