Number of found documents: 223
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Effects of urbanization on the landscape of a Modern City in Ghana: A case study of sunyani
Boateng, K. A.; Mensah, Caleb; Agyei, Thomas; Švik, Marian
2018 - English
According to the fifth assessment report of the Intergovernmental Panel on Climate Change, changes in land use through urbanization and agriculture are the key anthropogenic effects of climate change. Thus, the preservation of natural environment of urban areas is essential for conserving water and soil, while still adjusting the microclimatic variables (temperature, precipitation, relative humidity, etc.) and stabilizing the natural ecological system from destruction. It has been observed that most parts of city's green vegetation have been lost due to housing developments and commercial activities. This study was carried out to assess the effect of the change in land use on a modern city like Sunyani, by observing the significant changes in vegetation cover from LANDSAT TM imagery over a 31-year period (1986-2017). From the study, there was significant decline of vegetation cover from 1986 to 1999, and no significant change from 1999 to 2017. There were also significant changes in the built-up areas from 1986 to 1999 and no significant change from 1999 to 2017. Adoption of sustainable and environmentally friendly technologies that maintain open green vegetation is recommended for future city planning. Keywords: Climate change; Green vegetation; landsat; Open green spaces; Urbanization Available at various institutes of the ASCR
Effects of urbanization on the landscape of a Modern City in Ghana: A case study of sunyani

According to the fifth assessment report of the Intergovernmental Panel on Climate Change, changes in land use through urbanization and agriculture are the key anthropogenic effects of climate change. ...

Boateng, K. A.; Mensah, Caleb; Agyei, Thomas; Švik, Marian
Ústav výzkumu globální změny , 2018

Do Invasive Alien Species Affect Diversity of Local Communities?
Kindlmann, Pavel; Honěk, A.; Martinková, Z.
2017 - English
Here we present results of simulation models to investigate the diversity dynamics in a theoretical system consisting of an "original" community of native species and an invasive alien species that invades this community, thus creating a "new" community. See Kindlmann et al. (2017) for full details of the simulations and results. Keywords: invasive species; local diversity Available at various institutes of the ASCR
Do Invasive Alien Species Affect Diversity of Local Communities?

Here we present results of simulation models to investigate the diversity dynamics in a theoretical system consisting of an "original" community of native species and an invasive alien species that ...

Kindlmann, Pavel; Honěk, A.; Martinková, Z.
Ústav výzkumu globální změny , 2017

Highly time resolved measurement of atmospheric elemental and organic carbon at a typical background site in Central Europe.
Mbengue, Saliou; Fusek, M.; Schwarz, Jaroslav; Holoubek, Ivan
2017 - English
Atmospheric organic (OC) and elemental (EC) carbon play an important role in atmospheric chemistry, climate change and public health. There have been relatively few studies dealing with EC and OC in rural background sites which are less influenced by urban and industrial emissions. Nevertheless, measurements at background areas are important for understanding the transport and transformation characteristics of anthropogenic air pollutants, and their effects on various aspects of regional and global environment changes. In this study, we focus on variability of EC and OC concentrations (considering various day categories and seasons) from a rural background site which is representative for Central European rural areas.\n Keywords: organic carbon and elemental carbon; rural background; OC/EC ratio; variability Fulltext is available at external website.
Highly time resolved measurement of atmospheric elemental and organic carbon at a typical background site in Central Europe.

Atmospheric organic (OC) and elemental (EC) carbon play an important role in atmospheric chemistry, climate change and public health. There have been relatively few studies dealing with EC and OC in ...

Mbengue, Saliou; Fusek, M.; Schwarz, Jaroslav; Holoubek, Ivan
Ústav výzkumu globální změny , 2017

Impacts of hydrometeorological extremes in South Moravia based on documentary evidence
Chromá, Kateřina; Dolák, Lukáš; Brázdil, Rudolf; Řezníčková, Ladislava
2017 - English
Hydrometeorological extremes have influenced human lives significantly in the past, just as they continue\nto do today. To analyse these influences in the past, information is needed from before the start of systematic\nmeteorological and hydrological observations. Documentary evidence constitutes a very rich source of\ninformation about past hydrometeorological extremes. This paper focuses on impacts of hydrometeorological\nextremes on agriculture and material property and their socio-economic consequences. It also discusses\nthe potential and limitations of such documentary evidence. Despite documentary evidence’s several\nlimitations (e.g. spatial and temporal uncertainty, uncertainty in the annual distribution of records, in\nthe type of extreme, etc.), it is a promising source of information useful for future studies. Keywords: documentary evidence; hydrometeorological extremes; impacts; South Moravia Available at various institutes of the ASCR
Impacts of hydrometeorological extremes in South Moravia based on documentary evidence

Hydrometeorological extremes have influenced human lives significantly in the past, just as they continue\nto do today. To analyse these influences in the past, information is needed from before the ...

Chromá, Kateřina; Dolák, Lukáš; Brázdil, Rudolf; Řezníčková, Ladislava
Ústav výzkumu globální změny , 2017

Comparison of leaf area index dynamics and radiation use efficiency of C3 crops in the Czech Republic
Tripathi, Abishek; Pohanková, Eva; Trnka, Miroslav; Klem, Karel
2017 - English
Leaf area index (LAI) and radiation use efficiency (RUE) are key parameters for plant growth and productivity.\nBecause of irregularities in weather conditions, accurate estimation of crop production requires\nunderstanding relationships between weather, LAI, RUE, and final production. It is thus important to\nstudy how the LAI dynamics, leaf area duration (LAD), and RUE are related to aboveground biomass production\nfor different crops. In our study, we compared aboveground dry mass production, LAI dynamics,\nRUE, and LAD in three C3 crops (spring barley [SB], winter wheat [WW], and oilseed rape [OSR]) in the\nCzech Republic. LAI was measured on the basis of transmitted photosynthetically active radiation, LAD\nwas calculated by counting the number of days in the growing season, RUE was measured using Beer’s\nlaw, and the aboveground dry mass was estimated at the time of harvest. Results of our study showed high\nbiomass production and RUE in SB while there was highest maximum LAI (LAImax) and LAD in OSR. We\nconcluded that LAI dynamics or LAImax do not fully reflect the crop production and that RUE may be considered\nas a better indicator for aboveground dry mass production. Keywords: leaf area; index dynamics; radiations use efficiency; Czech Republic Available at various institutes of the ASCR
Comparison of leaf area index dynamics and radiation use efficiency of C3 crops in the Czech Republic

Leaf area index (LAI) and radiation use efficiency (RUE) are key parameters for plant growth and productivity.\nBecause of irregularities in weather conditions, accurate estimation of crop production ...

Tripathi, Abishek; Pohanková, Eva; Trnka, Miroslav; Klem, Karel
Ústav výzkumu globální změny , 2017

Stem emissions from poplar hybrids grown in a shortrotation plantation contribute to ecosystem balance of nitrous oxide and methane
Macháčová, Kateřina; Kreuzwieser, J.; Rennenberg, H.
2017 - English
The expansion of short-rotation coppices (SRCs) of fast-growing trees can affect the global balance of greenhouse\ngases (GHGs). These include not only carbon dioxide (CO2) but also methane (CH4) and nitrous oxide\n(N2O), both naturally produced by soil microorganisms. Trees are known to exchange CH4 and N2O with\nthe atmosphere. To date, however, the fluxes of these gases from fast-growing trees have been excluded from\nestimation of the GHGs balance for SRCs. Our objectives were to quantify and scale up CH4 and N2O fluxes\nfrom stems of the fast-growing poplar hybrids Max4 and Monviso at an SRC in southwest Germany. Our\ncase study shows that the stems of both hybrids were sources of N2O and CH4, even though consumption of\nCH4 was also observed. The hybrids did not differ in their exchange capacity. Nitrogen fertilization resulted in\nhigher stem N2O emissions compared to non-fertilized trees. The emissions of N2O and CH4 from stems contributed\nas much as 1.5% and 1.2% of soil N2O emission and soil CH4 uptake, respectively. Keywords: stem emission; poplar hybrids grown; short-rotation plantation; ecosystem balance; nitrous oxide Available at various institutes of the ASCR
Stem emissions from poplar hybrids grown in a shortrotation plantation contribute to ecosystem balance of nitrous oxide and methane

The expansion of short-rotation coppices (SRCs) of fast-growing trees can affect the global balance of greenhouse\ngases (GHGs). These include not only carbon dioxide (CO2) but also methane (CH4) and ...

Macháčová, Kateřina; Kreuzwieser, J.; Rennenberg, H.
Ústav výzkumu globální změny , 2017

Potential of flux-variance and surface renewal methods for sensible heat flux measurements at agricultural and forest surfaces
Fischer, Milan; Katul, G.; Pozníková, Gabriela; Noormets, A.; Domec, J.-C.; Trnka, Miroslav; King, J.
2017 - English
Two alternative micrometeorological methods, flux-variance (FV) and surface renewal (SR), based on\nmeasurements of high-frequency temperature fluctuation and Obukhov length stability parameter, were\ntested against eddy covariance (EC) sensible heat flux (H) measurements. The study was conducted at\nthree sites representing agricultural, forestry, and agroforestry systems. In terms of measurement setup,\nthese sites represented surface, roughness, and canopy top layer, respectively. As expected, the best match\nof all the methods was in the surface layer, whilst it was poorer in the roughness and canopy sublayers.\nSystematic deviation from EC across all three investigated surfaces was within 16% and 8% for FV and SR,\nrespectively. While FV resulted in higher correlation with EC measurements (0.93–0.98 vs. 0.89–0.97),\nSR provided less systematic biases (1.02–1.08 vs. 0.94–1.16). In general, both FV and SR provided slightly\nhigher H as compared to EC. We suggest that parallel deployment of FV and SR is useful, as both methods\nrequire the same instrumentation yet they are based on sufficiently different theories. Therefore, the agreement\nbetween FV and SR increases confidence in the results obtained and vice versa. Keywords: Temperature fluctuation; flux variance; agriculture and forest surface Available at various institutes of the ASCR
Potential of flux-variance and surface renewal methods for sensible heat flux measurements at agricultural and forest surfaces

Two alternative micrometeorological methods, flux-variance (FV) and surface renewal (SR), based on\nmeasurements of high-frequency temperature fluctuation and Obukhov length stability parameter, ...

Fischer, Milan; Katul, G.; Pozníková, Gabriela; Noormets, A.; Domec, J.-C.; Trnka, Miroslav; King, J.
Ústav výzkumu globální změny , 2017

Statistical analyses of Land Surface Temperature in Local Climate Zones: Case study of Brno and Prague (Czech Republic)
Geletič, Jan; Dobrovolný, Petr; Lehnert, M.
2017 - English
The classification of "local climate zones" (LCZs) emerged in urban climatology to standardize description of urban climate research sites. One of the goals of classification was to get beyond urban-rural dichotomy which enabled to study urban air temperature field in more detail. Based on empirical and modelling work LCZ have proven effective in examining intra-urban air temperature differences, however a robust examination of intra-urban land surface temperatures using the LCZ framework remains elusive. In this study a GIS-based method is used for LCZ delimitation in Prague and Brno (Czech Republic), while land surface temperatures (LSTs) derived from LANDSAT and ASTER satellite data are employed for exploring the extent to which LCZ classes discriminate with respect to LSTs. Results indicate that LCZs demonstrate the features typical of LST variability, and thus typical surface temperatures differ significantly among most LCZs. ANOVA and subsequent multiple comparison tests demonstrated that significant temperature differences between the various LCZs prevail in both cities (89.3% and 91.6% significant LST differences for Brno and Prague respectively). In general, LCZ 8 (large low-rise buildings), LCZ 10 (heavy industry) and LCZ D (low plants) are well-distinguishable, while LCZ 2 (compact midrise), LCZ 4 (open high-rise), and LCZ 9 (sparsely built-up) are less distinguishable in terms of their LST. In most of the scenes LCZ 10 (heavy industry), LCZ 2 (mid-rise buildings) and LCZ 3 (low-rise building) are the warmest and LCZ G (water bodies) and LCZ A (dense forest) are the coolest zones in term of their LST. Further studies are needed to account for observational errors (such as seasons differences or thermal anisotropy) on LCZ LST patterns. Keywords: Land Surface Temperature; Local Climate Zones; aster; landsat; Analysis of variance Available at various institutes of the ASCR
Statistical analyses of Land Surface Temperature in Local Climate Zones: Case study of Brno and Prague (Czech Republic)

The classification of "local climate zones" (LCZs) emerged in urban climatology to standardize description of urban climate research sites. One of the goals of classification was to get beyond ...

Geletič, Jan; Dobrovolný, Petr; Lehnert, M.
Ústav výzkumu globální změny , 2017

Modulation of ozone flux in a mountain spruce forest under different cloud cover
Juráň, Stanislav; Fares, S.; Urban, Otmar
2017 - English
Ozone (O3) fluxes were modelled from a concentration gradient in a Norway spruce forest at the Bílý Kříž experimental station for years 2012–2016. Daily and seasonal O3 depositions were calculated separately for days with cloudy, partly cloudy, and clear sky conditions. The hypothesis that overcast conditions modulate O3 flux in the forest ecosystem via controlled stomatal conductance is tested. Indeed, the highest stomatal conductance followed by the highest O3 deposition was found during partly cloudy and cloudy sky conditions in all seasons. Keywords: ozone; norway spruce; sky conditions; inverse lagrangian transport model Available at various institutes of the ASCR
Modulation of ozone flux in a mountain spruce forest under different cloud cover

Ozone (O3) fluxes were modelled from a concentration gradient in a Norway spruce forest at the Bílý Kříž experimental station for years 2012–2016. Daily and seasonal O3 depositions were calculated ...

Juráň, Stanislav; Fares, S.; Urban, Otmar
Ústav výzkumu globální změny , 2017

Influence of the chlorophylls-to-carotenoids ratio on light use efficiency estimation by optical parameters
Ač, Alexander; Kováč, Daniel; Veselovská, Petra; Večeřová, Kristýna; Klem, Karel
2017 - English
The influence is examined of changing leaf photosynthetic pigments concentrations on sensitivity of the\nphotochemical reflectance index (PRI) and ΔPRI optical parameters in relation to light use efficiency\n(LUE). Photosynthetic and leaf chlorophylls-to-carotenoids (Chl/Car) ratio changes during the growth of\nEuropean Beech (Fagus sylvatica) and Norway spruce (Picea abies) saplings were induced by altering the\nliving environment inside growth chambers. Point reflectance measurements of each individual tree were\nrecording changes in optical properties while measurements were being taken simultaneously of altering\nphotosynthesis. Based on the evaluation of 45 pairs of measurements conducted on six individual saplings,\nthe observed variability in the strength of the PRI and ΔPRI versus LUE relationships was compared to the\nresulting leaf Chl/Car ratio of each tree. Data were used to explain the influence of changing pigments on\nthe sensitivity of each individual optical parameter with regards to the LUE estimation. Keywords: chlorophylls carotenoids; light use efficiency; optical parameters Available at various institutes of the ASCR
Influence of the chlorophylls-to-carotenoids ratio on light use efficiency estimation by optical parameters

The influence is examined of changing leaf photosynthetic pigments concentrations on sensitivity of the\nphotochemical reflectance index (PRI) and ΔPRI optical parameters in relation to light use ...

Ač, Alexander; Kováč, Daniel; Veselovská, Petra; Večeřová, Kristýna; Klem, Karel
Ústav výzkumu globální změny , 2017

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