Theoretical Explanation Of Spectral Slopes In Stratospheric Turbulence Data And Implications For Vertical Transport

Theoretical Explanation of Spectral Slopes in Stratospheric Turbulence Data and Implications for Vertical Transport

This paper is motivated by the requirement to improve understanding of vertical motion of pollutants in the stratosphere. One method to estimate vertical transport due to the effects of turbulence is by means of the effective diffusivity coefficient. To calculate this parameter, it is often necessary to know the value of epsilon, the rate of turbulent dissipation. This parameter, epsilon, is also important to know in the context of the global numerical stratospheric simulation models now being created for environmental assessment purposes.

Vertical Transport by Small Scale Stratospheric Turbulence

This paper reviews the estimates to date of the vertical 'effective diffusion coefficient' for stratospheric small scale turbulence transport, KB. These estimates range (in order of magnitude) from 1.0 sq. meter/s to 0.01 sq. meter/s, that is to say from a value which would make turbulence a dominant factor in stratospheric transport to a value which would make it totally insignificant. Such a large range implies much ignorance in this subject. The various techniques are closely examined and the unanswered experimental questions are exhibited. The conclusion is reached that more experimental work needs to be done before one has a reliable estimate for KB.

Mixing in Billow Turbulence and Stratospheric Eddy Diffusion