Open Access
Table 7.
Higher degree polynomial regression results.
| Long term solar activity index | Polynomials |
|||
|---|---|---|---|---|
| Raw (ordinary) |
Orthogonal |
|||
| Max allowable degree | R 2 | Max allowable degree | R 2 | |
| SSN | 12 | 0.60 | 17 | 0.81 |
| Annual Ap mean | 10 | 0.22 | 12 | 0.30 |
| Annual Dst mean | 10 | 0.33 | 16 | 0.52 |
| Annual no. of days with Ap ≥ 40 | 10 | 0.43 | 13 | 0.58 |
| Annual no. of days with Dst ≤ –40 | 11 | 0.71 | 15 | 0.88 |
| Annual mean of daily K-index sum (Penteli) | 7 | 0.26 | 16 | 0.58 |
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