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401.
负荷勒夫数h'_n、l'_n、和k'_n用以表征地球在表面点负荷作用下的变形.当n→∞时,h'_n、nl'_n和nk'_n的渐近值均为常数,这是Farrell通过比较Boussinesq问题的解与地球在表面负荷作用下变形的球函数级数展开式得出的.本文直接由负荷勒夫数满足的微分方程推导出了它们的渐近表达式,方法更为直观和简明,而且更易于理解。 相似文献
402.
Study on tidal gravity observations obtained at stations Zhongshan and Changcheng, Antarctic 总被引:1,自引:0,他引:1
Lü Chun-cao 《地震学报(英文版)》2001,14(3):325-332
IntroductionThe purpose of the studies on the tidal gravity observations on the Earth(s surface is to investigate the properties of the deformation and the tidal gravity variations of the Earth under the action of the luni-solar tidal force. These variations relate to the internal structure, shape and the medium(s rheology properties of the Earth (Wahr, 1981; Dehant, 1987). The theoretical studies and observations indicated that the amplitudes and the tidal parameters, including the amplitud… 相似文献
403.
地磁日变幅的时空变化 总被引:3,自引:0,他引:3
胡久常 《地震地磁观测与研究》1992,13(3):73-77
本文利用13个全国Ⅰ类基准地磁台和3个Ⅱ类地磁台的《地磁观测报告》,通过对偏角、水平和垂直三分量日变幅值求季平均、年平均以及年滑动平均,再用各种均值点图,从而发现,(1)三分量日变幅皆有以一年为周期的季节变化和以约11年为周期的太阳黑子周变化;(2)三分量日变幅随地磁纬度的变化存在区域性,在区域内日变幅值与地磁纬度有明显的线性关系。此外,本文还对分析结果作了进一步的讨论。 相似文献
404.
Jeremy R. Henderson Ian G. Main Calum Maclean Michael G. Norman 《Pure and Applied Geophysics》1994,142(3-4):545-565
We present a cellular automaton model which simulates the process of seismogenesis using rules for evolution which are derived from the field of fracture mechanics, and include an interplay of positive and negative feedbacks. We describe the implementation of this model, and its analysis, in a massively parallel environment using the Connection Machine. Starting from a lattice with a fractal distribution of fracture toughnesses, theb value evolves in a way which closely mimics both the evolutions ofb value observed in the laboratory and derived from earthquake catalogues, reaching a broad and irregular maximum in the period preceding a major event, and declining rapidly during catastrophic failure. We conclude that the processes modelled are a reasonable representation of those occurring in Nature, and that the cellular automaton paradigm is a valuable way of simulating these processes on a large scale in an economical manner. 相似文献
405.
The Impacts of Initial Perturbations on the Computational Stability of Nonlinear Evolution Equations 下载免费PDF全文
The impacts of initial perturbations on the computational stability of nonlinear evolution equations for non-conservative difference schemes and non-periodic boundary conditions are studied through theoretical analysis and numerical experiments for the case of onedimensional equations.The sensitivity of the difference scheme to initial values is further analyzed.The results show that the computational stability primarily depends on the form of the initial values if the difference scheme and boundary conditions are determined.Thus,the computational stability is sensitive to the initial perturbations. 相似文献
406.
Louise Eriksson 《社会与自然资源》2018,31(4):409-423
Threats associated with climate change may damage forests. To encourage adaptation in countries with a lot of privately owned forest, policy measures directed at private forest owners may be implemented. By means of policy scenarios, the present study examined the effects of two hypothetical policies: an advice and an economic incentive, on climate change adaptation among private forest owners in Sweden (n?=?753 and n?=?729). Both policies strengthened the intention to adapt although results also revealed that individual variables (i.e., forest values) and a contextual variable (i.e., being in an encouraging social risk management context) were important for the owners’ response. Production forest values and social risk management context furthermore moderated the effect of policy on intention to adapt, suggesting that the economic incentive was mainly more effective than the advice among owners with strong production values and among owners in less encouraging social risk management contexts. 相似文献
407.
N. L. Mohan L. Anand Babu N. Sunderarajan S. V. Seshagiri Rao 《Pure and Applied Geophysics》1990,133(3):403-428
An interpretation technique using the Mellin transform is suggested for the analysis of magnetic anomalies due to some two-dimensional structures namely (i) a vertical sheet of both finite and infinite depth extent, (ii) a thick dyke and (iii) a horizontal circular cylinder. The Mellin transformed magnetic anomalies resemble gamma functions which are amenable to an easy interpretation. This procedure is illustrated with a small number of synthetic examples in each case. The practicality of the method is exemplified with the well-known vertical magnetic anomalies of Kursk (USSR) in the case of an infinite sheet model and Karimnagar magnetic anomaly (India) in the case of a horizontal circular cylinder. The results are compared with the techniques already available and found to be reliable. 相似文献
408.
Relationships between spatial and non-spatial preferences and place-based values in national forests
The management of multiple-use public lands such as national forests in the U.S. is controversial because of the wide range of potential uses and contested public values for these lands. Previous research on national forest values and management preferences examined these relationships non-spatially. The development of public participation GIS (PPGIS) and volunteered geographic information (VGI) systems provide new opportunities to assess spatial relationships between perceived national forest values and preferred uses. This research used empirical data collected from a PPGIS/VGI study for three national forests in California to examine spatial and non-spatial relationships between place-based forest values and preferred uses. The relationships suggest public participants translated some of their non-spatial forest values and preferences into behavioral choices when mapping place-specific values and preferred uses. The empirical relationships between place-based forest values and uses were generally consistent with previous survey research results. Positive, non-spatial attitudes toward extractive uses of national forests were correlated with participant mapping of economic values and related extractive uses, while nonmaterial forest attitudes were correlated with participant mapping of amenity values and conservation-related uses. Further, spatial preferences for extractive forest uses such as timber harvesting were mapped proximate to economic values, while nonmaterial spatial preferences were mapped proximate to amenity-related forest values. PPGIS offers the potential to translate philosophical and ideology-based national forest preferences into place-specific discourse about forest management activities where public accommodation may be more achievable. 相似文献
409.
410.
《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(4):248-258
The mountain areas of Europe have been of vital importance in the system of summer farming whereby the movement of livestock between different altitudinal levels is a key element. However, summer farming has been downscaled considerably during the 20th century. The article describes two areas where summer farming is still practised: Forollhogna in Norway, and Asturias in Spain. The authors document the transhumance system in the two areas, and investigate how farmers view the summer farming system and landscape, how they relate to nature protection, and whether specific value orientations can be detected in their views. The findings show that the logic behind summer farming is the same in both areas: economic motivation and access to grazing grounds. With regard to nature and landscape protection, the opinion that wild nature is given priority and that ‘managed nature’ of transhumance is overlooked was found in both areas, although it was expressed more strongly in Asturias than in Forollhogna. Opinions and ideals related to ‘good farming’ were found in both contexts, and were reflected in well-kept fields and productive and healthy livestock. 相似文献