Mixing Processes in the Extra Tropical Stratosphere

摘要: The general problem of trace gas mixing in the stratosphere is considered. Mixing divided into two parts: which occurs as part tracer realignment with flow streamlines, and evolution fluid flow. process fundamentally driven by strain or wind shear. straining produces filaments thin until molecular viscosity scale reached. At this point comes a dynamical (and chemical) balance ambient further highly correlated tracers, such potential vorticity, other long lived gases. Subsequent follows tracers. Estimates time required for to reach equilibrium show that linear shear even variation associated observed stratospheric energy spectrum cannot bring rapidly observed. Nonlinear phenomena producing random probably accelerate collapse viscous scales. This suggests models may be appropriate at meso synoptic scales under conditions.