Global ETD Search

1	Effect of snow interception on the energy balance above deciduous and coniferous forests during a snowy winter Suzuki, Kazuyoshi, Nakai, Yuichiro, Ohta, Takeshi, Nakamura, Tsutomu, Ohata, Tetsuo 07 1900 (has links) No description available. aerodynamic and canopy resistance coniferous forest deciduous forest energy balance snow interception
2	Seasonal variation in the energy and water exchanges above and below a larch forest in eastern Siberia Ohta, Takeshi, Hiyama, Tetsuya, Tanaka, Hiroki, Kuwada, Takeshi, Maximov, Trofim C., Ohata, Tetsuo, Fukushima, Yoshihiro 15 June 2001 (has links) No description available. Siberian larch forest Energy and water balance Canopy resistance Land surface condition GAME-Siberia
3	Surface Conductance of Five Different Crops Based on 10 Years of Eddy-Covariance Measurements Spank, Uwe, Köstner, Barbara, Moderow, Uta, Grünwald, Thomas, Bernhofer, Christian 16 January 2017 (has links) (PDF) The Penman-Monteith (PM) equation is a state-of-the-art modelling approach to simulate evapotranspiration (ET) at site and local scale. However, its practical application is often restricted by the availability and quality of required parameters. One of these parameters is the canopy conductance. Long term measurements of evapotranspiration by the eddy-covariance method provide an improved data basis to determine this parameter by inverse modelling. Because this approach may also include evaporation from the soil, not only the ‘actual’ canopy conductance but the whole surface conductance (gc) is addressed. Two full cycles of crop rotation with five different crop types (winter barley, winter rape seed, winter wheat, silage maize, and spring barley) have been continuously monitored for 10 years. These data form the basis for this study. As estimates of gc are obtained on basis of measurements, we investigated the impact of measurements uncertainties on obtained values of gc. Here, two different foci were inspected more in detail. Firstly, the effect of the energy balance closure gap (EBCG) on obtained values of gc was analysed. Secondly, the common hydrological practice to use vegetation height (hc) to determine the period of highest plant activity (i.e., times with maximum gc concerning CO2-exchange and transpiration) was critically reviewed. The results showed that hc and gc do only agree at the beginning of the growing season but increasingly differ during the rest of the growing season. Thus, the utilisation of hc as a proxy to assess maximum gc (gc,max) can lead to inaccurate estimates of gc,max which in turn can cause serious shortcomings in simulated ET. The light use efficiency (LUE) is superior to hc as a proxy to determine periods with maximum gc. Based on this proxy, crop specific estimates of gc,maxcould be determined for the first (and the second) cycle of crop rotation: winter barley, 19.2 mm s−1 (16.0 mm s−1); winter rape seed, 12.3 mm s−1 (13.1 mm s−1); winter wheat, 16.5 mm s−1 (11.2 mm s−1); silage maize, 7.4 mm s−1 (8.5 mm s−1); and spring barley, 7.0 mm s−1 (6.2 mm s−1). Baldachin Leitfähigkeit Baldachin Widerstand Energie-Balance-Verschluss Fehleranalyse Evapotranspiration hydrologische Modellierung leichte Gebrauchseffizienz Penman-Monteith-Ansatz Baustellenwasser Budget Bodenverdampfung Transpiration Unsicherheitsbewertung TU Dresden Publikationsfonds big leaf model canopy conductance canopy resistance energy balance closure error analysis evapotranspiration hydrological modelling light use efficiency Penman-Monteith approach site water budget soil evaporation transpiration uncertainty assessment TU Dresden Publishing Fund ddc:550 rvk:UA 1000
4	Surface Conductance of Five Different Crops Based on 10 Years of Eddy-Covariance Measurements Spank, Uwe, Köstner, Barbara, Moderow, Uta, Grünwald, Thomas, Bernhofer, Christian 16 January 2017 (has links) The Penman-Monteith (PM) equation is a state-of-the-art modelling approach to simulate evapotranspiration (ET) at site and local scale. However, its practical application is often restricted by the availability and quality of required parameters. One of these parameters is the canopy conductance. Long term measurements of evapotranspiration by the eddy-covariance method provide an improved data basis to determine this parameter by inverse modelling. Because this approach may also include evaporation from the soil, not only the ‘actual’ canopy conductance but the whole surface conductance (gc) is addressed. Two full cycles of crop rotation with five different crop types (winter barley, winter rape seed, winter wheat, silage maize, and spring barley) have been continuously monitored for 10 years. These data form the basis for this study. As estimates of gc are obtained on basis of measurements, we investigated the impact of measurements uncertainties on obtained values of gc. Here, two different foci were inspected more in detail. Firstly, the effect of the energy balance closure gap (EBCG) on obtained values of gc was analysed. Secondly, the common hydrological practice to use vegetation height (hc) to determine the period of highest plant activity (i.e., times with maximum gc concerning CO2-exchange and transpiration) was critically reviewed. The results showed that hc and gc do only agree at the beginning of the growing season but increasingly differ during the rest of the growing season. Thus, the utilisation of hc as a proxy to assess maximum gc (gc,max) can lead to inaccurate estimates of gc,max which in turn can cause serious shortcomings in simulated ET. The light use efficiency (LUE) is superior to hc as a proxy to determine periods with maximum gc. Based on this proxy, crop specific estimates of gc,maxcould be determined for the first (and the second) cycle of crop rotation: winter barley, 19.2 mm s−1 (16.0 mm s−1); winter rape seed, 12.3 mm s−1 (13.1 mm s−1); winter wheat, 16.5 mm s−1 (11.2 mm s−1); silage maize, 7.4 mm s−1 (8.5 mm s−1); and spring barley, 7.0 mm s−1 (6.2 mm s−1). info:eu-repo/classification/ddc/550 ddc:550

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