作为复杂适应系统的农业文化遗产：复杂性的挑战

本文首先阐述了农业系统的复杂性,并对农业系统所面对不确定性,以及外部系统的冲击和压力而形成的动态性进行了分析,提出“复杂适应性系统理论”为研究活态的农业系统,尤其为研究中国的全球重要农业文化遗产（GIAHS）提供了可能,而这些农业文化遗产系统（或其中某些部分）对于研究抵抗力和自我良性管理具有重要的意义.本文认为当前研究中的相关方法将会对整个系统的认识产生新的见解,同时避免把系统分解为各组分进行微观研究再重新还原成整体的研究思路.本文通过综述与GIAHS相关的方法并将旅游引入农村系统（作为一种扰动）,认为可以创造新的方法来认识农村发展干预措施对古老景观的影响,特别是分布在中国农村的许多景观.     

Pathways,motivations and challenges: contemporary Tuvaluan migration to New Zealand

The global climate change literature suggests that at some point in the future it is possible that low-lying areas may be drowned due to rising sea levels, and a number of Pacific Ocean states could be particularly vulnerable. It is increasingly evident that the emerging scenario of environmental change has compounded more established push–pull factors leading to migration, and has provided a new imperative for migration decision-making. By interrogating the proposition that there is a clear distinction between the policy categories of ‘migrants’ and ‘refugees,’ we examine a hitherto un-defined group of Tuvaluan migrants whose movement is in response to environmental change and possible climate change effects. The paper examines Tuvaluan migration to New Zealand through various immigration schemes for permanent residency, with an emphasis on the International/Humanitarian stream.     

The study of hydrodynamic behaviour of a complex karst system under low-flow conditions using natural and artificial tracers (the catchment of the Unica River,SW Slovenia)

In this study a multi-tracer test with fluorescent tracers was combined with time series analyses of natural tracers to characterize the dynamics of the solute transport through different recharge pathways and to study hydraulic behaviour of a binary karst system under low-flow conditions. Fluorescent tracer testing included the introduction of uranine, amidorhodamine G, or naphthionate at three injection points. Sampling and monitoring took place at two karst springs (Malenščica, Unica) and at two underground rivers (Pivka, Rak) recharging the Unica River at the Polje of Planina, SW Slovenia. Other monitored parameters included precipitation, spring or underground river discharge, water temperature, and electrical conductivity. Water samples were collected and analyzed for total organic carbon, Mg²⁺, SO₄ ²⁻, and NO₃ ⁻ in the laboratory. In the study area, results of the tracer test suggest that contaminant transport in karst may be retarded for several weeks during low-flow conditions followed by increases in contaminant concentrations after subsequent rainfall events. Based on interpretation of tracer concentration breakthrough curves, low apparent dominant flow velocities (i.e., between 5.8 and 22.8 m/h through the well developed karst conduits, and 3.6 m/h through the prevailing vadose zone with a dominant influence of a diffuse recharge) were obtained. Together with analyses of hydro-chemographs the artificial tracing identified different origins of water recharging the studied aquifer. During prolonged low-water conditions the Malenščica spring is mainly recharged from the karst aquifer and the Unica spring by the sinking Pivka River. After more intensive rainfall events allogenic recharge from Cerknica prevails in the Malenščica spring, while the Unica spring drains mainly the allogenic water from the Pivka Valley. These findings of alternating hydraulic connections and drainage areas due to respective hydrological conditions are important and should be considered when monitoring water quality, implementing groundwater protection measures, and optimizing future water exploitation.     

New Zealand geography: Sharpening the focus,raising the profile

Geography seems to be in good hands in New Zealand's schools and universities, but we cannot afford to be complacent. What are the key priorities for further strengthening geography in New Zealand in the years ahead? The New Zealand Geographical Society has to play a crucial role by helping to bring together geographers in the different sectors, as well as in promoting New Zealand geography internationally, and raising its profile in the media. Most of all, we need to demonstrate the vibrancy, significance and relevance of geography to the wider community.     

An analytical solution for rainfall infiltration into an unsaturated infinite slope and its application to slope stability analysis

Surficial slope failures in residual soils are common in tropical and subtropical regions as a result of rainfall infiltration. This study develops an analytical solution for simulating rainfall infiltration into an infinite unsaturated soil slope. The analytical solution is based on the general partial differential equation for water flow through unsaturated soils. It can accept soil–water characteristic curve and unsaturated permeability function of the exponential form into account. Numerical simulations are conducted to verify the assumptions of the analytical solution and demonstrate that the proposed analytical solution is acceptable for the coarse soils with low air entry values. The pore‐water pressure (pwp) distributions obtained from the analytical solution can be incorporated into a limit equilibrium method to do infinite slope stability analysis for a rain‐induced shallow slip. The analysis method takes into account the influence of the water content change on unit weight and hence on factor of safety. A series of analytical parametric analyses have been performed using the developed model. The analyses indicate that when the residual soil slope, consisting of a completely decomposed granite layer underlain by a less permeable layer, is subjected to a continuous heavy rainfall, the loss of negative pwp and the reduction in factor of safety were found to be most significant for the shallow soil layer and during the first 12 h. The antecedent and subsequent rainfall intensity, depth of a less permeable layer and slope angle all have a significant influence on the pwp response and hence the slope stability. Copyright © 2012 John Wiley & Sons, Ltd.     

Interactive Visualization to Advance Earthquake Simulation

The geological sciences are challenged to manage and interpret increasing volumes of data as observations and simulations increase in size and complexity. For example, simulations of earthquake-related processes typically generate complex, time-varying data sets in two or more dimensions. To facilitate interpretation and analysis of these data sets, evaluate the underlying models, and to drive future calculations, we have developed methods of interactive visualization with a special focus on using immersive virtual reality (VR) environments to interact with models of Earth’s surface and interior. Virtual mapping tools allow virtual “field studies” in inaccessible regions. Interactive tools allow us to manipulate shapes in order to construct models of geological features for geodynamic models, while feature extraction tools support quantitative measurement of structures that emerge from numerical simulation or field observations, thereby enabling us to improve our interpretation of the dynamical processes that drive earthquakes. VR has traditionally been used primarily as a presentation tool, albeit with active navigation through data. Reaping the full intellectual benefits of immersive VR as a tool for scientific analysis requires building on the method’s strengths, that is, using both 3D perception and interaction with observed or simulated data. This approach also takes advantage of the specialized skills of geological scientists who are trained to interpret, the often limited, geological and geophysical data available from field observations.     

关于“峰丛”、“峰林”与“锥状喀斯特”及“塔状喀斯特”涵义的比较和认识

“峰丛”和“峰林”是在中文文献中使用的两种主要的喀斯特地貌术语。而在其他国家,这两种地貌通常被定义为“锥状喀斯特”和“塔状喀斯特”,但峰丛、峰林与锥状喀斯特、塔状喀斯特并不完全相同。中国喀斯特分布广泛,本文把西方和中国的喀斯特专业术语连接起来,能让西方地貌学家更好地了解中国的喀斯特。本文是朱学稳教授近期发表于《中国岩溶》第28卷第2期上的 “我国峰林喀斯特的苦干问题讨论”论文的英文附加篇。 峰丛喀斯特地貌遍及贵州省及其临近省份大部分地区,其锥体石山较爪哇、牙买加和菲律宾群岛的更高更陡。尽管后者为西方所熟知,但贵州的峰丛可以说是峰丛和锥状喀斯特的典型代表。不过广西的峰林仅在中国以外东南亚的小部分地区可以看见。许多被西方认为是塔状喀斯特的地貌并非真正的峰林。问题产生的原因在于西方学者通过山体形状来区分锥状喀斯特和塔状喀斯特,而中国的学者是根据石峰之间是否存在喀斯特平原来区分峰林和峰丛。 峰丛喀斯特是一种发育成熟的石灰岩地貌,具有深厚的包气带、完整的地下排泄系统,以及发育时间长并免遭更新代冰川破坏的山体形貌。峰林喀斯特是一种极端地貌,仅在横向夷平持续时间比较长的特定环境中形成。峰林形成条件是:（1）石灰岩质纯;（2) 石灰岩层厚;（3）喀斯特平原上有冲积层发育;（4）地下水位变化幅度不大;（5）冲积平原有外源沉积物的流入补充;（6）缓慢构造抬升与喀斯特平原表面剥蚀相适应;（7）具有使石灰岩快速溶蚀的炎热湿润气候;（8）周围喀斯特平原下降时,地面蚀低和石灰岩山体边坡后退平衡。如果构造条件合适的话,峰丛可以演化为峰林。但如果有其他因素起作用,峰林和峰丛似乎可以并行发育。二者的起源仍然备受争论,并且峰林的起源恐怕是多种的。建议国际学术文献中应更加广泛地应用“峰丛”和“峰林”术语,“锥状喀斯特”和“塔状喀斯特”则主要用于对形态方面的描述。      

Heterogeneous characteristics of streambed saturated hydraulic conductivity of the Touchet River,south eastern Washington,USA

Traditionally a streambed is treated as a layer of uniform thickness and low saturated hydraulic conductivity (K) in surface‐ and ground‐water studies. Recent findings have shown a high level of spatial heterogeneity within a streambed and such heterogeneity directly affects surface‐ and ground‐water exchange and can have ecological implications for biogeochemical transformations, nutrient cycling, organic matter decomposition, and reproduction of gravel spawning fish. In this study a detailed field investigation of K was conducted in two selected sites in Touchet River, a typical salmon spawning stream in arid south eastern Washington, USA. In‐stream slug tests were conducted to determine K following the Bouwer and Rice method. For the upper and lower sites, each 50 m long and 9 m wide and roughly 20 m apart, a sampling grid of 5 m longitudinally and 3 m transversely was used. The slug tests were performed for each horizontal coordinate at 0·3–0·45, 0·6–0·75, 0·9–1·05 and 1·2–1·35 m depth intervals unless a shallower impenetrable obstruction was encountered. Additionally, water levels were measured to obtain vertical hydraulic gradient (VHG) between each two adjacent depth intervals. Results indicated that K ranged over three orders of magnitude at both the upper and lower sites and differed between the two sites. At the upper site, K did not differ significantly among different depth intervals based on nonparametric statistical tests for mean, median, and empirical cumulative distribution, but the spatial pattern of K varied among different depth intervals. At the lower site, K for the 0·3–0·45 m depth interval differed statistically from those at other depth intervals, and no similar spatial pattern was found among different depth intervals. Zones of upward and downward water flow based on VHG also varied among different depth intervals, reflecting the complexities of the water flow regime. Detailed characterization of the streambed as attempted in this study should be helpful in providing information on spatial variations of streambed hydraulic properties as well as surface‐ and ground‐water interaction. Copyright © 2009 John Wiley & Sons, Ltd.