Forest Climate in Vertical and Horizontal Scales
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Microclimate was investigated within a heterogeneous spruce forest in Northern Bavaria, Germany, at the Waldstein–Weidenbrunnen site, especially during the EGER project in 2007, 2008 and 2011. Besides standard tower measurements, two innovative measuring techniques were used to investigate horizontal and vertical gradients. A particular focus was paid to advection within the homogeneous part and its effect on NEE, as well as gradients near a forest edge, measured by a mobile measuring system.
The forest canopy shields the below-canopy trunk space and therefore huge gradients are prevalent. However, vertical exchange is PAI-dependent and thus small gaps in the canopy (‘sunny spots’) can facilitate vertical exchange by coherent structures and alter the CO2 concentration within the trunk space. The coupling of different canopy layers also plays an important role in altering trunk space conditions. Decoupling leads to an enrichment of CO2 close to the ground with large katabatic drainage, and coupling leads to depletion. Furthermore, the investigations showed that horizontal and vertical advection contributes significantly to the net ecosystem exchange at the Waldstein–Weidenbrunnen site, especially during nighttime and transition periods.
The investigations in 2011 showed that clearings, with their forest edges, play a key role in vertical exchange in heterogeneous forests. Roughness changes and thermal differences between forests and clearings facilitate downdrafts (during night) and updrafts (during day). This leads to the highest variations in turbulent influenced quantities, like temperature, humidity and trace gas concentrations directly at the forest edge, for example. Additionally, the formation of a secondary circulation system is possible above the clearing during midday, with effects on horizontal gradients.
KeywordsCoherent Structure Forest Edge Vertical Advection Vertical Exchange Trunk Space
The full functionality and fast construction of the measurement devices would not have been possible without the support of our technician J. Olesch and the technical workshops of the University of Bayreuth. We want to thank the Max Planck Institute for Chemistry, Mainz, for the collaboration during the EGER project and for lending us measuring devices. Thanks must also go to J. Tenhunen and the company enviscope GmbH for lending us measuring devices and to the company Sick Vertriebs-GmbH for giving us a bar code scanner as a gift. Furthermore, we want to thank all PhD students of the Department of Micrometeorology, student assistants and G. Müller from BayCEER for helping us during the EGER project. This research was funded by the German Science Foundation (DFG) within the projects FO 226/16-1 and ME 2100/4-1 as well as the DFG PAK 446 project, mainly the subprojects FO226/21-1, ME 2100/5-1. The HMMS was funded by the Max-Planck-Institute for Chemistry, Mainz and the University of Bayreuth.
- Baker TP, Jordan GJ, Steel EA, Fountain-Jones NM, Wardlaw TJ, Baker SC (2014) Microclimate through space and time: microclimatic variation at the edge of regeneration forests over daily, yearly and decadal time scales. Forest Ecol Manag 334:174–184. doi: 10.1016/j.foreco.2014.09.008 CrossRefGoogle Scholar
- Baumgartner A (1956) Untersuchungen über den Wärme- und Wasserhaushalt eines jungen Waldes. Berichte des Deutschen Wetterdienstes 5, Nr. 28Google Scholar
- Closa I, Irigoyen JJ, Goicoechea N (2010) Microclimatic conditions determined by stem density influence leaf anatomy and leaf physiology of beech (Fagus sylvatica L.) growing within stands that naturally regenerate from clear-cutting. Trees 24(6):1029–1043. doi: 10.1007/s00468-010-0472-3 CrossRefGoogle Scholar
- Davies-Colley RJ, Payne GW, van Elswijk M (2000) Microclimate gradients across a forest edge. New Zeal J Ecol 24(2):111–121Google Scholar
- Dlugi R (1993) Interaction of NOx and VOC’s within vegetation. In: Borrell PW (ed) Proceedings EUROTRAC symposium ’92, SPB, Academic Publication, The Hague, pp 682–688Google Scholar
- Feigenwinter C, Bernhofer C, Eichelmann U, Heinesch B, Hertel M, Janous D, Kolle O, Lagergren F, Lindroth A, Minerbi S, Moderow U, Molder M, Montagnani L, Queck R, Rebmann C, Vestin P, Yernaux M, Zeri M, Ziegler W, Aubinet M (2008) Comparison of horizontal and vertical advective CO2 fluxes at three forest sites. Agr For Meteorol 148(1):12–24. doi: 10.1016/j.agrformet.2007.08.013 CrossRefGoogle Scholar
- Foken T, Dlugi R, Kramm G (1995) On the determination of dry deposition and emission of gaseous compounds at the biosphere-atmosphere interface. Meteorol Z 4:91–118Google Scholar
- 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 JC, 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 (2012) 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(4):1923–1950. doi: 10.5194/acp-12-1923-2012 CrossRefGoogle Scholar
- Geiger R, Aron RH, Todhunter P (2009) The climate near the ground. Rowman & Littlefield, Lanham, MDGoogle Scholar
- Hutchison BA, Hicks BB (eds) (1985) The forest-atmosphere interaction. In: Proceedings of the forest environmental measurements conference held at Oak Ridge, Tennessee, Oct 23–28, 1983, D. Reidel Publishing Company, DordrechtGoogle Scholar
- Mahrt L, Sun J, Vickers D, MacPherson JI, Pederson JR, Desjardins RL (1994) Observations of fluxes and Inland breezes over a heterogeneous surface. J Atmos Sci 51(17):2484–2499. doi: 10.1175/1520-0469(1994)051<2484:OOFAIB>2.0.CO;2
- Molemaker MJ, Vilà -Guerau de Arellano J (1998) Control of chemical reactions by convective turbulence in the boundary layer. J Atmos Sci 55(4):568–579. doi: 10.1175/1520-0469(1998)055<0568:COCRBC>2.0.CO;2
- Oke TR (1987) Boundary layer climates. Routledge Chapman & Hall, LondonGoogle Scholar
- Serafimovich A, Siebicke L, Staudt K, Lüers J, Biermann T, Schier S, Mayer JC (2008a) ExchanGE processes in mountainous Regions (EGER) - Documentation of the intensive observation period (IOP1) Sept, 6th to Oct, 7th 2007. Arbeitsergebn, University of Bayreuth, Abt Mikrometeorol. ISSN 1614-8916 36:147Google Scholar
- Serafimovich A, Siebicke L, Staudt K, Lüers J, Biermann T, Schier S, Mayer JC (2008b) ExchanGE processes in mountainous Regions (EGER) - documentation of the intensive observation period (IOP2) June, 1st to July, 15th 2008. Arbeitsergebn, University of Bayreuth, Abt Mikrometeorol. ISSN 1614-8916 37:180Google Scholar
- Serafimovich A, Eder F, Hübner J, Falge E, VoSS, Sörgel M, Held A, Liu Q, Eigenmann R, Huber K, Duarte HF, Werle P, Gast E, Cieslik S, Heping L, Foken T (2011a) ExchanGE processes in mountainous regions (EGER): documentation of the intensive observation period (IOP3) June, 13th to July, 26th 2011. Arbeitsergebn, University of Bayreuth, Abt Mikrometeorol. ISSN 1614-8916 47:137Google Scholar
- Siebicke L (2008) Footprint synthesis for the FLUXNET site Waldstein/Weidenbrunnen (DE-Bay) during the EGER experiment. Arbeitsergebn, University of Bayreuth, Abt Mikrometeorol, ISSN 1614-8916 38:49Google Scholar
- Siebicke L (2010) Advection at a forest side - an updated approach. PhD thesis, University of Bayreuth, BayreuthGoogle Scholar
- Weaver CP, Avissar R (2001) Atmospheric disturbances caused by human modification of the landscape. Bull Am Meteorol Soc 82(2):269–281. doi: 10.1175/1520-0477(2001)082<0269:ADCBHM>2.3.CO;2
- Whittaker RH (1975) Communities and ecosystems. MacMillan, New York 2nd Revised edn.Google Scholar