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New tool for CO 2 flux partitioning with soil chamber flux implementation as a solution for site in topographically complex terrain Šigut, L., Mammarella, I., Kolari, P., Dařenová, E., Novosadová, K., Pietras, J., Pokorný, R., Sedlák, P., Mauder, M.
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Eddy covariance Fluxes of matter and energy in halfhour resolution Annual sum of NEE – the most important product Separation of NEE into GPP and R eco by simple models Fluxes of matter and energy in halfhour resolution Annual sum of NEE – the most important product Separation of NEE into GPP and R eco by simple models
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Light response curve (LRC) Temperature response curve (TRC) NEE GPP R eco
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MR05 (Reichstein et al., 2005) Nighttime based R eco estim.; temperature response curve (TRC) fitting GL10 (Lasslop et al., 2010) Daytime based R eco estim.; TRC + light response curve (LRC) fitting –only R eco temperature sensitivity from nighttime data Both of these are accesible online (http://www.bgc-jena.mpg.de/~MDIwork/eddyproc)http://www.bgc-jena.mpg.de/~MDIwork/eddyproc R script (here proposed new tool) Combined nighttime and daytime R eco estim.; TRC + LRC fitting
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Iterative TRC and LRC fitting
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Proper seasonality removal is really important – changing time window size according to data coverage – respiration sensitivity to temperature: 10 °C range – light response curve: PAR range meeting requirements (for alpha 150 µmol m -2 s -1, A max 500 µmol m -2 s -1 )
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Basic assumptions Homogenous vegetation Flat terrain Homogenous vegetation Flat terrain Bílý Kříž Beskydy Mts., Czech republic (877 m a.s.l., avg T=6.7 ± 1.1 °C) Norway Spruce monoculture 13° slope – advection Complex windflows, decoupling Beskydy Mts., Czech republic (877 m a.s.l., avg T=6.7 ± 1.1 °C) Norway Spruce monoculture 13° slope – advection Complex windflows, decoupling Advection
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Biotic CO 2 flux Biotic ≠ measured CO 2 flux Mainly nighttime problems –R eco affected u * -filtering – standard Cannot be used for the site Biotic ≠ measured CO 2 flux Mainly nighttime problems –R eco affected u * -filtering – standard Cannot be used for the site Guan et al. 2006
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Not filtered u * -filtered NEP = GPP - R eco NPP = GPP - R A
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Raich a Schlesinger, 1992: R soil = 40 – 80 % of R eco Kolari et al., 2009
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Measurements only during growing season (May-Oct) 1)keep nighttime eddy covariance data outside GS Measurements only during growing season (May-Oct) 1)keep nighttime eddy covariance data outside GS
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Measurements only during growing season (May-Oct) 2)use chamber based estimates outside of GS Measurements only during growing season (May-Oct) 2)use chamber based estimates outside of GS windfall the longest GS LAI increase
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Seasonality removal should get more attention R script for flux partitioning produces defensible NEP Seasonality removal should get more attention R script for flux partitioning produces defensible NEP R script Complex site Single value of R soil /R eco ratio not valid for all years Lack of chamber measurement outside GS is probably causing R eco under- (1)/overestimation (2) in selected approaches Interanual changes in stand density, LAI and GS length explain the best the observed NEP pattern Single value of R soil /R eco ratio not valid for all years Lack of chamber measurement outside GS is probably causing R eco under- (1)/overestimation (2) in selected approaches Interanual changes in stand density, LAI and GS length explain the best the observed NEP pattern
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University of Ostrava: OU SGS20/PřF/2014 Global Change Research Centre AS CR, v. v. i. CZ.1.05/1.1.00/02.0073, CZ.1.07/2.4.00/31.0056 University of Helsinki MICMoR graduate programme Bionetwork University of Ostrava: OU SGS20/PřF/2014 Global Change Research Centre AS CR, v. v. i. CZ.1.05/1.1.00/02.0073, CZ.1.07/2.4.00/31.0056 University of Helsinki MICMoR graduate programme Bionetwork
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