Fig. 3: Illustration of ensemble boosting approach.
From: Storylines for unprecedented heatwaves based on ensemble boosting
a 5-day running average of daily maximum temperature (Tx5day) anomalies for (green dashed) the unperturbed reference Event C, and minimum to maximum ranges for the boosted ensembles starting from different lead times, starting with a long lead time of 18 days (light gray) and an medium lead time of 12 days (dark gray). Solid black thin lines mark the time evolution for the 100 individual members of the boosted ensemble and the thick solid green line the member with the highest Tx5day anomaly. b Same as (a) but dark green range shows the minimum to maximum range of the larger boosting ensemble when increasing the boosted ensemble size from 100 to 500 members and light blue the range across the members after an iterative boosting, in which the maximum member is perturbed again a few days later (iterative boosting). The solid blue line corresponds to the member of the iterative boosting with the highest Tx5day anomaly. c Same as (a) but for Event A. The ensemble range for the long lead time (16 days) is shown in light gray with the maximum member shown in dark gray. The range for the medium lead time (9 days) is shown in dark gray, with the individual members (thin black lines) and the maximum boosted member (solid red line).
