Miracle-dz/UniFAR-FTUs huggingface dataset:
A simulation‐optimization model to control seawater intrusion in coastal aquifers using abstraction/recharge wells

Seawater intrusion is one of the most serious environmental problems in many coastal regions all over the world. Mixing a small quantity of seawater with groundwater makes it unsuitable for use and can result in abandonment of aquifers. Therefore, seawater intrusion should be prevented or at least controlled to protect groundwater resources. This paper presents development and application of a simulation‐optimization model to control seawater intrusion in coastal aquifers using different management scenarios; abstraction of brackish water, recharge of freshwater, and combination of abstraction and recharge. The model is based on the integration of a genetic algorithm optimisation technique and a coupled transient density‐dependent finite element model. The objectives of the management scenarios include determination of the optimal depth, location and abstraction/recharge rates for the wells to minimize the total costs for construction and operation as well as salt concentrations in the aquifer. The developed model is applied to analyze the control of seawater intrusion in a hypothetical confined coastal aquifer. The efficiencies of the three management scenarios are examined and compared. The results show that combination of abstraction and recharge wells is significantly better than using abstraction wells or recharge wells alone as it gives the least cost and least salt concentration in the aquifer. The results from this study would be useful in designing the system of abstraction/recharge wells to control seawater intrusion in coastal aquifers and can be applied in areas where there is a risk of seawater intrusion. Copyright © 2011 John Wiley & Sons, Ltd.
Multistep ahead streamflow forecasting: Role of calibration data in conceptual and neural network modeling

When choosing the rainfall‐runoff modeling approach to be integrated in a river flow forecasting system, two crucial issues are the minimum data requirement for calibration purposes and the reliability of the predictions over different time horizons (lead‐times). The paper presents an investigation of the real‐time forecasting ability of a conceptual and a neural network model, comparing the performances obtainable for increasing lead‐times and analyzing the influence of the amount of the calibration data over two real‐data case studies. Neural networks proved to be an excellent tool for the real‐time rainfall‐runoff simulation of continuous periods (including low, average and peak flows), provided that an extensive set of hydro‐meteorological data is available for calibration purposes. On the other hand, the comparison highlights that a conceptual formulation may allow a significant forecasting improvement in comparison with the data‐driven approach when focusing on the prediction of flood events and especially in case of a limited availability of calibration data.
Dynamics of Forced Coastal Trapped Disturbances

Abstract : The long-term goal of this project is to improve our ability to understand and predict meteorological conditions in the coastal marine atmospheric boundary layer. The objective of this project is to investigate the dynamics of coastal marine atmospheric boundary layer winds including the generation and propagation of coastal-trapped disturbances and their interaction with coastal orography and with orographically-modified ambient winds. The approach taken in this project is to obtain analytical and numerical solutions of idealized mathematical models of the marine atmospheric boundary layer and to compare these solutions to observations and to results from more complex models. Numerical and analytical models of the generation, propagation, and decay of linear and nonlinear coastal-trapped disturbances have been studied. Mesoscale simulations of the interaction of continuously stratified, hydraulically supercritical and transcritical flow with coastal orography have been carried out and analyzed, yielding new insight into the dynamics of coastal winds. Hydraulically transcritical model flows have been computed for comparison with observational data from the 1996 Coastal Waves Experiment along the California coast.
Thermal evolution of Mercury: Effects of volcanic heat‐piping

A 1D thermal evolution model of Mercury is presented. It accounts for stagnant lid convection, mantle differentiation and inner core growth. Early MESSENGER results indicate that—contrary to prior conclusions drawn from Mariner 10 imagery—volcanism has indeed played a significant role in Mercury's past. To study the effects of mantle heat bypassing the stagnant lid by means of volcanic heat‐piping, contrasting end‐member models are considered. Results show how break‐down of mantle convection and onset of inner core growth are influenced by the mode of heat removal. Structural models of present day Mercury are presented. Their dependence on the core sulphur contents predominates that on the choice of mantle heat removal. However, the latter clearly controls the timing of thermal history events.
VISCOUS PROPERTY OF TOYOURA SAND OVER A WIDE RANGE OF SHEAR DEFORMATION RATE AND ITS MODEL SIMULATION

As part of a long-term research program to evaluate the rate effects on the stress-strain behaviour of geomaterials, the viscous properties of a poorly-graded relatively angular quartz-rich sand, Toyoura sand, under air-dried conditions, were investigated by performing a comprehensive series of direct shear (DS) tests at a fixed normal stress equal to 50 kPa. The tests were performed on loose and dense specimens subjected to the following different loading histories: a) monotonic loading (ML) at constant shear displacement rate (s) differing by a factor up to 100,000; b) ML at constant s including otherwise a number of step changes in s by a factor of 100; and c) a number of sustained loading (SL) stages during otherwise ML at constant values of s differing by a factor up to 1,000. Tests a) revealed that, with dense specimens, the peak shear strength is remarkably independent of s while the residual shear strength noticeably decreases with an increase in s. That is, the viscous property is the so-called TESRA type at the peak stress state, while it is the so-called Positive & Negative (P&N) type at the residual state. With loose specimens, both peak and residual shear strengths decrease with an increase in s, indicating that the viscous property is already the P&N type at the peak stress state and definitely so at the residual state. These results are qualitatively and quantitatively consistent with those from tests b), by which the viscosity properties were quantified in terms of the rate-sensitivity coefficient. The results from tests c) showed that creep shear displacement, Δs, increases with a decrease in the tangent stiffness at the immediately preceding ML phase or with an increase in the shear stress level during the SL stage. The value of Δs for a given period steadily increases with an increase in s during the immediately preceding ML phase. These trends of viscous behaviour are simulated all very well by a non-linear three-component model incorporating a general expression of viscous stress.
The Impact of Chronic Tobacco Smoking on Retinal and Choroidal Thickness in Greek Population

Aim. To investigate the effect of more than 25-year cigarette smoking on choroidal and retinal thickness, using spectral domain optical coherence tomography (SD-OCT). Methods. Thirty-one smokers and 25 age- and sex-matched nonsmokers, serving as control group, were submitted to slit-lamp biomicroscopy and dilated fundoscopy, SD-OCT, measurements of intraocular pressure (IOP), central corneal thickness (CCT), and axial length (AL). Heidelberg Spectralis was used to calculate choroidal thickness (CT), ganglion cell complex (GCC), outer retina layers (ORL), and macular thicknesses (MT). Results. The smokers' group consisted of 17 males and 14 females with mean age of 57.8 ± 4.5 years, while the controls' group consisted of 14 males and 11 females with mean age of 68.0 ± 4.1 years. CT and GCC thicknesses were significantly reduced in smokers compared to control group. The differences in thicknesses of ORL were marginally significant between two groups. The measurements of MT, IOP, CCT, and AL had the same distributions between smokers and nonsmokers. Conclusions. Tobacco smoking seems to result in thinner choroid and retina compared to nonsmokers. This is the first study in literature that investigates the anatomical effect of smoking for more than 25 years on the choroid and retina.
Stability at M2 critical latitude in the Barents Sea

The Barents Sea is the site for one of the largest biomass productions in the world oceans. This is mainly due to the combined effect of winter thermohaline convection and a strong seasonal pycnocline during spring and summer. Secondary bloomings are due to wind-induced entrainment of nutrients to the upper layer, which may be especially effective near 74.5°N, the critical latitude for the M2 constituent. At this latitude, the inertial frequency equals the M2 frequency, resulting in a strongly depth-dependent tidal current and a thick benthic boundary layer. Our investigations of current meter measurements in the Barents Sea confirm these theoretical predictions. Statistical treatment of about 800 conductivity-temperature-depth stations between 70°N and 79°N reveals a stability minimum in the central part of the Barents Sea. This may be due to enhanced tidal mixing near the critical latitude. Observations of nutrients partly support this conclusion.
Large‐scale atmospheric dynamics and local intense precipitation episodes

Weather extreme events have important consequences in the environmental, social and economic sectors. Numerous efforts have been devoted to identify the large‐scale (LSC) climate dynamics connected to them. In this paper we show that the LSC circulation patterns associated with intense precipitation episodes (IPE) over a specific domain can be identified from clustering algorithms. For an extended winter season (from 16th October to 15th April), using daily maps of geopotential height at 500 hPa selected on the basis of precipitation threshold exceedence, we found that over western France, the LSC pattern linked to IPE occurrence displays a strong negative anomaly over Great Britain. This pattern corresponds to the structure observed during the transition from Zonal to Greenland Anticyclone standard weather regimes. It is the least likely transition from the Zonal regime, suggesting potential links between atmospheric dynamics and the occurrence of IPE.
Striations and hollow channels in rounded beryl crystals

Periodico di Mineralogia (2011), 79, 1 (Special Issue), 75-87 - DOI: 10.2451/2011PM0006 Special Issue in memory of Sergio Lucchesi Striations and hollow channels in rounded beryl crystals Gioacchino Tempesta * , Eugenio Scandale and Giovanna Agrosi Dipartimento Geomineralogico, Universita di Bari, Italy *Corresponding author: tempesta@geomin.uniba. it Abstract Structural defects in natural colourless beryl crystals from Minas Gerais (Brazil) were studied using X-ray Diffraction Topography (XRDT). The samples are characterised by a strongly rounded morphology and by the presence of hollow channels parallel to the c-axis, some of them visible to the naked eye and partially filled with kaolinite. The analysis of structural defects as dislocations, growth bands, solid inclusions and precipitates has been essential for the reconstruction of growth history in this study. The formation of hollow channels was attributed to the corrosion and post-genetic alteration of strongly deformed areas surrounding branches of dislocations parallel to the c-axis. The final rounded morphologies and the striations may have been attained either as the results of a parallel growth of some individuals or as the result of a variation of the growth rates in the final stages of growth. Due to the occurrence of kaolinite, post-genetic corrosion has been speculated. However, this process appears to have contributed solely to the hollow channel formation and not to the rounded morphology evident in these samples. Key words : X-ray topography; beryl; channels; morphology and striations.
Total Electron Content Estimation with Reg‐Est

[1] Total Electron Content (TEC) constitutes one of the key elements for observing the variable structure of the ionosphere. GPS provides a cost-effective alternative in TEC estimation through earth-based receivers. In this paper, one of the TEC estimation methods, namely Reg-Est, is investigated in detail in terms of its parameters and developed further to include improvements. Reg-Est estimates robust TEC using GPS measurements of 30 s time resolution. The method combines the vertical TEC computed from all the satellites in view over 10° horizon limit in the least squares sense through the minimization of a cost function which also includes a high pass penalty filter. Optional weighting functions and sliding window median filters are added to enrich the processing and smoothing of the data. In this study, the input to the Reg-Est is enlarged to include phase-corrected TEC. The best way of including the instrumental biases is investigated and the algorithm is updated to include the biases in the slant TEC computation. The effect of the thin shell height of the ionosphere in Reg-Est estimates is studied. It is concluded that the Reg-Est algorithm is very robust to the choice of thin shell height. The best weighting function to reduce the multipath effects and to minimize the non-ionospheric noise is selected. The improved Reg-Est algorithm can be used for all latitudes and for both quite and disturbed days of the ionosphere. The Reg-Est TEC are in excellent accordance with the estimates from IGS analysis centers.
A versatile index to characterize hysteresis between hydrological variables at the runoff event timescale

This study presents a versatile index for the quantification of hysteretic loops between hydrological variables at the runoff event timescale. The conceptual development of the index is based on a normalization of the input data and the computation of definite integrals at fixed intervals of the independent variable. The sum, the minimum and the maximum of the differences between integrals computed for the rising and the falling curves provide information on the direction, the shape and the extent of the loop. The index was tested with synthetic data and field data from experimental catchments in Northern Italy. Hysteretic relations between streamflow (the independent variable) and soil moisture, depth to water table, isotopic composition and electrical conductivity of stream water (dependent variables) were correctly identified and quantified by the index. The objective quantification of hysteresis by the index allows for the automatic classification of hysteretic loops and thus the determination of differences in hydrological responses during different events. The index was also used to examine the seasonal dynamics in the relation between streamflow and soil moisture and captured the switch in the direction of the loop with changes in event size and antecedent wetness conditions. The sensitivity of the index to the temporal resolution of the measurements and measurement errors was also tested. The index can successfully quantify hysteresis, except for very noisy data or when the temporal resolution of the measurements is not well suited to study hysteresis between the variables. Copyright © 2015 John Wiley & Sons, Ltd.
Budget analysis of the boundary layer grid flights during FIFE 1987

An aircraft grid pattern was flown by the Canadian Twin Otter to map the low-level fluxes and structure over the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) research area in 1987. The time dependence and horizontal advection of heat and moisture were extracted from these flights, combined with surface flux measurements and boundary layer top measurements from radiosondes, to analyze the boundary layer budget using a mixed layer model. The results confirm the suggestion of an earlier study that the boundary layer top entrainment (when parameterized using the buoyancy flux) is nearly double the value used by many modeling studies. Both surface and aircraft data have been revised, and it now appears that the direct measurements of the sensible and latent heat fluxes by the aircraft underestimated these fluxes by about 20%, because of filtering and undersampling of long wavelength contributions.
Local and global factors controlling water‐energy balances within the Budyko framework

Quantifying partitioning of precipitation into evapotranspiration (ET) and runoff is the key to assessing water availability globally. Here we develop a universal model to predict water‐energy partitioning (ϖ parameter for the Fu's equation, one form of the Budyko framework) which spans small to large scale basins globally. A neural network (NN) model was developed using a data set of 224 small U.S. basins (100–10,000 km2) and 32 large, global basins (~230,000–600,000 km2) independently and combined based on both local (slope, normalized difference vegetation index) and global (geolocation) factors. The Budyko framework with NN estimated ϖ reproduced observed mean annual ET well for the combined 256 basins. The predicted mean annual ET for ~36,600 global basins is in good agreement (R2 = 0.72) with an independent global satellite‐based ET product, inversely validating the NN model. The NN model enhances the capability of the Budyko framework for assessing water availability at global scales using readily available data.
Deposition of Evaporites

Modern oceanographic studies in estuaries and other restricted arms of the sea have shown that a characteristic circulation pattern exists. Surface currents flow from regions of low salinity to regions of higher salinity in response to hydrostatic head and are accompanied at depth by oppositely directed currents flowing from high to low salinity regions because of density distribution. Salts are deposited in restricted estuaries where evaporation exceeds precipitation plus runoff. The necessary restrictions of the estuary or basin are in part dynamic and in part static. Dynamic restriction is caused by the hydrostatic head and by frictional stresses between the oppositely directed surface and bottom currents, and between the bottom current and the channel floor. Static re triction is produced by topographic confinement. When high concentrations are developed a strong horizontal salinity gradient exists which produces lateral segregation of different salts during precipitation. The escaping deep current returns to the sea those salts which have not been precipitated. Fluctuations in equilibrium caused principally by changes in excess of evaporation or in degree of channel closure cause migrations of the horizontal salinity gradient along the longitudinal axis of the basin which produce vertical differentiation of salts. The order in which salts occur in the vertical column can be predicted from oceanographic and chemical data and agrees well with many vertical sequences which have been described.
The characteristics and formation of a high‐arctic proglacial icing

Abstract Well‐known from permafrost hydrology, icings (naled or Aufeis) are also frequently encountered at the margins of high‐latitude glaciers. The morphology of a proglacial icing at Scott Turnerbreen in the Norwegian Arctic archipelago of Svalbard is described, and the process of formation is considered in detail. Ground thermal‐regime modelling indicates an equilibrium permafrost depth of at least 200 m in the studied catchment, and it appears unlikely that groundwater contributes to icing formation. Meltwater flow through ice‐marginal drainage channels is accompanied by estimated heat fluxes of up to about 190 W m−2, suggesting that stored meltwater may continue to percolate through thawed sub‐channel sediments when surface runoff is absent during winter. A hydraulic conductivity of 6.9 × 10−3 m s−1 is implied, which is consistent with other studies of glacier drainage systems. The long residence time of winter‐draining meltwater, and solute rejection by refreezing water, account for high observed concentrations of solute in interstitial water in the icing. It has often been asserted that the presence of a proglacial icing indicates that a glacier is polythermal. However, as Scott Turnerbeen is entirely non‐temperate, the presence of an icing cannot always be treated as a reliable guide to the thermal regime of a glacier.
Biostratigraphy of the Cretaceous/Tertiary boundary in the Sirwan Valley (Sulaimani Region, Kurdistan, NE Iraq)

Biostratigraphy of the Cretaceous/Tertiary boundary in the Sirwan Valley (Sulaimani Region, Kurdistan, NE Iraq) The Cretaceous/Tertiary (K/T) boundary sequence, which crops out in the studied area is located within the High Folded Zone, in the Sirwan Valley, northeastern Iraq. These units mainly consist of flysch and flysch-type successions of thick clastic beds of Tanjero/Kolosh Formations. A detailed lithostratigraphic study is achieved on the outcropping uppermost part of the Upper Cretaceous successions (upper part of Tanjero Formation) and the lowermost part of the Kolosh Formation. On the basis of the identified planktonic foraminiferal assemblages, five biozones are recorded from the uppermost part of Tanjero Formation and four biozones from the lower part of the Kolosh Formation (Lower Paleocene) in the Sirwan section. The biostratigraphic correlations based on planktonic foraminiferal zonations showed a comparison between the biostratigraphic zones established in this study and other equivalents of the commonly used planktonic zonal scheme around the Cretaceous/Tertiary boundary in and outside Iraq.
Stratigraphic Control of Chemistry and Mineralogy in Metamorphosed Witwatersrand Quartzites

Within metamorphosed quartzites of the Witwatersrand Supergroup bulk chemistry is the major control on the distribution of metamorphic mineral phases and on their chemistry. Bulk chemistry is in turn controlled by stratigraphic position. Pyrophyllite distribution varies directly with, whereas feldspar distribution varies inversely with, bulk Al. Chloritoid distribution is more complex and varies with both bulk Al and bulk Fe/Mg. Despite the overprint of low-grade metamorphism and, possibly, of other alteration processes, both detrital and metamorphic phyllosilicates can be recognized and characterized. Al in metamorphic white mica and metamorphic chlorite varies with bulk Al; whereas the composition of detrital white mica is unrelated to bulk chemistry. Similarly, Mg in metamorphic chlorite varies with bulk Mg. Bulk chemical variation, particularly in Al, Mg, and Na, and thus metamorphic mineral chemistry, is controlled by stratigraphic position, both within individual stratigraphie units and in the stratigraphie succession as a whole. K content increases upward and varies more strongly with position in the entire section than with position in individual units. The quartzites display a high degree of chemical maturity, as measured by the Chemical Index of Alteration, which increases upward both within individual stratigraphie units and in the section as a whole. The strong stratigraphie control on bulk chemistry suggests that intense weathering occurred in the source area and that alteration events associated with faults and other structural features play no more than a minor role in controlling variations in bulk chemistry. The observation that these rocks are strongly leached, yet retain detrital pyrite and uraninite, indicates that the source area weathering occurred under reducing conditions.