Dynamic Geomagnetic Hazard Maps in Space Weather Operations
Wednesday, 17 December 2014
Traditionally, the use of geomagnetic data in space weather operations has been limited to specific geographic coordinates (i.e., magnetic observatories), or to global indices that average magnetic measurements into latitudinal bands of relatively general space weather interest (e.g., Dst, Kp, AE). However, modern technological systems (e.g., power grids, directional drilling platforms) are beginning to require and request information about ground magnetic variations that is more tailored to a specific locale. One solution is to simply install magnetic observatories near every newly built technological system, but this is both economically and operationally impractical. We have chosen instead to adopt an optimal interpolation scheme that inverts for spherical elementary current systems (SECS, Amm-1997), which in turn are used to fill gaps between magnetic observatories. The SECS technique has undergone extensive scientific vetting over the last decade-and-a-half, and will soon be implemented operationally over the continental U.S. as a joint NASA-NOAA-USGS space weather data product, disseminated by the Space Weather Prediction Center (SWPC). Because it will employ a relatively sparse array of high-quality geomagnetic observatories as input, it is important to characterize its ability to reproduce spatial variations in geomagnetic field at sub-continental scales, so the Lyon-Fedder-Mobarry (LFM) global geospace model is used to generate realistic synthetic observations. These include virtual magnetic observatories as input, and a regular geographic grid to serve as a proxy for “ground truth”. We look specifically at LFM output for the Whole Heliosphere Interval (WHI) in order to obtain statistically valid performance measures for a variety of quiet-to-moderate space weather conditions.