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Precipitation variability in the czech land since ad 1500. How strong is the signal contained within documentary sources?
Dobrovolný, Petr; Brázdil, Rudolf; Trnka, Miroslav; Kotyza, O.; Valášek, H.
2013 - anglický
Past climate may be reconstructed from a number of proxies. Some of them are “natural archives”, such as tree rings, ice cores and boreholes, most of which are sensitive to air temperature. Other valuable information can be also found in “man-made archives”. Various sources of documentary data very oft en refer not only to temperature but also to other aspects of past weather and climate, such as dry and wet periods. We use the long and homogeneous precipitation series from the recent instrumental period to calibrate precipitation indices derived from older documentary sources. Th e primary objective of this contribution is to provide a quantitative reconstruction of precipitation in the Czech Lands for the last 500 years. Calibration and verifi cation statistics are used to evaluate the strength of the signal. Reconstructed precipitation series are compared with similar Central European documentary-based reconstructions, as well as with reconstructions based on a range of natural proxies.
Klíčová slova:
documentary evidence; precipitation; reconstruction; Czech Lands
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Precipitation variability in the czech land since ad 1500. How strong is the signal contained within documentary sources?
Past climate may be reconstructed from a number of proxies. Some of them are “natural archives”, such as tree rings, ice cores and boreholes, most of which are sensitive to air temperature. Other ...
Comparison of eddy covariance and bowen ratio energy balance method. Energy balance cloruse versus bowen ratio similarity assumption
Fischer, Milan; Trnka, Miroslav; Pozníková, Gabriela; Sedlák, Pavel; Orság, Matěj; Kučera, J.; Žalud, Z.
2013 - anglický
The Bowen ratio and the Monin-Obukhov similarity principles are based on the assumption that the eddy diff usivities for temperature and humidity are equal to each other under all atmospheric stratifi cations within turbulent surface boundary layer. However, several authors reported that this equality was violated under advective inversion or during the non-stationary conditions due to clouds passing by and sudden change of wind speed and direction. Th e inequality of the eddy diff usivity can lead to errors in the energy partitioning estimates by gradient techniques like the Bowen ratio energy balance (BREB) and the aerodynamical method, or methods based on residual energy balance such as the Penman-Monteith or Priestley-Taylor models. Th is study investigates two seasons of simultaneous measurement by eddy covariance (EC) and BREB above a high density poplar plantation at the Domanínek locality. Th e direct measurement of eddy diff usivities by EC is reinvestigating the validity of the long term measurement (since 2008) by BREB. Results showed unequal exchange coeffi cients with their mean 0.31 to 0.35 m2 s-1 for 2011 and 2012, respectively, favouring the transport of latent heat. Th is might be explained by the diff erent footprints of the BREB and EC methods, an undeveloped internal boundary layer or instrumental errors.
Klíčová slova:
eddy covariance; Bowen ratio energy balance method; eddy exchange coefficient; energy balance closure
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Comparison of eddy covariance and bowen ratio energy balance method. Energy balance cloruse versus bowen ratio similarity assumption
The Bowen ratio and the Monin-Obukhov similarity principles are based on the assumption that the eddy diff usivities for temperature and humidity are equal to each other under all atmospheric ...
Determination of errors in energy flux estimates using the bowen ratio energy balance method
Pozníková, G.; Fischer, Milan; Trnka, Miroslav; Žalud, Zdeněk
2013 - anglický
The Bowen ratio energy balance method (BREB) is based on the measurement of air temperature and humidity gradients in at least two vertical levels above the surface of interest. So far, there have been a limited number of studies dealing with the footprint of the BREB. Staying conservative, many authors used the upper sensor of the BREB as a single point to determine the footprint of the BREB. In fact, the footprint of the fl uxes rather should be explained as a source area of the single point measurement carried out somewhere between the two BREB levels. It was suggested that this single point lies close to the geometrical mean of the two aero dynamical heights. However, there has still been no consensus regarding if this apparent height is fi xed or not, and if the second is true, whether it is a function of the Bowen ratio itself. Th e submitted study deals with the footprint of the BREB using several BREB experiments above various covers with diff erent fetches. Moreover, by simulating diff erent Bowen ratios between the area of interest and the contaminating area we attempt to investigate for which conditions (dry or wet) and type of transition (from drier to wetter or vice versa) the method is more sensitive to the limited fetch.
Klíčová slova:
Bowen ratio energy balance method; footprint; limited fetch; energy fluxes; poplar plantation; grassland
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Determination of errors in energy flux estimates using the bowen ratio energy balance method
The Bowen ratio energy balance method (BREB) is based on the measurement of air temperature and humidity gradients in at least two vertical levels above the surface of interest. So far, there have ...
Zonation of NP as an important tool of nature conservation: consequences of fragmentation of zonatio in Šumava NP
Křenová, Zdeňka
2013 - anglický
The Šumava NP zonation has been debated since the very establishment of the National park and refl ects the views and opinions on nature conservation principles among various groups of experts. Th e fi rst zonation developed in 1991 fully respected the original intention of the goals of the National park, i.e. leaving space for spontaneous processes in nature. In 1995, the zonation was dramatically changed, because the NP’s senior managers supported the opinion that a European Spruce Bark Beetle (Ips typographus) outbreak can be reduced only by forest management measures, i.e. by extensive felling. Th us, only 13 % of the NP’s territory was within the Zone I and was fragmented into 135 patches, which was strongly criticized by experts. Th e necessity to adopt the new zonation graduated aft er the hurricane Kyrill in 2007, when large parts of fragmented forests were destroyed by wind. A new proposal for delineating the Zone I is based on botanical, forest management and zoological criteria, carefully assessing the NP’s values. Th e proposed Zone I covers 39.2 % of the NP territory and is distributed into 10 units. Th e proposal was delivered as a background for a working group draft ing a New Act on Šumava NP on behalf of the Ministry of the Environment of the Czech Republic. Good zonation of NPs is concluded to be an important tool of nature conservation but respect for legislation, international NP principles, and current scientifi c knowledge should be the main rule for responsible decision making in protected areas and biodiversity conservation.
Klíčová slova:
zonation; management of national park; transboundary protected area; Natura 2000
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Zonation of NP as an important tool of nature conservation: consequences of fragmentation of zonatio in Šumava NP
The Šumava NP zonation has been debated since the very establishment of the National park and refl ects the views and opinions on nature conservation principles among various groups of experts. Th e ...
Mathematical methods of modelling the morphology of spruce trees
Janoutová, Růžena; Novotný, Jan; Pivovarník, Marek; Zemek, František
2013 - anglický
Radiative transfer (RT) models are simulation tools which can be used to quantify relationships between vegetation canopy properties and observed remotely sensed data. Th is study aims at creating a spruce tree growth model as a key input for use in RT models. Th e spruce tree model is built on data obtained from terrestrial laser scanning of spruce trees. Each tree model is unique. Th is uniqueness is achieved by using L-systems which are able to simulate natural randomness while complying with the given tree parameters. L-systems are established on a theory of grammar that enables rewriting a string of symbols according to specifi ed rewriting rules. In practice, our tree models are generated in Blender visualization soft ware, implementing an algorithm written in Python. Th e algorithm generates the basic parameters of the whole tree and then creates the parameters of the spruce trunk and initial branches. Th e parameters are generated randomly within a range that is calculated from measured data. Th en each branch is grown on the basis of annual increments defi ned by fi eld measurements. Tree needles are distributed with respect to the age of individual branches; therefore, the needles have diff erent colours according to their age. Cones and faces are graphical representations of the spruce model. Branches are represented by cones and needles are represented by faces around the branches. Th e faces are transparent, thus simulating light transmittance in-between the needles. The whole model is highly computationally demanding, especially with respect to computer memory.
Klíčová slova:
3-D spruce model; L-system; radiative transfer
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Mathematical methods of modelling the morphology of spruce trees
Radiative transfer (RT) models are simulation tools which can be used to quantify relationships between vegetation canopy properties and observed remotely sensed data. Th is study aims at creating a ...
Co-registration of chlorophyll fluorescence emission and 3D models of plants
Ryba, Tomáš; Železný, Miloš
2013 - anglický
Chlorophyll fl uorescence is a powerful optical reporter signal yielding information about modulation of light use effi ciency. In standard imaging applications, fl uorescence transients are captured in 2 spatial dimensions and in time. Here, we demonstrate that it is possible to combine the information obtained in the 2D-t format with the 3D reconstruction of the entire plant using a process called co-registration. Two diff erent approaches to co-registration are presented here. Th e fi rst one is based on an image registration method, where the precise transformation parameters are iteratively estimated. Th is approach assumes that the initial position of a scanner is known and thus makes the method less general. To remove this assumption, a second approach can be used, which is based on analysis of a known calibration object. Th ere is no need to re-calibrate the system between individual measurements.
Klíčová slova:
chlorophyll fluorescence; 3D model of plant; co-registration; image registration; calibration object
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Co-registration of chlorophyll fluorescence emission and 3D models of plants
Chlorophyll fl uorescence is a powerful optical reporter signal yielding information about modulation of light use effi ciency. In standard imaging applications, fl uorescence transients are captured ...
Valutation of ecosystem services provided by habitat on the basis of biodiversity characteristics and the rate and sustainability of selected ecosystem functions
Cudlín, Pavel; Prokopová, Marcela; Cudlín, O.
2013 - anglický
Increasing human impacts on ecosystems result in a continuous decrease in biodiversity; scientists try to estimate the consequences in ecosystem functioning and ecosystem service (ES) provision. A suitable space framework to study this relationship could be the habitat and its relative value expressed by the monetary valuation of a selected fi nal ES. A cross connection of the methods for ecosystem functioning assessment with biodiversity valuation of habitats would enable an estimation of the role of biodiversity in ES provision. It is necessary to identify not only present functioning, described by eff ect traits, but also its sustainability under global environmental change conditions, described by response traits. Th is approach could reveal the resilience and adaptation potential of present habitats to environmental change and subsequently potential changes in ES provision.
Klíčová slova:
ecosystem services; biodiversity characteristics; ecosystem functions
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Valutation of ecosystem services provided by habitat on the basis of biodiversity characteristics and the rate and sustainability of selected ecosystem functions
Increasing human impacts on ecosystems result in a continuous decrease in biodiversity; scientists try to estimate the consequences in ecosystem functioning and ecosystem service (ES) provision. A ...
Towards the issue of ecosystem services of small watercourses in the Czech Republic
Jakubínský, Jiří
2013 - anglický
Th e issue of ecosystem services represents a hot topic especially in connection with quantitative expression of their values and research of functions, which the landscape provides to a human society. Th e question of ecosystem values research is solved with a focus on the river landscape, defi ned as the ecosystem along watercourses whose functioning is directly conditioned by the presence of the hydrographical network. Since it is a very attractive area for the implementation of human needs, there is oft en what is seen as a confl ict between activities of human society and the eff ects of natural processes. Catchment areas of small watercourses or their parts which are specifi c in terms of mutually diff erent intensity of anthropogenic pressure on the landscape were selected as the model sites. Th e main aim of this paper is to analyse the relationship between the value of landscape ecosystem services – either usage of existing methodologies for ecosystem valuation, the rate of small watercourse degradation and changes in their natural parameters (morphology of the river channel and riparian zones).
Klíčová slova:
ecosystem services; smal watercourse; ecohdydrology; fluival geomorphology; the Czech Republic
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Towards the issue of ecosystem services of small watercourses in the Czech Republic
Th e issue of ecosystem services represents a hot topic especially in connection with quantitative expression of their values and research of functions, which the landscape provides to a human ...
Phenological response of flood-plain forest ecosystem during 1961-2011
Bartošová, Lenka; Trnka, Miroslav; Bauer, Z.; Štěpánek, P.; Možný, M.; Žalud, Zdeněk
2013 - anglický
The presented study is focused on 50 years of phenological observations (1961–2011) of the herbs, shrubs, trees and bird populations and the phenological phases that create a continuous phenological sequence covering the whole spring aspect of the fl oodplain forest ecosystem. Th e phenological phases were observed for 5 herbs, 5 shrubs, 3 trees and 2 bird species. Th e phenological phases were observed as precisely as possible by only one observer during the whole time of observation. All observed plants and bird species showed statistically signifi cant shift s to the earlier time but the rate of shift ing among the parts of the fl ood-plain forest ecosystem was diff erent. Th e most progressive shift s were detected for herbs (the rate of shift ing was on average 13.9 days), followed by shrubs (phenophases advanced by 11.3 days on average), trees (phenophases advanced by 10.2 days) and fi nally by bird species (phenophases advanced by 9.6 days on average). Consequently the length of overlap of the chosen phenological phases was elaborated. Th e rate of shortening or lengthening of the overlap diff ers among all parts of the ecosystem and indicates not only the separation of phenophases but also no statistically signifi cant change in the length of overlap in each part of the ecosystem.
Klíčová slova:
forest ecosystem; flood plain; phenological response
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Phenological response of flood-plain forest ecosystem during 1961-2011
The presented study is focused on 50 years of phenological observations (1961–2011) of the herbs, shrubs, trees and bird populations and the phenological phases that create a continuous phenological ...
Long term investigation of resveratrol content in moravian red wines in relation to climate conditions
Vrchotová, Naděžda; Tříska, Jan; Totušek, J.; Balík, J.
2013 - anglický
The considerable commercial importance of wine together with the necessary quality control and investigation of the biological quality of constituent compounds leads to the development of adequate and reliable methods for the determination of macro- and micro-components in wine. Although wine contains a large amount of known compounds e.g. volatile (fl avour compounds), semi-volatile (phenolic) and non-volatile components (pigments), new compounds from all the above mentioned classes are still found in wine and are under heavy investigation, especially regarding their biological activity and their relation to the vinifi cation processes. Th e most signifi cant and famous due to the so-called French paradox is resveratrol-3,4´,5-trihydroxystilbene. Resveratrol is a stress metabolite formed in the grapevine in response to abiotic (UV irradiation) and biotic stresses (Botrytis cinerea). UV irradiation transforms trans isomer to cis form. But according the recent literature cis resveratrol could be also a result of organic farming – natural means of defence in organic viticulture against fungal infections. In our study we have investigated resveratrol content in diff erent vineyards in relation to annual mean temperature, precipitation and sun irradiation.
Klíčová slova:
resveratrol; moravian red wine; climatic conditions
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Long term investigation of resveratrol content in moravian red wines in relation to climate conditions
The considerable commercial importance of wine together with the necessary quality control and investigation of the biological quality of constituent compounds leads to the development of adequate ...
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