Table 1.
Baseline value, integrated enhancement, and enhancement factor of each radionuclide record used.
| Summary of results | ||||
|---|---|---|---|---|
| Ice core | Isotope | Baseline × 104 atoms/g | Integrated enhancement × 104 atoms/g | Enhancement factor |
| NGRIP | 10Be | 1.71 ± 0.25 | 6.58 ± 0.61 | 3.85 ± 0.68 |
| 36Cl | 0.36 ± 0.05 | 2.18 ± 0.28 | 6.09 ± 1.21 | |
| GRIP | 10Be | 1.50 ± 0.17 | 5.60 ± 0.96 | 3.74 ± 0.77 |
| EDML | 10Be | 3.81 ± 0.52 | 16.07 ± 3.58 | 4.21 ± 1.10 |
| EGRIP | 10Be | 1.63 ± 0.28 | 4.84 ± 0.84 | 2.98 ± 0.70 |
The baseline is calculated as the average concentration of each radionuclide excluding the peak values. The enhancement factors are calculated as the ratio between integrated enhancement over one year and baseline. Uncertainties are based on error propagation and include standard deviation of the baseline and measurement error.