Advertisement

Dispersion of Tracers in the Stable Atmosphere of a Valley Opening onto a Plain

  • Julian Quimbayo-DuarteEmail author
  • Chantal Staquet
  • Charles Chemel
  • Gabriele Arduini
Research Article
  • 29 Downloads

Abstract

We quantify the impact of a valley-wind system on the transport of passive tracers in the stably-stratified atmosphere of a valley dynamically decoupled from the atmosphere above. The simple configuration of an idealized Alpine-type valley opening onto a plain is considered, for two values of the initial buoyancy frequency and of the valley steepness. The valley-wind system consists of thermally-driven downslope flows that induce a pressure difference between the valley interior and the plain, thereby triggering a down-valley flow. A steady-state regime is eventually reached, at the beginning of which passive tracers are emitted at the valley floor and at different heights above it. The tracer emitted at the valley floor is fully mixed below the height of the maximum speed of the down-valley flow, which behaves like a jet, and remains decoupled from the tracers emitted above. The down-valley flow increases linearly in the along-valley direction y so that, from the conservation of tracer flux, the tracer concentration decays as 1 / y. A simple theoretical model is proposed to fully account for the down-valley flow and tracer behaviour. The tracer concentration emitted at the valley floor also displays marked oscillations, induced by internal gravity waves radiated via a hydraulic-jump process when the downslope flow reaches the valley floor. The amplitude of the oscillations can be as high as 50% of their mean value, implying that averaged values in an urbanized valley may disguise high instantaneous—and potentially harmful-values.

Keywords

Idealized Alpine valley Numerical modelling Passive tracer transport Stable conditions Valley-wind system 

Notes

Acknowledgements

The PhD work of J. Quimbayo is supported by the Colombian Administrative Department of Science, Technology and Innovation (COLCIENCIAS). Numerical simulations were run on the French national HPC facilities at CINES.

References

  1. Anquetin S, Guilbaud C, Chollet JP (1999) Thermal valley inversion impact on the dispersion of a passive pollutant in a complex mountainous area. Atmos Environ 33(24):3953–3959CrossRefGoogle Scholar
  2. Arduini G, Staquet C, Chemel C (2016) Interactions between the nighttime valley-wind system and a developing cold-air pool. Boundary-Layer Meteorol 161(1):49–72CrossRefGoogle Scholar
  3. Arduini G, Chemel C, Staquet C (2017) Energetics of deep alpine valleys in pooling and draining configurations. J Atmos Sci 74(7):2105–2124CrossRefGoogle Scholar
  4. Banta RM, Pichugina YL, Newsom RK (2003) Relationship between low-level jet properties and turbulence kinetic energy in the nocturnal stable boundary layer. J Atmos Sci 60(20):2549–2555CrossRefGoogle Scholar
  5. Beychok M (1995) Fundamentals of stack gas dipersion. In: Beychok MR (ed), Irvine, CaliforniaGoogle Scholar
  6. Brulfert G, Chemel C, Chaxel E, Chollet J (2005) Modelling photochemistry in alpine valleys. Atmos Chem Phys 5(9):2341–2355CrossRefGoogle Scholar
  7. Burns P, Chemel C (2014) Evolution of cold-air-pooling processes in complex terrain. Boundary-Layer Meteorol 150(3):423–447CrossRefGoogle Scholar
  8. Chemel C, Burns P (2015) Pollutant dispersion in a developing valley cold-air pool. Boundary-Layer Meteorol 154(3):391–408CrossRefGoogle Scholar
  9. Chemel C, Staquet C, Largeron Y (2009) Generation of internal gravity waves by a katabatic wind in an idealized alpine valley. Meteorol Atmos Phys 103(1–4):187–194CrossRefGoogle Scholar
  10. Cuxart J, Jiménez M (2007) Mixing processes in a nocturnal low-level jet: an les study. J Atmos Sci 64(5):1666–1679CrossRefGoogle Scholar
  11. Deardorff JW (1980) Stratocumulus-capped mixed layers derived from a three-dimensional model. Boundary-Layer Meteorol 18(4):495–527CrossRefGoogle Scholar
  12. Drazin P, Reid W (1982) Hydrodynamic stability. Cambridge University Press, CambridgeGoogle Scholar
  13. Dudhia J (1989) Numerical study of convection observed during the winter monsoon experiment using a mesoscale two-dimensional model. J Atmos Sci 46:3077–3107CrossRefGoogle Scholar
  14. Jiménez PA, Dudhia J, González-Rouco JF, Navarro J, Montávez JP, García-Bustamante E (2012) A revised scheme for the wrf surface layer formulation. Mon Weather Rev 140(3):898–918CrossRefGoogle Scholar
  15. Klemp J, Dudhia J, Hassiotis A (2008) An upper gravity-wave absorbing layer for nwp applications. Mon Weather Rev 136(10):3987–4004CrossRefGoogle Scholar
  16. Lang M, Gohm A, Wagner J (2015) The impact of embedded valleys on daytime pollution transport over a mountain range. Atmos Chem Phys 15(20):11,981–11,998CrossRefGoogle Scholar
  17. Lareau NP, Crosman E, Whiteman CD, Horel JD, Hoch SW, Brown WO, Horst TW (2013) The persistent cold-air pool study. Bull Am Meteorol Soc 94(1):51–63CrossRefGoogle Scholar
  18. Largeron Y, Staquet C (2016) The atmospheric boundary layer during wintertime persistent inversions in the Grenoble valleys. Front Earth Sci 4:70CrossRefGoogle Scholar
  19. Lehner M, Gohm A (2010) Idealised simulations of daytime pollution transport in a steep valley and its sensitivity to thermal stratification and surface albedo. Boundary-Layer Meteorol 134(2):327–351CrossRefGoogle Scholar
  20. McNider RT (1982) A note on velocity fluctuations in drainage flows. J Atmos Sci 39(7):1658–1660CrossRefGoogle Scholar
  21. Mlawer EJ, Taubman SJ, Brown PD, Iacono MJ, Clough SA (1997) Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave. J Geophys Res 102:663–682CrossRefGoogle Scholar
  22. Peckham SE, Grell GA, McKeen SA, Barth M, Pfister G, Wiedinmyer C, Fast JD, Gustafson WI, Ghan SJ, Zaveri R, et al. (2012) WRF/Chem Version 3.3 User’s Guide. US Department of Commerce, National Oceanic and Atmospheric Administration, Oceanic and Atmospheric Research Laboratories, Global Systems DivisionGoogle Scholar
  23. Prandtl L (1952) Essentials of fluid dynamics: with applications to hydraulics, aeronautics, meteorology and other subjets (English translation). Blackie & SonGoogle Scholar
  24. Rampanelli G, Zardi D, Rotunno R (2004) Mechanisms of up-valley winds. J Atmos Sci 61(24):3097–3111CrossRefGoogle Scholar
  25. Rendón AM, Salazar JF, Palacio CA, Wirth V, Brötz B (2014) Effects of urbanization on the temperature inversion breakup in a mountain valley with implications for air quality. J Appl Meteorol Climatol 53(4):840–858CrossRefGoogle Scholar
  26. Renfrew IA (2004) The dynamics of idealized katabatic flow over a moderate slope and ice shelf. Q J R Meteorol Soc 130:1023–1045CrossRefGoogle Scholar
  27. Schmidli J, Rotunno R (2015) The quasi-steady state of the valley wind system. Front Earth Sci 3:79CrossRefGoogle Scholar
  28. Scotti A, Meneveau C, Lilly DK (1993) Generalized smagorinsky model for anisotropic grids. Phys Fluids A Fluid Dyn (1989–1993) 5(9):2306–2308CrossRefGoogle Scholar
  29. Silcox GD, Kelly KE, Crosman ET, Whiteman CD, Allen BL (2012) Wintertime pm 2.5 concentrations during persistent, multi-day cold-air pools in a mountain valley. Atmos Environ 46:17–24Google Scholar
  30. Wagner J, Gohm A, Rotach M (2014) The impact of valley geometry on daytime thermally driven flows and vertical transport processes. Q J R Meteorol Soc 141(690):1780–1794CrossRefGoogle Scholar
  31. Whiteman CD, Pospichal B, Eisenbach S, Weihs P, Clements CB, Steinacker R, Mursch-Radlgruber E, Dorninger M (2004) Inversion breakup in small rocky mountain and alpine basins. J Appl Meteorol 43(8):1069–1082CrossRefGoogle Scholar
  32. Whiteman CD, Hoch SW, Horel JD, Charland A (2014) Relationship between particulate air pollution and meteorological variables in utah’s salt lake valley. Atmos Environ 94:742–753CrossRefGoogle Scholar
  33. Zardi D, Whiteman CD (2013) Diurnal mountain wind systems. In: Chow FK, De Wekker SF, Snyder BJ (eds) Mountain weather research and forecasting: recent progress and current challenge. Springer, Berlin, pp 35–119CrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.CNRS, Grenoble INP, LEGIUniv. Grenoble AlpesGrenobleFrance
  2. 2.National Centre for Atmospheric Science (NCAS)Centre for Atmospheric & Instrumentation Research University of HertfordshireHatfieldUK
  3. 3.Centre for Atmospheric & Instrumentation ResearchUniversity of HertfordshireHatfieldUK
  4. 4.European Centre for Medium-Range Weather Forecasts (ECMWF), ReadingBerkshireUK

Personalised recommendations