Overriding hindcast experimental results in MIROC6 climate model

To examine the impact of winter NPO on subsequent ENSO development, we perform the identical-twin hindcast experiments taking the two ensemble members from the large ensemble historical simulations as a reference. In our overriding experiments, we rerun each ENSO event by applying NPO forcings with different intensities. Five different levels of NPO forcing are considered: no NPO forcing, 0.5 times NPO forcing, 1.0 times NPO forcing, 2.0 times NPO forcing, and 3.0 times NPO forcing. For El Niño events, five levels of positive NPO forcing are applied in the preceding winter, labeled as EXP-Clm, EXP-0.5P, EXP-1.0P, EXP-2.0P, and EXP-3.0P. Similarly, experiments for La Niña/-NPO events are labeled as EXP-Clm, EXP-0.5N, EXP-1.0N, EXP-2.0N, and EXP-3.0N, representing five intensities of negative NPO forcing.