Presentation | A43M: The Dynamics of Large-Scale Atmospheric Circulation in Present and Future Climates: Jet Streams, Storm Tracks, Stationary Waves, and Monsoons III Oral
Oral
A43M-08: The Subseasonal North Atlantic Oscillation is a Quasi-Semiannual, Propagating Disturbance
Author(s): Jian Lu, Ocean University of China (First Author, Presenting Author) Samuel Smith, University of Chicago Paul Staten, Indiana University Bloomington
The North Atlantic Oscillation (NAO) is the most consequential mode of climate variability around the North Atlantic. Until now, it was thought to have only two phases, which arise and decay gradually over a few weeks and correspond to a “see-sawing” in the intensity of the Icelandic Low and Azores High. Here we show the NAO has two additional, previously unrecognized phases, which correspond to northward and southward displacements of the Icelandic Low and Azores High. These phases alternate with the traditional ones, resulting in an approximately five-month cycle, which appears in temperature, wind speeds, precipitation, and sea-level pressure. More than simply affecting the weather, these phases boost North Atlantic climate predictability while also imprinting on regional climate change.
