Seasonal Climate Verifications

Download: Descriptions of the IRI Climate Forecast Verification Scores

The verification maps and time series show skills of IRI’s forecasts issued in real time from late 1997 to present. The forecasts since April 2017 are upscaled to a 2.5-degree grid for precipitation (2.0 degree grid for temperature) to match the horizontal resolution of the previous system for continuity. The observed datasets used are the NOAA/Climate Prediction Center CAMS data for temperature, and the NOAA/Climate Prediction Center CAMS/OPI (satellite data only) for precipitation.

Hindcast skill verification for the current forecast system (as of May 2023) using RPSS and Reliability are available here.

IRI Climate Verification

Verification of IRI’s Seasonal Climate Forecast

 

Description of Score

The generalized ROC score (GROC), like the ROC, shows the degree of correct probabilistic forecast discrimination, even if the forecasts have biases or calibration problems. However, unlike ROC, GROC is generalized to encompass all forecast categories (below, near, and above normal) collectively, rather than being specific to a single category.

Generalized ROC (GROC): Lead 0.5 months, Temperature Forecast Skill: JFM

Gray indicates no (or negative) skill, Purple indicates highest skill.


Individual Forecast Score

Interactive Chart Instructions

  • Zoom: click and drag an area with your mouse to zoom into a section of the graph
  • Unzoom: Click the "Reset Zoom" button in the upper right of the graph window
  • Show/Hide: Select the items in the legend (bottom, center) to show or hide the graph values
  • Download/Print: Select the icons in the upper right of the graph to print or download the graph as an image