Numerical simulation of the seasonal variation of mesospheric water vapor

The results indicate that a Prandtl number of 10 or more gives a simulation of mesospheric water vapor characterized by a strong decrease with height and a seasonal cycle with maximum mixing ratios during late summer. The test with a small Prandtl number gives, in contrast, very weak vertical gradients of concentration and a semiannual cycle with maxima in late winter and late summer. The very high Prandtl number case was included to test the role of vertical diffisuion in the model when the effective diffusivity coefficient is very small. -from Authors