"Polar vortex" was the buzzword of 2014, as millions of people in the northeastern U.S., Europe, and Asia experienced first-hand its connection to record-cold winter temperatures. This high-altitude, low-pressure system that hovers over the Arctic in the winter goes through strong and weak phases, acting like a spinning top that eventually wobbles as it slows down. When the system is strong, the cold air is tightly contained on top of the North Pole; when it's weak, fragments of Arctic air can more easily escape into the mid-latitudes.
New research, funded by CPO's Modeling, Analysis, Predictions, and Projections (MAPP) program, shows that the polar vortex has shifted towards more frequent weak states and fewer strong states over the past few decades, with subsequent cold extremes seen during Eurasian winters. While these results can explain the variability (about 60%) of winter temperatures since 1990, the authors note that improvements in seasonal forecasts of winter conditions will likely depend in part on improved understanding of the influence of stratosphere (high-altitude) variability.
To learn more, read the research paper in the Bulletin of the American Meteorological Society.
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 climate system. 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.
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