The Madden-Julian Oscillation (MJO) greatly influences global climate and weather extremes, thus making it a notable factor in subseasonal prediction. However, it is not yet accurately simulated by models. A recent CPO/Climate Variability and Predictability (CVP) Program-funded study, published in Nature, explored determinants of MJO propagation, and used these findings to suggest refinements to existing MJO models. The study states that current models are inadequate as a result of problems in representing MJO cloud organization. Using a General Circulation Model, the authors experimented with an “aqua-planet” atmospheric-only GCM configuration. Results show that the MJO is largely impacted by broader background environmental conditions, specifically the large-scale background state, which include things such as moisture gradient and winds. The modeling inadequacy is also a product of the double-ITCZ problem, a common model flaw which shows excessive or insufficient precipitation in various regions. The authors conclude that fine tuning these background conditions is a critical step in improving model accuracy. This study is a step towards accurate modeling of the MJO, a challenge that has troubled the weather and climate science community for some time.
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