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Improvement of CO2 eddy fluxes modelling in topographically complex terrain
Šigut, Ladislav
Annual sums of net ecosystem exchange (NEE) estimated by eddy covariance method (EC) are often used for comparisons among sites. But application of EC in topographically complex terrain restrains application of standard methods for their estimation. Analysis of friction air velocity response of night-time CO2 fluxes and estimation of mean daily ecosystem respiration from daytime NEE showed that night-time data and fluxes measured early after sunrise or late before sunset are not sufficiently reliable for computation of accurate annual sums of NEE. Therefore presented method takes into account auxiliary soil chamber measurements and applies correction factor in ecosystem respiration model calibrated to biomass inventory results. Also automated algorithm for computation of light response curve parameters in constrained range was established. This method produced accurate annual sums of NEE that were only 7.2% ± 5.2 higher than values determined by biomass inventory method.
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Liquidation of Brominated Flame Retardants from Waste Water
Vajglová, Zuzana ; Vychodilová, Hana ; Kotas, Petr ; Jiřičný, Vladimír
In this work we focused on the degradation method with a high potential for degradation of polybrominated diphenyl ethers from liquid waste. Very good results were achieved with the chemical degradation methods using nanostructured iron. Electrochemical method gave the best results of degradation of PBDE. Within the frame of this work we have used for the first time an electrochemical microreactor whose application in this context has not been described in the literature. The obtained original experimental results confirm the significantly higher efficiency and speed of degradation in comparison with the classic electrochemical reactor and chemical methods of PBDE degradation.
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Transpiration and biomass increment in short rotation poplar coppice
Orság, Matěj ; Fischer, Milan ; Trnka, Miroslav ; Kučera, J. ; Žalud, Zdeněk
This paper deals with interaction between amount of water lost by tree transpiration and aboveground biomass increment in poplar based short rotation coppice in conditions of CzechMoravian highlands. Stem sap-flow measured on 8 poplar trees by Granier heat dissipation method was put in relation with biomass increments measured both with automated dendrometers so with manual measurements with caliper gauge. Transpiration totals ranged between 28.3–175.6 liters per tree in executed period 3.8.–31.8.2011. Above-ground biomass increments in this period varied between 30.07–519.28 g per tree and mean value of water use efficiency of all monitored trees reached 2.76 g.kg–1. Mean diurnal sap-flow total of all sampled trees was 3.25 liters. Results show that it is possible to establish relationship between transpiration totals and biomass increments (coefficient of determination R2 = 0.90) and also relationship between transpiration totals and stem diameter (R2 = 0.81). These results (especially after obtaining experimental data from spring growth conditions) can be further used for calculations of biomass increments and transpiration as scaling factors from tree level to whole stand level.
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Evapotranspiration of selected agricultural and forest species
Kučera, J. ; Urban, J. ; Trnka, Miroslav ; Fischer, Milan ; Krofta, K. ; Duffková, R.
The aim of this article is a comparison of evapotranspiration (ET) of different covers (turf grass, clover (Trifolium pratense), winter wheat (Triticum aestivum), hops (Humulus lupulus) and the high density poplar stand (J-105, Populus nigra x Populus Maximowiczii)) with the potential evapotranspiration (PET) and the general description the ET rates dynamic during the season. The second goal is to quantify the ratio of the transpiration and the whole evapotranspiration for the two contrasting cultures – the hops and poplars stand. The daily maximal sum of the grass ET reached, similarly like for the other species, up to 5–6 mm per day, which comprises 85–93 % of PET. Significantly higher ET was showed by the culture of clover. On the other hand, the lowest values were performed by the poplar stand in the first year after coppicing. The transpiration to evapotranspiration ratio resulted in 40–70 % by the hops and 80–90 % in case of the poplars.
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Water balance in short rotation poplar coppice and reference grass-plot in conditions of Czech-Moravian Highlands
Orság, Matěj ; Fischer, Milan ; Trnka, Miroslav ; Hlavinka, Petr ; Kučera, J. ; Balek, J. ; Žalud, Zdeněk
This text presents results of a study focusing on differences of water balance between two contrasting cultures - short rotation poplar coppice and grass plot in conditions of Czech-Moravian Highlands. Actual evapotranspiration (by Bowen ratio energy balance method), precipitation and soil moisture in two layers (0 – 0.45 m and 0.45 – 0.90 m) were measured on both plots during seasons 2008 – 2010. The seasonal water lost through evapotranspiration was higher for the grass (560.4 and 508 mm for grass and 523.8 and 351.8 mm for poplar during growing season 2009 and 2010 respectively), but generally the observed amounts of ETa are comparable for both cultures and within the range of values described in literature. Results of soil moisture measurements expressed as soil water availability [mm] were compared with simulations obtained from water balance model SoilClim. The model a little bit underestimated the amount of available water in the system, since based on water balance closure we suggest that there is a higher water income than was recorded from precipitation. This extra water found in observed systems may be supplied probably by lateral underground water inflow from the upper fields.
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Water-use effeciency-different computation strategies
Slípková, Romana
Water use efficiency (WUE) of the plants can be expressed as a ratio weight of biomass increment and consumed water. Two Norway spruce (Picea abies (L.) Karst) in density 1820 individuals ha-1 (FS) and 2440 individuals ha-1 (FD) in Bílý Kříž study site were studied during growing season 2003. WUE (g l-1) in this study was calculated as a ratio of total aboveground biomass increment (TB) defined by two approaches and stand transpiration. TB was defined by (i) one allometric relationship of diameter of the trunk in breast height and total aboveground biomass and (ii) as a sum of increment of stem, branch and leaves biomass allometrically obtained separately. Resulted WUE was marked as WUEI and WUEII. Mean WUEI was in FS 6,5 g l-1 and FD 14,0 g l-1; in case of WUEII FS 4,9 g.l-1 and FD 10,1 g.l-1, any difference was not significant. TBI was significantly higher than TBII in FD. We recommend WUEII approach for long term WUE evaluation.
Fulltext: content.csg - PDF
Plný tet: Slípková_SylvaNet WoodNet 2010 - PDF
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Energy balance of a mountain spruce forest. Definition, importance and utilization
Slípková, Romana
Incident solar radiation gives a potential for utilitation and convertion of this energy. Budget between available energy and turbulent sensible and latent heat fluxes we call energy balance closure. We have studied a forest in a mountain region in the Beskydy Mountains in the Czech Republic. Amount of available energy was higher for about 29% on average than amount of turbulent fluxes. In general, we have observed a 9% higher disbalance compared to the other FLUXNET sites. This difference might be caused by overestimation of the available energy and/or underestimation of the turbulent fluxes. Both of these hypothesis will be taken into account in the next research of the energy balance closure.
Fulltext: content.csg - PDF
Plný tet: Slípková_Romana_SilvaNet-WoodNet - PDF
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Potentials of the hyperspectral remote sensing - Aisa Eagle system and future perspectives
Lukeš, Petr ; Hanuš, Jan ; Kaplan, Věroslav ; Zemek, František
Since 2004 the Global Change Research Centre (CVGZ) operates a hyperspectral airborne imaging system AISA Eagle. A basic introduction to hyperspectral remote sensing and its potential applications in science as well as for commercial and military uses are presented, followed by a description of the system together with an overview of the key data pre-processing steps. The application of a rapidly developing technology, hyperspectral remote sensing, is presented within the field of quantitative remote sensing of plant health status. Finally, the future development of hyperspectral remote sensing at the CVGZ is outlined.
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