Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 9 2 2009 10.5194/acpd-9-8619-2009 http://www.atmos-chem-phys-discuss.net/9/8619/2009/ http://www.atmos-chem-phys-discuss.net/9/8619/2009/acpd-9-8619-2009.html http://www.atmos-chem-phys-discuss.net/9/8619/2009/acpd-9-8619-2009.pdf 8619 8633 2009-04-01 Sensitivity of ensemble Lagrangian reconstructions to assimilated wind time step resolution I. Pisso ipisso@damtp.cam.ac.uk V. Marécal B. Legras G. Berthet Laboratoire de Météorologie Dynamique (UMR 8539), ENS – CNRS, Paris, France Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (UMR 6115), Université d'Orléans – CNRS, Orléans, France now at: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK The aim of this study is to define the optimal temporal and spatial resolution required for accurate offline diffusive Lagrangian reconstructions of high resolution in-situ tracers measurements based on meteorological wind fields and on coarse resolution 3-D tracer distributions. Increasing the time resolution of the advecting winds from three to one hour intervals has a modest impact on diffusive reconstructions in the case studied. This result is discussed in terms of the effect on the geometry of transported clouds of points in order to set out a method to assess the effect of meteorological flow on the transport of atmospheric tracers. Berthet, G., Huret, N., Lefévre, F., Moreau, G., Robert, C., Chartier, M., Catoire, V., Barret, B., Pisso, I., and Pomathiod, L.: On the ability of chemical transport models to simulate the vertical structure of the N₂O, NO₂ and HNO₃ species in the mid-latitude stratosphere, Atmos. Chem. Phys., 6, 1599–1609, 2006. Bregman, B., Meijer, E., and Scheele, R.: Key aspects of stratospheric tracer modeling using assimilated winds, Atmos. Chem. Phys., 6, 4529–4543, 2006. M Demazure: Bifurcations and Catastrophes, Geometry of Solutions to Nonlinear Problems, Universitext, Springer, Berlin, 268~pp., 2000. Hansford, G M., Freshwater, R A., Bosch, R A.,~Anthony Cox, R., Jones, R L., Pratt, K F E., and Williams, D E.: A low cost instrument based on a solid state sensor for balloon-borne atmospheric $O_3$ profile sounding, J. Environ. Monitor., 7, 158–162, 2005. Lefèvre, F.,~Figarol, F.,~Carslaw, K., and~Peter, T.: The 1997 arctic ozone depletion quantified from three-dimensional model simulations, Geophys. Res. Lett., 25, 2425–2428, 1998. Legras, B., Joseph, B., and~~Lefèvre, F.: Vertical diffusivity in the lower stratosphere from Lagrangian back-trajectory reconstructions of ozone profiles, J. Geophys. Res., 108(D18), 4562, doi:10.1029/2002JD003045, 2003. Legras, B., Pisso, I., Berthet, G., and Lefèvre, F.: Variability of the Lagrangian turbulent diffusion in the lower stratosphere, Atmos. Chem. Phys., 5, 1605–1622, 2005. Norton, W A.: Breaking rossby waves in a model stratosphere diagnosed by a vortex-following coordinate system and a technique for advecting material contours, J. Atmos. Sci., 51, 654–673, 1994. Pisso, I. and Legras, B.: Turbulent vertical diffusivity in the sub-tropical stratosphere, Atmos. Chem. Phys., 8, 697–707, 2008. Pommereau, J.-P., Garnier, A., Held, G., Gomes, A.-M., Goutail, F., Durry, G., Borchi, F., Hauchecorne, A., Montoux, N., Cocquerez, P., Letrenne, G., Vial, F., Hertzog, A., Legras, B., Pisso, I., Pyle, J. A., Harris, N. R. P., Jones, R. L., Robinson, A., Hansford, G., Eden, L., Gardiner, T., Swann, N., Knudsen, B., Larsen, N., Nielsen, J., Christensen, T., Cairo, F., Pirre, M., Marécal, V., Huret, N., Riviére, E., Coe, H., Grosvenor, D., Edvarsen, K., Di Donfrancesco, G., Ricaud, P., Berthelier, J.-J., Godefroy, M., Seran, E., Longo, K., and Freitas, S.: An overview of the HIBISCUS campaign, Atmos. Chem. Phys. Discuss., 7, 2389–2475, 2007. Stohl, A., Forster, C., Frank, A., Seibert, P., and Wotawa, G.: Technical note: The Lagrangian particle dispersion model FLEXPART version 6.2, Atmos. Chem. Phys., 5, 2461–2474, 2005. Sutton, R.: Lagrangian flow in the middle atmosphere, Q. J. Roy. Meteorol. Soc., 120B(519), 1299–1320, 1994.