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topes, Inc., are following one version of the first approach.In it, a preconceived model of mixing and organized circulation (in the meridional
plane) is verified by a known tracer experiment. The arbitrary parameters suchas the intensities of the horizontal and the vertical eddydiffusion coefficients and the magnitude of a certain meridional circulation are tested through a time-iterative process, For example, a source
at say 56,000 ft and 10°N (simulating the radiotungsten experiment) is
inserted at the initial time. Then through aniterative transport process
employing Fickian diffusion and a Brewer—Dobson circulation witha
certain intensity, an electronic computer determines the concentrations
(and some other elements) at all latitudes and heights as a function of
time. The computed pattern at a given time may be compared with the
observed radiotungsten distribution at the same number of months following the injection. The differences can suggest the way the meteorological parameters should be changed to improve the comparison. An
example of the procedure based on a computer model devised by W., B.
Ramsay of the Weather Bureau is given as Fig. 12. The source is at the
star. After one year of rather rapid circulation, the peak has moved to
45°N latitude. The radiotungsten experiment clearly indicates that this
combination of mixing rates and circulation speeds is erroneous,
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