WSA Derived Coronal Hole Comparison with STEREO EUVI Observations

Global estimates of the solar photospheric magnetic field distribution are critical for space weather forecasting. These global maps are the essential data input for accurate modeling of the corona and solar wind, which is vital for gaining the basic understanding necessary to improve forecasting models needed for Air Force operations. We are now testing the global photospheric field maps generated by the Air Force Data Assimilative Photospheric flux Transport (ADAPT) model as input to the Wang-Sheeley-Arge (WSA) coronal and solar wind model. ADAPT incorporates the Los Alamos National Laboratory data assimilation methodology with a modified version of the Worden and Harvey photospheric magnetic flux transport model. The ADAPT maps provide a more instantaneous snapshot of the global photospheric field distribution compared to traditional synoptic maps. In this paper, we compare WSA model output with EUVI observations from the two STEREO spacecraft. The current orbital configuration of the two STEREO spacecraft are such that, in combination, they provide a nearly instantaneous global snapshot of the Sun's coronal hole distribution. Global EUVI observations from STEREO A & B provide an unique and ideal opportunity to directly compare WSA coronal hole predictions using both ADAPT and standard updated photospheric field maps as input to the model.