A preview on the determination of mass return flow of air and water vapour into the stratosphere using tritium as a tracer

Abstract

A preview is presented of recent work on the uses of tritium in tracing general atmospheric motions. Using monthly moisture flux data it was possible to determine the regions of major outflow of air and water vapour through the tropopause into the stratosphere over North America for July 1962. It was found that these areas were closely related to the mean position of the jet stream. Computations were made of the total masses of air and water vapour leaving the troposphere. It is postulated that the energy involved in the outflow of air from the troposphere in the vicinity of the mid latitude jet stream and originating entirely from the large scale transient eddies is transferred directly into the lower stratosphere. This transfer of kinetic energy through the tropopause is considered to be the principal mechanism for the maintenance of the dynamic circulation of the lower stratosphere. It is tentatively suggested that such outflow of tropospheric air at least in mid latitudes initiates extrusions of stratospheric air as a compensatory mechanism in an effort to restore equilibrium in an otherwise dynamically inactive stratosphere.