The Madden-Julian oscillation (MJO) is a system of clouds, rainfall, winds, and pressure which moves eastward across the tropics, returning to its starting point every 30 to 60 days. As the MJO moves over the Maritime Continent, or the region made up of parts of Southeast Asia and the islands of Indonesia and the Philippines, observations show that its signal can weaken or completely decay in a phenomenon scientists have called the “barrier effect.” The barrier effect and the variety of weather and climate processes which go along with it present a challenge to understanding the way the MJO propagates around the globe, but a new study supported by the Climate Program Office’s Climate Variability & Predictability (CVP) Program works to close that gap. PhD student Justin Hudson and CVP-supported scientist Eric Maloney explored the possibility that changes in surface fluxes, or energy exchanges between Earth’s surface and atmosphere, help to maintain MJO propagation through the Maritime Continent. The paper, published in the Journal of Climate, presents a new algorithm to identify and track MJO events and investigate the role of surface fluxes. The results show that an MJO event is more likely to pass through the Maritime Continent when more heat is transferred from the surface to the atmosphere and when the flux spans a larger area. The MJO not only impacts weather and climate in the tropics, but exerts influence all over the world, so optimizing our understanding is important for predicting climate variability. This project was supported by CVP to investigate different processes that affect the speed, intensity, disruption, and/or geographic placement of MJO propagation.