Diffusion coefficients in the upper atmosphere from chemiluminous trails

Measurement of the radial growth of chemiluminous trails deposited in the upper atmosphere yields diffusion coefficients. The square of the Gaussian half-width of the cylindrical trail has been observed to increase linearly with time in the 107- to 160-km altitude region. The total inventory of radiating species varies because of chemical reactions, but this does not affect the radial growth. The measured diffusion coefficients are in good agreement with estimates using the 1965 Cospar international reference atmosphere.