DOE OSTI2015
We investigate the correlation of Ertel potential vorticity, Q, with Bernoulli streamfunction, B,on potential-temperature surfaces, θ, in Earth’s atmosphere poleward of ± 30° latitude. For input, we use the 1979–2010 CMAM30-SD specified-dynamics data set. We fit the model Q=Q 0 exp [-λ 0 (B-B0)] separately in the midlatitude [30°, 60°) and polar [60°, 90°] regions, and nondimensionalize the slope parameter as $\hat{λ}_0\equiv$ ($\overline{NH}$) 2 λ 0 In the troposphere, the peak of $\hat{λ}_0$ is approximately 2-3 in winter and 3–4 in summer in both regions. In the stratosphere during winter, both $\hat{λ}_0$| midlat and $\hat{λ}_0$| polar hover around unity. In spring and fall, $\hat{λ}_0$| polar continues to hover near unity, but $\hat{λ}_0$| midlat rises by a factor of two, with its maximum located at θ ~ 700 to 900 K. In summer, the polar value drops to $\hat{λ}_0$| polar << 1, while the midlatitude value swings negative to $\hat{λ}_0$| midlat ~ 22 to 23. In the mesosphere, $\hat{λ}_0$ exhibits incessant fluctuations with values that usually fall within the range 0 to 1. The results support the paradigm $\hat{λ}_0$ << 1for dynamically active regions primarily in the vicinity of θ ~ 3000–4000 K (~62–72 km) in the mesosphere, whereas except in summer, we get the simple result that the monthly climate-averaged profile, $\langle$ $\hat{λ}_0$ $\rangle$, in the polar regions is nearly unity across the entire stratosphere. In conclusion, during extended recoveries following SSWs, the midlatitude vertical profile develops a peak near 2000 K that descends over the course of a few weeks, alongside the descent of the elevated stratopause in the polar region.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗