| G (W·m−2) | α (%/˚C) | β (%/˚C) | δ (%/˚C) |
| 200 | 0.064 | −0.37 | −0.39 |
| 400 | 0.066 | −0.31 | −0.42 |
| 600 | 0.064 | −0.30 | −0.42 |
| 1000 | 0.067 | −0.29 | −0.41 |