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The Maritime Continent is a densely populated area of complex topography located between the Pacific and Indian Oceans. It is an area where model skill is particularly important but also difficult to obtain. In this study we examine interannual austral summer rainfall variability in the region and the teleconnection to the El Nino-Southern Oscillation (ENSO) in observation-based data, reanalyses, and global and regional atmosphere-only model simulations. We show that model ability to capture interannual rainfall variability is strongly related to model skill in reproducing the ENSO teleconnection to the region, despite strong spatial variability in the ENSO-rainfall response in coastal areas. Model ability in capturing the spatial pattern of both the midtropospheric moisture and circulation response to ENSO is a strong predictor for model performance in capturing the ENSO-Maritime Continent rainfall teleconnection. High-resolution regional simulations and better performing models have opposing ENSO-rainfall teleconnections between land and sea areas.

Plain Language Summary The Maritime Continent experiences substantial rainfall variability resulting in droughts and flooding. It is also a region of complex topography that is poorly resolved in global climate models. Here we analyze the year-to-year rainfall variability of the region in more detail. We find that models that perform well in capturing year-to-year variability have more realistic teleconnections to the El Nino-Southern Oscillation (ENSO). Models that have better represented ENSO-rainfall relationships capture the observed spatial pattern of both the atmospheric moisture and circulation responses to ENSO. A high-resolution model exhibits much more detailed representation of the atmospheric state with opposing ENSO-rainfall relationships over land and sea that are not captured by the worst performing global models. The large range in model performance in the region should be considered when making climate projections for the Maritime Continent.