Olchev, Alexander

[["dc.bibliographiccitation.firstpage","122"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Ecological Modelling"],["dc.bibliographiccitation.lastpage","130"],["dc.bibliographiccitation.volume","212"],["dc.contributor.author","Olchev, A."],["dc.contributor.author","Ibrom, Andreas"],["dc.contributor.author","Ross, Thomas"],["dc.contributor.author","Falk, U."],["dc.contributor.author","Rakkibu, Golam"],["dc.contributor.author","Radler, K."],["dc.contributor.author","Grote, S."],["dc.contributor.author","Kreilein, H."],["dc.contributor.author","Gravenhorst, Gode"],["dc.date.accessioned","2018-11-07T11:17:03Z"],["dc.date.available","2018-11-07T11:17:03Z"],["dc.date.issued","2008"],["dc.description.abstract","An one-dimensional process-based SVAT model (Mixfor-SVAT) was developed to describe energy, water and carbon dioxide exchanges between vegetation canopy and the atmosphere at a local scale. Simulation of the energy, water and CO(2) fluxes in Mixfor-SVAT is based on aggregated description of the physical and biological processes on the leaf, tree (plant) and stand levels that allows to apply this model for prediction of atmospheric fluxes for the different vegetation types from grasslands and agricultural crops to vertically structured mono-specific and mixed forest stands represented by one or by many different tree species, as well as for description of the flux partitioning among different canopy sub-layers and different tree species. Upper boundary conditions of the model are measured or predicted meteorological parameters (air temperature and humidity, wind speed, CO(2) concentration, precipitation rate and global radiation) at some height above a plant canopy within the atmospheric surface layer. For simulation of exchange processes within a multi-specific forest stand Mixfor-SVAT uses both averaged and species specific biophysical parameters of the trees describing their structure (e.g. height, crown shape, stem diameter, root depth) and biological properties (e.g. leaf stomatal conductance, photosynthesis and respiration rates, etc.). Mixfor-SVAT assumes that trees of the different species are evenly distributed over some homogeneous ground surface area and that there are no differences in biophysical properties between the same tree species. Mixfor-SVAT was applied to a natural tropical rainforest in Central Sulawesi, Indonesia. The modelled H(2)O and CO(2) fluxes were compared with results of eddy covariance flux measurements above the forest canopy for the period from October 2003 to February 2005. All necessary biophysical parameters of vegetation and soil were obtained during several intensive field campaigns in 2004-2006. Comparisons showed a good agreement between modelled and measured H(2)O and CO(2) fluxes especially for smoothed daily flux trends. However, a large number of spikes in measured data series caused by some instrumental errors, sensor wetting, changes in the footprint or fast changes in turbulence conditions resulted in some reduction of correlation between modeled and measured fluxes (e.g. r(2) = 0.62 for CO(2) and r(2) = 0.64 for H(2)O fluxes under friction velocity u > 0.3 ms(-1)). The developed Mixfor-SVAT model could be applied for solutions of the different theoretical and applied tasks, e.g. to describe the response of H(2)O and CO(2) budgets of the different forest ecosystems to environmental and land use changes in different time scales, or to recover the long-term records of H(2)O and CO(2) fluxes in the cases of data loss or not reliable measured fluxes. (c) 2007 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.ecolmodel.2007.10.021"],["dc.identifier.isi","000254227100016"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54724"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","5th European Conference on Ecological Modelling"],["dc.relation.eventlocation","Pushchino, RUSSIA"],["dc.relation.issn","0304-3800"],["dc.relation.orgunit","Abteilung Bioklimatologie"],["dc.title","A modelling approach for simulation of water and carbon dioxide exchange between multi-species tropical rain forest and the atmosphere"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","131"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Ecological Modelling"],["dc.bibliographiccitation.lastpage","137"],["dc.bibliographiccitation.volume","212"],["dc.contributor.author","Olchev, A."],["dc.contributor.author","Ibrom, A."],["dc.contributor.author","Priess, J."],["dc.contributor.author","Erasmi, S."],["dc.contributor.author","Leemhuis, Constanze"],["dc.contributor.author","Twele, Andre"],["dc.contributor.author","Radler, K. H."],["dc.contributor.author","Kreilein, Heinrich"],["dc.contributor.author","Panferov, Oleg"],["dc.contributor.author","Gravenhorst, Gode"],["dc.date.accessioned","2018-11-07T11:17:04Z"],["dc.date.accessioned","2020-05-11T13:29:09Z"],["dc.date.available","2018-11-07T11:17:04Z"],["dc.date.available","2020-05-11T13:29:09Z"],["dc.date.issued","2008"],["dc.description.abstract","The impact of deforestation and land-use changes on evapotranspiration of mountainous tropical rain forest area in the northern part of the Lore-Lindu National Park (LLNP) in Central Sulawesi (Indonesia) was quantified using a regional process-based SVAT model \"SVAT-Regio\". Description of evapotranspiration of a non-uniform land surface in local and regional scales in SVAT-Regio is based on equations of energy and water balances of individual plants, plant canopy and soil layers for each of many grid cells into which the entire study area is divided. The model uses a multi-layered representation of vegetation cover and soil structure that allows to describe the partitioning of energy and H2O-fluxes among different canopy layers and soil, and to quantify more precisely the total ecosystem fluxes. Selective integration of grid cell fluxes on space and time allows estimating the energy and water fluxes for e.g. ecosystems, catchments or entire study area for different time spans from 1 day to several years. September of 2004 was selected as a test period for modelling experiments. The regional patterns of meteorological parameters were reconstructed using measurements provided by 10 mobile meteorological stations. Ecophysiological parameters for different vegetation types were determined from own measurements as well as from results of previous scientific studies in the area. The present spatial distribution of the different land-use types was described from analysis of LANDSAT ETM+ observations. The spatial pattern of leaf area index (LAI) was derived from analysis of NDVI data (calculated from LANDSAT ETM+ data) and field measurements at key experimental plots. A deforestation scenario (allowing for mainly anthropogenic impacts) which was applied in this study assumes a relatively strong decrease of the areas covered by tropical rain forests, i.e. about 15%, and an increase of agricultural (coffee plantations, corn and rice fields) and urban areas. Moreover, the scenario assumes a small increase of grassland areas as well. The results of modelling experiments show that 15% deforestation of the study area results in relatively small decrease of monthly evapotranspiration by about 2%, transpiration by about 6% and interception evaporation by about 5%, as well as an increase of soil evaporation by about 21%. The evapotranspiration decrease was highest in days with cloudy and rainy weather conditions, and lowest in sunny and dry days. (c) 2007 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.ecolmodel.2007.10.022"],["dc.identifier.isi","000254227100017"],["dc.identifier.scopus","2-s2.0-38949186752"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/65057"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54725"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-38949186752&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0304-3800"],["dc.relation.orgunit","Abteilung Bioklimatologie"],["dc.title","Effects of land-use changes on evapotranspiration of tropical rain forest margin area in Central Sulawesi (Indonesia): Modelling study with a regional SVAT model"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3046"],["dc.bibliographiccitation.issue","21"],["dc.bibliographiccitation.journal","Ecological Modelling"],["dc.bibliographiccitation.lastpage","3056"],["dc.bibliographiccitation.volume","220"],["dc.contributor.author","Olchev, A."],["dc.contributor.author","Radler, K."],["dc.contributor.author","Sogachev, A."],["dc.contributor.author","Panferov, Oleg"],["dc.contributor.author","Gravenhorst, Gode"],["dc.date.accessioned","2018-11-07T11:22:09Z"],["dc.date.available","2018-11-07T11:22:09Z"],["dc.date.issued","2009"],["dc.description.abstract","A three-dimensional model Mixfor-3D of soil-vegetation-atmosphere transfer (SVAT) was developed and applied to estimate possible effects of tree clear-cutting on radiation and soil temperature regimes of a forest ecosystem. The Mixfor-31D model consists of several closely coupled 3D sub-models describing: forest stand structure; radiative transfer in a forest canopy; turbulent transfer of sensible heat, H(2)O and CO(2) between ground surface and the atmospheric surface layer; evapotranspiration of ground surface vegetation and soil; heat and moisture transfer in soil. The model operates with the horizontal grid resolution, 2 m x 2 m; vertical resolution, 1 m and primary time step, 1 h. The model was tested against meteorological data obtained at a small clear-cutting area in Otterbach in central Germany during summer 2005. The meteorological data including air temperature and humidity, precipitation, solar radiation, wind speed and direction, soil temperatures at 10 and 20 cm depth were measured by five automatic stations within the clear-cut area. One reference station was placed about 100 m from the clear-cut inside the forest stand. Comparisons of modelled and measured solar radiation fluxes and soil temperature profiles showed that the model adequately describes the spatial heterogeneity and dynamics of these variables under different weather conditions. The model can be used to explore solar radiation and soil temperature patterns within heterogeneous forest plots, with applications to various silvicultural tasks. (C) 2009 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.ecolmodel.2009.02.004"],["dc.identifier.isi","000272332900021"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55933"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","6th European Conference on Ecological Modelling, Challenges for Ecological Modelling in a Changing World"],["dc.relation.eventlocation","Trieste, ITALY"],["dc.relation.issn","0304-3800"],["dc.relation.orgunit","Abteilung Bioklimatologie"],["dc.title","Application of a three-dimensional model for assessing effects of small clear-cuttings on radiation and soil temperature"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]