Articles | Volume 5, issue 6
Atmos. Chem. Phys., 5, 1605–1622, 2005

Special issue: Data exploitation and modeling for the upper troposphere and...

Atmos. Chem. Phys., 5, 1605–1622, 2005

  22 Jun 2005

22 Jun 2005

Variability of the Lagrangian turbulent diffusion in the lower stratosphere

B. Legras1, I. Pisso1, G. Berthet2, and F. Lefèvre2 B. Legras et al.
  • 1Laboratoire de Météorologie Dynamique, UMR8539, Paris, France
  • 2Service d’Aéronomie, UMR7620, Paris, France

Abstract. Ozone and nitrous oxide are measured at high spatial and temporal resolution by instruments flying on the ER-2 NASA research aircraft. Comparing the airborne transects to reconstructions by ensemble of diffusive backward trajectories allows estimation of the average vertical Lagrangian turbulent diffusion experienced by the air parcels. The resulting estimates show large Lagrangian diffusion of the order of 0.1in the surf zone outside the polar vortex and smaller values of the order of 0.01 inside. Locally, large variation of Lagrangian diffusion occurs over mesoscale distances. It is found that high temporal resolution (3h or less) is required for off-line transport calculations and that the reconstructions are sensitive to spurious motion in standard analysed winds.

Final-revised paper