Panferov, Oleg I.

[["dc.bibliographiccitation.firstpage","499"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Tree Physiology"],["dc.bibliographiccitation.lastpage","508"],["dc.bibliographiccitation.volume","28"],["dc.contributor.author","Ibrom, Andreas"],["dc.contributor.author","Oltchev, Alexander"],["dc.contributor.author","June, Tania"],["dc.contributor.author","Kreilein, Heiner"],["dc.contributor.author","Rakkibu, Golam"],["dc.contributor.author","Ross, Thomas"],["dc.contributor.author","Panferov, Oleg"],["dc.contributor.author","Gravenhorst, Gode"],["dc.date.accessioned","2018-11-07T11:17:00Z"],["dc.date.available","2018-11-07T11:17:00Z"],["dc.date.issued","2008"],["dc.description.abstract","Photosynthetically active radiation (Q)-use efficiency (F) is an important parameter for deriving carbon fluxes between forest canopies and the atmosphere from meteorological ground and remote sensing data. A common approach is to assume gross primary production (P,) and net primary production (P-n) are proportional to Q absorbed by vegetation (Q(abs)) by defining the proportionality constants epsilon(Pg) and epsilon(Pn) (for P-g and P-n respectively). Although remote sensing and climate monitoring provide Q(abs) and other meteorological data at the global scale, information on c is particularly scarce in remote tropical areas. We used a 16-month continuous CO2 flux and meteorological dataset from a mountainous tropical rain forest in central Sulawesi, Indonesia to derive values of epsilon(Pg). and to investigate the relationship between P-g and Q(abs). Absorption was estimated with a 1D SVAT model from measured canopy structure and short wave radiation. The half-hourly P, data showed a saturation response to Q(abs). The amount Of Q(abs) required to saturate P-g was reduced when water vapor saturation deficit (D) was high. Light saturation of P-g was still evident when shifting from half-hourly to daily and monthly time scales. Thus, for a majority of observations, P-g was insensitive to changes in Q(abs). A large proportion of the observed seasonal variability in P-g could not be attributed to changes in Q(abs) or D. Values of epsilon(Pg) varied little around the long-term mean of 0.0179 mol CO2 (mol photon)(-1) or 0.99 g C MJ(-1) (the standard deviations were +/- 0.006 and +/- 0.0018 mol CO2 (mol photon)(-1) for daily and monthly means, respectively). In both cases, c p. values were more sensitive to Q(abs) than to daytime D. These findings show that the current epsilon-approaches fail to predict P-g at our tropical rain forest site for two reasons: (1) they neglect saturation of P-g when Q(abs), is high; and (2) they do not include factors, other than Q(abs) and D, that determine seasonality and annual sums of P-g."],["dc.identifier.doi","10.1093/treephys/28.4.499"],["dc.identifier.isi","000255123200004"],["dc.identifier.pmid","18244937"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54712"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oxford Univ Press"],["dc.publisher.place","Oxford"],["dc.relation.conference","International Traveling Workshop on Regional Forest Responses to Environmental Change"],["dc.relation.eventlocation","Black Rock, NY"],["dc.relation.issn","1758-4469"],["dc.relation.issn","0829-318X"],["dc.relation.orgunit","Abteilung Bioklimatologie"],["dc.title","Variation in photosynthetic light-use efficiency in a mountainous tropical rain forest in Indonesia"],["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","169"],["dc.bibliographiccitation.issue","2-4"],["dc.bibliographiccitation.journal","Theoretical and Applied Climatology"],["dc.bibliographiccitation.lastpage","185"],["dc.bibliographiccitation.volume","80"],["dc.contributor.author","Sogachev, A."],["dc.contributor.author","Panferov, Oleg"],["dc.contributor.author","Gravenhorst, Gode"],["dc.contributor.author","Vesala, Timo"],["dc.date.accessioned","2018-11-07T11:14:18Z"],["dc.date.available","2018-11-07T11:14:18Z"],["dc.date.issued","2005"],["dc.description.abstract","A model for the canopy - planetary boundary layer flow and scalar transport based on E-is an element of closure was applied to estimate footprint for CO2 fluxes over different inhomogeneous landscapes. Hypothetical heterogeneous vegetation patterns - forest with clear-cuts as well as hypothetical heterogeneous relief - a bell-shaped valley and a ridge covered by forest were considered. The distortions of airflow caused by these heterogeneities are shown - the upwind deceleration of the flow at the ridge foot and above valley, acceleration at the crest and the flow separation with the reversed flow pattern at lee slopes of ridge and valley. The disturbances induce changes in scalar flux fields within the atmospheric surface layer comparing to fluxes for homogeneous conditions: at a fixed height the fluxes vary as a function of distance to disturbance. Correspondingly, the flux footprint estimated from model data depends oil the location of the point of interest (flux measurement point) and may significantly deviate from that for a flat terrain. It is shown that proposed method could be used for the choice of optimal sensor position for flux measurements over complex terrain as well as for the interpretation of data for existing measurement sites. To illustrate the latter the method was applied for experimental site in Selling, Germany, taking into account the complex topography and vegetation heterogeneities. Results show that in certain situations (summer, neutral stratification, south or north wind) and for a certain sensor location the assumptions of idealized air flow structure could be used for measurement interpretation at this site, though in general, extreme caution should be applied when analytical footprint models are used in the interpretation of flux measurements over complex sites."],["dc.identifier.doi","10.1007/s00704-004-0098-8"],["dc.identifier.isi","000229478000008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54093"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","Vienna"],["dc.relation.conference","Joint Meeting of the European-Geophysical-Society/American-Geophysical-Union and European-Union-of-Geoscience"],["dc.relation.eventlocation","Nice, FRANCE"],["dc.relation.issn","0177-798X"],["dc.title","Numerical analysis of flux footprints for different landscapes"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","241"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","IEEE Transactions on Geoscience and Remote Sensing"],["dc.bibliographiccitation.lastpage","253"],["dc.bibliographiccitation.volume","39"],["dc.contributor.author","Panferov, Oleg"],["dc.contributor.author","Knyazikhin, Y."],["dc.contributor.author","Myneni, R. B."],["dc.contributor.author","Szarzynski, J."],["dc.contributor.author","Engwald, S."],["dc.contributor.author","Schnitzler, K. G."],["dc.contributor.author","Gravenhorst, Gode"],["dc.date.accessioned","2018-11-07T09:24:23Z"],["dc.date.available","2018-11-07T09:24:23Z"],["dc.date.issued","2001"],["dc.description.abstract","This paper presents empirical and theoretical analyses of spectral hemispherical reflectances and transmittances of individual leaves and the entire canopy sampled at two sites representative of equatorial rainforests and temperate coniferous forests, The empirical analysis indicates that some simple algebraic combinations of leaf and canopy spectral transmittances and reflectances eliminate their dependencies on wavelength through the specification of two canopy-specific wavelength-independent variables. These variables and leaf optical properties govern the energy conservation in vegetation canopies at any given wavelength of the solar spectrum. The presented theoretical development indicates these canopy-specific wavelength-independent variables characterize the capacity of the canopy to intercept and transmit solar radiation under two extreme situations, namely, when individual leaves 1) are completely absorptive and 2) totally reflect and/or transmit the incident radiation. The interactions of photons with the canopy at red and near-infrared (IR) spectral bands approximate these extreme situations well. One can treat the vegetation canopy as a dynamical system and the canopy spectral interception and transmission as dynamical variables, The system has two independent states: canopies with totally absorbing and totally scattering leaves. Intermediate states are a superposition of these pure states, Such an interpretation provides powerful means to accurately specify changes in canopy structure both from ground-based measurements and remotely sensed data, This concept underlies the operational algorithm of global leaf area index (LAI), and the fraction of photosynthetically active radiation absorbed by vegetation developed for the moderate resolution imaging spectroradiometer (MODIS) and multiangle imaging spectroradiometer (MISR) instruments of the Earth Observing System (EOS) Terra mission."],["dc.identifier.doi","10.1109/36.905232"],["dc.identifier.isi","000167249800003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29812"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Ieee-inst Electrical Electronics Engineers Inc"],["dc.relation.issn","0196-2892"],["dc.title","The role of canopy structure in the spectral variation of transmission and absorption of solar radiation in vegetation canopies"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["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"]]