Integrating isolated and riparian wetland modules in the PHYSITEL/HYDROTEL modelling platform: model performance and diagnosis

Mathematical modelling is a well‐accepted framework to evaluate the effects of wetlands on stream flow and watershed hydrology in general. Although the integration of wetland modules into a distributed hydrological model represents a cost‐effective way to make this assessment, the added value brought by landscape‐specific modules to a model's ability to replicate basic hydrograph characteristics remains unclear. The objectives of this paper were the following: (i) to present the adaptation of PHYSITEL (a geographic information system) to parameterize isolated and riparian wetlands; (ii) to describe the integration of specific isolated wetland and riparian wetland modules into HYDROTEL, a distributed hydrological model; and (iii) to evaluate the performance of the updated modelling platform with respect to the capacity of replicating various hydrograph characteristics. To achieve this, two sets of simulations were performed (with and without wetland modules), and the added value was assessed at three river segments of the Becancour River watershed, Quebec, Canada, using six general goodness‐of‐fit indicators and 14 water flow criteria. A sensitivity analysis of the wetland module parameters was performed to characterize their impact on stream flows of the modelled watershed. Results of this study indicate the following: (i) integration of specific wetland modules can slightly increase the capacity of HYDROTEL to replicate basic hydrograph characteristics; and (ii) the updated modelling platform allows for the explicit assessment of the impact of wetlands (e.g. typology and location) on watershed hydrology. Copyright © 2015 John Wiley & Sons, Ltd.     

Lithification of gas-rich chondrite regolith breccias by grain boundary and localized shock melting

We studied the fine-grained matrices (< 150 μm) of 14 gas-rich ordinary chondrite regolith breccias in an attempt to decipher the nature of the lithification process that converted loose regolith material into consolidated breccias. We find that there is a continuous gradation in matrix textures from nearly completely clastic (class A) to highly cemented (class C) breccias in which the remaining clasts are completely surrounded by interstitial, shock-melted material. We conclude that this interstitial material formed by shock melting in the porous regolith. In general, the abundances of solar-wind-implanted ⁴He and ²⁰Ne are inversely correlated with the abundance of interstitial, shock-melted, feldspathic material. Chondrites with the highest abundance of interstitial, melted material (class C) experienced the highest shock pressures and temperatures and suffered the most extensive degassing. It is this interstitial, feldspathic melt that lithifies and cements the breccias together; those breccias with very little interstitial melt (class A) are the most porous and least consolidated.     

Rb-Sr whole-rock age of the contact aureole of the Stillwater Igneous Complex,Montana

Fourteen whole-rock samples from three traverses through the contact aureole of the Stillwater Complex were analyzed for Rb, Sr and⁸⁷Sr/⁸⁶Sr. Twelve of these samples yielded an age of 2750 ± 45m.y.; (⁸⁷Sr/⁸⁶Sr)₀ = 0.705 ± 0.003 (2σ). In addition one whole rock and a biotite separate derived from it gave an age of 2544 m.y.; (⁸⁷Sr/⁸⁶Sr)₀ = 0.714. These data support a minimum age of 2750 m.y. for the intrusion of the complex.     

Two Experimental Methods to Determine the Speciation of Cadmium in Sediment from the River Neckar

The binding forms of Cd to an anaerobic sediment of low sulfide content from Lauffen reservoir (River Neckar, Germany) were studied using two different approaches, i. e. sequential extraction (modified from published protocols) and titrimetric study of the pH-dependent Cd release. Thermodynamic equilibrium calculations were applied to calculate both the release pattern of Cd during the titrations and the speciation of Cd within the single fractions of the extraction protocol. The calculations were based on measured sediment parameters such as hydrous ferric oxide (HFO), acid volatile sulfide, carbonate content and total Cd content, and the extractants (oxalate, acid etc.) used. The results of the two independent approaches coincided well in that they both assigned more than two thirds of the total Cd content to be adsorbed to organic matter. Cd bound as CdS is of little importance. Sequential extraction after a 3-month oxidation period at pH 7 revealed a shift of Cd from being mainly bound in stronger surface complexes with organic matter to being mainly bound in weaker surface complexes with organic matter and HFO, and thus becoming more bioavailable. This study suggests that the use of sequential extraction although being frequently criticized due to its operational character can be used to determine binding forms of metal ions if they are accompanied by 1) careful supporting experiments, 2) analysis of important sediment parameters, and 3) the use of thermodynamic equlibrium models which can help to understand Cd speciation within the extraction fractions.     

Geomagnetic Pc3 Pulsations During the Total Solar Eclipse on Aug 11, 1999

The solar eclipse on August 11, 1999, observed in the region covered by many geomagnetic observatories, has offered a unique opportunity to look for an effect of the eclipse on geomagnetic pulsations. The pulsation activity digital data have been taken from Budkov Observatory in the Czech Republic (in the X component only), from observatories in Germany (Niemegk, Fürstenfeldbruck, Bad Bergzabern), in Hungary (Nagycenk), and for comparison in South Africa (Hermanus, conjugate-point station), and in Finland (Sodankylä, far from the eclipse zone). At all these stations the field in all three component has been recorded. The pulsation amplitudes in the X component exhibit a long-term minimum near the time of the eclipse. Spectral analysis of selected short intervals confirmed this decrease and also revealed a decrease of the average pulsation period during the eclipse. Such a change in the amplitude or in the period was not observed outside of the eclipse interval or in other days. Investigation in some narrower frequency bands showed that the maximal decrease occurred in the 15–20 s band. All these changes can be found in records from all the stations near the eclipse totality belt, also in records at the conjugate-point station, where no eclipse occurred. No signature has been found in records at the station situated far from the eclipse zone.     

Avalanche risk assessment for mountain roads: a case study from Iceland

This paper presents an assessment of the avalanche hazard potential and the resulting risks on mountain roads for a 38.7-km-long section of road no 76 (Siglufjarearvegur) in northern Iceland following a regional scale approach developed in the Alps. The assessment of the individual avalanche death risk proved applicable to distinguish areas of avalanche hazard with a risk above the accepted level, which should be given priority in following detailed investigations and the planning of possible protective measures, from road sections where the avalanche death risk is low and accepted according to international practice. The cumulative individual and collective avalanche death risks in the investigated road section provide a comparable measure for assessing the avalanche hazard both within the Icelandic public road network and on an international scale. The case study on road no 76 in northern Iceland shows that a standardised regional scale risk-based approach is practical to determine, analyse and assess the avalanche hazard situation on mountain roads in Iceland and guarantees comprehensible, reproducible and comparable results as a basis for a sustainable planning of measures.     

Policy concerns in Bulgarian food distribution

The Bulgarian food distribution system, like those of its Central and East European neighbours, lags behind the West in critical performance areas. Previous research quantified Central and East European food distribution deficiencies on the basis of a five factor model. This study investigates the attitudes of 250 Bulgarian consumers using these same five factors: food processing, quality, cost, availability and retailing. The findings show that the Bulgarian food distribution system does not satisfy consumer wants as well as do systems in other former communist countries in four of the five factors. At the same time, Bulgarian consumers are more satisfied than UK and US consumers in the system's ability to make some foods available. The study also shows that Bulgarian consumers who use privatised shops perceive the system more positively than those who use state and cooperative outlets. The implications of these and other findings are discussed in terms of critical policy concerns for government and industry stakeholders.     

Analysis of geodetic satellite (Geos I) observations in North America

Geos I observations made at thirty optical and four Secor stations were analyzed in the geometric and short-arc modes for the purpose of detecting systematic distortions in the North American Datum. The results indicate that the Nad at its origin (Meades Ranch, Kansas) requires an easterly rotation in azimuth and a westerly rotation in the prime vertical plane, both in the magnitude of one second of arc to fit the satellite data. There is also evidence of the need for a reduction in scale of about 1:200.000.