Počet nalezených dokumentů: 498
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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 - anglický
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. Klíčová slova: Climate change; Green vegetation; landsat; Open green spaces; Urbanization Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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

Characterization of equivalent black carbon (ebc) at a regional backgound site in Central Europe: Variability and source identification
Mbengue, Saliou; Serfozo, Norbert; Holubová Šmejkalová, Adéla; Holoubek, Ivan
2018 - anglický
Black carbon (BC) is recognized to play an important role on adverse public health and in the Earth’s climate system (Bond et al., 2013). It is the most efficient light-absorbing aerosol species in the visible spectrum emitted as primary pollutant from a variety of combustion related sources. Although measurements of Equivalent Black Carbon (EBC) with multiple wavelength aethalometer have been used to provide insights regarding the influence of fossil fuel (traffic emissions) and wood smoke in ambient air (Sandradewi et al., 2008; Vaishya et al 2017), scarce studies have been reported in Eastern Central Europe using real-time EBC measurements.\nThis study focuses on the seasonal, diurnal and weekly trends of EBC at a regional background site in Central Europe during a 5-year measurement. Our aim is to identify the potential sources of EBC, especially the influence from fossil fuel and biomass burning. Klíčová slova: Equivalent Black Carbon; 7-wavelength aethalometer; Ångström absorption exponent; Delta-C; BC variability and sources Plné texty jsou dostupné v digitálním repozitáři Akademie Věd.
Characterization of equivalent black carbon (ebc) at a regional backgound site in Central Europe: Variability and source identification

Black carbon (BC) is recognized to play an important role on adverse public health and in the Earth’s climate system (Bond et al., 2013). It is the most efficient light-absorbing aerosol species in ...

Mbengue, Saliou; Serfozo, Norbert; Holubová Šmejkalová, Adéla; Holoubek, Ivan
Ústav výzkumu globální změny , 2018

Změny mikroklimatu ostřicové louky během posledních 40 let
Dušek, Jiří; Stellner, Stanislav; Hudecová, S.
2018 - český
Průměrná, maximální a minimální teplota vzduchu postupně vzrostla během let 1977 až 2017. Vzestup teplot není stejný během různých období roku. Zjistili jsme různý vzestup teplot vzduchu pro jednotlivé měsíce roku. Denní průměrná teplota průkazně vzrostla ve vegetačním období (duben - květen). Nejvyšší vzrůst maximální teploty vzduchu byl zaznamenán v měsíci dubnu. Charakter srážek se také během měřeného období změnil a je konsistentní s růstem teplot vzduchu. Pokles srážek lze pozorovat v teplejším dubnu. Frekvence extrémních srážek a s nimi související kolísání vodní hladiny je podstatně vyšší v posledních letech, než tomu bylo před rokem 2000. Podrobná znalost týkající se mikroklimatických změn v ostřicové louce jsou důležité z hlediska ekosystémových funkcí mokřadu v krajině.\n The average, maximum and minimum air temperatures have been gradually increasing since 1977 to 2017. The air temperature rise was not the same in all periods of the year. We found different increases for individual months. The daily mean air temperature rose significantly in the growing period (April-August). The precipitation characteristics have been changing in the sedge-grass marsh too. The observed trends differ among months in sign as well as in the magnitude, and they are consistent with the air temperature changes. We found that extreme precipitation seems to occur significantly more frequently in recent years compared to the period before 2000. Awareness of these changes is important for possible positive human intervention when a desirable wetland ekosystem function is threatened.\n Klíčová slova: temperature; precipitation; Carex; wetland; floods Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd.
Změny mikroklimatu ostřicové louky během posledních 40 let

Průměrná, maximální a minimální teplota vzduchu postupně vzrostla během let 1977 až 2017. Vzestup teplot není stejný během různých období roku. Zjistili jsme různý vzestup teplot vzduchu pro ...

Dušek, Jiří; Stellner, Stanislav; Hudecová, S.
Ústav výzkumu globální změny , 2018

Response of aerosol concentrations to the daily atmospheric boundary layer variability at the national atmospheric observatory Košetice
Holubová Šmejkalová, Adéla; Zíková, Naděžda; Ždímal, Vladimír; Komínková, Kateřina; Holoubek, Ivan
2018 - anglický
The atmospheric boundary layer (ABL) is the part of the troposphere directly influenced by the properties of the Earth’s surface. The ABL thickness reaches from hundreds of meters to a few kilometres. The daily cycle of the ABL height is primarily result of interaction between incoming solar radiation and Earth’s surface heat fluxes because a turbulent motion is dominant in this layer. Air pollutants are generally emitted from surface and their measured concentrations are also influenced by dilution of the atmosphere, or ABL thickness. This study is focused on the linkage between the diurnal ABL height evolution and aerosol particle number concentrations. Klíčová slova: Atmospheric boundary layer; Aerosol total number concentrations; Polynomial regression Plné texty jsou dostupné v digitálním repozitáři Akademie Věd.
Response of aerosol concentrations to the daily atmospheric boundary layer variability at the national atmospheric observatory Košetice

The atmospheric boundary layer (ABL) is the part of the troposphere directly influenced by the properties of the Earth’s surface. The ABL thickness reaches from hundreds of meters to a few kilometres. ...

Holubová Šmejkalová, Adéla; Zíková, Naděžda; Ždímal, Vladimír; Komínková, Kateřina; Holoubek, Ivan
Ústav výzkumu globální změny , 2018

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 - anglický
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 Klíčová slova: organic carbon and elemental carbon; rural background; OC/EC ratio; variability Dokument je dostupný na externích webových stránkách.
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 - anglický
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. Klíčová slova: documentary evidence; hydrometeorological extremes; impacts; South Moravia Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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 - anglický
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. Klíčová slova: leaf area; index dynamics; radiations use efficiency; Czech Republic Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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 - anglický
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. Klíčová slova: stem emission; poplar hybrids grown; short-rotation plantation; ecosystem balance; nitrous oxide Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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 - anglický
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. Klíčová slova: Temperature fluctuation; flux variance; agriculture and forest surface Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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

Vývoj metody optimalizace kultivace sinice Nostoc sp. CCAP 1453/38
Chmelík, Dominik; Červený, Jan
2017 - český
Předmětem výzkumné zprávy je identifikace a detailní popis optimálních podmínek produkce sinice Nostoc v přirozeném mikrobiálním konsorciu. Dále byla pro účely ověření molekulární identifikace genetického mechanismu produkce vybraného sekundárního metabolitu provedena axenizace sinice Nostoc. The subject of the research report is the identification and detailed description of the optimal conditions for the production of filamentous cyanobacterium Nostoc in a natural microbial consortium. In addition, the axonization of Nostoc was performed to allow verifycation of the molecular identification of the genetic mechanism of production of the selected secondary metabolite. Klíčová slova: bioproduction; biotechnology; cyanobacteria; socindary metabolite; optimization Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Vývoj metody optimalizace kultivace sinice Nostoc sp. CCAP 1453/38

Předmětem výzkumné zprávy je identifikace a detailní popis optimálních podmínek produkce sinice Nostoc v přirozeném mikrobiálním konsorciu. Dále byla pro účely ověření molekulární identifikace ...

Chmelík, Dominik; Červený, Jan
Ústav výzkumu globální změny , 2017

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