Comparison of Solar and Geomagnetic Activity Effects on the Northern Hemisphere Weather Changes     

Bochníček  Josef  Hejda  Pavel  Pýcha  Josef 《Studia Geophysica et Geodaetica》2001,45(2):133-154

The changes of pressure and temperature fields in the winter lower troposphere observed in association with changes in solar and/or geomagnetic activity are compared. It is shown that the fact whether it was solar or geomagnetic activity was not so important as whether the levels of the two activities were high or low. The differences between the effects of solar/geomagnetic activity, however, are revealed, the pressure and temperature data being stratified according to the QBO phase. The relationship obtained are discussed from the viewpoint of mechanisms resting upon both the planetary wave propagation and the changes of atmospheric air currents in the global electric circuit.  相似文献   

对哈萨克斯坦浙斯卡扎干矿区地面塌落的地震监测     

Vladimir A MANSUROV  Pavel I PAVLOV 《CT理论与应用研究》2000,9(Z1):81-86

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A possible new molecular mechanism of thundercloud electrification   总被引：1，自引：1，他引：1  

Pavel Jungwirth  Daniel Rosenfeld  Victoria Buch 《Atmospheric Research》2005,76(1-4):190

Thunderclouds are electrified when charge is transferred between small and large ice particles colliding in a cloud that contains strong updrafts. The small ice particles rise with one type of charge and the large ice particles fall and carry with them downward the other type of charge, which is most often negative, so that normally lightning lowers negative charge from cloud to the ground. While the collisional mechanism of thundercloud charging is well established, the nature of the charge transfer between the colliding ice particles is not very well understood on the atomic level, and no present theory can explain it in full detail. Here we propose a new charge separation mechanism that is based on molecular dynamics simulations of particle surfaces and collisions, keeping track of the individual charges as they move in the form of salt ions from one ice particle to another. Under normal conditions, when sulfates dominate as cloud condensation nuclei, this ionic mechanism is consistent with the prevailing negative charging of graupels in thunderclouds. Moreover, with dearth of sulfate anions, the present mechanism predicts a shift towards positive charging. This fits well to a large range of observations of enhanced positive lightning, connected with smoke rich in chlorides and nitrates, that could not be explained satisfactorily previously.  相似文献   

Dynamics of the Subsurface Temperature Field Caused by Mining-Related Groundwater Management     

Štulc  Petr  Stoje  Vladimír  Kopecký  Pavel 《Studia Geophysica et Geodaetica》2000,44(3):442-459

The subsurface temperature field was studied on a set of 46 borehole logs measured in the vicinity of uranium deposits in the Bohemian Cretaceous Basin. Vertical variations of the steady state temperature and the temperature gradient are governed by thermal conductivity which strongly varies in dependence on lithology. Large departures from undisturbed temperature detected in many holes are associated with uranium mining. A positive anomaly is observed in leaching fields where large amounts of acid are injected into the uranium-bearing Cenomanian. A negative anomaly is linked to the operation of hydraulic barriers which enclose the mining area and helps to contain pollution by pumping clean water into the Cenomanian aquifer. The spatial distribution of the observed temperature anomalies helps to map the migration of the fluids used in both processes. The temperature disturbance is propagated from the Cenomanian aquifer up through overlying impermeable sediments. The good fit of transient conductive models to the measured temperatures rules out heat advection and hence upward water flow towards and contamination of the upper Middle Turonian aquifer in the vicinity of the holes studied.  相似文献   

Large-scale motion of solar filaments     

Pavel Ambro  Alfred Schroll 《Journal of Astrophysics and Astronomy》2000,21(3-4):205-208

Precise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.  相似文献   

Retrieval of missing values in water temperature series using a data-driven model     

Iyan E. Mulia  Toshiyuki Asano  Pavel Tkalich 《Earth Science Informatics》2015,8(4):787-798

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Optimization of ice cuttings transportation by cable-suspended core auger drills     

HONG Jialin  Pavel Talalay  Mikhail Sysoev 《世界地质(英文版)》2014,17(1):48-54

Ice cores contain an abundance of information about the Earth''s climate in the past,and recovered from shallow drilling down to 300--350 m give sufficient information for reconstructing of the last climatic chan- ges and for monitoring of pollution from human being． Cable-suspended core auger drills use an armored cable with a winch to provide power to the down-hole motor system and to retrieve the down-hole unit． Because of their lightweight,convenient transportation and installation,high penetration rates and low power consumption, core auger drills are widely used for shallow drilling in ice． Nowadays at least 14 types of auger electromechani- cal drills were designed and tested in different foreign and national glaciological laboratories． However,auger options were usually determined by experience,and the main parameters (helix angle of the fights and rotational speed) are varied in a wide range from drill to drill． If parameters of auger are not chosen properly,poorly en- gineered drills had troubles with low efficiency of cuttings transportation,jam of ice cuttings,repeated fragmen- tation,cutters icing and stop penetration,abnormal power consumption,high rotation torques,and so on． Thus,this paper presents the method of optimization of ice cuttings transportation of cable-suspended core auger drill on the base of the theory of rotary auger． As the result,the optimal helix angle was determined correspond- ing to the rotational speed from the transportation efficiency point of view．  相似文献   

ANN application for prediction of atmospheric nitrogen deposition to aquatic ecosystems   总被引：1，自引：0，他引：1  

Palani S  Tkalich P  Balasubramanian R  Palanichamy J 《Marine pollution bulletin》2011,62(6):1198-1206

The occurrences of increased atmospheric nitrogen deposition (ADN) in Southeast Asia during smoke haze episodes have undesired consequences on receiving aquatic ecosystems. A successful prediction of episodic ADN will allow a quantitative understanding of its possible impacts. In this study, an artificial neural network (ANN) model is used to estimate atmospheric deposition of total nitrogen (TN) and organic nitrogen (ON) concentrations to coastal aquatic ecosystems. The selected model input variables were nitrogen species from atmospheric deposition, Total Suspended Particulates, Pollutant Standards Index and meteorological parameters. ANN models predictions were also compared with multiple linear regression model having the same inputs and output. ANN model performance was found relatively more accurate in its predictions and adequate even for high-concentration events with acceptable minimum error. The developed ANN model can be used as a forecasting tool to complement the current TN and ON analysis within the atmospheric deposition-monitoring program in the region.  相似文献   

Relation between two common localisation methods for the EnKF   总被引：3，自引：0，他引：3  

Pavel Sakov  Laurent Bertino 《Computational Geosciences》2011,15(2):225-237

This study investigates the relation between two common localisation methods in ensemble Kalman filter (EnKF) systems: covariance localisation and local analysis. Both methods are popular in large-scale applications with the EnKF. The case of local observations with non-correlated errors is considered. Both methods are formulated in terms of tapering of ensemble anomalies, which provides a framework for their comparison. Based on analytical considerations and experimental evidence, we conclude that in practice the two methods should yield very similar results, so that the choice between them should be based on other criteria, such as numerical effectiveness and scalability.  相似文献   

Assessment of ¹³⁷Cs and ⁹⁰Sr fluxes in the Barents Sea     

G. G. Matishov  D. G. Matishov  I. S. Usyagina  N. E. Kasatkina  E. V. Pavel’skaya 《Doklady Earth Sciences》2011,439(2):1190-1195

The annual balance of radionuclides inflow/outflow was assessed for ¹³⁷Cs and ⁹⁰Sr isotopes in the Barents Sea, taking into account the atmospheric precipitation, inflow from the Norwegian and the White seas, as well as riverine discharge, liquid radioactive waste disposal (LRWD), and outflow to the adjacent seas. The original and published data for the period of 1950–2009 were analyzed. According to the multiyear dynamics (1960–2009), the inflow of ¹³⁷Cs and ⁹⁰Sr into the Barents Sea was significantly preconditioned by the Norwegian Sea currents; and precipitation played a major role in the 1950s, 1960s, and in 1986. Currently, the trans-border redeposition of ⁹⁰Sr prevails over ¹³⁷Cs redeposition in the Barents Sea, and constitutes about 99% of inflow of each element.  相似文献