Boundary-Layer Meteorology

, Volume 159, Issue 1, pp 161–172 | Cite as

Existence of Large Turbulent Eddies in the Early-Morning Boundary Layer Acting as an Effective Mountain to Force Mountain Waves

  • R. M. Worthington


Numerical modelling suggests that the turbulent boundary layer can act as an effective mountain forcing mountain waves. In the daytime, convective rolls can cover the mountains, raising the mountain-wave launching height. In non-convective conditions, the nature of the effective mountain is unknown. Here, we investigate if the early-morning boundary layer, moving rapidly across mountains, also contains large eddies of size comparable with convective cells. Temperature profiles from thousands of high-resolution radiosondes show superadiabatic gradients of vertical scale a few hundred metres in the boundary layer, appearing as the boundary-layer wind speed increases. These are explained by the overturning of potential temperature surfaces in large eddies advected with the wind and/or longitudinal rolls. An early-morning satellite image shows longitudinal rolls over mountains up to 1 km height. It is suggested that early-morning fast-moving airflow over mountains, producing mountain waves, also creates a turbulent boundary layer underneath them containing large eddies of scale a few hundred metres, in addition to classic turbulence. These are part of the effective mountain, higher than the actual mountain, which explains the formation of mountain waves.


Mountain wave Radiosonde Turbulence 



Radiosonde data are from the Met Office and British Atmospheric Data Centre. Natural Environment Research Council MST radar and surface-wind data are from BADC. AVHRR images are from the Satellite Receiving Station, Dundee University, Scotland. Thanks to Z K Olewicz, K Slater, Team TBE and Kubuntu, and Lakshmi Kantha for a sceptical review recommending publication.


  1. Atkinson BW, Zhang JW (1996) Mesoscale shallow convection in the atmosphere. Rev Geophys 34:403–431CrossRefGoogle Scholar
  2. Bishop BB (1966) Mountain wave flow. Sailplane Gliding 17:3–8Google Scholar
  3. Bradbury TAM (1990) Links between convection and waves. Meteorol Mag 119:112–120Google Scholar
  4. Clayson CA, Kantha L (2008) On turbulence and mixing in the free atmosphere inferred from high-resolution soundings. J Atmos Ocean Technol 25:833–852CrossRefGoogle Scholar
  5. Corby GA (1957) A preliminary study of atmospheric waves using radiosonde data. Q J R Meteorol Soc 83:49–60CrossRefGoogle Scholar
  6. Drobinski P, Brown RA, Flamant PH, Pelon J (1998) Evidence of organised large eddies by ground-based doppler lidar, sonic anemometer and sodar. Boundary-Layer Meteorol 88:343–361CrossRefGoogle Scholar
  7. Etling D, Brown RA (1993) Roll vortices in the planetary boundary layer: a review. Boundary-Layer Meteorol 65:215–248CrossRefGoogle Scholar
  8. Förchtgott J (1967) Evidence for mountain-sized lee eddies. Weather 24:255–260CrossRefGoogle Scholar
  9. Hocking WK (1985) Measurement of turbulent energy dissipation rates in the middle atmosphere by radar techniques: a review. Radio Sci 20:1403–1422CrossRefGoogle Scholar
  10. Hooper WP, James JE, Lind RJ (1996) Lidar observations of turbulent vortex shedding by an isolated topographic feature. Boundary-Layer Meteorol 80:95–108CrossRefGoogle Scholar
  11. Jiang Q, Doyle JD, Smith RB (2006) Interaction between trapped waves and boundary layers. J Atmos Sci 63:617–633CrossRefGoogle Scholar
  12. Jiang Q, Smith RB, Doyle JD (2008) Impact of the atmospheric boundary layer on mountain waves. J Atmos Sci 65:592–608CrossRefGoogle Scholar
  13. Kalthoff N, Binder HJ, Kossmann M, Vögtlin R, Corsmeier U, Fiedler F, Schlager H (1998) Temporal evolution and spatial variation of the boundary layer over complex terrain. Atmos Environ 32:1179–1194CrossRefGoogle Scholar
  14. Kossmann M, Vögtlin R, Corsmeier U, Vogel B, Fiedler F, Binder HJ, Kalthoff N, Beyrich F (1998) Aspects of the convective boundary layer structure over complex terrain. Atmos Environ 32:1323–1348CrossRefGoogle Scholar
  15. Laird AR (1952) Standing wave at Aberporth. Meteorol Mag 81:337–339Google Scholar
  16. Lester PF, Fingerhut WA (1974) Lower turbulent zones associated with mountain lee waves. J Appl Meteorol 13:54–61CrossRefGoogle Scholar
  17. Ordnance Survey (2012) Cardigan and New Quay Aberteifi a Cheinewydd Explorer Map No.198. Ordnance Survey, SouthamptonGoogle Scholar
  18. Peng MS, Thompson WT (2003) Some aspects of the effect of surface friction on flows over mountains. Q J R Meteorol Soc 129:2527–2557CrossRefGoogle Scholar
  19. Scorer RS (1949) Theory of waves in the lee of mountains. Q J R Meteorol Soc 75:41–56CrossRefGoogle Scholar
  20. Scorer RS (1954) Isle of Man lee-wave. An unusual cloud formation seen during the I.C. meteorological expedition. Flight Aircr Eng 65:693–694Google Scholar
  21. Shutts G (1992) Observations and numerical model simulation of a partially trapped lee wave over the Welsh mountains. Mon Weather Rev 120:2056–2066CrossRefGoogle Scholar
  22. Shutts G (1997) Operational lee wave forecasting. Meteorol Appl 4:23–35CrossRefGoogle Scholar
  23. Shutts G, Broad A (1993) A case study of lee waves over the Lake District in northern England. Q J R Meteorol Soc 119:377–408CrossRefGoogle Scholar
  24. Shutts GJ, Healey P, Mobbs SD (1994) A multiple sounding technique for the study of gravity waves. Q J R Meteorol Soc 120:59–77CrossRefGoogle Scholar
  25. Smith RB (2007) Interacting mountain waves and boundary layers. J Atmos Sci 64:594–607CrossRefGoogle Scholar
  26. Smith CM, Skyllingstad ED (2009) Influence of upstream boundary layer influence on mountain wave breaking and lee wave rotors using a large-eddy simulation. J Atmos Sci 66:3147–3164CrossRefGoogle Scholar
  27. Vosper SB, Worthington RM (2002) VHF radar measurements and model simulations of mountain waves over Wales. Q J R Meteorol Soc 128:185–204CrossRefGoogle Scholar
  28. Wilson R, Dalaudier F, Luce H (2011) Can one detect small-scale turbulence from standard meteorological radiosondes? Atmos Meas Technol 4:795–804CrossRefGoogle Scholar
  29. Wood N (2000) Wind flow over complex terrain: a historical perspective and the prospect for large-eddy modelling. Boundary-Layer Meteorol 96:11–32CrossRefGoogle Scholar
  30. Worthington RM (1999a) Alignment of mountain wave patterns above Wales: a VHF radar study during 1990–1998. J Geophys Res 104:9199–9212CrossRefGoogle Scholar
  31. Worthington RM (1999b) Calculating the azimuth of mountain waves, using the effect of tilted fine-scale stable layers on VHF radar echoes. Ann Geophys 17:257–272CrossRefGoogle Scholar
  32. Worthington RM (2001) Alignment of mountain lee waves viewed using NOAA AVHRR imagery, MST radar, and SAR. Int J Remote Sens 22:1361–1374CrossRefGoogle Scholar
  33. Worthington RM (2002) Mountain waves launched by convective activity within the boundary layer above mountains. Boundary-Layer Meteorol 103:469–491CrossRefGoogle Scholar
  34. Worthington RM (2005) Convective mountain waves above Cross Fell, northern England. Weather 60:43–44CrossRefGoogle Scholar
  35. Worthington RM (2006) Diurnal variation of mountain waves. Ann Geophys 24:2891–2900CrossRefGoogle Scholar
  36. Worthington RM (2014) Boundary-layer effects on mountain waves: a new look at some historical studies. Meteorol Atmos Phys 126:1–12CrossRefGoogle Scholar
  37. Worthington RM (2015) Type 1 and 2 mountain waves observed by MST radar and AVHRR. Meteorol Atmos Phys 127:325–331CrossRefGoogle Scholar
  38. Young GS, Kristovich DAR, Hjelmfelt MR, Foster RC (2002) Rolls, streets, waves, and more. A review of quasi-two-dimensional structures in the atmospheric boundary layer. Bull Am Meteorol Soc 83:997–1001CrossRefGoogle Scholar
  39. Zhou B, Chow FK (2014) Nested large-eddy simulations of the intermittently turbulent stable atmospheric boundary layer over real terrain. J Atmos Sci 71:1021–1039CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  1. 1.UskUK

Personalised recommendations