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991.
am ¶rt; mauau uu u u aamuam u a. m num u m a¶rt;a muu nmuaa u ¶rt;uau nmu¶rt;uu.

Invited Paper, 9th Brazilian Congress in Cartography, Curitiba, Paraná, Brazil, February 4–9, 1979.  相似文献   
992.
Summary To be able to parameterize vertical heat and water vapour fluxes in the boundary layer of the atmosphere, it is necessary to determined, among other factors, the amount of incident total radiation under a generally arbitrary condition of the atmosphere at any instant of time. This paper deals with a simple model for computing the total radiation based on known solar elevation, total cloud cover and the atmospheric turbidity parameter. This variant of the model was formulated on the basis of a two-year series of total radiation observations made in the radiation network of the Czech Hydrometeorological Institute, and on the measurements and observations made at the observatory of the Institute of the Physics of the Atmosphere in Kopisty. An example of comparing the observed and theoretical values of total radiation will also be given.
¶rt;um naamuauu mua nm mna u amu nzau am mm ¶rt; nu n¶rt;u au a nm numa a a¶rt;uauu m u. mam auam n naamuauu a a¶rt;uauu n ¶rt;a m a, ammu am u mnu az na. ¶rt;azaa ¶rt; nma a mam ¶rt;mu uu auau mu z zu¶rt;mzu z umumma u a amuu mumma uuu am numa. mam ma nu¶rt; nu au u u n n¶rt; ¶rt;u u au a a¶rt;uauu.
  相似文献   
993.
Summary Predictor vectors, including upper air as well as surface data, were used for categorical forecasting convective events over a subregion of the Czech territory, and the effect of including surface variables in the predictor vector was examined. While upper air data were considered as Perfect Prognosis, the surface data were successively included according to the time of their origin. The forecasting technique was based on linear multiple regression with learning, and the accuracy of the forecast was measured by the Critical Success Index. The input data from the three May-September periods in 1989–91 were used, and the first year served as the learning set. The aerological data from TEMP 12 UTC, simulating Perfect Prognosis, were the source of the upper air predictors. The performance of all, upper air, surface and combined, predictors were evaluated and compared. It turned out that the improvement of prediction accuracy due to the inclusion of surface variables was not negligible. Significant improvements were made in the forecasts of thunderstorm occurrence between 18 and 24 UTC.  相似文献   
994.
995.
Summary The results of a magnetic study of two batches of sized natural haematite fractions (from Kada, Czech Republic) are reported. One of the sample batches was prepared by ultrasonic micro precision sieving in propanon (acetone), the other in ethanol (alcohol). Surprisingly, the magnetic behaviour of the ethanol-sieved fractions was much softer (e.g. Hcr 20 kA/m) as compared with the propanon-sieved fractions (Hcr > 200 kA/m). Thermomagnetic measurements suggest a maghemite portion is present in the material used for the preparation of the ethanol-sieved samples. Possible causes of this puzzling behaviour are discussed. However, no definite conclusion can be drawn on the basis of the data presently available.Presented at 3rd Biennial Meeting on New Trends in Geomagnetism, Smolenice Castle, West Slovakia, June 22–29, 1992.  相似文献   
996.
Summary The first attempt has been made at determining the differences between mean sea-levels, using the recent satellite altimetry data [1].  相似文献   
997.
mam mm ua a na Pn, Pg, Sn u Sg nu¶rt;u u au -ma. aa, m ¶rt; amu 5° m numa ua¶rt;a ¶rt;am mu a na n au ma¶rt;amu u mu anmau , uu m n u ma¶rt;am¶rt;a. am nmau a uu m anmau mmu aua.  相似文献   
998.
The sorption capacity of two natural sorbents of different origin and of Wofatit KPS is determined by dynamic laboratory investigations and the influence of a thermal pretreatment of clinoptilolite, of the type and quantity of regenerants and of the presence of other cations is investigated. There are represented results of the ammonia removal from biologically treated municipal wastewater and of the removal of caesium-ions from laundry wastewaters. The capacity of clinoptilolite is lower than that of the ion-exchange resin, but clinoptilolite has the advantage of a considerably higher affinity for ammonium-ions, so that it can be used also in the presence of other salts in water to be treated. The ammonium concentration should not exceed 30 mg/l, in order to avoid too short filter runs.  相似文献   
999.
Summary The data of borehole resistivity logs were collected, analysed, classified and a contour map of electrical conductance of the sedimentary complex overlying the crystalline basement of the Czech Republic was computer-generated. The map contributes to estimating the distortion fields produced by conductance variations in the surface layer. Information on the basement relief is also obtained from the contour map patterns.  相似文献   
1000.
    
Ground fissures, especially if they open due to a sudden collapse of the surface, is a serious risk for populated areas. Their common occurrence in unconsolidated sediments of the Main Ethiopian Rift was found to be mostly a result of piping. The fissures start by piping in linear sub-horizontal underground voids, which often propagate upwards resulting in ceiling collapse and formation of deep and long ground fissures with vertical walls. In the southern and central Main Ethiopian Rift the fissures pose a serious risk to infrastructure and settlements. The ground fissures are often linear (up to several kilometres long and often tens of metres deep) and accompanied by sinkholes (along the length). A detailed field mapping of the geological (rock composition, orientation and character of lithological boundaries, primary fabrics and brittle structures) and geomorphological features (especially a length, width and depth of fissures, sinkholes and gullies) followed by in situ seismic anisotropy measurements and a laboratory determination of the geomechanical properties of volcanoclastic deposits was carried out to investigate the ground fissures' origin. The conditions and factors leading to the formation of the ground fissures have been linked to: (a) the presence of regional normal faults and the associated extensional joints and (b) the alternation of lithological units with contrasting hydraulic permeability. The latter corresponds to a sequence of less permeable hard rocks (e.g., rhyolitic ignimbrites) overlain by heterogeneous, soft and permeable, unconsolidated volcaniclastic deposits with a low amount of clay (less than 10%). The ground fissures' occurrence has shown affiliation to areas which have a significantly high seismic anisotropy (more than 20% at the study sites), which can be used as a proxy to map out high risk areas prone to piping and ground fissure formation.  相似文献   
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