Improving the Forecasting of the Drivers of Sever Space Weather*

The Sun produces large flares which often produce solar proton events that endanger astronauts. MAG4 is a forecasting technique for an active region’s (AR’s) next day production rate of flares from an AR’s free energy proxy. The free-energy proxy is measured from an HMI vector magnetogram of the AR. We quantify the improvements in MAG4’s major-flare forecasting performance that result from using HMI forecasting curves instead of using MDI forecasting curves. We use a Monte Carlo division to divide the magnetograms into two halves: control and experimental samples. Forecasting curves are made from the control sample and then that curve is used to make a forecast for each magnetogram in the experimental sample. These forecasts are then compared to the major-flare productivity of the experimental-sample and the Heidke skill score is calculated. From histograms of the differences in the Heidke scores from the two MAG4 magnetogram databases, we find an increase in Heidke score of over 0.1 from using HMI forecasting curves instead of MDI forecasting curves. MAG4 will soon be upgraded to use HMI forecasting curves for more accurate forecasts.