The Role of Atmospheric Transport for El Niño‐Southern Oscillation Teleconnections

The El Niño‐Southern Oscillation (ENSO) is one of Earth's main modes of climate variability, having huge impacts on weather, agriculture, and people worldwide. Although these impacts and teleconnections have been studied for decades, the role of atmospheric transport is not completely understood. We analyze the atmospheric transport outgoing from the Equatorial Pacific with the Lagrangian particle dispersion model FLEXPART driven by reanalysis data. Our results demonstrate the interocean‐basin exchange via the atmosphere: anomalously energetic air from the ENSO region mainly remains within the Tropics and Subtropics, while more air is transported toward the east during El Niño. Transport of anomalous moist air can directly be linked to several observed teleconnections, for example, droughts in the Amazon Basin and precipitation in Southeastern U.S. during El Niño. These results show that atmospheric transport plays a role in several ENSO teleconnections. Plain Language Summary The El Niño Southern Oscillation (ENSO) is a climate variability that is associated with changes in the climate state every 2–7 years. It occurs due to changes in the sea surface temperature (SST) in the Equatorial Pacific (EP) and causes shifts in the atmospheric circulation. Influences on weather, agriculture and thus the lives of many people worldwide makes understanding the role of the atmosphere important. In order to uncover the role of the atmosphere, we model the atmospheric transport with specialized computer code. We find that the air from the EP Ocean, where the largest anomalies in SSTs occur, is relatively warm when arriving over the Atlantic Ocean and releases its heat into the Ocean. Over South Central America, northern South America, and West Africa warmer and drier air is arriving, which leads to droughts associated with the ENSO. Over Mexico, North America's Gulf Coast and along the Gulf Stream wetter air is arriving, thus favoring precipitation during El Niño. Our results show that the transport of temperature and moisture anomalies from the EP via the atmosphere plays an important role for the weather conditions in several regions. Key Points Transported air from the Equatorial Pacific (EP) shows significant anomalies in moisture and heat compared to its environment The transport of anomalously dry or wet air can be linked to several observed atmospheric teleconnections associated with El Niño Southern Oscillation Deposition of excess energy into the Atlantic Ocea