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Classification of precipitation regimes in Congo
Moliba, Jacques Celestin
Statisticals methods have been used to classify a rainfall regimes in the Democratic Republic of Congo. Using this classification method 3 main types of rainfall regimes are identified. The mains factors for their spatial distribution and characteristic are the apparent movement of the sun, the seasonal interaction of intertropical front and Benguela current.
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Rain Data Analysis for cm and mm radiowave attenuation
Fišer, Ondřej
Rain is a random lossy dielectrics that is necessary to respect by the design of cm and mm links. The contribution deals with the physical (especially absorption and scattering) properties of rain drops. The inference of the formula for the specific rain attenuation is denoted. The main parameters and its statistical properties describing the rain volume are shown (it is,for instance, the rain rate and its cumulative distribution). The technique to measure the rain rate is discussed. The main goal of the contribution is the drop size distribution and its impact on the radio waves.
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Radar Meteorology Principles and Possibilities
Fišer, Ondřej ; Kráčmar, J.
The contribution describes the principles of meteorological radars and the wavelength choice. The description of meteorological targets is also shown as well as typical technical parameters of meteorological radars. The radar equation for meteorological targets is shown on the base of the difference from the air traffic radars. The basic terms such as equivalent radar reflectivity factor are defined. The estimation technique of the precipitation intensity is deduced. The possible uncertainty is discussed . Also dual wavelength and polarimetric radars and its improved possibilities are added.
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Modelování profilů rychlosti větru naměřených sodarem v komplexním terénu
Hošek, Jiří
The wind profiles with two Doppler sodars were measured in wide range of synoptic situations in Ore mountains (Erzgebirge) and in the region of Orlické hory (mountains), both in the Czech republic. Ore mountains represent the region most suitable for construction of wind turbines in the Czech republic. Concerning the observed wind profiles, their generalization may serve for improvement of precision of the simulated wind profile fields. In the second part of the work, we performed the modelling of wind speed profiles in the complex terrain of above-mentioned mountain ranges. We have applied the non-hydrostatic meso-scale models KAMM and PIAP. The numerical simulations with the models were performed for different situations of the ambient flow, described by geostrophic wind speed and direction, and temperature stratification.
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The solid depozited precipitation in the small catchments in the Czech Republic
Fišák, Jaroslav ; Tesař, Miroslav
The samples were collected in two localities differing in the industrial pollutant load. The first locality situated in the Sumava Mts. represents a relatively clean region of the Czech Republic. The second locality is situated in the Northern Bohemia. This locality is represented by the Milesovka Observatory of the IAP ASCR. The region is heavy polluted by the industrial load in this case. The one-shot sample collection in the Sumava Mts. at 28 localities was made on January 4th, 1990. There were shown: i) The ion concentrations in the rime water depend on the industrial load of the region and on the local pollutant sources; ii) The local pollutant sources play the main role in ion concentrations in rime water; iii) The ion concentrations decrease with altitude.
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Comparison of chemical composition of throughfall and deposited precipitation
Chaloupecký, Pavel ; Špičková, Jitka ; Fišák, Jaroslav ; Skřivan, Petr
Since June 2004 throughfall samples in beech and spruce vegetation have been taken at the observatory Milesovka. Ever since 1998 fog water samples have been taken there as well. In this paper are compared the concentrations of main ions and trace elements in throughfall and in deposited precipitation. The concentrations of main ions and trace elements in throughfal are primarily affected by the volume of samples. The highest concentrations of monitored sustances in throughfall were recorded in September and in October when the lowest rainfall totals were measured. The concentrations of monitored sustances were in throughfall mostly higher in spruce vegetation in comparison with beech vegetation. It is probably due to the thicker treetop in spruce vegetation on Milesovka observatory. Due to the thicker treetop a smaller volume of throughfall is let fall and the substances from ambient air are captured more effectively in comparison with beech vegetation. In the case of main ions the lowest concentrations were measured in fog water samples. For trace elements wasn´t data. From comparison with reference locality Lesni potok is obvious that concentrations of monitored sustances in throughfall on Milesovka exceed sharply concentrations in locality Lesni potok. This difference is considerably higher by spruce vegetation in comparison to beech vegetation which indicate that it is necessary take not only local air quality into account but also type of vegetation and thick of treetop which can very significantly contribute to the chemical composition of throughfall.
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Pollutant concentrtion in fog-water at Kopisty (1999 – 2004)
Fišák, Jaroslav ; Chaloupecký, Pavel ; Fottová, D.
In this contribution, results of our studies devoted to analyses of fog water samples collected at the meteorological observatory over the period of 1999 - 2004 are summarized. The study deals with the parameters: conductivity, acidity and following selected ions: NH4+, Na+, Ca2+, Mg2+, K+, F-, Cl-, NO3- and SO42-. Overall, the total concentration of selected ions was remarkably decreasing during the period 2000 - 2004. Specifically, we found out an increase in the cation fraction for NH4+ and Ca2+, and a decrease in the anion NO3- fraction in the mean annual sample.
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