Variable Masking for Climate Emulation in ACE
Abstract
In the recent AI Model Intercomparison Project (AIMIP) benchmark, the ACE2.1-ERA5 emulator was shown to underestimate the true near-surface warming trend both during the training period and the out-of-sample extrapolation period. In this work, we present M-ACE2S (Masked-ACE2S), a modified version of the stochastic ACE2S model, which uses variable masking during training and reduces the reliance of M-ACE2S on any single input channel. We show that M-ACE2S improves long-term near-surface air temperature prediction. We also present a novel data normalization strategy called "global mean removal", which, combined with masking, further improves the near-surface temperature forecasts. We show that M-ACE2S outperforms the ACE2S baseline on in-sample data for ERA5 while improving training stability and generalizability of near-surface temperature to unseen forcing when paired with global mean removal.
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BibTeX
@misc{yermakov2026variable,
title = {{Variable Masking for Climate Emulation in ACE}},
author = {Alexey Yermakov and Troy Arcomano and Jeremy McGibbon and Brian Henn and Oliver Watt-Meyer},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.21012},
eprint = {2610.21012},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.21012},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Variable Masking for Climate Emulation in ACE
AU - Alexey Yermakov
AU - Troy Arcomano
AU - Jeremy McGibbon
AU - Brian Henn
AU - Oliver Watt-Meyer
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.21012
UR - https://arxiv.org/abs/2610.21012
AB - In the recent AI Model Intercomparison Project (AIMIP) benchmark, the ACE2.1-ERA5 emulator was shown to underestimate the true near-surface warming trend both during the training period and the out-of-sample extrapolation period. In this work, we present M-ACE2S (Masked-ACE2S), a modified version of the stochastic ACE2S model, which uses variable masking during training and reduces the reliance of M-ACE2S on any single input channel. We show that M-ACE2S improves long-term near-surface air temperature prediction. We also present a novel data normalization strategy called "global mean removal", which, combined with masking, further improves the near-surface temperature forecasts. We show that M-ACE2S outperforms the ACE2S baseline on in-sample data for ERA5 while improving training stability and generalizability of near-surface temperature to unseen forcing when paired with global mean removal.
ER -