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Original Research Papers

Fluxes and (co-)variances of reacting scalars in the convective boundary layer

Authors:

Jean-François Vinuesa ,

Meteorology and Air Quality Section, Wageningen University; TNO-MEP, NL
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Jordi Vilá-Guerau de Arellano

Meteorology and Air Quality Section, Wageningen University, NL
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Abstract

The effects of chemistry on the transport and the mixing of reacting scalars in the convective atmospheric boundary layer (CBL) are investigated. To do this, we use large-eddy simulation (LES) to calculate explicitly the different terms of the flux and (co-)variance budget equations and to analyse in particular the role of the chemical term with respect to the thermodynamical terms. We examine a set of chemical cases that are representative of various turbulent reacting flows. The chemical scheme involves two reacting scalars undergoing a second-order reaction. In addition, we study a chemical cycle, based on a first- and a second-order reaction, to study the behaviour of chemical systems in equilibrium in turbulent flows. From the budget analysis, we found that the chemical terms become more relevant when the chemical timescale is similar to the turbulent timescale. In order to determine the importance of the chemical terms, we compared these terms to the dynamical terms of the budget equations. For the flux of reactants, the chemical term becomes the dominant sink in the bulk of the CBL. As a result, flux profiles of reacting scalars have non-linear shapes. For the covariance, which accounts for the segregation of species in the CBL, the chemical term can act as a sink or source term. Consequently, reacting scalar covariance profiles deviate considerably from the inert scalar profile. When the chemistry is in equilibrium, the chemical term becomes negligible and therefore the flux and (co-)variance profiles are similar to those of inert scalrs. On the basis of the previous budget results, we develop a parameterisation that represents the segregation of reacting species in large-scale models under convective conditions. The parameterisation is applied to an atmospheric chemical mechanism that accounts for ozone formation and depletion in the CBL. We found a good agreement between the parameterisation and the LES results.

How to Cite: Vinuesa, J.-F. and de Arellano, J.V.-G., 2003. Fluxes and (co-)variances of reacting scalars in the convective boundary layer. Tellus B: Chemical and Physical Meteorology, 55(4), pp.935–949. DOI: http://doi.org/10.3402/tellusb.v55i4.16382
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  Published on 01 Jan 2003
 Accepted on 3 Mar 2003            Submitted on 16 May 2002

References

  1. Bretherton , C. S. , MacVean , M. K. , Bechtold , P. , Chlond , A. , Cotton , W. R. , Cuxart , J. , Cuijpers , H. , Khairoutdinov , M. , Kosovic , B. , Lewellen , D. , Moeng , C. H. , Sibiesma , P. , Stevens , B. , Stevens , D. E. , Sykes , I. and Wyant , M. C . 1999 . An intercomparison of radiatively driven entrain-ment and turbulence in a smoke cloud, as simulated by different numerical models . Q. J. R. Meteorol. Soc ., 125 , 391 – 423 .  

  2. Cuijpers , J. W. M. and Duynkerke , P. G . 1993 . Large eddy simulations of trade wind with cumulus clouds. J. Atmos. Sc i . 50 , 3894 – 3908 .  

  3. Cuijpers , J. W. M. and Holtslag , A. A. M . 1998 . Impact of skewness and nonlocal effects on scalar and buoyancy fluxes in convective boundary layers. J. Atmos. Sc i . 55 , 151 – 162 .  

  4. Deardorff , J. W . 1974 . Three-dimensional numerical study of turbulence in an entraining mixed layer . Boundary Layer MeteoroL 7 , 199 – 226 .  

  5. Deardorff , J. W . 1979 . Prediction of convective mixed-layer entrainment for realistic capping inversion structure. J. At-mos. Sc i . 36 , 424 – 436 .  

  6. Gao , W. and Wesely , M. L . 1994 . Numerical modelling of the turbulent fluxes of chemically reactive trace gases in the atmospheric boundary layer . J. AppL MeteoroL 33 , 835 – 847 .  

  7. Hamba , E 1993 . A modified K model for chemically reactive species in the planetary boundary layer . J. Geophys. Res . 98 , 5173 – 5182 .  

  8. Herwehe , J. A. , McNider , R. T. and Newchurch , M. J . 2000. A numerical study of the effects of large eddies on pho-tochemistry in the convective boundary layer. 14th Sym-posium on Boundary Layers and Turbulence. American Meteorological Society, 235 – 238  

  9. Krol , M. C. , Molemaker , M. J. and Vilà-Guerau de Arel-lano , J. 2000 . Effects of turbulence and heterogeneous emissions on photochemically active species in the cconvective boundary layer . J. Geophys. Res . 105 , 6871 – 6884 .  

  10. Lenschow , D. H. , Wyngaard , J. C and Pennell, W. T. 1980. Mean-field and second-moment budgets in a baroclinic, convective boundary layer. J. Atmos. Sci . 37 , 1313 – 1326.  

  11. McDonald-Butler , E. C. , Liljestrand , H. M. and Sepehrnoori , K . 1999 . Numerical modeling of dry deposition coupled to 22 photochemical reactions . Atmos. Environ . 33 , 1491 – 1502 .  

  12. Moeng , C. H. and Wyngaard , J. C. 1984. Statistics of conser-vative scalars in the convective boundary layer. J. Atmos. Sci . 41 , 3161 – 3169.  

  13. Moeng , C.-H. and Wyngaard , J. C. 1989. Evaluation of tur-bulent transport and dissipation closures in second-order modeling. J. Atmos. Sci . 46 , 2311 – 2330.  

  14. Molemaker , M. J. and Vilà-Guerau de Arellano, J. 1998. Turbulent control of chemical reactions in the convective boundary layer. J. Atmos. Sci . 55 , 568 – 579.  

  15. Patton , E. G. , Davis , K. J. , Barth , M. C. and Sullivan , P. P. 2001. Decaying scalars emitted by a forest canopy: a nu-merical study. Boundary Layer MeteoroL 100, 91 – 129.  

  16. Petersen , A. C. and Holtslag , A. A. M . 1999 . A first-order closure for covariances and fluxes of reactive species in the convective boundary layer . J. Appl. MeteoroL 38 , 1758 – 1776 .  

  17. Petersen , A. C. , Beets , C. , van Dop , H. and Duynkerke , P. G . 1999 . Mass-flux schemes for transport of non-reactive and reactive scalars in the convective boundary layer . J. Atmos. Sci . 56 , 37 – 56 .  

  18. Petersen , A. C . 2000 . The impact of chemistry on flux esti-mates in the convective boundary layer . J. Atmos. Sci . 57 , 3398 – 3405 .  

  19. Poppe , D. and Lustfeld , H . 1996 . Nonlinearities in the gas phase chemistry of the troposphere: Oscillating concen-trations in a simplified mechanism . J. Geophys. Res . 101 , 14373 – 14380 .  

  20. Schumann , U . 1989 . Large-eddy simulation of turbulent dif-fusion with chemical reactions in the convective boundary layer . Atmos. Environ . 23 , 1713 – 1729 .  

  21. Siebesma , A. P. and Cuijpers , J. W. M. 1995. Evaluation of parametric assumptions for shallow cumulus convection. J. Atmos. Sci . 52 , 650 – 666.  

  22. Stockwell , R. W. , Middleton , R , Chang, J. S. and Tang, X. 1990. The second generation regional acid deposition model chemical mechanism for regional air quality mod-eling. J. Geophys. Res . 96 , 16343 – 16367.  

  23. Sykes , R. I. , Parker , S. F. , Henn , D. S. and Lewellen , W. S. 1994. Turbulent mixing with chemical reactions in the planetary boundary layer. J. AppL MeteoroL 33 , 825 – 834.  

  24. Verver , G. H. L. 1994. Comment on “a modified K model for chemically reactive species in the planetary boundary layer” by Fujihiro Hamba. J. Geophys. Res . 99 , 19021 – 19023.  

  25. Verver , G. H. L. , van Dop , H. and Holtslag , A. A. M . 1997 . Turbulent mixing of reactive gases in the convec-tive boundary layer . Boundary Layer Meteorol . 85 , 197 – 222 .  

  26. Vilà-Guerau de Arellano , J. and Cuijpers , J. W. M. 2000. The chemistry of a dry cloud: the effects of radiation and turbulence. J. Atmos. Sci . 57 , 1573 – 1584.  

  27. Vilà-Guerau de Arellano , J. and Lelieveld , J. 1998. Chemistry in the atmospheric boundary layer. In: Clear and cloudy boundary layers (eds. A. A. M. Holtslag and P. G. Duynkerke ). Royal Netherlands Academy of Arts and Sciences , Amsterdam, The Netherlands , 267 – 286  

  28. Vilà-Guerau de Arellano , J. , Duynkerke , P. G. , Jonker , P. J. and Builtjes , P. J. H. 1993. An observational study on the effects of time and space averaging in photochemical models. Atmos. Environ. 27 , 353 – 362.  

  29. Wyngaard , J. C . 1983. Lectures on the planetary boundary layer. In: Mesoscale meteorology-Theories, observations and models. NATO ASI Series, D. Reidel, Dordrecht, 603 – 650  

  30. Wyngaard , J. C . 1985 . Structure of the planetary boundary layer and implications for its modeling . J. Climate AppL MeteoroL 24 , 1131 – 1142 .  

  31. Wyngaard , J. C. and Brost , R. A . 1984 . Top-down and bottom-up diffusion of a scalar in the convective boundary layer . J. Atmos. Sci . 41 , 102 – 112 .  

  32. Wyngaard , J. C. , Pennell , W. T. , Lenschow , D. H. and LeMone , M. A . 1978 . The temperature-humidity covari-ance budget in the convective boundary layer . J. Atmos. Sci . 35 , 47 – 58 .  

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