小尺度环境地形认知与空间行为的关系分析——以南京大学浦口校区为例   总被引：4，自引：0，他引：4  

蒋志杰  张捷  李丽  聂守宏 《地理学报》2011,66(6):821-830

地形认知与空间行为间的交互影响是重要的人地关系,也是行为地理学近期重视的课题,但相关研究甚少。为考察日常活动中的上述交互作用,文章选择南大浦口校园为案例区,在预研究基础上,采用分层比例抽样,分别抽取认知与行为样本,并运用言语描述和草图方法获得被试的认知与行为数据。随后,通过绘制公共地形认知与行为地图及地理环境编码等定性方法,同时使用空间叠置与缓冲区及偏相关定量分析方法,得到以下结论：① 被试在认知地图中已编码了地形高程的等级秩序,基本认知了研究区的地形空间格局。② 校园行为节点以必要性活动场所为主,自发性活动与社会性活动场所为次;必要性活动路径分布于校园南部,呈直线,两端连接生活区和教学区;而自发性活动路径离散分布,连接更多的运动场所和环境景点。③ 地形认知与空间行为存在交互影响,具体表现为：地形认知影响了行为的空间格局,但此影响受行为的动机和效率认知的调控;反之空间行为是影响地形认知的主要因素,其影响受行为的动机与持续时间的调控。④ 宿舍位置是影响地形认知与空间行为交互作用的主要因素,而性别与学科的影响不显著。最后探讨了研究不足及发展方向。  相似文献   

The kriging update equations and their application to the selection of neighboring data   总被引：1，自引：0，他引：1  

Xavier Emery 《Computational Geosciences》2009,13(3):269-280

A key problem in the application of kriging is the definition of a local neighborhood in which to search for the most relevant data. A usual practice consists in selecting data close to the location targeted for prediction and, at the same time, distributed as uniformly as possible around this location, in order to discard data conveying redundant information. This approach may however not be optimal, insofar as it does not account for the data spatial correlation. To improve the kriging neighborhood definition, we first examine the effect of including one or more data and present equations in order to quickly update the kriging weights and kriging variances. These equations are then applied to design a stepwise selection algorithm that progressively incorporates the most relevant data, i.e., the data that make the kriging variance decrease more. The proposed algorithm is illustrated on a soil contamination dataset.  相似文献   

Spinel–quartz high temperature paragenesis in Al–Fe granulites from the Ihouhaouene area (NW Hoggar, Algeria)     

Saïda Aït-Djafer  Zouhir Adjerid  Assia Badani  Khadidja Ouzegane  Jean Robert Kienast   《Journal of African Earth Sciences》2009,55(1-2):79

The spinel–quartz-bearing Al–Fe granulites from Ihouhaouene (In Ouzzal, West Hoggar) have a migmatitic appearance with quartzo-feldspathic layers intercalated with restitic layers. These granulites are characterized by a hercynitic spinel–quartz assemblage typical of high grade terranes. The stability of the spinel–quartz assemblage is attributed to an elevation of temperature (from 800 to >1100 °C) at high pressures (10–11 kbar), followed by an isothermal decompression from 9 to 5 kbar, an evolution typical of the In Ouzzal clockwise P–T path. The Al–Fe granulites’ history can be subdivided into different successive crystallisation stages. During the first stage, the spinel–quartz assemblage formed, probably following a prograde event that also produced partial melting. During a second stage, the primary spinel–garnet–sillimanite–quartz paragenesis broke-down to give rise to the secondary assemblage. The metamorphic evolution and phase relations during this stage are shown in P–T–X pseudosections calculated for the simple FMASH system. These pseudosections show that the orthopyroxene–cordierite–spinel symplectite appeared during a high temperature decompression, as a product of destabilisation of garnet in sillimanite-free microdomains with high X_Mg values. At the same time, the spinel–quartz association broke-down into cordierite in Fe-rich microdomains. Average pressure and temperature estimates for the orthopyroxene–spinel–garnet–cordierite–quartz association are close to the thermal peak of metamorphism (1000 ± 116 °C at 6.3 ± 0.5 kbar). With decreasing temperatures garnet–sillimanite corona developed from the breakdown of the primary spinel–quartz assemblage in the Fe-rich microdomains, whereas cordierite–spinel formed at the expense of primary sillimanite and garnet in the Mg-rich microdomains.  相似文献   

Pc3–4 ULF waves at polar latitudes     

V.A. Pilipenko  O.M. Chugunova  M.J. Engebretson 《Journal of Atmospheric and Solar》2008,70(18):2262-2274

A search for Pc3–4 wave activity was performed using data from a trans-Antarctic profile of search-coil magnetometers extending from the auroral zone through cusp latitudes and deep into the polar cap. Pc3–4 pulsations were found to be a ubiquitous element of ULF wave activity in all these regions. The diurnal variations of Pc3 and Pc4 pulsations at different latitudes have been statistically examined using discrimination between wave packets (pulsations) and noise. Daily variations of the Pc3–4 wave power differ for the stations at the polar cap, cusp, and auroral latitudes, which suggests the occurrence of several channels of propagation of upstream wave energy to the ground: via the equatorial magnetosphere, cusp, and lobe/mantle. An additional maximum of Pc3 pulsations during early-morning hours in the polar cap has been detected. This maximum, possibly, is due to the proximity of the geomagnetic field lines at these hours to the exterior cusp. The statistical relation between the occurrence of Pc3–4 pulsations and interplanetary parameters has been examined by analyzing normalized distributions of wave occurrence probability. The dependences of the occurrence probability of Pc3–4 pulsations on the IMF and solar wind parameters are nearly the same at all latitudes, but remarkably different for the Pc3 and Pc4 bands. We conclude that the mechanisms of high-latitude Pc3 and Pc4 pulsations are different: Pc3 waves are generated in the foreshock upstream of the quasi-parallel bow shock, whereas the source of the Pc4 activity is related to magnetospheric activity. Hourly Pc3 power has been found to be strongly dependent on the season: the power ratio between the polar summer and winter seasons is 8. The effect of substantial suppression of the Pc3 amplitudes during the polar night is reasonably well explained by the features of Alfven wave transmission through the ionosphere. Spectral analysis of the daily energy of Pc3 and Pc4 pulsations in the polar cap revealed the occurrence of several periodicities. Periodic modulations with periods 26, 13 and 8–9 days are caused by similar periodicities in the solar wind and IMF parameters, whereas the 18-day periodicity, observed during the polar winter only, is caused, probably, by modulation of the ionospheric conductance by atmospheric planetary waves. The occurrence of the narrow-band Pc3 waves in the polar cap is a challenge to modelers, because so far no band-pass filtering mechanism on open field lines has been identified.  相似文献   

Turbulent measurements in the stable atmospheric boundary layer during SHEBA: ten years after   总被引：4，自引：0，他引：4  

Andrey A. Grachev  Edgar L. Andreas  Christopher W. Fairall  Peter S. Guest  P. Ola G. Persson 《Acta Geophysica》2008,56(1):142-166

This paper surveys results of the comprehensive turbulent measurements in the stable boundary layer (SBL) made over the Arctic pack ice during the Surface Heat Budget of the Arctic Ocean experiment (SHEBA) in the Beaufort Gyre from October 1997 through September 1998. Turbulent fluxes and mean meteorological data were continuously measured and reported hourly at five levels on a 20-m main SHEBA tower. Eleven months of measurements during SHEBA cover a wide range of stability conditions, from the weakly unstable regime to very stable stratification, and allow studying the SBL in detail. A brief overview of the SBL regimes, the flux-profile relationships, the turbulent Prandtl number, and other parameters obtained during SHEBA is given. The traditional Monin—Obukhov approach, z-less scaling, and gradient-based scaling are evaluated and discussed based on the data from SHEBA.  相似文献   

Seasonal variation in the importance of pelagic fish in the diet of piscivorous fish in the Moray Firth, NE Scotland: a response to variation in prey abundance?   总被引：5，自引：2，他引：3  

Greenstreet  Simon P.R.; McMillan  Julie A.; Armstrong  Eric 《ICES Journal of Marine Science》1998,55(1):121-133

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Local relationships between the disturbing density, the disturbing potential and the disturbing gravity of the Earth's gravity field     

Z. L. Fei  M. G. Sideris 《Journal of Geodesy》1999,73(10):534-542

A function having some properties of a wavelet and being harmonic around a given point in R ³ is defined, and three models showing the local relationships between the disturbing density, the disturbing potential and the disturbing gravity are established by using the function as the kernel function of the integrals in the models. The local relationship has two meanings. One is that we can evaluate with a high accuracy the integrals in the models by using mainly high-accuracy and high-resolution data in a local area. The other is that we can obtain a stable solution with high resolution when we invert the integrals in the models because of the rapid decrease of the kernel function of the integrals. As a result, with these models we evaluate one quantity with high resolution, in a band limited by the maximum degree of a set of geopotential coefficients or by the resolution (spacing) of the local data, from another quantity (or quantities) in a local area, and the resulting solution is stable. Received: 6 April 1998 / Accepted: 16 June 1999  相似文献   

Stages on Journeys: Some Remarks about Human Geography andPsychotherapeutic Practice     

Liz Bondi 《The Professional geographer》1999,51(1):11-24

This paper attempts to open up discussion about interconnectionsbetween psychotherapeutic practice and human geography. I offer brief “here and now” observations to introduce the importance of personal experience and interpersonal relationships. I then construct an autobiographical narrative to elaborate the themes of separation and connection. This frames my preliminary explorations of tensions and convergences between ideas flowing from psychotherapeutic practice and human geography. I conclude by stressing limits to knowledge.  相似文献   

On the stability relationships between tidal asymmetry and morphologies of tidal basins and estuaries          下载免费PDF全文

Zeng Zhou  Giovanni Coco  Ian Townend  Zheng Gong  Zhengbing Wang  Changkuan Zhang 《地球表面变化过程与地形》2018,43(9):1943-1959

Simple stability relationships are practically useful to provide a rapid assessment of coastal and estuarine landforms in response to human interventions and long‐term climate change. In this contribution, we review a variety of simple stability relationships which are based on the analysis of tidal asymmetry (TA). Most of the existing TA‐based stability relationships are derived using the one‐dimensional tidal flow equations assuming a certain regular shape of the tidal channel cross‐sections. To facilitate analytical solutions, specific assumptions inevitably need to be made, for example by linearizing the friction term and dropping some negligible terms in the tidal flow equations. We find that three major types of TA‐based stability relationships have been proposed between three non‐dimensional channel geometric ratios (represented by the ratio of channel widths, ratio of wet surface areas and ratio of storage volumes) and the tide‐related parameter a/h (i.e. the ratio between tidal amplitude and mean water depth). Based on established geometric relations, we use these non‐dimensional ratios to restate the existing relationships so that they are directly comparable. Available datasets are further extended to examine the utility of these TA‐based relationships. Although a certain agreement is shown for these relationships, we also observe a large scatter of data points which are collected in different types of landscape, hydrodynamic and sedimentological settings over the world. We discuss in detail the potential reasons for this large scatter and subsequently elaborate on the limited applicability of the various TA‐based stability relationships for practical use. We highlight the need to delve further into what constitutes equilibrium and what is needed to develop more robust measures to determine the morphological state of these systems. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

南海北部东沙海域巨型水下沙丘的分布及特征   总被引：3，自引：2，他引：1       下载免费PDF全文

耿明会  宋海斌  关永贤  拜阳  刘胜旋  陈业伟 《地球物理学报》2017,60(2):628-638

本文基于多波束测深和高分辨率多道反射地震数据研究了东沙海域深水巨型水下沙丘的特征.巨型水下沙丘发育在230~830m水深的上陆坡范围内,呈斑块状分布.NW-SE向的近海底流体运动不仅冲蚀地层,形成了三条与水下沙丘间隔分布的冲蚀带,为水下沙丘提供了沉积物来源,同时也为水下沙丘的形成提供了动力源.研究区水下沙丘波长(L)范围55~510m,波高(h)范围1.5~20m,二者呈指数关系分布.沙丘的波长随水深增大而增大,波高则在500~700m水深范围内最大.水下沙丘NE—SW向展布的脊线和几何参数关系是与现今水动力条件相平衡的结果.  相似文献