Thermal upper limit on eddy diffusion in the mesosphere and lower thermosphere

摘要: The thermodynamic stability of the mesosphere and lower thermosphere requires that there be a downward transport heat associated with any turbulent mixing. maximum amount is available for transportation through level by eddy conduction can determined from absorption solar energy above level; losses infrared radiation or large-scale circulation only reduce heat. This evaluation used to place an upper limit on vertical diffusivity, this substantially below values frequently quoted basis vapor meteor trail studies. about 106 cm2/sec 80 km 4×105 50 70 km. fact diffusive equilibrium distributions atmospheric constituents prevail no than 105 km, where molecular diffusion coefficient cm2/sec, indicates at altitude has limiting value obtained thermal considerations.