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| Titel |
Estimation of mixing in the troposphere from Lagrangian trace gas reconstructions during long-range pollution plume transport |
| VerfasserIn |
I. Pisso, E. Real, K. S. Law, B. Legras, N. Bousserez, J. L. Attié, H. Schlager |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250030586
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| Zusammenfassung |
| The dispersion and mixing of pollutant plumes during long range transport across the North
Atlantic is studied using ensembles of diffusive backward trajectories in order to estimate
turbulent diffusivity coefficients in the free troposphere. Values of the order of 0.5 - 1m2s-1
and 1 Ã 104m2s-1 for the vertical and horizontal diffusivity coefficients Dv and Dh
respectively have been derived. Uncertainties related to the method are discussed and results
compared with previous estimates of mixing rates in the atmosphere. These diffusivity
estimates also yield an estimate of the vertical:horizontal aspect ratio of tracer structures in
the troposphere. The representation of sub-grid mixing in the global Eulerian 3D
Chemical Transport Model MOCAGE is also assessed, and optimal time and space grid
resolutions required to simulate the long-range transport of pollutants are investigated on
inter-continental scales, suggesting the need for vertical/horizontal resolutions of the
order of 500m/40 km for this case study. This work is the basis of a detailed study
including chemical transformations along ensembles of diffusive backward trajectories. |
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