Drivers of uncertainty in future projections of Madden–Julian Oscillation teleconnections

Abstract. Teleconnections from the Madden–Julian Oscillation (MJO) are a key source of predictability weather on extended timescale about 10–40 d. The MJO teleconnection is sensitive to number factors, including mean dry static stability, flow, and propagation intensity characteristics MJO, which traditionally difficult separate across models. Each these factors may evolve in response increasing greenhouse gas emissions, will impact teleconnections potentially timescales. Current state-of-the-art climate models do not agree how over central eastern North America change future climate. Here, we use results Coupled Model Intercomparison Project Phase 6 (CMIP6) historical SSP585 experiments concert with linear baroclinic model (LBM) investigate alternate mechanisms explaining why boreal winter (January) Pacific identify sources inter-model uncertainty. LBM simulations suggest that weakening due increases tropical stability alone robust CMIP6 uncertainty state winds driver teleconnections. Uncertainty changes MJO's intensity, eastward speed, zonal wavenumber, extent other important We find no systematic relationship between Rossby wave or wind stationary America. reduction an uncertain America, large spread both regions lends weak confidence overall outlook. While quantitatively determining relative importance versus uncertainties remains challenge, larger contributor projections than MJO.