Estimating the Global Solar Photospheric Magnetic Field Distribution Using the ADAPT Model

As the primary input to nearly all coronal models, reliable estimates of the global solar photospheric magnetic field distribution are critical for accurate modeling and understanding of solar and heliospheric magnetic fields. Over the last several years AFRL, in collaboration with Los Alamos National Laboratory (LANL) and the National Solar Observatory (NSO), has been developing a model that produces much more realistic estimates of the instantaneous global photospheric magnetic field distribution than that provided by traditional photospheric field synoptic maps. The Air Force Data Assimilative Photospheric flux Transport (ADAPT) model is a photospheric flux transport model, originally developed at NSO, that makes use of data assimilation methodologies developed at LANL. The flux transport model evolves the observed solar magnetic flux using relatively well understood transport processes when measurements are not available and then updates the modeled flux with new observations (available from both the Earth and the far side of the Sun) using data assimilation methods that rigorously take into account model and observational uncertainties. This paper provides an overview of the ADAPT model followed by several examples of how it is being used to improve coronal and solar wind modeling as well as space weather forecasts.