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Physiological equivalent temperature as an indicator of the UHI effect with the city of Prague as an example
Zahradníček, Pavel ; Žák, M. ; Skalák, Petr
Description of an Urban Heat Island (UHI) using the difference in air temperature is one of the world's most studied characteristics. If, however, one wants to express how the temperature is perceived by humans, one must consider the overall effect of air temperature, wind speed, air humidity and radiation flows, which is expressed using temperature bioclimatological indexes. One of them is the socalled physiological equivalent temperature (PET), which is used for quantification of the overall effect of meteorological parameters combined with human energetic balance and which is perceived by humans. The RayMan (MATZARAKIS et al. 2007, 2010) microscale models in the city of Prague were used to simulate biometeorological conditions describing the effect on humans using PET.
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Drought monitor for the Czech Republic-www.intersucho.cz
Trnka, Miroslav ; Hlavinka, Petr ; Semerádová, Daniela ; Balek, Jan ; Možný, M. ; Štěpánek, Petr ; Zahradníček, Pavel ; Hayes, M. ; Eitzinger, Josef ; Žalud, Zdeněk
Because drought and its impacts are among the worst hydrometeorological extremes (including also Central European conditions), the aim of this paper is to describe the core and use of the Integrated drought monitoring system for the Czech Republic. Land-use, information about soil, vegetation characteristics and meteorological data are used as inputs to validated water balance SoilClim model, which is applied for estimates of actual and reference evapotranspiration and water saturation of the soil profile in % or soil moisture content in mm. Moreover the prognosis of expected soil moisture (based on probabilistic analysis) is calculated for next 1, 2, 4 and 8 weeks. Main results are weekly updated in form of drought occurrence maps, which are published in spatial resolution 500 m for whole territory of the Czech Republic and for all its 76 districts separately. Final maps with detail comments are available at drought topic dedicated web page (ANONYM 3 2014).
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Detection of drought events using combination of satellite data and soil moisture modelling
Semerádová, Daniela ; Trnka, Miroslav ; Hlavinka, Petr ; Balek, Jan ; Bohovič, Roman ; Tadesse, T. ; Hayes, M. ; Wardlow, B. ; Žalud, Zdeněk
The use of satellite data offers a potentially well usable tool to accurate drought monitoring. The study examines the space-time possibility of agricultural drought detection using freely available data from the MODIS instrument onboard Terra and Aqua satellites that reflects vegetation condition. Vegetation greenness metrics used in this study are based on the spectral reflectance curves in the visible red and near-infrared part of the spectrum and are expressed in relation to the average for the period of 2000-2014. The results are presented in weekly time step for the whole area of the Czech Republic, and are compared to the drought monitor system, based on the SoilClim dynamic model for soil water content estimates. These data, as well as other parameters, such as soil properties and land use, are integrated at 500 meters spatial resolution.
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Application of DSSAT model to simulated thermophilic crops in central and southern Europe
Potop, V. ; Mateescu, C.D. ; Türkott, L. ; Zahradníček, Pavel ; Boroneant, C. ; Constantinescu, F. ; Iamandei, M.
This study presents applications of DSSAT version 4.5 software package to simulate thermophilic crops. The results are used to identified adaptation options to reduce impacts of climate changes, pest and diseases in thermophilic crops in the central and southeastern Europe, specifically in Elbe River lowland and Romania. For the Czech Republic, experimental research at farm level includes: (1) testing thermophilic assortment of vegetables in Elbe lowland conditions; (2) monitoring the meteorological data, phenological phases, soil characteristics, leaf area and the amount of aboveground biomass on farmer vegetable fields. For Romania, the focus is put on crop water use efficiency under current and future climate scenarios for thermophilic species (maize) in different agricultural sites from south and south-eastern regions. CERES Maize and CROPGRO-vegetables modules embedded in DSSAT were used.
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Drivers of soil moisture trends in the Czech Republic between 1961 and 2012
Trnka, Miroslav ; Brázdil, Rudolf ; Balek, J. ; Semerádová, Daniela ; Hlavinka, Petr ; Možný, M. ; Štěpánek, Petr ; Dobrovolný, Petr ; Zahradníček, Pavel ; Dubrovský, Martin ; Eitzinger, Josef ; Fuchs, B. ; Svoboda, M. ; Hayes, M. ; Žalud, Zdeněk
Soil moisture dynamics and their temporal trends in the Czech Republic are forced by various drivers. Our analysis of temporal trends indicates that shifts in drought severity between 1961 and 2012 and especially in the April, May, and June period, which displayed such results as a 50% increase in drought probability during 1961–1980 in comparison to 2001–2012. We found that increased global radiation and air temperature together with decreased relative humidity (all statistically significant at p < 0.05) led to increases in the reference evapotranspiration in all months of the growing season; this trend was particularly evident in April, May, and August, when more than 80% of the territory displayed an increased demand for soil water. These changes, in combination with the earlier end of snow cover and the earlier start of the growing season (up to 20 days in some regions), led to increased actual evapotranspiration at the start of the growing season that tended to deplete the soil moisture earlier, leaving the soil more exposed to the impacts of rainfall variability. These results support concerns related to the potentially increased severity of drought events in Central Europe. The reported trend patterns are of particular importance with respect to expected climate change, given the robustness and consistency of the trends shown and the fact that they can be aligned with the existing climate model projections. Introduction
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Reliability of regional crop yield predictions in the Czech Republic based on remotely sensed data
Hlavinka, Petr ; Semerádová, Daniela ; Balek, Jan ; Bohovič, Roman ; Žalud, Zdeněk ; Trnka, Miroslav
Vegetation indices sensed by satellite optical sensors are valuable tools for assessing vegetation conditions including field crops. The aim of this study was to assess the reliability of regional yield predictions based on the use of the Normalized Difference Vegetation Index and the Enhanced Vegetation Index derived from the Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite. Data available from the year 2000 were analysed and tested for seasonal yield predictions within selected districts of the Czech Republic. In particular, yields of spring barley, winter wheat, and oilseed winter rape during 2000–2014 were assessed. Observed yields from 14 districts were collected and thus 210 examples (15 years within 14 districts) were included. Selected districts differ considerably in soil fertility and terrain configuration and represent a transect across various agroclimatic conditions (from warm/dry to relatively cool/wet regions). Two approaches were tested: 1) using 16-day temporal composites of remotely sensed data provided by the United States Geological Survey, and 2) using daily remotely sensed data in combination with an originally developed smoothing method. Yields were predicted based on established regression models using remotely sensed data as an independent parameter. In addition to other findings, the impact of severe drought episodes within vegetation was identified and yield reductions at a district level were predicted. As a result, those periods with the best relationship between remotely sensed data and yields were identified. The impact of drought conditions as well as normal or above-normal yields of the tested field crops were predicted using the proposed method within the study region up to 30 days prior to harvest.
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The Bowen Ratio/Energy Balance method and detailed temperature profile measurements to improve data quality control
Pozníková, Gabriela ; Fischer, Milan ; Orság, Matěj ; Trnka, Miroslav ; Žalud, Zdeněk
Water plays a key role in the functionality and sustainability of ecosystems. In light of predicted climate change, research should focus on the water cycle and its individual components. The main component of water balance driving water from ecosystems is evapotranspiration (ET). One standard method for measuring ET is the Bowen Ratio/Energy Balance (BREB) method. It is based on the assumption that water vapour and heat are transported by identical eddies with equal efficiency. When using the BREB method, we assume that the profiles of temperature and air humidity are ideally logarithmic or at least consistent. Since the BREB method is usually based on measurements of temperature and humidity at only two heights, it is difficult to verify whether this assumption has been fulfilled. Potential profile inconsistencies are more likely for temperature because the sensible heat flux changes its sign more often and negative latent heat flux is not physically possible during positive sensible heat flux. We therefore conducted a field experiment using a 4-mhigh measurement mast with 20 thermocouples for detailed measurement of air temperature profiles above different covers, e.g. grassland, spring barley, and poplar plantations. Our main objective was to investigate the basic assumptions of the BREB method, i.e. the temperature profile’s consistency under various weather conditions. To be more specific, we aimed to investigate whether inflexion points occurred within the temperature profile and if so when.
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The influence of land cover changes and landscape fragmentation on provision of the carbon sequestration ecosystem service
Pechanec, V. ; Purkyt, Jan ; Cudlín, Pavel
The aim of our contribution is to analyse the influence of land cover changes and landscape fragmentation in two small catchments (Všeminka, Fryštácký potok) within the forest–agricultural landscape of eastern Moravia (Czech Republic) on the carbon sequestration ecosystem service. Fragmentation was analysed using landscapeecological indices within ArcGIS 10.x software using the Patch Analyst extension. Data about the carbon sequestration ecosystem service were processed in the InVEST model. In the Všeminka catchment, carbon sequestration increased over the entire period of observation of 1953–2012. In the Fryštácký potok catchment, carbon sequestration decreased from 1950 to 2005, but increased from 2005 to 2012. The changes in fragmentation were not significant between 1953 and 2012, and so changes in carbon sequestration were caused mostly by land cover changes. The relationships among land cover change, fragmentation, and carbon sequestration from 1953 to 2012 are discussed.
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Forestry operations focusing on different types of felling related to carbon and economic efficiencies
Plch, Radek ; Pecháček, O. ; Vala, V. ; Pokorný, Radek ; Cudlín, Pavel
Assessments of carbon and economic efficiencies, completed by an environmental load computation using the Life Cycle Assessment (LCA) method, could be a useful tool for assessing sustainable forest management (e.g. Berg & Lindholm 2005, Michelsen et al. 2008). The purpose of this study was to compare forestry operations focused on manually operated (chainsaw) and fully mechanized (harvester) felling in Norway spruce monocultures and mixed forests within the Novohradské Mts. (Czech Republic) using the methods of carbon efficiency (including LCA) and economic efficiency. In general terms, these methods consist of comparing quantified human inputs (e.g. fossil fuels, electricity, used machinery, and fertilizers, converted into emission units of carbon in t C in CO2 equivalent or EUR) with quantified ecosystem outputs (biomass production in t C or EUR). Forest operations were modelled for one rotation period. The results showed the main differences in carbon emissions and carbon efficiency related to forest operations with different types of felling. In contrast, the economic efficiency results did not differ much with different types of felling. Differences between Norway spruce monocultures and mixed forests using the same type of felling were relatively small for carbon efficiency but large for economic efficiency (Norway spruce monocultures recorded higher economic efficiency).
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The importance of hydromorphological analysis in evaluating floodplain disturbances – an upper Stropnice River case study
Jakubínský, Jiří ; Pelíšek, I. ; Cudlín, Pavel
This contribution deals with a comparative analysis of the hydromorphological state of a river network and the ecological status of a neighbouring floodplain area. The issue has gained great importance especially in addressing the causes and effects of flood events, which are an increasingly frequent manifestation of global environmental change at the local level. The area of interest was the upper part of the Stropnice River basin in Southern Bohemia with an area of about 100 km2. The basin is characterized by wide variability of natural conditions and human activities. The main objective was to analyse how the river’s morphological status affects habitat type naturalness. We endeavoured to determine the extent to which hydromorphological modifications contributed to transforming riparian natural habitats into more human-influenced habitats. Based on the results, we can conclude that within the area of interest the direct link between rivers and their close surroundings was only minimal. A significant role in shaping this relationship was played by a large anthropogenic modification of the entire floodplain area as well as the actual riverbed, which often causes completely different results. In areas where the floodplain ecosystem displayed relatively favourable environmental values, the relevant channel reach was degraded significantly, and vice versa. These facts point to longterm effects from anthropogenic pressure, which are manifested in the mutually and not well coordinated management of the river network and land-use system within the watershed.
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