The journal Communications in Numerical Methods in Engineering with Biomedical Applications becomes the International Journal for Numerical Methods in Biomedical Engineering (IJNMBE) from 1st January 2010

Communications in Numerical Methods in Engineering, founded by Roland W. Lewis in 1985, will change its title to the ‘International Journal for Numerical Methods in Biomedical Engineering’ and has a revised Aims and Scope. Copyright © 2009 John Wiley & Sons, Ltd.     

Annual cycle and budgets of nutrients in the Bohai sea

The environmental problems in the Bohai Sea have become more serious in the last decade. High nutrient concentration contributes much to it. A Sino-German cooperation program has been carried out to improve the understanding of the ecosystem by observations and modelling. A three-dimensional ecosystem model, coupled with a physical transport model, is adopted in this study. The simulation for the year 1982 is validated by the data collected in 1982/1983. The simulated annual mean nutrient concentrations are in good agreement with observations. The nutrient concentrations in the bohai Sea, which are crucial to the algal growth, are high in winter and low in summer. There are depletion from spring to summer and elevation from autumn to winter for nutrients. The nutrients’ depletion is a response to the consumption of the phytoplankton bloom in spring. Internal recycle and external compensation affect the nutrient cycle. Their contributions to the nutrient budgets are discussed based on the simulated results. Production and respiration are the most important sink and source of nutrients. The process of photosynthesis consumes 152 kilotons-P and 831.1 kilotons-N while respiration releases 94.5 kilotons-P and 516.6 kilotons-N in the same period. The remineralization of the detritus pool is an important source of nutrient regeneration, It can compensate 23 percent of the nutrient consumed by the production process. The inputs of phosphates and nitrogen from rivers are 0.55 and 52.7 kilotons respectively. The net nutrient budget is −3.05 kilotons-P and 31.6 kilotons-N.     

Grampian migmatites in the Buchan Block,NE Scotland

Rocks exposed along the Scottish coast between Fraserburgh and Inzie Head contain information critical to understanding the evolution of the Buchan Block, the type locality for low‐P, high‐T regional metamorphism, and its relationship with the rest of the Grampian terrane, one of the major tectonostratigraphic components of the Scottish Caledonides. The ~8 km long section traverses a regional network of shear zones and, at the highest grades around Inzie Head, passes into the core of the Buchan Anticline, a large‐scale open fold that is commonly regarded as a late structure, post‐dating metamorphism. The metasedimentary rocks increase in grade from upper amphibolite to granulite facies and preserve unequivocal evidence for partial melting. The diatexite migmatites around Inzie Head, along with other gneissose units within the Buchan Block, have been regarded as allochthonous Precambrian basement rocks that were thrust into their current position during the Grampian orogenesis. However, field observations show that the onset of in situ partial melting in metapelitic rocks, which was associated with the formation of garnet‐bearing aplites and associated pegmatites, occurred around Fraserburgh, where shear fabrics are absent. Thus, the rocks preserve a continuous metamorphic field gradient that straddles the shear zone network. This observation supports an alternative interpretation that anatexis was the result of mid‐Ordovician (Grampian) metamorphism, rather than an older tectonothermal event, and that the Inzie Head gneisses are autochthonous. Using an average mid‐Dalradian pelite as a plausible representative protolith, phase equilibria modelling satisfactorily reproduces the observed appearance and disappearance of key minerals providing that peritectic garnet produced with the first formed melts (represented by the garnet‐bearing aplites) depleted the source rocks in Mn. The modelled metamorphic field gradient records a temperature increase of at least 150 °C (from ~650 °C near Fraserburgh to in excess of 800 °C at Inzie Head) but is isobaric at pressures of 2.7–2.8 kbar, suggesting the Buchan Anticline developed synchronous with partial melting. The Buchan Anticline is likely an expression of crustal thinning and asthenospheric upwelling, which produced voluminous gabbroic intrusions that supplied the heat for Buchan metamorphism.     

Water balance components estimation under scenarios of land cover change in the Vea catchment,West Africa

ABSTRACT

The need for a detailed investigation of the Vea catchment water balance components cannot be overemphasized due to its accelerated land-cover dynamics and the associated impacts on the hydrological processes. This study assessed the possible consequences of land-use change scenarios (i.e. business as usual, BAU, and afforestation for the year 2025) compared to the 2016 baseline on the Vea catchment’s water balance components using the Soil and Water Assessment Tool (SWAT) model. The data used include daily climate and discharge, soil and land use/land cover maps. The results indicate that the mean annual water yield may increase by 9.1% under the BAU scenario but decrease by 2.7% under the afforestation scenario; actual evapotranspiration would decrease under BAU but increase under afforestation; and groundwater recharge may increase under both scenarios but would be more pronounced under the afforestation scenario. These outcomes highlight the significance of land-cover dynamics in water resource management and planning at the catchment.     

Validation of a soil water balance model using soil water content and pressure head data

The validation of soil water balance models and the evaluation of the quality of the model predictions at field‐scale require time‐series of in situ measured model outputs. In our study, we have validated such a model using a 6‐year period with time‐series of automatically recorded, daily volumetric soil water contents measured with the time‐domain reflectometry with intelligent microelements (TRIME) method and daily pressure heads measured with tensiometers. The comparisons of simulated with measured soil water contents and pressure heads were analysed using the modelling efficiency index (IA) and the square root of the mean square error (RMSE) in order to evaluate the prediction quality of the model. In our study, IA and RMSE, obtained either from the comparison of simulated with measured soil water contents or the comparison of calculated with observed pressure heads, in some cases lead to different results regarding the evaluation of the simulation quality of the soil water balance model. For example, a good fit between simulated and observed soil water contents does not necessarily result in a comparably good fit between the corresponding calculated and measured pressure heads. Therefore, a combined use of both measurement techniques, which takes into account their respective advantages and disadvantages, gives a more complete overview on the simulation quality of the soil water balance model than the single use of one of those techniques. Copyright © 2004 John Wiley & Sons, Ltd.     

Long‐term final void salinity prediction for a post‐mining landscape in the Hunter Valley,New South Wales,Australia

Opencast mining alters surface and subsurface hydrology of a landscape both during and post‐mining. At mine closure, following opencast mining in mines with low overburden to coal ratios, a void is left in the final landform. This final void is the location of the active mine pit at closure. Voids are generally not infilled within the mines' lifetime, because of the prohibitive cost of earthwork operations, and they become post‐mining water bodies or pit lakes. Water quality is a significant issue for pit lakes. Groundwater within coal seams and associated rocks can be saline, depending on the nature of the strata and groundwater circulation patterns. This groundwater may be preferentially drawn to and collected in the final void. Surface runoff to the void will not only collect salts from rainfall and atmospheric fallout, but also from the ground surface and the weathering of fresh rock. As the void water level rises, its evaporative surface area increases, concentrating salts that are held in solution. This paper presents a study of the long term, water quality trends in a post‐mining final void in the Hunter Valley, New South Wales, Australia. This process is complex and occurs long term, and modelling offers the only method of evaluating water quality. Using available geochemical, climate and hydrogeological data as inputs into a mass‐balance model, water quality in the final void was found to increase rapidly in salinity through time (2452 to 8909 mg l⁻¹ over 500 years) as evaporation concentrates the salt in the void and regional groundwater containing high loads of salt continues to flow into the void. Copyright © 2004 John Wiley & Sons, Ltd.     

Estimation of source water to cedar elm in a central Texas riparian ecosystem

A riparian ecosystem downstream of a small dam in central Texas was instrumented for sap flow, soil moisture content, and stream level from 2001. Stable isotopes in water (D and ¹⁸O) were analysed from rainfall, stream, lake, and cored sapwood cellulose from cedar elm (Ulmus crassifolia). The isotope signature of water source to cedar elm was identified by back calculation starting with the water isotopes in cellulose, and accounting for leaf‐water evaporation and biological fractionation during cellulose synthesis. The estimated mean isotope of the source water to cedar elm was enriched above rainfall in similarity to stream water during 2002. Flow paths that may have contributed to estimated variability from regional base flow and recharge water were identified using the variably saturated HYDRUS‐2D model. Copyright © 2004 John Wiley & Sons, Ltd.