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Drivers of soil moisture trends in the Czech Republic between 1961 and 2012
Trnka, M. ; Brázdil, R. ; Balek, J. ; Semerádová, D. ; Hlavinka, P. ; Možný, M. ; Štěpánek, P. ; Dobrovolný, P. ; Zahradníček, P. ; Dubrovský, Martin ; Eitzinger, J. ; Fuchs, B. ; Svoboda, M. ; Hayes, M. ; Žalud, Z.
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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A study on the influence of Dukovany power station on microclimate for the EIA documentation
Sokol, Zbyněk ; Řezáčová, Daniela
The study stems from the previous studies. We adapted the basic mathematical model CT-PLUME to assess the impact of cooling towers with natural draft, stationed in Dukovany site, on the given model area of 60 km x 60 km. The evaluation used meteorological data from 2010-2015 and compared the effect of the current towers with the new system EDU1-4 specified by the customer. This study differs significantly from the previous works in two aspects. It uses 6-year period (years 2010-2015) of data and analyzes the impact of 8 configurations with natural draft cooling towers contemplated in connection with the expansion of the Dukovany power station. The mathematical model CT-PLUME was adapted to the conditions of a specific task and is referred to as CT-PLUME / EDU_3.
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Wind resource assessment for selected sites in the territory of the Czech Republic
Hanslian, David
This set of studies analyses the wind conditions and expected wind power production at selected sites in the Czech Republic. At first, the calculation of wind conditions by VAS/WAsP 1, VAS/WAsP 2 and PIAP models is performed. Based on the comparison and analysis of model results, the generalized wind climate pertaining to the assessed site is estimated. The final results are calculated by WAsP model using this generalized wind climate. The expected wind power production of proposed wind turbine or wind farm is calculated as well as the map of simulated average wind speed and potential wind turbine production over the surrounding area. The uncertainty analysis is performed as well. This set consists of 6 partial reports.
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Impact of the troposphere on the inosphere
Koucká Knížová, Petra ; Mošna, Zbyšek ; Potužníková, Kateřina ; Boška, Josef ; Kouba, Daniel
Ionosphere represents weakly ionized plasma that reflects solar and geomagnetic activity and processes\nin the neutral atmosphere. Correlation of long time series of the ionospheric plasma critical frequencies,\nobtained by mean of vertical sounding from European stations, is analysed with respect to latitudinal and\nlongitudinal difference and surface distance of stations. Time series of critical frequencies are highly correlated\nreflecting the dominant solar influence. Correlation coefficients are high not only for raw data and subtracted\nmean courses but for fluctuations around mean as well. At the surface distance exceeding 1000 km and/ or about\n10 degrees of latitudinal difference between stations, the correlation coefficients of fluctuations decrease\nrapidly. Such effect is less visible on the latitudinal dependence, where the correlation coefficients decrease with\nincreasing distance with less pronounced threshold. We explain the existence of the ‘break point’ at 10 degrees\nin longitude and/or 1000 km by the ‘local’ influence of the neutral atmosphere and the wave activity. As a\npossible source of the common influence on scale 1000 km/10 degree we propose tropospheric systems that are\nknown to be an important source of atmospheric waves in a broad period range. Large tropospheric mesoscale\nsystems have typically up to 2000 km in size.
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Seasonal Variation in Propagation Directions of Acoustic Gravity Waves in the Thermosphere
Fišer, Jiří ; Chum, Jaroslav
We investigate seasonal behaviour of acoustic gravity waves (AGWs) in\nthe thermosphere. For this purpose, measurements of HF Doppler sounding stations\noperated by or in cooperation with our institute are used. These measurements\nare compared with previously reported studies which employed different techniques\nof ionospheric observations. The propagation of AGWs is found to have strong\nseasonal dependence. AGWs in summer generally tend to propagate poleward in\nsummer and equatorward in winter.
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Wind resource assessment for selected sites in the territory of the Czech Republic
Hanslian, David
This set of studies analyses the wind conditions and expected wind power production at selected sites in the Czech Republic. At first, the calculation of wind conditions by VAS/WAsP 1, VAS/WAsP 2 and PIAP models is performed. Based on the comparison and analysis of model results, the generalized wind climate pertaining to the assessed site is estimated. The final results are calculated by WAsP model using this generalized wind climate. The expected wind power production of proposed wind turbine or wind farm is calculated as well as the map of simulated average wind speed and potential wind turbine production over the surrounding area. The uncertainty analysis is performed as well. This set consists of 6 partial reports.
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Wind resource assessment of wind farm based on local wind measurement
Hanslian, David
The expected energy production of proposed wind farm was calculated on the basis of local wind mast measurements. The study includes detailed analysis of measured wind data, correction of discovered inaccuracies and correction for long-term wind conditions (measure-correlate-predict analysis). The final calculation of wind energy production was performed by WAsP model. The uncertainty analysis was performed as well.
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Wind resource assessment of wind farm based on local wind measurement
Hanslian, David
The expected energy production of proposed wind farm was calculated on the basis of local wind mast measurements. The study includes detailed analysis of measured wind data, correction of discovered inaccuracies and correction for long-term wind conditions (measure-correlate-predict analysis). The final calculation of wind energy production was performed by WAsP model. The uncertainty analysis was performed as well.
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