Watershed‐scale controls on snow accumulation in a small montane watershed,southwestern Alberta,Canada

Snow accumulation in mountain headwater basins is a major water source, particularly in semi‐arid environments such as southern Alberta where water resources are stressed and snowmelt supplies more than 80% of downstream runoff. Relationships between landscape predictor variables and snow water equivalent (SWE) were quantified by combining field and LiDar measurements with classification and regression tree analysis over two winter seasons (2010 and 2011) in a small, montane watershed. 2010 was a below average snow accumulation year, while 2011 was well above normal. In both the field and regression tree data, elevation was the dominant control on snow distribution in both years, although snow distribution was driven by melt processes in 2010 and accumulation processes in 2011. The importance of solar radiation and wind exposure was represented in the regression trees in both years. The regression trees also noted the lower importance of canopy closure, slope, and aspect, which was not observed in the field data. This technique could provide an additional method of forecasting annual water supply from melting snow. However, further research is required to address the lack of data collected above treeline, to provide a full‐basin estimate of SWE. Copyright © 2012 John Wiley & Sons, Ltd.     

Comparing resident and tourist preferences for public beach access and related amenities

As coastal destinations continue to grow, due to tourism and residential expansion, the demand for public beach access and related amenities will also increase. The issue confronting management agencies responsible for providing and maintaining public beach access and related amenities is the varying needs and preferences of both residents and tourists of coastal destinations. The purpose of this paper is to provide comprehensive information about coastal recreational needs of residents and tourists with regards to public beach access and associated amenities using the stated preference choice method. Overall, the results indicate tourists were more interested in additional public beach access points and commercial development, while residents supported beach rules and regulations but opposed high levels of crowding and noise. Implications of these results for management agencies include the utilization of parking fees to subsidize additional public beach access points, identifying appropriate types and levels of commercial development that moderate the use of coastal resources by tourists and day-trip users, and implementing beach rules and regulations that reduce the potential for conflict between user groups. Providing management agencies with comprehensive information of the preferences of different beach user groups can assist in the development of more effective policies and management programs.     

A case study using support vector machines, neural networks and logistic regression in a GIS to identify wells contaminated with nitrate-N

Accurate and inexpensive identification of potentially contaminated wells is critical for water resources protection and management. The objectives of this study are to 1) assess the suitability of approximation tools such as neural networks (NN) and support vector machines (SVM) integrated in a geographic information system (GIS) for identifying contaminated wells and 2) use logistic regression and feature selection methods to identify significant variables for transporting contaminants in and through the soil profile to the groundwater. Fourteen GIS derived soil hydrogeologic and landuse parameters were used as initial inputs in this study. Well water quality data (nitrate-N) from 6,917 wells provided by Florida Department of Environmental Protection (USA) were used as an output target class. The use of the logistic regression and feature selection methods reduced the number of input variables to nine. Receiver operating characteristics (ROC) curves were used for evaluation of these approximation tools. Results showed superior performance with the NN as compared to SVM especially on training data while testing results were comparable. Feature selection did not improve accuracy; however, it helped increase the sensitivity or true positive rate (TPR). Thus, a higher TPR was obtainable with fewer variables.     

Mexico City subsidence observed with persistent scatterer InSAR

We analyzed 23 satellite SAR (synthetic aperture radar) scenes using Persistent Scatter Interferometry (PSI) to study subsidence in Mexico City associated with groundwater withdrawal. The data were acquired by the Envisat ASAR system between January 2004 and July 2006. The spatial pattern of subsidence and the maximum subsidence rate (300 mm/year) are similar to earlier studies. Comparison to independent GPS data indicates RMS agreement between the two techniques of 6.9 mm/year, about the level expected based on joint data uncertainty. Significant annual variation in the GPS vertical data is not observed, suggesting minimal aquifer recharge during the rainy season, and justifying a simple linear model of phase variation through time for the PSI analysis.     

Forestry and agriculture: options for resource allocation in choosing lands for transmigration development

The Indonesian Transmigration program aims to resettle people from heavily populated areas of Java, Madura and Bali in the less developed Outer Islands. The development of a successful program poses problems for the resource planner in balancing three major variables: the economic activity which forms the basis of individual projects, the choice of sites to suit those economic activities, and the background and skills of the potential migrants. This paper concentrates on questions of resource allocation in choosing sites for transmigration development. It is based on the hypothesis that ample land resources are available and that of the three main ecosystems used—tidal swamp forests, mature upland forests, and alang-alang (Imperata cylindrica) grasslands—the economic opportunity costs of using forested lands can be considerable.The biophysical characteristics of the three resource systems are examined and the options for the development of new agricultural sites or sustained-yield forestry are explored through the use of a Net Present Value Analysis. The analysis suggests that the choice is not one of forestry versus agriculture but that, with proper consideration of site selection and use of inputs and cultural practices, both forestry and agriculture can be developed. The main conclusion is that alang-alang grasslands provide potential sites for sustained agricultural production which avoid the loss of long-term benefits that can be derived from well-managed forests.     

SOIL GEOMORPHOLOGY AS AN INTEGRATIVE APPROACH IN PHYSICAL GEOGRAPHY: A REVIEW OF FOUR RECENT BOOKS

Relict barrier beaches occur around the margins of many former pluvial lakes in the California desert. In common with modern barrier beaches along ocean coasts, these relict barriers possess geometric and compositional properties indicative of beach-forming processes, notably waves and currents. Because lake waves are a direct response to wind action, past wave climates may in turn be used to infer paleowind regimes. Where beaches of known age occur, wave climates and wind regimes may be invoked for specific time intervals. Using barrier beaches from former Lake Mojave and Lake Manly, this paper explores the extent to which the above theory may be applied to invoke past processes and wind regimes. The data indicate beach emplacement mainly by wave-related accretion and overwash generated by winds similar in direction to those of today, doubtless influenced then as now by topographic corridors. However, textural properties, predicted wave heights and entrainment velocities indicate that sustained southerly winds were probably twice as strong (by a factor ranging from 1.2 to 2.2 or more) and probably more persistent than today, at least towards the close of pluvial conditions. [Key words: barrier beaches, wave climate, paleoclimate, paleowinds, pluvial lakes, Quaternary, California desert.]     

中国西部地区猎隼(Falco cherrug)繁殖生物学与保护

自2001-2006年,中国科学院与英国鸟类研究中心联合对新疆准噶尔盆地和昆仑山、青海玉树地区、西藏那曲地区的猎隼(Falco cherrug)分布状况与繁殖生态进行深入调查。考察行程上万公里。卫星跟踪显示在俄罗斯、蒙古繁殖的猎隼迁往青藏高原越冬。但是,实地调查表明,在新-青-藏还有一些繁殖种群;繁殖区的海拔高度从600 m,上升至5 200 m。根据观察,猎隼喜欢沿用旧巢,多数巢属于"垃圾巢"。因为高原缺乏合适的巢材,那些人类遗弃的皮管、铁丝、皮带、破布、汽车零件、骨片、绳子等垃圾充斥于巢穴之中。考察期间,共找到100多只猎隼成鸟、约35个猎隼巢或巢区;分布地点涉及昆仑山脉、准噶尔盆地、卡拉麦里山脉、北塔山、可可西里、唐古拉山脉等,包括新疆奇台、且末、青河、塔城,青海楚玛尔河、五道梁、曲麻莱、雁石坪、玉树,西藏安多、那曲等。猎隼巢址多位于悬崖凹陷处(21个)、河岸砂土洞(5)、桥梁(2)等处;巢高于地面7~30 m。通常沿用渡鸦、大鵟、棕尾鵟、金雕的旧巢,有同步繁殖现象。附近有鼠兔、雪雀、地鸦、岩鸽、石鸡、沙鸡等活动。巢区沿着山脉或者丘陵连续分布,巢间距最近2.5 km,通常4~8 km或更远。在准噶尔盆地其繁殖密度1.1~1.6对/1 000 km2。通常4~5月产卵,窝卵数3~5枚;5月上旬和中旬已有部分幼鸟出壳。虽然在中国捕捉猎隼现象十分猖獗,但考察结果依然令人振奋。建议中国猎隼研究小组(CSRG)积极开展国际合作,通过卫星跟踪、GPS定位、电子微芯片标记(PIT)、DNA指纹图谱分析、人工猎隼栖架和巢穴招引技术等,不断完善监测手段和管理机制,为猎隼的保护与合理利用做出努力。     

Adaptation of the antioxidant defence system in hydrothermal-vent mussels (Bathymodiolus azoricus) transplanted between two Mid-Atlantic Ridge sites

The vent mussel Bathymodiolus azoricus is the dominant member of the Northern Mid‐Atlantic Ridge (MAR) hydrothermal megafauna, and lives in an environment characterized by temporal and spatial variations in the levels of heavy metals, methane and hydrogen sulphide, substances which are known to increase reactive oxygen species levels in the tissues of exposed organisms. To evaluate the effects of two contrasting hydrothermal environments on the antioxidant defence system of this vent mussel species, a 2‐week transplant experiment was carried out involving mussels collected from the relatively deep (2300 m), and chemical rich, Rainbow vent field. These were transplanted to the shallower (1700 m), and relatively less toxic, Lucky Strike vent field. To achieve this objective, levels of superoxide dismutase, catalase (CAT), total glutathione peroxidase (GPx), selenium‐dependent glutathione peroxidase and lipid peroxidation (LPO) were measured in the gills and mantle tissues of resident and transplant mussels before and after the transplant experiment. With the exception of CAT, the gills of the transplanted mussels had significantly higher antioxidant enzyme activity compared with the basal levels in the donor (Rainbow) and recipient (Lucky Strike) populations; whereas the antioxidant enzyme levels in the mantle tissues of the transplants reflected the baseline levels of activity in the native Lucky Strike mussels after 2 weeks. In contrast, LPO levels were significantly higher in both tissue types in the transplants than in either the source or the recipient populations, which suggested a response to hydrostatic pressure change (note, the transplant animals were brought to the surface for transportation between the two vent fields). The fact that the Rainbow mussels survived the transplant experience indicates that B. azoricus has a very robust constitution, which enables it to cope behaviourally, physiologically and genetically with the extreme conditions found in its naturally contaminated deep‐sea environment.     

Geological context of potential landing site of the Luna-Glob mission

The region planned for performing the Luna-Glob mission is located in the southern part of the swell surrounding the largest South Pole-Aitken (SPA) basin. The photogeological analysis of the surface topography of this region using the LRO-WAC (resolution of 100 Mpxl) photomaps made it possible to define the following groups of morphological units (area types): (1) related to the formation of relatively fresh impact craters; (2) associated with larger (>100 km across) degraded craters including (2a) external and (2b) inner facies; and (3) occupying intercrater spaces. The comparison of the geological map with the map illustrating the distribution of the epithermal neutron flow (Mitrofanov et al., 2012) shows no correlation between them. Consequently, one should not expect development of rock complexes, which would be characterized by elevated concentrations of water in the region chosen for the Luna-Glob mission and, thus, considered among the first-priority targets. The comparison of the neutron flow distribution with the map of circular polarization of the Mini-RF radar beam also shows no correlation. This means that high values of circular polarization reflect elevated concentrations of rock fragments rather than water accumulations. Even though ice fragments are present, their sizes should only slightly be less as compared with the radar wavelength (12.6 cm). The region planned for investigations in the scope of the Luna-Glob mission corresponds to the swell of the largest (and, likely, oldest) preserved basin and offers a potential opportunity to analyze ancient material of this planet and introduce important constraints into the spectrum of models proposed for explaining the Moon’s origin.     

Application of numerical modelling in the design of a full‐scale heated Tunnel Sealing Experiment

The Tunnel Sealing Experiment (TSX) was a full‐scale in situ demonstration of technology for constructing nearly water tight‐seals in excavations through crystalline rock deep below the surface of the earth. The experiment has been carried out at Atomic Energy of Canada Limited's (AECL's) Underground Research Laboratory near Lac du Bonnet, Canada, in support of international programs for geologic disposal of radioactive waste. The TSX, with partners from Canada, Japan, France and the United States, was carried under conditions of high pressure (up to 4 MPa) and elevated temperature (up to 85°C). Comparing numerical model predictions with eight years of data collected from approximately 900 sensors was an important component of this experiment. Model of Transport In Fractured/porous Media (MOTIF), a finite element computer program developed by AECL for simulating fully coupled or uncoupled fluid flow, solute transport and heat transport, was used to model both the ambient temperature and heated phases of the TSX. The plan to heat the water in the TSX to 85°C was developed using model predictions and a comparison of simulated results with measurements during heating of the water in the TSX to about 50°C. The three‐dimensional MOTIF simulations were conducted in parallel with axisymmetric modelling using Fast Lagrangian Analysis of Continua (FLAC), which computed the heat loss from pipes that carried the heated water through the rock to and from the experiment. The numerical model was initially used to develop a plan for operation of the experiment heaters, and then subsequently used to predict temperatures and hydraulic heads in the TSX bulkhead seals and surrounding rock. Copyright © 2005 John Wiley & Sons, Ltd.