Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 7 19 2007 10.5194/acp-7-5147-2007 http://www.atmos-chem-phys.net/7/5147/2007/ http://www.atmos-chem-phys.net/7/5147/2007/acp-7-5147-2007.html http://www.atmos-chem-phys.net/7/5147/2007/acp-7-5147-2007.pdf 5147 5158 2007-10-08 Behaviour of tracer diffusion in simple atmospheric boundary layer models P. S. Anderson philip.s.anderson@bas.ac.uk S. J.-B. Bauguitte British Antarctic Survey, Madingley Road, Cambridge, CB3 0ET, UK 1-D profiles and time series from an idealised atmospheric boundary layer model are presented, which show agreement with boundary layer measurements of polar NO_x. Diffusion models are increasingly being used as the framework for studying tropospheric air chemistry dynamics. Models based on standard boundary layer diffusivity profiles have an intrinsic behaviour that is not necessarily intuitive, due to the variation of turbulent diffusivity with height. The simple model presented captures the essence of the evolution of a trace gas released at the surface, and thereby provides both a programming and a conceptual tool in the analysis of observed trace gas evolution. A time scale inherent in the model can be tuned by fitting model time series to observations. This scale is then applicable to the more physically simple but chemically complex zeroth order or box models of chemical interactions. Ambach, W.: The influence of cloudiness on the net radiation balance of a snow surface with high albedo, J. Glaciol., 13, 73–84, 1974. Davis, D., Eisele, F., Chen, G., et al.: An overview of ISCAT 2000, Atmos. Environ., 38(32), 5363–5373, 2004. Dibb, J. E. and Jaffrezo, J. L.: Air-snow exchange investigations at Summit, Greenland: An overview, J. Geophys. Res., 102, 26 795–26 807, 1997. Jones, A. E., Anderson, P. S., Wolff, E. W., Turner, J., Rankin, A. M., and Colwell, S. R.: A role for newly forming sea ice in springtime polar tropospheric ozone loss? Observational evidence from Halley station, Antarctica, J. Geophys. Res., 111, D08306, doi:10.1029/2005JD006566, 2006. King, J. C. and Anderson, P. S.: Heat and Water Vapour fluxes and Scalar Roughness Lengths over an Antarctic Ice Shelf, Bound.-Lay. Meteorol., 69, 101–121, 1994. King, J. C., Argentini, S. A., and Anderson, P. S.: Contrasts between summer time surface energy balance and boundary layer structure at Dome C and Halley stations, Antarctica, J. Geophys. Res., 111, D02105, doi:10.1029/2005JD006130, 2006. Lee-Taylor, J. and Madronich, S.: Calculation of actinic fluxes with a coupled atmosphere-snow radiative transfer model, J. Geophys. Res., 107(D24), 4796, doi:10.1029/2002JD002084, 2002. Mahrt, L.: Stratified Atmospheric Boundary Layers, Bound.-Lay. Meteorol., 90, 375–396, 1998. Warren, S. G.: Optical Properties of Snow, Rev. Geophys. Space Phys., 20, 67–89, 1982. Trudinger, C. M., Enting, I. G., Etheridge, D. M., Francey, R. J., Levchenko, V. A., Steele, L. P., Raynaud, D., and Arnaud, L.: Modelling air movement and bubble trapping in firn, J. Geophys. Res., 102(D6), 6747–6763, 1997. Wolff, E. W., Jones, A. E. Martin, T. J., and Grenfell, T. C.: Modelling photochemical NO_x production and nitrate loss in the upper snowpack of Antarctica. Geophys. Res. Lett., 29(20), 1944, doi:10.1029/2002GL015823, 2002.