The air motions within the stratosphere are poorly constrained, since direct observation at these altitudes is difficult. Be ratio calculated in the GISS general circulation model during January and March.
Circled area indicate maximum isotope production.
These tracers, which are borne on aerosol particles, are removed from the stratosphere by radioactive decay. The only sink for 10 Be occurs after it enters the troposphere , where the radionuclides are efficiently removed by precipitation. Be as air moves from the midlatitude production region to other parts of the stratosphere, the ratio will generally increase, as 7 Be decays. In the tropical stratosphere, air rises from the troposphere and continues to ascend, but exchange with higher latitudes is inhibited. During the early northern hemisphere spring, air from the lower tropical stratosphere moves to higher latitudes relatively quickly.