Dig Deeper, Learn More
18 hours ago
Guest Post by Willis Eschenbach
Over at Phys.Org, there’s a new article claiming the following:
Order in chaos: Atmosphere’s Antarctic oscillation has natural cycle, discover researchers
Climate scientists at Rice University have discovered an “internally generated periodicity”—a natural cycle that repeats every 150 days—in the north-south oscillation of atmospheric pressure patterns that drive the movement of the Southern Hemisphere’s prevailing westerly winds and the Antarctic jet stream.
Here, from the underlying study, are their Fourier analyses supporting their claim.
“Hmmm”, sez I, “seems kinda unlikely” … so I took a look at the study. For unknown reasons, the Antarctic Oscillation (AAO) is also called the Southern Annular Mode (SAM). The abstract says:
However, here we show using observational data, model data, and theory that SAM has an intrinsic 150-day periodicity arising from the internal dynamics of the extratropical atmosphere. This 150-day oscillation clearly influences the variability of the hemispheric-scale precipitation and ocean surface wind stress, suggesting broader impacts of this periodicity on the SH weather and climate.
We also found that many state-of-the-art climate models cannot faithfully reproduce this periodicity, providing an explanation for some of the previously reported shortcomings of these models in simulating SAM’s variability. Based on these findings, we propose new metrics and ideas for evaluating these models and understanding their shortcomings, and potentially, improving them.
“Hmmm”, sez I …
https://wattsupwiththat.com/2023/06/09/dig-deeper-learn-more/
