Boundary-Layer Meteorology

, Volume 158, Issue 3, pp 429–452 | Cite as

The Impact of Upstream Flow on the Atmospheric Boundary Layer in a Valley on a Mountainous Island

  • Bianca AdlerEmail author
  • Norbert Kalthoff


Comprehensive measurements on the mountainous island of Corsica were used to investigate how the mountain atmospheric boundary layer (mountain ABL) in a valley downstream of the main mountain ridge was influenced by the upstream flow. The data used were mainly collected with the mobile observation platform KITcube during the first special observation period of the Hydrological cycle in the Mediterranean Experiment (HyMeX) in 2012 and were based on various in situ, remote sensing and aircraft measurements. Two days in autumn 2012 were analyzed in detail. On these days the mountain ABL evolution was a result of convection and thermally-driven circulations as well as terrain-induced dynamically-driven flows. During periods when dynamically-driven flows were dominant, warm and dry air from aloft with a large-scale westerly wind component was transported downwards into the valley. On one day, these flows controlled the mountain ABL characteristics in a large section of the valley for several hours, while on the other day their impact was observed in a smaller section of the valley for about 1 h only. To explain the observations we considered a theoretical concept based on uniform upstream stratification and wind speed, and calculated the non-dimensional mountain height and the horizontal aspect ratio of the barrier to relate the existing conditions to diagnosed regimes of stratified flow past a ridge. On both days, wave breaking, flow splitting and lee vortices were likely to occur. Besides the upstream conditions, a reduction of stability in the valley seemed to be important for the downward transport to reach the ground. The spatio-temporal structure of such a mountain ABL over complex terrain, which was affected by various interacting flows, differed a lot from that of the classical ABL over homogeneous, flat terrain and it is stressed that the traditional ABL definitions need to be revised when applying them to complex terrain.


Convection Corsica Dynamically-driven flows HyMeX KITcube Thermally-driven flows 



This work is a contribution to the HyMeX program. We thank Veronique Ducrocq from METEO-FRANCE and Evelyne Richard and Dominique Lambert from the University of Toulouse/CNRS for their support in performing the KITcube measurements on Corsica during HyMeX. We further acknowledge the help of Antoine Pieri from the fire brigade at Corte/University of Corsica and Olivier Pailly from INRA in San Giuliano and thank them for hosting us during the nearly three-month-long campaign. We are grateful to Jan Handwerker, Martin Kohler and Andreas Wieser and the whole IMK team for their commitment to deploying the KITcube. We also thank Rolf Hankers and the aircraft team from the University of Braunschweig for performing the aircraft measurements and Stefan Heise and Jens Wickert from Deutsches Geoforschungszentrum (GFZ) for loaning a microwave radiometer. The authors thank IGN and ACTIPLAN for operating the permanent GPS stations in Ajaccio as well as IGN/SGN for processing these data operationally and Olivier Bock (LAREG) for the screening of GPS data and conversion of zenith total delay into integrated water vapour using the methodology described in Bock et al. (2007). The authors acknowledge METEO-FRANCE for supplying the data and the HyMeX database teams (ESPRI/IPSL and SEDOO/Observatoire Midi-Pyrénées) for their help in accessing the data.


  1. Adler B (2014) Boundary-layer processes producing mesoscale water-vapour variability over a mountainous island. KIT Scientific Publishing, Karlsruhe, 242 ppGoogle Scholar
  2. Adler B, Kalthoff N (2014) Multi-scale transport processes observed in the boundary layer over a mountainous island. Boundary-Layer Meteorol 153:515–537CrossRefGoogle Scholar
  3. Adler B, Kalthoff N, Kohler M, Handwerker J, Wieser A, Corsmeier U, Kottmeier C, Lambert D, Bock O (2015) The variability of water vapour and pre-convective conditions over the mountainous island of Corsica. Q J R Meteorol Soc. doi: 10.1002/qj.2545
  4. Atkinson BW (1981) Meso-scale atmospheric circulations. Academic Press, London, 495 ppGoogle Scholar
  5. Barthlott C, Adler B, Kalthoff N, Handwerker J, Kohler M, Wieser A (2015) The role of Corsica in initiating nocturnal offshore convection. Q J R Meteorol Soc. doi: 10.1002/qj.2415
  6. Bock O, Bouin MN, Walpersdorf A, Lafore J, Janicot S, Guichard F, Agusti-Panareda A (2007) Comparison of ground-based GPS precipitable water vapour to independent observations and Numerical Weather Prediction model reanalyses over Africa. Q J R Meteorol Soc 133:2011–2027CrossRefGoogle Scholar
  7. Colman BR, Dierking C (1992) The Taku Wind of southeast Alaska: its identification and prediction. Wea Forecast 7:49–64CrossRefGoogle Scholar
  8. Corsmeier U, Hankers R, Wieser A (2001) Airborne turbulence measurements in the lower troposphere onboard the research aircraft Dornier 128–6, D-IBUF. Meteorol Z 10(4):315–329CrossRefGoogle Scholar
  9. Drobinski P, Ducrocq V, Alpert P, Anagnostou E, Branger K, Borga M, Braud I, Chanzy A, Davolio S, Delrieu G, Estournel C, Filali Boubrahmi N, Font J, Grubisic V, Gualdi S, Homar V, Ivancan-Picek B, Kottmeier C, Kotroni V, Lagouvardos K, Lionello P, Llasat M, Ludwig W, Lutoff C, Mariotti A, Richard E, Romero R, Rotunno R, Roussot O, Ruin I, Somot S, Taupier-Letage I, Tintore J, Uijlenhoet R, Wernli H (2014) HyMeX, a 10-year multidisciplinary program on the Mediterranean water cycle. Bull Am Meteorol Soc 95:1063–1082CrossRefGoogle Scholar
  10. Ducrocq V, Braud I, Davolio S, Ferretti R, Flamant C, Jansa A, Kalthoff N, Richard E, Taupier-Letage I, Ayral PA, Belamari S, Berne A, Borga M, Boudevillain B, Bock O, Boichard JL, Bouin MN, Bousquet O, Bouvier C, Chiggiato J, Cimini D, Corsmeier U, Coppola L, Cocquerez P, Defer E, Delanoë J, Di Girolamo P, Doerenbecher A, Drobinski P, Dufournet Y, Fourrié N, Gourley JJ, Labatut L, Lambert D, Le Coz J, Marzano FS, Molini G, Montani A, Nord G, Nuret M, Ramage K, Rison B, Roussot O, Saïd F, Schwarzenboeck A, Testor P, van Baelen J, Vincendon B, Aran M, Tamayo J (2014) HyMeX-SOP1, the field campaign dedicated to heavy precipitation and flash flooding in the northwestern Mediterranean. Bull Am Meteorol Soc 95:1083–1100CrossRefGoogle Scholar
  11. Durran D (2015) Downslope winds. In: North GR, Pyle J, Zhang F (eds) Encyclopedia of atmospheric sciences, 2nd edn. Academic Press, Oxford, pp 69–74CrossRefGoogle Scholar
  12. Epifanio C (2015) Lee vortices. In: North GR, Pyle J, Zhang F (eds) Encyclopedia of atmospheric sciences, 2nd edn. Academic Press, Oxford, pp 84–94CrossRefGoogle Scholar
  13. Fast JD, Zhong S (1998) Meteorological factors associated with inhomogeneous ozone concentrations within the Mexico City basin. J Geophys Res 103(D15):18,927–18,946CrossRefGoogle Scholar
  14. Hertenstein RF (2009) The influence of inversions on rotors. Mon Weather Rev 137(1):433–446CrossRefGoogle Scholar
  15. Jackson PL, Mayr G, Vosper S (2013) Dynamically-driven winds. In: Chow FK, De Wekker SF, Snyder BJ (eds) Mountain weather research and forecasting. Springer atmospheric sciences, Springer, Dordrecht, pp 121–218CrossRefGoogle Scholar
  16. Jiang Q, Smith RB, Doyle JD (2008) Impact of the atmospheric boundary layer on mountain waves. J Atmos Sci 65(2):592–608CrossRefGoogle Scholar
  17. Kalthoff N, Adler B, Wieser A, Kohler M, Träumner K, Handwerker J, Corsmeier U, Khodayar S, Lambert D, Kopmann A, Kunka N, Dick G, Ramatschi M, Wickert J, Kottmeier C (2013) KITcube—a mobile observation platform for convection studies deployed during HyMeX. Meteorol Z 22(6):633–647Google Scholar
  18. Kossmann M, Corsmeier U, De Wekker SFJ, Fiedler F, Vögtlin R, Kalthoff N, Güsten H, Neininger B (1999) Observations of handover processes between the atmospheric boundary layer and the free troposphere over mountainous terrain. Contr Atmos Phys 72:329–350Google Scholar
  19. Lambert D, Mallet M, Ducrocq V, Dulac F, Gheusi F, Kalthoff N (2011) CORSiCA: a Mediterranean atmospheric and oceanographic observatory in Corsica within the framework of HyMeX and ChArMEx. Adv Geosci 26:125–131CrossRefGoogle Scholar
  20. Lenschow DH, Mann J, Kristensen L (1994) How long is long enough when measuring fluxes and other turbulence statistics? J Atmos Oceanic Technol 11:661–673CrossRefGoogle Scholar
  21. Löhnert U, Crewell S (2003) Accuracy of cloud liquid water path from ground-based microwave radiometry 1. dependency on cloud model statistics. Radio Sci 38(3):8041CrossRefGoogle Scholar
  22. Löhnert U, Turner D, Crewell S (2009) Ground-based temperature and humidity profiling using spectral infrared and microwave observations. Part I: simulated retrieval performance in clear-sky conditions. J Appl Meteorol Climatol 48(5):1017–1032CrossRefGoogle Scholar
  23. Mayr GJ, Armi L (2010) The influence of downstream diurnal heating on the descent of flow across the Sierras. J Appl Meteorol Climatol 49:1906–1912CrossRefGoogle Scholar
  24. Metzger J, Barthlott C, Kalthoff N (2014) Impact of upstream flow conditions on the initiation of moist convection over the island of Corsica. Atmos Res 145:279–296CrossRefGoogle Scholar
  25. Reinecke PA, Durran DR (2008) Estimating topographic blocking using a Froude number when the static stability is nonuniform. J Atmos Sci 65(3):1035–1048CrossRefGoogle Scholar
  26. Richard E, Mascart P, Nickerson EC (1989) The role of surface friction in downslope windstorms. J Appl Meteorol 28(4):241–251CrossRefGoogle Scholar
  27. Schär C, Smith RB (1993) Shallow-water flow past isolated topography. Part I: vorticity production and wake formation. J Atmos Sci 50:1373–1400CrossRefGoogle Scholar
  28. Seibert P, Beyrich F, Gryning SE, Joffre S, Rasmussen A, Tercier P (2000) Review and intercomparison of operational methods for the determination of the mixing height. Atmos Environ 34(7):1001–1027CrossRefGoogle Scholar
  29. Shin HH, Hong SY (2011) Intercomparison of planetary boundary-layer parametrizations in the WRF model for a single day from CASES-99. Boundary-Layer Meteorol 139(2):261–281CrossRefGoogle Scholar
  30. Smith R (2015) Hydraulic flow. In: North GR, Pyle J, Zhang F (eds) Encyclopedia of atmospheric sciences, 2nd edn. Academic Press, Oxford, pp 332–333CrossRefGoogle Scholar
  31. Smith RB (2007) Interacting mountain waves and boundary layers. J Atmos Sci 64(2):594–607CrossRefGoogle Scholar
  32. Smith RB, Skubis S, Doyle JD, Broad AS, Kiemle C, Volkert H (2002) Mountain waves over Mont Blanc: influence of a stagnant boundary layer. J Atmos Sci 59:2073–2092CrossRefGoogle Scholar
  33. Vergeiner I, Dreiseitl E (1987) Valley winds and slope winds—observations and elementary thoughts. Meteorol Atmos Phys 36(1–4):264–286CrossRefGoogle Scholar
  34. Vosper S, Brown A (2007) The effect of small-scale hills on orographic drag. Q J R Meteorol Soc 133(627):1345–1352Google Scholar
  35. Vosper SB (2004) Inversion effects on mountain lee waves. Q J R Meteorol Soc 130(600):1723–1748CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  1. 1.Institute of Meteorology and Climate ResearchKarlsruhe Institute of Technology (KIT)KarlsruheGermany

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