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:                0.468
Li [2004]:                  0.742

Prediction Efficiencies for Day 2 Forecast:
Persistence:               -0.302
Li [2004]:                  0.414

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:                0.468
Li [2004] with Source:      0.653

Prediction Efficiencies for Day 2 Forecast:
Persistence:               -0.302
Li [2004] with Source:      0.217

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:                0.468
Turner and Li [2008]:       0.496

Prediction Efficiencies for Day 2 Forecast:
Persistence:               -0.302
Turner and Li [2008]:      -0.313

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:                0.468
Li [2004]:                  0.742
Li [2004] with Source:      0.653
Turner and Li [2008]:       0.496
Best Combination:           0.742

Weighting coefficients for maximum PE:
Li [2004]:                   1.00
Li [2004] with Source:       0.00
Turner and Li [2008]:        0.00

Prediction Efficiencies for Day 2 Forecast:
Persistence:               -0.302
Li [2004]:                  0.414
Li [2004] with Source:      0.217
Turner and Li [2008]:      -0.313
Best Combination:           0.416

Weighting coefficients for maximum PE:
Li [2004]:                   1.00
Li [2004] with Source:       0.00
Turner and Li [2008]:        0.00