Plots and Discussion of the Forecast Models

Li [2004]

This model uses real-time data from ACE as the only input for the standard radial diffusion equation. The radial diffusion equation is solved after making the diffusion coefficient a function of the solar wind velocity and interplanetary magnetic field, with appropriate boundary conditions. The solar wind velocity is the most important parameter in the variation of relativistic electron fluxes at geostationary orbit. The model is described in [Li, 2004] and [Li et al., 2001a].

Prediction Efficiencies for Day 1 Forecast:
Persistence:                0.651
Li [2004]:                  0.737

Prediction Efficiencies for Day 2 Forecast:
Persistence:                0.114
Li [2004]:                  0.326

Li [2004] with Source

This model is Li [2004], with the addition of a source term. The source term represents internal heating mechanisms like wave-particle interactions. The source term's amplitude is a function of the AL index, which is forecast in real-time here.

Prediction Efficiencies for Day 1 Forecast:
Persistence:                0.651
Li [2004] with Source:      0.751

Prediction Efficiencies for Day 2 Forecast:
Persistence:                0.114
Li [2004] with Source:      0.329

Turner and Li [2008]

This model uses low-energy electron flux to forecast relativistic flux, taking advantage of the fact that changes in the low-energy electron population are followed at a later time by similar changes in the high-energy population. The day 2 forecast is based on persistence of the day 1 forecast. This model is described in Turner and Li [2008].

Prediction Efficiencies for Day 1 Forecast:
Persistence:                0.651
Turner and Li [2008]:       0.689

Prediction Efficiencies for Day 2 Forecast:
Persistence:                0.114
Turner and Li [2008]:       0.135

Best Combination of Models

This shows the best combination of the three models, using a weighted average which gives the maximum PE for the last 30 days. The weights indicate how well each model's forecast matched the measured data. The weights are then applied to the 1 and 2 day forecasts of each model. This ensemble most often outperforms the individual models.

Prediction Efficiencies for Day 1 Forecast:
Persistence:                0.651
Li [2004]:                  0.737
Li [2004] with Source:      0.751
Turner and Li [2008]:       0.689
Best Combination:           0.751

Weighting coefficients for maximum PE:
Li [2004]:                   0.14
Li [2004] with Source:       0.86
Turner and Li [2008]:        0.00

Prediction Efficiencies for Day 2 Forecast:
Persistence:                0.114
Li [2004]:                  0.326
Li [2004] with Source:      0.329
Turner and Li [2008]:       0.135
Best Combination:           0.340

Weighting coefficients for maximum PE:
Li [2004]:                   0.43
Li [2004] with Source:       0.57
Turner and Li [2008]:        0.00