Theoretical and Applied Climatology

, Volume 103, Issue 1–2, pp 119–131 | Cite as

Coherent structures and flux contribution over an inhomogeneously irrigated cotton field

  • Yu Zhang
  • Heping LiuEmail author
  • Thomas Foken
  • Quinton L. Williams
  • Matthias Mauder
  • Christoph Thomas
Original Paper


The turbulence data measured at two levels (i.e., 8.7 and 2.7 m) in the Energy Balance Experiment (EBEX), which was conducted in San Joaquin Valley in California during the period from July 20 to August 24, 2000, are used to study the characteristics of coherent structures over an irrigated cotton field. Patch-to-patch irrigation in the field generated the dry-to-wet horizontal advection and the oasis effects, leading to the development of a stably internal boundary layer (SIBL) in the late mornings or the early afternoons. The SIBL persisted in the rest of the afternoons. Under this circumstance, a near-neutral atmospheric surface layer (ASL) developed during the period with a stratification transition from the unstable to stable conditions during the daytime. Therefore, EBEX provides us with unique datasets to investigate the features of coherent structures that were generated over the patches upstream and passed by our site in the unstable ASL, the near-neutral ASL, and the SIBL. We use an objective detection technique and the conditional average method that is developed based on the wavelet analysis. Our data reveal some consistencies and inconsistencies in the characteristics of coherent structures as compared with previous studies. Ramp-like structures and sweep–ejection cycles under the daytime SIBL have similar patterns to those under the nocturnal stable ASL. However, some features (i.e., intermittence) are different from those under the nocturnal stable ASL. Under the three stratifications, thermal and mechanical factors in the ASL perform differently in affecting the ramp intensity for different quantities (i.e., velocity components, temperature, and specific humidity), leading to coherent structures that modulate turbulence flow and alter turbulent transfer differently. It is also found that coherent structures contribute about 10–20% to the total fluxes in our case with different flux contributions under three stratifications and with higher transporting efficiency in sensible heat flux than latent heat and momentum fluxes.


Coherent Structure Convective Boundary Layer Atmospheric Surface Layer Cotton Field Internal Boundary Layer 
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.



Each participant in EBEX was funded primarily through his or her own institution, and some contributed personal resources. Funding for the deployment of NCAR facilities was provided by the National Science Foundation. Arrangement for use of the field site was facilitated by Bruce Roberts, Director of the University of California Cooperative Extension, Kings County. Westlake Farms generously provided both use of the land for this experiment and helped with logistical support. We are grateful to all of these people and organizations. Steven Oncley is especially acknowledged for his great efforts in organizing EBEX. We acknowledge support from NSF under AGS0847549. Yu Zhang’s Post-doc work was partly supported by NOAA Howard-NCAS under grant no. NA06OAR4810172. Heping Liu’s participation in EBEX was partly supported by City University of Hong Kong (grant 8780046 and SRG 7001038). We thank two anonymous reviewers for their valuable comments.


  1. Antonia RA, Chambers AJ, Friehe CA, Van Atta CW (1979) Temperature ramps in the atmospheric surface layer. J Atmos Sci 36:99–108CrossRefGoogle Scholar
  2. Barthlott C, Drobinski P, Fesquet C, Dubos T, Pietras C (2007) Long-term study of coherent structures in the atmospheric surface layer. Boundary-Layer Meteorol 125:1–24CrossRefGoogle Scholar
  3. Bergström H, Högström U (1989) Turbulent exchange above a pine forest. II. Organized structures. Boundary-Layer Meteorol 49:231–263CrossRefGoogle Scholar
  4. Brunet Y, Collineau S (1994) Diurnal and nocturnal turbulence above a maize crop. In: Foufoula-Georgiou E, Kumar P (eds) Wavelets in geophysics. Academic, New York, pp 129–150Google Scholar
  5. Brunet Y, Irvine MR (2000) The control of coherent eddies in vegetation canopies: streamwise structure spacing, canopy shear scale and atmospheric stability. Boundary-Layer Meteorol 94:139–163CrossRefGoogle Scholar
  6. Cava D, Giostra U, Siqueira MB, Katul GG (2004) Organised motion and radiative perturbations in the nocturnal canopy sublayer above an even-aged pine forest. Boundary-Layer Meteorol 112:129–157CrossRefGoogle Scholar
  7. Chen J, Hu F (2003) Coherent structures detected in atmospheric boundary-layer turbulence using wavelet transforms at Huaihe river basin, China. Boundary-Layer Meteorol 107:429–444CrossRefGoogle Scholar
  8. Chen H, Chen J, Hu F, Zeng Q (2004) The coherent structure of water vapour transfer in the unstable atmospheric surface layer. Boundary-Layer Meteorol 111:543–552CrossRefGoogle Scholar
  9. Collineau S, Brunet Y (1993a) Detection of turbulent coherent motions in a forest canopy. Part I: wavelet analysis. Boundary-Layer Meteorol 65:357–379Google Scholar
  10. Collineau S, Brunet Y (1993b) Detection of turbulent coherent motions in a forest canopy. Part II: time-scales and conditional averages. Boundary-Layer Meteorol 66:49–73CrossRefGoogle Scholar
  11. Farge M (1992) Wavelet transforms and their applications to turbulence. Annu Rev Fluid Mech 24:395–457CrossRefGoogle Scholar
  12. Feigenwinter C, Vogt R (2005) Detection and analysis of coherent structures in urban turbulence. Theor Appl Climatol 81:219–230CrossRefGoogle Scholar
  13. Finnigan J (1979) Turbulence in waving wheat. II. Structure of momentum transfer. Boundary-Layer Meteorol 16:213–236CrossRefGoogle Scholar
  14. Finnigan J (2000) Turbulence in plant canopies. Annu Rev Fluid Mech 32:519–571CrossRefGoogle Scholar
  15. Foken T (2008) The energy balance closure problem: an overview. Ecol Appl 18:1351–1367CrossRefGoogle Scholar
  16. Gao W, Li BL (1993) Wavelet analysis of coherent structure at the atmosphere–forest interface. J Appl Meteor 32:1717–1725CrossRefGoogle Scholar
  17. Gao W, Shaw RH, Paw UKT (1989) Observation of organized structure in turbulent flow within and above a forest canopy. Boundary-Layer Meteorol 47:349–377CrossRefGoogle Scholar
  18. Gao W, Shaw RH, Paw UKT (1992) Conditional analysis of temperature and humidity microfronts and ejection/sweep motions within and above a deciduous forest. Boundary-Layer Meteorol 59:35–57CrossRefGoogle Scholar
  19. Katul GG, Kuhn G, Schieldge J, Hsieh CI (1997) The ejection–sweep character of scalar fluxes in the unstable surface layer. Boundary-Layer Meteorol 83:1–26CrossRefGoogle Scholar
  20. Kohsiek W, Liebethal C, Foken T, Vogt R, Oncley SP, Bernhofer C, de Bruin HAR (2007) The energy balance experiment EBEX-2000. Part III: behaviour and quality of the radiation measurements. Boundary-Layer Meteorol 123:55–75CrossRefGoogle Scholar
  21. Krusche N, De Oliveira AP (2004) Characterization of coherent structures in the atmospheric surface layer. Boundary-Layer Meteorol 110:191–211CrossRefGoogle Scholar
  22. Kumar P, Foufoula-Georgiou E (1994) Wavelet analysis in geophysics: an introduction. In: Foufoula-Georgiou E, Kumar P (eds) Wavelet analysis and its application. Academic, San Diego, pp 1–43Google Scholar
  23. Lu CH, Fitzjarrald DR (1994) Seasonal and diurnal variations of coherent structures over a deciduous forest. Boundary-Layer Meteorol 69:43–69CrossRefGoogle Scholar
  24. Mauder M, Jegede OO, Wimmer F, Foken T (2007a) Surface energy balance measurements at a tropical site in West Africa during the transition from dry to wet season. Theor Appl Climatol 89:171–183CrossRefGoogle Scholar
  25. Mauder M, Oncley SP, Vogt R, Weidinger T, Ribeiro L, Bernhofer C, Foken T, Kohsiek W, De Bruin HAR, Liu H (2007b) The energy balance experiment EBEX-2000. Part II: Intercomparison of eddy-covariance sensors and post-field data processing methods. Boundary-Layer Meteorol 123:39–54CrossRefGoogle Scholar
  26. Oncley SP, Foken T, Vogt R, Kohsiek W, de Bruin HAR, Bernhofer C, Christen A, van Gorsel E, Grantz D, Feigenwinter C, Lehner I, Liebethal C, Liu H, Mauder M, Pitacco A, Ribeiro L, Weidinger T (2007) The energy balance experiment EBEX-2000. Part I: overview and energy balance. Boundary-Layer Meteorol 123:1–28CrossRefGoogle Scholar
  27. Paw UKT, Brunet Y, Collineau S, Shaw RH, Maitani T, Qiu J, Hipps LE (1992) On coherent structures in turbulence above and within agricultural plant canopies. Agric For Meteorol 61:55–68CrossRefGoogle Scholar
  28. Poggi D, Porporato A, Ridolfi L, Albertson JD, Katul GG (2004) The effect of vegetation density of canopy sub-layer turbulence. Boundary-Layer Meteorol 111:565–587CrossRefGoogle Scholar
  29. Qiu J, KT PU, Shaw RH (1995) Pseudo-wavelet analysis of turbulence patterns in three vegetation layers. Boundary-Layer Meteorol 72:177–204CrossRefGoogle Scholar
  30. Raupach MR, Finnigan JJ, Brunet Y (1996) Coherent eddies and turbulence in vegetation canopies: the mixing-layer analogy. Boundary-Layer Meteorol 78:351–382CrossRefGoogle Scholar
  31. Robinson SK (1991) Coherent motions in the turbulent boundary layer. Annu Rev Fluid Mech 23:601–639CrossRefGoogle Scholar
  32. Shaw RH, Tavangar J, Ward DP (1983) Structure of the Reynolds stress in a canopy layer. J Clim Appl Meteorol 22:1922–1931CrossRefGoogle Scholar
  33. Thomas C, Foken T (2005) Detection of long-term coherent exchange over spruce forest using wavelet analysis. Theor Appl Climatol 80:91–104CrossRefGoogle Scholar
  34. Thomas C, Foken T (2007a) Flux contribution of coherent structures and its implication for the exchange of energy and matter in a tall spruce canopy. Boundary-Layer Meteorol 123:317–337CrossRefGoogle Scholar
  35. Thomas C, Foken T (2007b) Organised motion in a tall spruce canopy: temporal scales, structure spacing and terrain effects. Boundary-Layer Meteorol 122:123–147CrossRefGoogle Scholar
  36. Thomas C, Mayer JC, Meixner FX, Foken T (2006) Analysis of low-frequency turbulence above tall vegetation using a Doppler sodar. Boundary-Layer Meteorol 119:563–587CrossRefGoogle Scholar
  37. Wesson KH, Katul GG, Siqueira MB (2003) Quantifying organization of atmospheric turbulent eddy motion using nonlinear time series analysis. Boundary-Layer Meteorol 106:507–525CrossRefGoogle Scholar
  38. Wilczak JM (1984) Large-scale eddies in the unstably stratified atmospheric surface layer. Part I: velocity and temperature structure. J Atmos Sci 41:3537–3550CrossRefGoogle Scholar
  39. Zhang G, Thomas C, Leclerc MY, Karipot A, Gholz HL, Binford M, Foken T (2007) On the effect of clearcuts on turbulence structure above a forest canopy. Theor Appl Climatol 88:133–137CrossRefGoogle Scholar
  40. Zhang Y, Liu H, Foken T, Williams QL, Liu S, Mauder M, Liebethal C (2010) Turbulence spectra and cospectra under the influence of large-scale coherent eddies in the energy balance experiment (EBEX). Boundary-Layer Meteorol (in revision)Google Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Yu Zhang
    • 1
  • Heping Liu
    • 1
    Email author
  • Thomas Foken
    • 2
  • Quinton L. Williams
    • 1
  • Matthias Mauder
    • 3
  • Christoph Thomas
    • 4
  1. 1.Department of Physics, Atmospheric Sciences and GeoscienceJackson State UniversityJacksonUSA
  2. 2.Department of MicrometeorologyUniversity of BayreuthBayreuthGermany
  3. 3.Karlsruhe Institute of TechnologyInstitute for Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU)Garmisch-PartenkirchenGermany
  4. 4.College of Oceanic and Atmospheric SciencesOregon State UniversityCorvallisUSA

Personalised recommendations