On the importance of historical context and bias correction in deep learning MJO prediction models
摘要
At present, state-of-the-art predictions for the Madden-Julian Oscillation (MJO) combine forecasts from numerical weather models together with bias-correction methods. Recently, deep learning (DL) models have outperformed numerical models on global benchmarks, but their potential for improved MJO prediction remains underexplored. Here, we address two key gaps in DL-based MJO prediction: (1) whether incorporating extended historical context improves forecast skill, and (2) whether bias-correction methods are as effective for DL models as for numerical models. Our results show that MJO predictability is governed by the current MJO state rather than prior propagation. Unlike in numerical models, where bias correction significantly improves forecasts across all lead times, bias correction in DL models only takes effect beyond 3 weeks, reducing errors by 11% in weeks 5–6 and extending the skillful horizon from 37 to 40 days. We conclude that existing bias-correction methods are most effective at correcting dataset inconsistencies rather than model deficiencies.