Incorporation of a Generalized Data Assimilation Module within a Global Photospheric Flux Transport Model

Abstract : The objective of this research effort was to improve significantly our ability to represent the instantaneous state of the global solar photospheric magnetic field distribution by incorporating advanced data assimilation techniques into a photospheric flux transport model. Prior to this work, all global photospheric magnetic field maps of the Sun were constructed using either simple magnetogram merging methods or from magnetic flux transport models that made use of either direct insertion or simple weighted averaging to update them with new observations. In addition, the new model was developed so that it could assimilate both near-side magnetogram and far-side helioseismically detected active region data so that truly instantaneous global solar photospheric magnetic field maps are generated. The photospheric flux magnetic flux transport model selected for this effort was the Worden and Harvey (WH) model originally developed at the National Solar Observatory. Along with the WH model, we incorporated the advanced data assimilation framework originally developed for radiation belt studies at Los Alamos National Laboratory (LANL). The main outcome of this research effort is the state-of-the-art data assimilative photospheric flux transport model now referred to as ADAPT (Air Force Data Assimilative Photospheric Flux Transport). The development of the ADAPT model significantly advances our ability to accurately specify the global photospheric magnetic field distribution, which serves as the primary input to solar and heliospheric models used by Air Force operations for space weather forecasting purposes.