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Spatial correlation between the three different models employed for different time periods. All correlations are significant at the 99.9% confidence interval based on the standard Pearson r-test.
| 1960–1989 | r1/2 = 0.77 | r1/3 = 0.92 | r2/3 = 0.78 |
| 1990–2009 | r1/2 = 0.75 | r1/3 = 0.92 | r2/3 = 0.75 |
