The El Niño-Southern Oscillation (ENSO) is a phenomenon where atmosphere and ocean dynamics couple to change the temperature of waters in the central and eastern Pacific Ocean, the circulation of the tropical atmosphere, and the global atmospheric circulation. ENSO patterns can be described as warming, cooling, or neutral. With warming and cooling phases leading to Pacific Ocean temperature anomalies anywhere from 1°C to 3°C compared to normal, this climate pattern impacts weather across the United States and other parts of the world. ENSO teleconnections, or linkages between the tropical Pacific and midlatitudes, have been recognized as possible negative influences on crop yields in the United States during the summer growing season, especially in a developing La Niña summer – the cooling phase of ENSO.
In a new Journal of Climate article, authors Bor-Ting Jong, Mingfang Ting, Richard Seager, and Weston B. Anderson examine the physical processes of the ENSO summer teleconnections and remote impacts on the US during a multi-year La Niña life-cycle. It has been found that since 1950, a developing La Niña summer occurs either when an El Niño is transitioning to a La Niña or when a La Niña persists. Both oceanic and atmospheric conditions are different during these events, leading to different teleconnection patterns. During the transitioning summer, it was found that there is a strong warming signal over the Midwest. In contrast, during the persisting summer, there is a weak and insignificant extratropical teleconnection. Because of the differing teleconnections related to these two events, it was found that it is necessary to separately consider the transitioning and persisting La Niña events as their teleconnections and impacts on crop yields vary significantly. In addition, this study demonstrated that improved understanding of ENSO summer teleconnections and seasonal prediction of US summertime hydroclimate will require further study and the seasonal evolution of ENSO characteristics within a multi-year ENSO lifecycle.
This project was a collaboration between the NOAA/Earth System Research laboratory (ESRL) and Columbia University and was funded in part by the MAPP program.
The Modeling, Analysis, Predictions, and Projections (MAPP) Program is a competitive research program in NOAA Research’s Climate Program Office. MAPP’s mission is to enhance the Nation’s and NOAA’s capability to understand, predict, and project variability and long-term changes in Earth’s system and mitigate human and economic impacts. To achieve its mission, MAPP supports foundational research, transition of research to applications, and engagement across other parts of NOAA, among partner agencies, and with the external research community. MAPP plays a crucial role in enabling national preparedness for extreme events like drought and longer-term climate changes. For more information, please visit www.cpo.noaa.gov/MAPP.