Project dustorm report: ozone transport, in situ measurements, and meteorological analyses of tropopause folding


  • Edwin F. Danielsen,

  • Volker A. Mohnen


Estimates of the annual mass and ozone transport from the stratosphere to the troposphere are presented for the northern hemisphere. The mass transport is based on the radioactivity concentrations previously measured in tropopause folding events and the observed rate of deposition Of 90Sr from bomb tests. The ozone transport is deduced from the positive correlations between the ozone mixing ratio and potential vorticity and between potential vorticity and 90Sr radioactivity. To support these concepts, new observational data obtained from fast-responding ozone and meteorological sensors aboard the National Center for Atmospheric Research Electra aircraft and a similar ozone sensor aboard a commercial aircraft are compared to folded tropopause structures analyzed from radiosonde observations. Two tropopause folding events were predicted in advance to coordinate the flights and to traverse the predicted structures. Excellent agreement is shown between the aircraft and radiosonde data for the macroseale structures. For the first time, direct observations of the effects of mesoscale wave motions on the ozone mixing ratio, potential temperature, and wind speed perturbations are presented. The wave modes have not yet been identified, but transverse gravity waves can be eliminated from the observed polarization relations.