1 / 12

# Verification of Probabilistic Forecast - PowerPoint PPT Presentation

RA VI Clips Workshop. Verification of Probabilistic Forecast. J.P. Céron – Direction de la Climatologie S. Mason - IRI. The Exercise. identify the forecasts of El Niño, Neutral, and La Niña years. L. E E E E E.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' Verification of Probabilistic Forecast' - derica

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Verification of Probabilistic Forecast

J.P. Céron – Direction de la Climatologie

S. Mason - IRI

• identify the forecasts of El Niño, Neutral, and La Niña years

L

E E E E E

E L

• identify the forecasts of El Niño, Neutral, and La Niña years

• calculate forecast probabilities for El Niño, neutral, and La Niña events

0 % 80 % 20 %

100 % 0 % 0 %

20 % 60 % 20 %

• calculate forecast probabilities for El Niño, neutral, and La Niña events

• calculate forecast biases

20 % - 33 %

The frequency of La Niña forecasts is 18 / (18*5) = 0,20

The observed frequency of La Niña events is 6 / 18 = 0,33

• calculate forecast biases

• calculate the Hit Rate and False Alarme Rate

1,00 1,00

0,83 0,25

0,83 0,00

0,50 0,00

0,50 0,00

0,17 0,00

• calculate the Hit Rate and False Alarme Rate

• ROC diagram

• ROC diagram

• Brier skill scores

• Differences between the ROC areas and Brier skill scores

• The ROC areas indicate more optimistic estimates of forecast skill, most notably for the neutral conditions.

• The Brier skill score indicates negative skill for forecasts of neutral conditions. The Brier skill scores for this category are weak because of the large forecast bias, but the ROC ignores the bias.