Few Comments on the Relation Between the Initial Proto-planetary Disc Model and the Oort Cloud Formation     

Tomáš Paulech  Marián Jakubík  Luboš Neslušan  Piotr A. Dybczyński  Giuseppe Leto 《Earth, Moon, and Planets》2009,105(2-4):367-371

A fraction of small bodies from the once existing proto-planetary disc was ejected, by the giant planets, to large heliocentric distances and start to build the comet Oort cloud. Considering four models of initial proto-planetary disc, we attempt to roughly map a dependence between the initial disc’s structure and some properties of the Oort cloud. We find that it is difficult to construct the proto-planetary disc if (i) the amount of heavy chemical elements in Jupiter and Saturn is as high as currently accepted and (ii) the total mass of the minimum-mass solar nebula is assumed to be lower than $\approx0.05\,\hbox{M}_{\odot}.$ The behaviour of the Oort cloud formation does not crucially depend on the initial disc model. Some differences in its structure are obvious: since the cloud is known to be filled mainly by Uranus and Neptune, the efficiency of its formation is higher when the initial amount of particles in the Uranus-Neptune region is relatively higher. A significantly large number of Jupiter Trojans in our simulation appears, however, only in the case of the initially non-gapped disc, with the particles situated also close to the Jupiter’s orbit.  相似文献   

Exploring earth system governance: A case study of floodplain management along the Tisza river in Hungary     

Saskia E. Werners  Zsuzsanna Flachner  Piotr Matczak  Maria Falaleeva  Rik Leemans 《Global Environmental Change》2009,19(4):503-511

This paper discusses a recently proposed conceptualisation of ‘earth system governance’ by applying it to floodplain management in the Hungarian Tisza river basin. By doing so it aims to improve our understanding of governance systems facilitating adaptation to a changing world. The conceptualisation of earth system governance consists of three elements: problem structure, principles and research challenges. These three elements are assessed using results from actor interviews and policy review. A regional example of natural resources management is found to be a valid case for earth system governance research. The proposed conceptualisation of earth system governance explains well the main problems, barriers and opportunities for adapting floodplain management to climate change in the Tisza region. Problem structure analysis highlights how previous socio-economic and political orders continue to shape expectations and patterns of conduct. Current barriers can be attributed to a lack of the key governance principles credibility, stability, inclusiveness and adaptiveness. Interviewees perceived the lack of credibility and effective cooperation between organisations as the largest barrier. The research challenges proposed for earth system governance agree well with opportunities identified for adapting Tisza floodplain management, calling for inclusion of actors beyond governments and state agencies, and equitable resource allocation in particular. The analysis suggests that an additional challenge for earth system governance is the prioritisation of actions to support an existing governance system and its actors in adapting.  相似文献   

Comparison of global storm activity rate calculated from Schumann resonance background components to electric field intensity E_0Z     

Zenon Nieckarz  Andrzej Ku&#x;ak  Stanis&#x;aw Zi&#x;ba  Marek Kubicki  Stanis&#x;aw Michnowski  Piotr Bara&#x;ski 《Atmospheric Research》2009,91(2-4):184-187

This work presents the results of a comparison between the global storm activity rate I_RS and electric field intensity E_0Z. The permanent analysis of the I_RS may become an important tool for testing Global Electric Circuit models. I_RS is determined by a new method that uses the background component of the first 7 Schumann resonances (SR). The rate calculations are based on ELF observations carried out in 2005 and 2006 in the observatory station “Hylaty” of the Jagiellonian University in the Eastern Carpathians (Kułak, A., Zięba, S., Micek, S., Nieckarz, Z., 2003. Solar variations in extremely low frequency propagation parameters: I. A two-dimensional telegraph equation (TDTE) model of ELF propagation and fundamental parameters of Schumann resonances, J. Geophys. Res., 108, 1270, doi:10.1029/2002JA009304). Diurnal runs of the I_RS rate were compared with diurnal runs of E_0Z amplitudes registered at the Earth's surface in the Geophysical Observatory of the Polish Academy of Sciences in Świder (Kubicki, M., 2005. Results of Atmospheric Electricity and Meteorological Observations, S. Kalinowski Geophysical Observatory at Świder 2004, Pub. Inst. Geophysics Polish Academy of Sciences, D-68 (383), Warszawa.). The days with the highest values of the correlation coefficient (R) between amplitudes of both observed parameters characterizing atmosphere electric activity are shown. The seasonal changes of R, I_RS and E_0Z are also presented.  相似文献   

Short-Period Secular Variations (SPSV) of the geomagnetic field recorded in highly scattered palaeomagnetic records of Holocene lake sediments from North Poland     

Piotr Tucholka 《Earth and Planetary Science Letters》1980,48(2):379-384

A simple method of calculating running means over different intervals within palaeomagnetic records has been used to identify short-period secular variations of the geomagnetic field. The records from Polish lake sediments reveal variations in declination with a period between 290 and 372 years. The periodicity of variations in the inclination has been estimated to be between 522 and 670 years.  相似文献   

Geomorphology of medium‐high mountains under changing human impact,from managed slopes to nature restoration: a study from the Sudetes,SW Poland     

Agnieszka Latocha  Piotr Migo&#x; 《地球表面变化过程与地形》2006,31(13):1657-1673

In the last few hundred years, medium‐high mountain geomorphic systems of the East Sudetes, central Europe, have evolved under varying human impacts and have shown distinctive behaviours, depending on the nature and intensity of human activities. The general trend within this period has been from initial disturbance brought about by the spread of agriculture, through managed rural landscapes in the 19th and early 20th century, to gradual restoration of natural conditions observed in the last few tens of years, concurrent with considerable population decline in the mountain valleys. Accelerated soil erosion was successfully mitigated by the introduction of agricultural terraces in the 19th century, and most sediment could have been stored within the slopes. The current phase of nature restoration is understood as a return to general slope stability, weak coupling between slopes and channels, and limited sediment transfer across and out of mountainous drainage basins, which typified most of the Holocene prior to human colonization. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

An Architecture for the Management of GIS Data Files     

Gregory Vert  Molly Stock  Piotr Jankowski  Paul Gessler 《Transactions in GIS》2002,6(3):259-275

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Snow research in Svalbard–an overview     

Jan-Gunnar Winther  Oddbjørn Bruland  Knut Sand  Sebastian Gerland  David Marechal  Boris Ivanov  Piotr Gøowacki  Max König 《Polar research》2003,22(2):125-144

This paper summarizes the most significant snow-related research that has been conducted in Svalbard. Most of the research has been performed during the 1990s and includes investigations of snow distribution, snow-melt, snow pack characteristics, remote sensing of snow and biological studies where snow conditions play an important role. For example, studies have shown regional trends with about 50% higher amounts of snow accumulation at the east coast of Spitsbergen compared to the west coast. Further, the accumulation rates are about twice as high in the south compared to the north. On average, the increase in accumulation with elevation is 97 mm water equivalents per 100 m increase in elevation. Several researchers reported melt rates, which are primarily driven by incoming short-wave radiation, in the range of 10-20 mm/day during spring. Maximum melt rates close to 70 mm/day have been measured. In addition to presenting an overview of research activities, we discuss new, unpublished results in areas where considerable progress is being made. These are i) modelling of snow distribution, ii) modelling of snowmelt runoff and iii) monitoring of snow coverage by satellite imagery. We also identify some weaknesses in current research activities. They are lacks of i) integration between various studies, ii) comparative studies with other Arctic regions, iii) applying local field studies in models that can be used to study larger areas of Svalbard and, finally, iv) using satellite remote sensing data for operational monitoring purposes.  相似文献   

The drainage pattern of Hansbreen and Werenskioldbreen, two polythermal glaciers in Svalbard   总被引：2，自引：0，他引：2  

Anja Pälli  John C. Moore  Jacek Jania  Leszek Kolondra  Piotr Glowacki 《Polar research》2003,22(2):355-371

To improve our understanding of Svalbard-type polythermal glacier drainage, hydraulic geometry models of the subglacial hydrology of two contrasting glaciers in Svalbard have been constructed. The models are tested against a uniquely long and rich set of field observations spanning 45 years. Digital elevation models (DEMs) were constructed from bedrock data measured with ground penetrating radar and surface data of two medium-sized polythermal glaciers, Hansbreen and Werenskioldbreen, in south-west Spitsbergen. Hansbreen has a low angle bed with over-deepenings and a calving front, while Werenskioldbreen has steeper bed and terminates on land. Together they are representative of many Svalbard glaciers. The DEMs were used to derive maps of hydraulic potential and subglacial drainage networks. Validation of the models was done using field observations including location mapping and speleological exploration of active moulins, positions of main river outflows, dyetracing and water chemistry studies, and observations of water pressure inside moulins. Results suggest that the water pressure is generally close to ice overburden pressure but varies greatly depending on local conditions such as bed location, the thickness of cold ice layer, the thickness of the glacier and seasonal changes in meltwater input.  相似文献   

The zebra mussel (Dreissena polymorpha) and the benthic community in a coastal Baltic lagoon: another example of enhancement?     

Teresa Radziejewska  Christiane Fenske  Brygida Wawrzyniak-Wydrowska  Philip Riel  Adam Wo&#;niczka  & Piotr Gruszka 《Marine Ecology》2009,30(S1):138-150

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On the influence of relativistic effects on X-ray variability of accreting black holes     

Piotr T. &#;ycki  Andrzej Nied&#;wiecki 《Monthly notices of the Royal Astronomical Society》2005,359(1):308-314

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