Development of an Operational L1 to Earth Delay Time Product

We present a report on the development of an operational space weather tool for use with the upcoming DSCOVR spacecraft to forecast the delay time between L1 and Earth using the Weimer and King [2008] tilted phase front technique. The present technique for propagating the solar wind from L1 to Earth currently used by NOAA Space Weather Prediction Center (SWPC) assumes that all observed solar wind discontinuities, such as interplanetary shocks and interplanetary coronal mass ejection boundaries, are in a flat plane perpendicular to the Sun-Earth line traveling in the GSE X direction at the solar wind velocity. In reality, these phase plane fronts can have significantly tilted orientations, and by relying on a ballistic propagation method, delay time errors of ±15 minutes are common. The L1 to Earth delay time product presented here is designed to more accurately predict the delay time from L1 to Earth by taking into account these tilted phase plane fronts. This algorithm is based on the work of Weimer and King [2008] and is currently running in real-time in test mode at SWPC as part of the SWPC Testbed. We discuss the current algorithm performance, observed improvements in space weather forecasting, as well as the limitations of this model. Both real-time and historic events will be presented.