Theoretical and Applied Climatology

, Volume 105, Issue 1–2, pp 217–228 | Cite as

The study of near-ground free convection conditions at Nam Co station on the Tibetan Plateau

  • Degang Zhou
  • Rafael Eigenmann
  • Wolfgang Babel
  • Thomas Foken
  • Yaoming Ma
Original Paper


This study investigates the near-ground free convection conditions (FCCs) based on eddy covariance (EC) measurements at Nam Co station near the Nam Co Lake on the Tibetan Plateau (TP). The spatial and temporal structure of EC measurements at this station is evaluated by using the comprehensive software package TK2 together with a footprint model. The obtained high-quality turbulent flux data are used to study the occurrence of FCCs, which can be detected with the EC system by calculating the stability parameter. Two types of generation of FCCs can be identified. (1) During the wind direction change of a diurnal thermally forced land-lake circulation system in the morning, strongly reduced wind speeds and simultaneously high buoyancy fluxes lead to a period of dominance of buoyancy over shear, and hence, to the occurrence of FCCs. (2) On days with the appearance of clouds, the land-lake circulation is weakened or reversed, dependent on the temperature gradients between the land and the Nam Co Lake. During the period of adaptation of the land-lake breeze to the alternating situation of heating differences, wind speeds decrease and buoyancy again dominates over shear near the ground. These are the situations where FCCs are also detected during the entire day at Nam Co station. The investigation of FCCs regarding the whole measurement period shows that FCCs can be mainly attributed to case (1) during the non-monsoon period, while FCCs are generated by both mechanisms (1 and 2) during the monsoon season. An impact of the FCCs on the near-ground profiles of air temperature and humidity is demonstrated. The FCCs are assumed to play an important role for the land surface-atmosphere exchange processes and the atmospheric boundary layer (ABL) conditions on the TP by providing an effective transport mechanism of near-ground air mass characteristics into upper parts of the ABL.


Tibetan Plateau Atmospheric Boundary Layer Eddy Covariance Horizontal Wind Speed Surface Skin Temperature 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This paper was realized under the auspices of the National Natural Science Foundation of China (40825015), the Chinese National Key Program for Developing Basic Sciences (2010CB951701), and EU-FP7 CEOP-AEGIS(212921). The authors wish to acknowledge the support and data provision by the participants of Nam Co Monitoring and Research Station for Multisphere Interactions. The visit of the first author at Bayreuth was funded by the German Science Foundation (DFG) within the Priority Program SPP 1372 and the Chinese Academy of Science. The contribution of the University of Bayreuth to this study was funded within the DFG projects FO 226/18-1 and FO 226/19-1.


  1. Aubinet M, Grelle A, Ibrom A, Rannik Ü, Moncrieff J, Foken T, Kowalski AS, Martin PH, Berbigier P, Bernhofer C, Clement R, Elbers J, Granier A, Grünwald T, Morgenstern K, Pilegaard K, Rebmann C, Snijders W, Valentini R, Vesala T (2000) Estimates of the annual net carbon and water exchange of forests: the EUROFLUX methodology. Adv Ecol Res 30:113–175CrossRefGoogle Scholar
  2. Ayra SP (2001) Introduction to micrometeorology. Academic, San DiegoGoogle Scholar
  3. Baldocchi D, Falge E, Gu L, Olson R, Hollinger D, Running S, Anthoni P, Bernhofer C, Davis K, Evans R, Fuentes J, Goldstein A, Katul G, Law B, Lee X, Malhi Y, Meyers T, Munger W, Oechel W, KT PU, Pilegaard K, Schmid HP, Valentini R, Verma S, Vesala T, Wilson K, Wofsy S (2001) FLUXNET: a new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor, and energy flux densities. Bull Am Meteorol Soc 82:2415–2434CrossRefGoogle Scholar
  4. Banta RM (1990) The role of mountain flows in making clouds. In: Blumen W (ed) Atmospheric processes over complex terrain, chap 9. Meteorological monographs, 23(45). American Meteorological Society, Boston, pp 229–283, 23(45)Google Scholar
  5. Chen F, Avissar R (1994) Impact of land-surface moisture variability on local shallow convective cumulus and precipitation in large-scale models. J Appl Meteorol 33:1382–1401CrossRefGoogle Scholar
  6. Chen Z, Zhou M, Qian F, Li S, Su L et al (2002) Convection activities in the atmospheric boundary layer over the western plateau of China (in Chinese). J Appl Meteorol Sci 13:142–145Google Scholar
  7. Culf AD, Foken T, Gash JHC (2004) The energy balance closure problem. In: Kabat P et al (eds) Vegetation, water, humans and the climate: a new perspective on an interactive system. Springer, Berlin, pp 159–166Google Scholar
  8. Eigenmann R, Metzger S, Foken T (2009) Generation of free convection due to changes of the local circulation system. Atmos Chem Phys 9:8587–8600CrossRefGoogle Scholar
  9. Foken T (2008a) The energy balance closure problem: an overview. Ecol Appl 18:1351–1367CrossRefGoogle Scholar
  10. Foken T (2008b) Micrometeorology. Springer, HeidelbergGoogle Scholar
  11. Foken T, Göckede M, Mauder M, Mahrt L, Amiro BD, Munger JW (2004) Post-field data quality control. In: Lee X, Massman W, Law B (eds) Handbook of micrometeorology: a guide for surface flux measurement and analysis. Kluwer, Dordrecht, pp 181–208Google Scholar
  12. Foken T, Mauder M, Liebethal C, Wimmer F, Beyrich F, Leps JP, Raasch S, DeBruin HAR, Meijninger WML, Bange J (2010) Energy balance closure for the LITFASS-2003 experiment. Theor Appl Climatol. doi: 10.1007/s00704-009-0216-8 Google Scholar
  13. Foken T, Wichura B (1996) Tools for quality assessment of surface-based flux measurements. Agric For Meteorol 78:83–105CrossRefGoogle Scholar
  14. Foken T, Wimmer F, Mauder M, Thomas C, Liebethal C (2006) Some aspects of the energy balance closure problem. Atmos Chem Phys 6:4395–4402CrossRefGoogle Scholar
  15. Fujinami H, Nomura S, Yasunari T (2005) Characteristics of diurnal variations in convection and precipitation over the southern Tibetan Plateau during summer. SOLA 1:49–52CrossRefGoogle Scholar
  16. Göckede M, Foken T, Aubinet M, Aurela M, Banza J, Bernhofer C, Bonnefond JM, Brunet Y, Carrara A, Clement R, Dellwik E, Elbers J, EugsterW FJ, Granier A, Grünwald T, Heinesch B, Janssens IA, Knohl A, Koeble R, Laurila T, Longdoz B, Manca G, Marek M, Markkanen T, Mateus J, Matteucci G, Mauder M, Migliavacca M, Minerbi S, Moncrieff J, Montagnani L, Moors E, Ourcival JM, Papale D, Pereira J, Pilegaard K, Pita G, Rambal S, Rebmann C, Rodrigues A, Rotenberg E, Sanz MJ, Sedlak P, Seufert G, Siebicke L, Soussana JF, Valentini R, Vesala T, Verbeeck H, Yakir D (2008) Quality control of CarboEurope flux data—part 1: coupling footprint analyses with flux data quality assessment to evaluate sites in forest ecosystems. Biogeosciences 5:433–450CrossRefGoogle Scholar
  17. Göckede M, Markkanen T, Hasager CB, Foken T (2006) Update of a footprint-based approach for the characterization of complex measurement sites. Bound Lay Meteorol 118:635–655CrossRefGoogle Scholar
  18. Göckede M, Markkanen T, Mauder M, Arnold K, Leps JP, Foken T (2005) Validation of footprint models using natural tracer measurements from a field experiment. Agric For Meteorol 135:314–325CrossRefGoogle Scholar
  19. Göckede M, Rebmann C, Foken T (2004) A combination of quality assessment tools for eddy covariance measurements with footprint modelling for the characterisation of complex sites. Agric For Meteorol 127:175–188CrossRefGoogle Scholar
  20. Guan Z, Chen C, Ou Y et al (1984) Rivers and lakes of Xizang province (in Chinese). Science Press, BeijingGoogle Scholar
  21. Hanesiak JM, Raddatz RL, Lobban S (2004) Local initiation of deep convection on the Canadian prairie provinces. Bound Lay Meteorol 110:455–470CrossRefGoogle Scholar
  22. Inagaki A, Letzel MO, Raasch S, Kanda M (2006) Impact of surface heterogeneity on energy imbalance: a study using LES. J Meteorol Soc Jpn 84:187–198CrossRefGoogle Scholar
  23. Li M, Dai Y, Ma Y, Zhong L, Lu S (2006) Analysis on structure of atmospheric boundary layer and energy exchange of surface layer over Mount Qomolangma region (in Chinese with English abstract). Plateau Meteorol 25:807–813Google Scholar
  24. Lugauer M, Winkler P (2005) Thermal circulation in South Bavaria—climatology and synoptic aspects. Meteorol Z 14:15–30CrossRefGoogle Scholar
  25. Lu Y, Ma Y, Li M, Yang X (2008) Numerical simulation of typical atmospheric boundary layer characteristics over lake Namco region, Tibetan Plateau in summer (in Chinese with English abstract). Plateau Meteorol 27:733–740Google Scholar
  26. Ma Y, Fan S, Ishikawa H, Tsukamoto O, Yao T, Koike T, Zuo H, Hu Z, Su Z (2005) Diurnal and inter-monthly variation of land surface heat fluxes over the central Tibetan Plateau area. Theor Appl Climatol 80:259–273CrossRefGoogle Scholar
  27. Ma Y, Tsukamoto O, Wang J, Ishikawa H, Tamagawa I (2002) Analysis of aerodynamic and thermodynamic parameters over the grassy marshland surface of Tibetan Plateau. Prog Nat Sci 12:36–40Google Scholar
  28. Massman WJ, Lee X (2002) Eddy covariance flux corrections and uncertainties in long-term studies of carbon and energy exchanges. Agric For Meteorol 113:121–144CrossRefGoogle Scholar
  29. Mauder M, Foken T (2004) Documentation and instruction manual of the eddy covariance software package TK2. Work Report University of Bayreuth, Department of Micrometeorology, Print: ISSN 1614-8916, pp 42Google Scholar
  30. Mauder M, Foken T, Clement R, Elbers JA, Eugster W, Grünwald T, Heusinkveld B, Kolle O (2008) Quality control of CarboEurope flux data—part 2: inter-comparison of eddy-covariance software. Biogeosciences 5:451–462CrossRefGoogle Scholar
  31. Mauder M, Liebethal C, Göckede M, Leps JP, Beyrich F, Foken T (2006) Processing and quality control of flux data during LITFASS-2003. Bound Lay Meteorol 121:67–88CrossRefGoogle Scholar
  32. Mayer JC, Staudt K, Gilge S, Meixner FX, Foken T (2008) The impact of free convection on late morning ozone decreases on an Alpine foreland mountain summit. Atmos Chem Phys 8:5941–5956CrossRefGoogle Scholar
  33. Metzger S, Ma Y, Markkanen T, Göckede M, Li M, Foken T (2006) Quality assessment of Tibetan Plateau eddy covariance measurements utilizing footprint modeling. Adv Earth Sci 21:1260–1267Google Scholar
  34. Moncrieff J (2004) Surface turbulent fluxes. In: Kabat P, Claussen M, Dirmeyer PA, Gash JHC, Bravo de Guenni L, Meybeck M, Pielke RA Sr, Vörösmarty CJ, Hutjes RWA, Lütkemeier S (eds) Vegetation, water, humans and the climate: a new perspective on an interactive system. Springer, BerlinGoogle Scholar
  35. Rabin RM, Stadler S, Wetzel PJ, Stensrud DJ, Gregory M (1990) Observed effects of landscape variability on convective clouds. Bull Am Meteorol Soc 71:272–280CrossRefGoogle Scholar
  36. Rannik Ü, Markkanen T, Raittila J, Hari P, Vesala T (2003) Turbulence statistics inside and over forest: influence on footprint prediction. Bound Lay Meteorol 109:163–189CrossRefGoogle Scholar
  37. Raymond D, Wilkening M (1980) Mountain-induced convection under fair weather conditions. J Atmos Sci 37:2693–2706CrossRefGoogle Scholar
  38. Rebmann C, Göckede M, Foken T, Aubinet M, Aurela M, Berbigier P, Bernhofer C, Buchmann N, Carrara A, Cescatti A, Ceulemans R, Clement R, Elbers JA, Granier A, Grünwald T, Guyon D, Havránková K, Heinesch B, Knohl A, Laurila T, Longdoz B, Marcolla B, Markkanen T, Miglietta F, Moncrieff J, Montagnani L, Moors E, Nardino M, Ourcival JM, Rambal S, Rannik Ü, Rotenberg E, Sedlak P, Unterhuber G, Vesala T, Yakir D (2005) Quality analysis applied on eddy covariance measurements at complex forest sites using footprint modelling. Theor Appl Climatol 80:121–141CrossRefGoogle Scholar
  39. Schmid HP (2002) Footprint modeling for vegetation atmosphere exchange studies: a review and perspective. Agric For Meteorol 113:159–183CrossRefGoogle Scholar
  40. Segal M, Arritt RW (1992) Nonclassical mesoscale circulations caused by surface sensible heat-flux gradients. Bull Amer Meteorol Soc 73:1593–1604CrossRefGoogle Scholar
  41. Stull RB (1988) An introduction to boundary layer meteorology. Kluwer Academic Publishers, DordrechtGoogle Scholar
  42. Tanaka K, Ishikawa H, Hayashi T, Tamagawa I, Ma Y (2001) Surface energy budget at Amdo on the Tibetan Plateau using GAME/Tibet IOP98 data. J Meteorol Soc Jpn 79:505–517CrossRefGoogle Scholar
  43. Whiteman CD (1990) Observations of thermally developed wind systems in mountainous terrain. In: Blumen W (ed) Atmospheric processes over complex terrain, chap 2. Meteorological monographs, 23(45). American Meteorological Society, Boston, pp 5–42Google Scholar
  44. Wilczak JM, Oncley SP, Stage SA (2001) Sonic anemometer tilt correction algorithms. Bound Lay Meteorol 99:127–150CrossRefGoogle Scholar
  45. Yang K, Koike T, Fujii H, Tamagawa K, Hirose N (2002) Improvement of surface flux parameterizations with a turbulence-related length. Q J R Meteorol Soc 128:2073–2088CrossRefGoogle Scholar
  46. Yang K, Koike T, Ishikawa H, Ma Y (2004) Analysis of the surface energy budget at a site of GAME/Tibet using a single-source model. J Meteorol Soc Jpn 82:131–153CrossRefGoogle Scholar
  47. Yang K, Wang J (2008) A temperature prediction-correction method for estimating surface soil heat flux from soil temperature to moisture data. Sci China Ser D 51:721–729CrossRefGoogle Scholar
  48. Ye D, Gao Y (1979) The meteorology of the Qinghai-Xizang Plateau (in Chinese). Science Press, BeijingGoogle Scholar
  49. Zuo H, Hu Y, Li D, Lu S, Ma Y (2005) Seasonal transition and its boundary characteristics in Amdo area of Tibetan Plateau. Prog Nat Sci 15:239–245CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Degang Zhou
    • 1
  • Rafael Eigenmann
    • 2
  • Wolfgang Babel
    • 2
  • Thomas Foken
    • 2
  • Yaoming Ma
    • 3
  1. 1.Centre for Monsoon System Research, Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina
  2. 2.Department of MicrometeorologyUniversity of BayreuthBayreuthGermany
  3. 3.Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijingChina

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