Abstract
Little is known about the influence of coherent structures on the exchange process, mainly in the case of forest edges. Thus, in the framework of the ExchanGE processes in mountainous Regions (EGER) project, measurements of atmospheric turbulence were taken at different heights between a forest and an adjacent clear cutting using sonic anemometers and high-frequency optical gas analyzers. From these turbulence data, dominant coherent structures were extracted using an already existing wavelet methodology, which was developed for homogeneous forest canopies. The aim of this study is to highlight differences in properties of coherent structures between a forest and a clear cutting. Distinct features of coherent exchange at the forest edge are presented and a careful investigation of vertical and horizontal coupling by coherent structures around the surface heterogeneity is made. Within the forest, coherent structures are less frequent but possess larger time scales, indicating that only the largest coherent motions can penetrate through the forest canopy. At the forest edge, there is no crown layer that can hinder the vertical exchange of coherent structures, because these exhibit similar time scales at all heights. In contradiction to that, no improved vertical coupling was detected at the forest edge. This is mainly because the structures captured by the applied routine contribute less to total turbulent fluxes at the edge than within the forest. Thus, coherent structures with time scales between 10 and 40 s are not the dominant exchange mechanism at the forest edge. With respect to the horizontal direction, a consistent picture of coherent transport could be derived: along the forest edge there is mainly good coupling by coherent structures, whereas perpendicular to the forest edge there is mainly decoupling. Finally, it was found that there is a systematic modulation of coherent structures directly at the forest edge: strong ejection motions appear in all time series during the daytime, whereas strong sweeps dominate at night. An effect of wind direction relative to the forest edge is excluded. Consequently, it is hypothesized that this might be an indication of a quasi-stationary secondary circulation above the clear cutting that develops due to differences in surface temperature and roughness. Such circulations might be a relevant turbulent transport mechanism for ecosystem-atmosphere exchange in heterogeneous landscapes.
Similar content being viewed by others
References
Amiro BD (1990) Comparison of turbulence statistics within three boreal forest canopies. Boundary-Layer Meteorol 51:99–121
Antonia RA (1981) Conditional sampling in turbulence measurement. Annu Rev Fluid Mech 13:131–156
Aubinet M, Feigenwinter C, Heinesch B, Bernhofer C, Canepa E, Lindroth A, Montagnani L, Rebmann C, Sedlak P, Van Gorsel E (2010) Direct advection measurements do not help to solve the night-time \(\text{ CO }_2\) closure problem: evidence from three different forests. Agric For Meteorol 150:655–664
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 Ecolog Res 30:113–175
Aubinet M, Heinesch B, Yernaux M (2003) Horizontal and vertical \(\text{ CO }_2\) advection in a sloping forest. Boundary-Layer Meteorol 108:397–417
Baldocchi DD, Meyers TP (1988) A spectral and lag-correlation analysis of turbulence in a deciduous forest canopy. Boundary-Layer Meteorol 45:31–58
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 125:1–24
Bergström H, Högström U (1989) Turbulent exchange above a pine forest II. Organized structures. Boundary-Layer Meteorol 49:231–263
Cantwell BJ (1981) Organized motion in turbulent flow. Annu Rev Fluid Mech 13:457–515
Cassiani M, Katul GG, Albertson JD (2008) The effects of canopy leaf area index on airflow across forest edges: large-eddy simulation and analytical results. Boundary-Layer Meteorol 126:433–460
Cava D, Giostra U, Siqueira M, Katul G (2004) Organised motion and radiative perturbations in the nocturnal canopy sublayer above an even-aged pine forest. Boundary-Layer Meteorol 112:129–157
Cellier P, Brunet Y (1992) Flux-gradient relationships above tall plant canopies. Agric For Meteorol 58:93–117
Collineau S, Brunet Y (1993a) Detection of turbulent coherent motions in a forest canopy part I: wavelet analysis. Boundary-Layer Meteorol 65:357–379
Collineau S, Brunet Y (1993b) Detection of turbulent coherent motions in a forest canopy part II: time-scales and conditional averages. Boundary-Layer Meteorol 66:49–73
Denmead OT, Bradley EF (1985) Flux-gradient relationships in a forest canopy. In: Hutchinson BA, Hicks BB (eds) The forest-atmosphere interaction. D. Reidel Publishing Company, Dordrecht, pp 421–442
Denmead OT, Bradley EF (1987) On scalar transport in plant canopies. Irrig Sci 8:131–149
Detto M, Katul GG, Siqueira M, Juang JY, Stoy P (2008) The structure of turbulence near a tall forest edge: the backward-facing step flow analogy revisted. Ecol Appl 18:1420–1435
Dupont S, Brunet Y (2009) Coherent structures in canopy edge flow: a large-eddy simulation study. J Fluid Mech 630:93–128
Dupont S, Irvine M, Bonnefond JM, Lamaud E, Brunet Y (2012) Turbulent structures in a pine forest with a deep and sparse trunk space: stand and edge regions. Boundary-Layer Meteorol 143:309–336
Fazu C, Schwerdtfeger P (1989) Flux-gradient relationships for momentum and heat over a rough natural surface. Q J R Meteorol Soc 115:335–352
Feigenwinter C, Vogt R (2005) Detection and analysis of coherent structures in urban turbulence. Theor Appl Climatol 81:219–230
Finnigan J (1979) Turbulence in waving wheat. Boundary-Layer Meteorol 16:213–236
Finnigan J (2000) Turbulence in plant canopies. Annu Rev Fluid Mech 32:519–571
Foken T (2008a) Micrometeorology. Springer, Heidelberg, p 308
Foken T (2008b) The energy balance closure problem: an overview. Ecol Appl 18:1351–1367
Foken T, Leuning R, Oncley SR, Mauder M, Aubinet M (2012a) Corrections and data quality control. In: Aubinet M, Vesala T, Papale D (eds) Eddy covariance: a practical guide to measurement and data analysis. Springer, Dordrecht, pp 85–131
Foken T, Meixner FX, Falge E, Zetzsch C, Serafimovich A, Bargsten A, Behrendt T, Biermann T, Breuninger C, Dix S, Gerken T, Hunner M, Lehmann-Pape L, Hens K, Jocher G, Kesselmeier J, Lüers J, Mayer J-C, Moravek A, Plake D, Riederer M, Rütz F, Scheibe M, Siebicke L, Sörgel M, Staudt K, Trebs I, Tsokankunku A, Welling M, Wolff V, Zhu Z (2012b) Coupling processes and exchange of energy and reactive and non-reactive trace gases at a forest site: results of the EGER experiment. Atmos Chem Phys 12:1923–1950
Foufoula-Georgiou E, Kumar P (1994) Wavelet analysis in geophysics: an introduction. In: Foufoula-Georgiou E, Kumar P (eds) Wavelets in geophysics. Academic Press, San Diego, pp 1–44
Gao W, Shaw RH, Paw UKT (1989) Observation of organized structure in turbulent flow within and above a forest canopy. Boundary-Layer Meteorol 47:349–377
Garratt JR (1978) Flux profile relations above tall vegetation. Q J R Meteorol Soc 104:199–211
Garratt JR (1980) Surface influence upon vertical profiles in the atmospheric near-surface layer. Q J R Meteorol Soc 106:803–819
Gerstberger P, Foken T, Kalbitz K (2004) The Lehstenbach and Steinkreuz catchments in NE Bavaria, Germany. In: Matzner E (ed) Biogeochemistry of forested catchments in a changing environment: a german case study. Springer, Berlin, pp 15–41
Glickman TS (ed) (2000) Glossary of meteorology, 2nd edn. American Meteorological Society, Boston, p 855
Goeckede M, Thomas C, Markkanen T, Mauder M, Ruppert J, Foken T (2007) Sensitivity of Lagrangian stochastic footprints to turbulence statistics. Tellus B 59:577–586
Grossmann A, Kronland-Martinet R, Morlet J (1989) Reading and understanding continous wavelet transforms. In: Combes JM, Grossmann A, Tchamitchian P (eds) Wavelets: time-frequency methods and phase space. Springer, New York, pp 2–20
Grossmann A, Morlet J (1984) Decomposition of hardy functions into square integrable wavelets of constant shape. SIAM J Math Anal 15:723–736
Harman I, Finnigan J (2007) A simple unified theory for flow in the canopy and roughness sublayer. Boundary-Layer Meteorol 123:339–363
Harman I, Finnigan J (2008) Scalar concentration profiles in the canopy and roughness sublayer. Boundary-Layer Meteorol 129:323–351
Holmes P, Lumley JL, Berkooz G (1996) Turbulence, coherent structures, dynamical systems and symmetry. Cambridge University Press, New York, p 420
Huang J, Cassiani M, Albertson J (2011) Coherent turbulent structures across a vegetation discontinuity. Boundary-Layer Meteorol 140:1–22
Inagaki A, Castillo M, Yamashita Y, Kanda M, Takimoto H (2012) Large-eddy simulation of coherent flow structures within a cubical canopy. Boundary-Layer Meteorol 142:207–222
Katul G, Poggi D, Cava D, Finnigan J (2006) The relative importance of ejections and sweeps to momentum transfer in the atmospheric boundary layer. Boundary-Layer Meteorol 120:367–375
Klaassen W, Breugel PB, Moors EJ, Nieveen JP (2002) Increased heat fluxes near a forest edge. Theor Appl Climatol 72:231–243
Kline SJ, Reynolds WC, Schraub FA, Runstadler PW (1967) The structure of turbulent boundary layers. J Fluid Mech 30:741–773
Kronland-Martinet R, Morlet J, Grossmann A (1987) Analysis of sound patterns through wavelet transforms. Int J Pattern Recog 1:273–302
Leclerc MY, Karipot A, Prabha T, Allwine G, Lamb B, Gholz HL (2003) Impact of non-local advection on flux footprints over a tall forest canopy: a tracer flux experiment. Agric For Meteorol 115:19–30
Lu CH, Fitzjarrald DR (1994) Seasonal and diurnal variations of coherent structures over a deciduous forest. Boundary-Layer Meteorol 69:43–69
Lu SS, Willmarth WW (1973) Measurements of the structure of the Reynolds stress in a turbulent boundary layer. J Fluid Mech 60:481–511
Mahrt L (2010) Computing turbulent fluxes near the surface: needed improvements. Agric For Meteorol 150:501–509
Maitani T, Shaw RH (1990) Joint probability analysis of momentum and heat fluxes at a deciduous forest. Boundary-Layer Meteorol 52:283–300
Paw UKT, Brunet Y, Collineau S, Shaw RH, Maitani T, Qiu J, Hipps L (1992) On coherent structures in turbulence above and within agricultural plant canopies. Agric For Meteorol 61:55–68
Poggi D, Porporato A, Ridolfi L, Albertson JD, Katul GG (2004) The effect of vegetation density on canopy sub-layer turbulence. Boundary-Layer Meteorol 111:565–587
Raupach MR, Finnigan JJ, Brunet Y (1996) Coherent eddies and turbulence in vegetation canopies: the mixing-layer analogy. Boundary-Layer Meteorol 78:351–382
Robinson SK (1991) Coherent motions in the turbulent boundary layer. Annu Rev Fluid Mech 23:601–639
Schlegel F, Stiller J, Bienert A, Maas HG, Queck R, Bernhofer C (2012) Large-eddy simulation of inhomogeneous canopy flows using high resolution terrestrial laser scanning data. Boundary-Layer Meteorol 142:223–243
Serafimovich A, Eder F, Hübner J, Falge E, Voss L, Sörgel M, Held A, Liu Q, Eigenmann R, Huber K, Ferro Duarte H, Werle P, Gast E, Cieslik S, Liu H, and Foken T (2011) ExchanGE processes in mountaineous regions (EGER). Documentation of the intensive oberservation period (IOP3) June, 13th–July, 26th. Arbeitsergebnisse/Department of Micrometeorology, University of Bayreuth. ISSN:1614-8916. no. 47, p 137
Serafimovich A, Thomas C, Foken T (2011b) Vertical and horizontal transport of energy and matter by coherent motions in a tall spruce canopy. Boundary-Layer Meteorol 140:429–451
Shaw RH, Tavangar J, Ward DP (1983) Structure of the reynolds stress in a canopy layer. J Clim Appl Meteorol 22:1922–1931
Sogachev A, Leclerc MY, Karipot A, Zhang G, Vesala T (2005) Effect of clearcuts on footprints and flux measurements above a forest canopy. Agric For Meteorol 133:182–196
Sogachev A, Leclerc MY, Zhang G, Rannik Ü, Vesala T (2008) \(\text{ CO }_2\) fluxes near a forest edge: a numerical study. Ecol Appl 18:1454–1469
Staebler RM, Fitzjarrald DR (2004) Observing subcanopy \(\text{ CO }_2\) advection. Agric For Meteorol 122:139–156
Staudt K, Foken T (2007) Documentation of recference data for the experimental areas of the Bayreuth Centre for Ecology and Environmental Research (BayCEER) at the Waldstein site. Arbeitsergebnisse, Department of Micrometeorology, University of Bayreuth. Bayreuth. ISSN:1614–8916, no. 35, p 37
Steiner AL, Pressley SN, Botros A, Jones E, Chung SH, Edburg SL (2012) Analysis of coherent structures and atmosphere-canopy coupling strength during the CABINEX field campaign. Atmos Chem Phys 11:11921–11936
Stull RB (1988) An introduction to boundary layer meteorology. Kluwer Academic Publishers, Dordrecht, p 666
Thomas C, Foken T (2005) Detection of long-term coherent exchange over spruce forest using wavelet analysis. Theor Appl Climatol 80:91–104
Thomas C, Foken T (2007a) Flux contribution of coherent structures and its implications for the exchange of energy and matter in a tall spruce canopy. Boundary-Layer Meteorol 123:317–337
Thomas C, Foken T (2007b) Organised motion in a tall spruce canopy: temporal scales, structure spacing and terrain effects. Boundary-Layer Meteorol 122:123–147
Thomas C, Mayer JC, Meixner F, Foken T (2006) Analysis of low-frequency turbulence above tall vegetation using a Doppler sodar. Boundary-Layer Meteorol 119:563–587
Torrence C, Compo GP (1998) A practical guide to wavelet analysis. Bull Am Meteorol Soc 79:61–78
Vickers D, Mahrt L (1997) Quality control and flux sampling problems for tower and aircraft data. J Atmos Oceanic Technol 14:512
Webb EK, Pearman GI, Leuning R (1980) Correction of flux measurements for density effects due to heat and water vapour transfer. Q J R Meteorol Soc 106:85–100
Wilczak J, Oncley S, Stage S (2001) Sonic anemometer tilt correction algorithms. Boundary-Layer Meteorol 99:127–150
Wilson K, Goldstein A, Falge E, Aubinet M, Baldocchi D, Berbigier P, Bernhofer C, Ceulemans R, Dolman H, Field C, Grelle A, Ibrom A, Law BE, Kowalski A, Meyers T, Moncrieff J, Monson R, Oechel W, Tenhunen J, Valentini R, Verma S (2002) Energy balance closure at FLUXNET sites. Agric For Meteorol 113:223–243
Yang B, Morse A, Shaw R, Paw UKT (2006a) Large-eddy simulation of turbulent flow across a forest edge. Part II: momentum and turbulent kinetic energy budgets. Boundary-Layer Meteorol 121:433–457
Yang B, Raupach MR, Shaw RH, Paw UKT, Morse AP (2006b) Large-eddy simulation of turbulent flow across a forest edge. Part I: flow statistics. Boundary-Layer Meteorol 120:377–412
Zeeman MJ, Eugster W, Thomas CK (2013) Concurrency of coherent structures and conditionally sampled daytime sub-canopy respiration. Boundary-Layer Meteorol 146:1–15
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 88:133–137
Acknowledgments
This research was funded within the DFG PAK 446 project, mainly the subproject FO 226/21-1. The authors thank all participants of the experiment, especially J. Hübner, R. Eigenmann, H. Liu and S. Cieslik for their support during the field measurements.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Eder, F., Serafimovich, A. & Foken, T. Coherent Structures at a Forest Edge: Properties, Coupling and Impact of Secondary Circulations. Boundary-Layer Meteorol 148, 285–308 (2013). https://doi.org/10.1007/s10546-013-9815-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10546-013-9815-0