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Calculation of the effective diffusivity in the middle atmosphere using a general atmospheric circulation model. (Russian. English summary) Zbl 1212.86035

Summary: The mixing of a passive tracer in the stratosphere and the lower mesosphere is studied on the basis of the coefficient of effective diffusion (CED). In the 2D-case, this coefficient is analogous to the usual diffusivity, but for the corresponding quantities averaged over the contour of the constant tracer concentration. The CED distribution is completely defined from the tracer distribution. The data time series describing the evolution of the tracer on the isentropic surfaces is obtained by solving the advection-diffusion equation. We only use the non-divergent isentropic component of the wind field, which is obtained after a 6-year run of the Middle Atmosphere Global Climate Model of the Institute of Computational Mathematics of RAS. Some results of the CED distribution are discussed on the basis of the homogenization theory and the effects of the Rossby wave generation and the breaking in atmospheric currents.

MSC:

86A10 Meteorology and atmospheric physics
76M20 Finite difference methods applied to problems in fluid mechanics
76B65 Rossby waves (MSC2010)
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