The Goodness Index Simon Mason simoniri columbia edu
The Goodness Index Simon Mason simon@iri. columbia. edu Cari. COF 2020 -21 Dry Season – Seasonal Forecast Training Workshop Virtual, 02 December 2020
DJF = 445 – 80 × NIÑO 3. 4 2 Seasonal Forecast Training Workshop 2020 Dec 02
Cross-validation 3 Seasonal Forecast Training Workshop 2020 Dec 02
Goodness Index Definition • Goodness index: the spatially averaged Kendall’s correlation between the cross-validated predictions and the observations Tools ~ Validation ~ Cross-validate ~ Skill Maps (2 AFC Score) • Options ~ Goodness Index provides an option to average the Pearson’s or Spearman’s correlation instead of Kendall’s, but the procedure is more complicated. 4 -0. 8 -0. 6 Workshop -0. 4 -0. 2 Seasonal Forecast Training 2020 Dec 02 0. 0 0. 2 0. 4 0. 6 0. 8
Goodness Index Interpretation What constitutes a “good” or “bad” Goodness Index? Negative Terrible Bad -1 Poor Useless Positive Ok Good Excellent 0 But even if the Goodness Index is negative, there may be some areas in which the forecasts do work. 5 Seasonal Forecast Training Workshop 2020 Dec 02 +1
Goodness Index Options • Options ~ Goodness Index 6 Seasonal Forecast Training Workshop 2020 Dec 02
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