Diffusive Separation of the Lower Atmosphere
Yosuke Adachi,*
Kenji Kawamura,
Laurence Armi,
Ralph F. Keeling
The separation of atmospheric constituents by gravity has been proposed theoretically for almost two centuries. However, turbulent mixing has prevented the detection of this phenomenon in the lower atmosphere. By using precise measurements of the Ar/N2 ratio of air samples taken under strong nocturnal inversions, we have detected such separation in near-surface layers. The effect is shown to be consistent with combined influence of thermal and gravimetric separation, with the thermal contribution being more important.
Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093–0244, USA.
* Present address: Department of Applied Chemistry, Keio University, Yokohama 223-8522, Japan.
To whom correspondence should be addressed. E-mail: rkeeling{at}ucsd.edu
