Phase-space reconstruction and self-exciting threshold modeling approach to forecast lake water levels

Lake water level forecasting is very important for an accurate and reliable management of local and regional water resources. In the present study two nonlinear approaches, namely phase-space reconstruction and self-exciting threshold autoregressive model (SETAR) were compared for lake water level forecasting. The modeling approaches were applied to high-quality lake water level time series of the three largest lakes in Sweden; Vänern, Vättern, and Mälaren. Phase-space reconstruction was applied by the k-nearest neighbor (k-NN) model. The k-NN model parameters were determined using autocorrelation, mutual information functions, and correlation integral. Jointly, these methods indicated chaotic behavior for all lake water levels. The correlation dimension found for the three lakes was 3.37, 3.97, and 4.44 for Vänern, Vättern, and Mälaren, respectively. As a comparison, the best SETAR models were selected using the Akaike Information Criterion. The best SETAR models in this respect were (10,4), (5,8), and (7,9) for Vänern, Vättern, and Mälaren, respectively. Both model approaches were evaluated with various performance criteria. Results showed that both modeling approaches are efficient in predicting lake water levels but the phase-space reconstruction (k-NN) is superior to the SETAR model.     

Magnetic susceptibility of cambisol profiles in the vicinity of the Vír dam,Czech Republic

Magnetic susceptibility of 72 cambisol profiles from the vicinity of the Vír dam, NW Moravia was measured. The enhanced susceptibility of topsoil, particularly of the horizon O, was assessed from the aspect of vegetation setting and magnetic mineralogy. Magnetic susceptibility variations with field and temperature as well as frequency dependent susceptibility were applied to indicate magnetic carriers. It was found that the enhanced magnetic susceptibility is caused very likely by the presence of maghemite and magnetite of various grain sizes. Magnetic minerals are pedogenic in origin in all three horizons, while in the O and A horizons they are mostly anthropogenic in origin. Magnetic susceptibility was correlated with contents of trace elements Mo, Cu, Pb, Zn, Ag, As, Cd, Sb, Bi, Hg, Se, furthermore with TOT/C, TOT/S, and ¹³⁷C. The close association of susceptibility with Pb, Sb and Hg, or also with Mo, As, Se and their similar depth variations suggest a slight anthropogenic input in soils from a long-distant source. The same is valid for ¹³⁷C, its strong correlation with magnetic susceptibility has been found.     

Structure of a Volcanic Continental Margin Derived from Ocean-bottom Seismographic Data: The Northern Vøring Margin, off Norway

—This paper presents a crustal model derived from an Ocean Bottom Seismograph (OBS) study along the northern Vøring margin off Norway. The profile was acquired to map the crustal structure in the northernmost part of the Vøring Basin, and to link crustal models of the Lofoten and central Vøring Basin obtained by previous OBS studies. The Vøring margin, as well as the Lofoten margin to the north, was created by continental breakup between Norway and Greenland in late Paleocene-early Eocene. The rifting and continental breakup process were accompanied by intense extrusive and intrusive magmatic activities. The OBS data provide the whole crustal structure along the northern Vøring margin, in the area where the deep crustal structure cannot be resolved by conventional multichannel reflection data due to sill intrusions in the sedimentary sequence. The shallow part of the crustal model is characterized by up to 10 km thick sediments, a sequence of flood basalts and sill intrusions. The P-wave velocities in the flood basalts and sill intrusions are estimated to 5.0 km/s and 4.7–5.8 km/s, respectively. The model indicates an abrupt thickening of the upper crystalline crust from approx.3 km in the NE, to about 10 km towards the SE, with velocities of 6.0–6.2 km/s. The lower crustal velocities are not well resolved due to lack of clear refraction arrivals from the lower crust. However, the observed amplitude versus offsets are best explained by a model with a change in lower crustal velocities from 6.8 to 7.2 km/s beneath the Bivrost lineament. The modelling infers the presence of a lower crustal reflector beneath the lineament, which represents the landward continuation of the Bivrost lineament. Reflection arrivals from the Moho reveal a Moho depth of 23 km in the middle of the profile and 18– 20 km in the northeastern part of the profile. A 370 km long crustal section from the central part of the Vøring Basin to the Lofoten margin, obtained by the results of this study and previous OBS studies, shows a simple thinned continental crust on the Lofoten margin, and a high velocity lower crust underlying an upper crust of varying thickness in the Vøring Basin. The transition between these structures is situated beneath the Bivrost lineament in the lower crust, and beneath the basement high about 40 km south of the lineament in the upper crust.     

Hydrodynamic derivation of storage parameters of the Muskingum model

The St. Vénant equations for unsteady flow in open channels and the Muskingum method are written both in their conventional forms and in the state-space formulation. The hydrodynamic equation of motion is solved by the method of state trajectory variation and the result for the first-order variation in the state-space variables is used as a basis of linking the parameters of the Muskingum model with the hydraulic parameters of the open channel reach. The results are applicable to any shape of cross-section and to any type of friction law.     

Extended-range luminescence chronologies for the Middle Pleistocene units at the Sima del Elefante archaeological site (Sierra de Atapuerca,Burgos, Spain)

The Sima del Elefante site is located within the Sierra de Atapuerca karst system (Burgos, northern Spain), and forms part of a series of important Early, Middle and Late Pleistocene archaeological complexes that have been dated previously with luminescence techniques (Gran Dolina, Galería Complex, Sima de los Huesos, Galería de las Estatuas). This study focuses on the upper Middle Pleistocene units (TE18 and TE19) at Sima del Elefante, which contain Acheulean and transitional lithic assemblages (Mode 2/3), as well as large and small mammal fossils. Importantly, these uppermost units are associated with a sediment plug located in the cave's interior at Galería Baja, which marks the closure of a significant palaeoentrance to the Atapuerca karst system. Establishing the accumulation history of these related deposits is important for understanding both Lower Palaeolithic technological dynamics via comparisons with similar levels at other Atapuerca sites (i.e., Gran Dolina and Galería Complex), as well as past human occupation patterns and carnivore use of (and accessibility to) the caves. We present single-grain TT-OSL and multi-grain pIR-IR chronologies for the Sima del Elefante upper sequence and the Galería Baja sediment cone, as well as U-series dating results for a stalagmitic crust capping the combined clastic infill sequence. The paired luminescence ages for the upper occupation levels are in agreement with each other and reveal that the host deposits accumulated 576–481 ka for the TE18 stratified scree layers, 266–237 ka for TE19 and 206–250 ka for the Galería Baja upper cone section (weighted mean 2σ age ranges). A concordant U-series age of 202 ± 65 ka is obtained for the overlying stalagmitic crust at Galería Baja. The Sima del Elefante ages are consistent with those previously obtained using U-series and biochronology, confirming that there is an erosional unconformity and complex carbonate deposition phase associated with the upper layers of unit TE18 and that the original cave entrance likely closed by ∼200 ka. Chronological correlation with other Atapuerca sites reveals potential equivalence between TE18 and unit TD8 (at Gran Dolina), and between TE19 and units GIIb–GIIIb (at Galería Complex) and, possibly, TD10.1 and TD10.2 (at Gran Dolina), though more refined dating is required to confirm the latter.     

Spatial evolution of nitrogen and phosphorus loads along a small Mediterranean river: implication of bed sediments

This study addresses the spatial variations in water quality along the River Vène (France). The Vène drains a 67 km² rural basin, with a large karstic area, located in a Mediterranean context. A 1 day sampling campaign was conducted along the river, in winter low‐flow conditions (February 2003). Physico‐chemical parameters and water flow discharge were measured in situ during the sampling campaign. Water quality was evaluated by determining the concentrations of nitrogen and phosphorus in water and bed‐sediment samples. Nitrogen and phosphorus loads were evaluated taking into account the measured concentrations and discharge. The campaign included 18 sampling points and concerned the whole river from the spring to the outlet, plus the main inputs, i.e. sewage treatment works, main tributaries and karstic springs. The spatial evolution of nitrogen and phosphorus loads along the river allowed the significant role of point‐source inputs to be demonstrated. The decrease in nutrient loads along the river occurred mainly in specific reaches where fine sediments had accumulated. In these zones, phosphorus is trapped in the bed sediments in calcium‐bound phosphates due to precipitation processes. Copyright © 2005 John Wiley & Sons, Ltd.     

The zooplankton communities of small water reservoirs with different trophic conditions in two catchments in western Slovakia

Our study summarizes data from six small water reservoirs in West Slovakia and analyzes the occurrence of zooplankton groups in relation to physico-chemical and catchment variables. The reservoirs are in two different catchments – of the Morava and Váh rivers. A total of 103 species were identified; 64 crustaceans (in both the pelagic and littoral zones) and 39 planktonic Rotifera in the pelagic zones. Significant differences were observed in species richness, abundance and biomass of planktonic crustaceans: 48 species were characteristic of the Váh catchment, while 53 were found in the Morava catchment. The density of zooplankton in the three reservoirs of the Váh River catchment ranged from 102 ind L^?1 to 21,488 ind L^?1 and the zooplankton biomass ranged from 0.12 mg L^?1 to 103.29 mg L^?1. The density of zooplankton in three Morava River catchment reservoirs ranged from 2 ind L^?1 to 3928 ind L^?1 and the zooplankton biomass ranged from 0.1 mg L^?1 to 27.3 mg L^?1. The differences were found to be related to catchment (altitude and catchment affiliation), chemical (BOD5, DO) and biological (Chromophyta, Chlorophyta) factors. Eutrophication of reservoirs in the Váh catchment was mainly due to agriculture and fish management, resulting in high nutrient concentrations. Species richness showed an unimodal response to BOD₅ and N-NH₄ with near optimum low values, 4.6 and 0.19 respectively. The relationship to oxygen content reflects preferences for less eutrophic waters and species richness tended to decrease with increasing DO and to decrease with increasing nutrient content.     

The false Basel earthquake of May 12, 1021

The Basel (CH) area is a place with an increased seismic hazard. Consequently, it is essential to scrutinize a famous statement by Stumpf (Gemeiner loblicher Eydgnoschafft Stetten, Landen und Völckeren Chronikwirdiger thaaten beschreybung. Durch Johann Stumpffen beschriben, 1548) that allegedly a large earthquake took place in Basel in 1021. This can be disproved unambiguously by applying historical and philosophical methods.     

OSL-dating the Quaternary landscape evolution in the Vértes Hills forelands (Hungary)

Fluvial, colluvial, and aeolian sediments were dated by optically stimulated luminescence (OSL) on quartz to improve the chronological framework for Quaternary sedimentation and landscape evolution in the forelands of the Vértes Hills (central Hungary). The separated quartz was suitable for age determination based on an OSL SAR protocol. Most samples have asymmetric equivalent dose distributions and OSL ages were calculated by the mean, central, and minimum D_e values. Considering geomorphology and earlier age data from the area, the central D_e values seem most appropriate for age calculation. A fan on the geomorphological level QV in the western foreland of the Vértes Hills was deposited 79–75 (±8) ka ago. In the south-eastern foreland an alluvial fan on level QIIb is at most 42 ± 4 ka old. Fluvial incision and aggradation occurred 16–10 (±1) ka ago on the geomorphic surface QIIa. Loess is 14 ± 1 ka old, and slope sedimentation was active 11–9 (±1) ka ago. Our OSL data demonstrate that in the north-western foreland of the Vértes Hills wind remained an important agent after the last glacial times, into the early Holocene (9–8 ± 1 ka) and was able to accumulate large aeolian dunes.     

Particulate heavy metal transport in the lower Paraíba do Sul River basin,southeastern, Brazil

In the present study an attempt has been made to calculate the mass transfers of suspended particulate matter and associated heavy metal within the lower portion of the Paraíba do Sul River drainage basin and the contribution of its tributaries. The highest metal loads were related with the highest water flows and, consequently, with the highest suspended particulate matter loads, which increased both by surface runoff and sediment resuspension. The highest flow month for the total transported load contributed between 34 and 66% of the total metal transported per year. The total load transported during the entire rainy season ranges from 82 to 93% of the total transported load. The importance of the tributary input for the total transported load of the Paraíba do Sul River was generally lower than 10%, although in some months, when the Paraíba do Sul River had low water discharge and strong local rain occurred, this increased upto 40%. Copyright © 2001 John Wiley & Sons, Ltd.     

Flow and nutrient transport in intermittent rivers: a modelling case-study on the Vène River using SWAT 2005

Abstract

Intermittent rivers have a specific hydrological behaviour which also influences water quality dynamics. The objective of this work was to model the flow and water quality dynamics of a coastal Mediterranean intermittent river using the Soil and Water Assessment Tool (SWAT 2005). Flow, sediment, nitrogen and phosphorus transport were simulated on the Vène experimental catchment, France. The model was sequentially calibrated at sub-catchment scale and validated both at sub-catchment and catchment scales. A procedure for building the data records for the point sources is presented. The results indicate that, while the model produces good results for flow simulation, its performance for sediment transport is less satisfactory. This in turn impacts on the nutrient transport module. The reasons behind these shortcomings are analysed, taking into account the length of the data records, their distribution and the equations used in the SWAT model. The need for a thorough multi-objective model validation is illustrated.

Citation Chahinian, N., Tournoud, M.-G., Perrin, J.-L. & Picot, B. (2011) Flow and nutrient transport in intermittent rivers: a modelling case-study on the Vène River using SWAT 2005. Hydrol. Sci. J. 56(2), 268–287.     

Evolution of paleostress fields and brittle deformation in Hronov-Poříčí Fault Zone,Bohemian Massif

This paper investigates the tectonic history and describes the paleostress evolution of the Hronov-Po?í?í Fault Zone in the northeastern part of the Bohemian Massif. A detailed structural research has been carried out in 50 localities. Faults and fractures have been investigated and measured. An analysis of the fault-slip data within the studied area resulted in the identification of four tectonic phases. The maximum principal stress was observed to be acting NE-SW during the first and youngest phase. The trend of the horizontal compression runs at 223° in the horizontal plane perpendicular to the reverse faults occurring in this phase, as well as to the studied fault zone. The minimum principal stress was found to be subvertical dipping at 87° and trending at 358°. Both the brittle tectonic investigations and paleostress analysis have documented that, at present, the Hronov-Po?í?í Fault Zone is under compressive regime with dextral component.     

Hydrological modelling with SWAT under conditions of limited data availability: evaluation of results from a Chilean case study

Abstract

The Biobío River basin is of high strategic importance for Chilean development, at both the regional and the national levels. For this reason, advances in the general understanding of, and in the capacity to describe and predict, in a spatially explicit way, the impact of climate and anthropogenic forcing on the hydrology of the Biobío basin are urgently needed. The work presented here attempts to set the basis for future modelling applications within the Biobío basin by analysing the applicability of a readily available modelling tool, the SWAT model, to one of its sub-basins. Modelling results show that the model performs well in most parts of the study basin. The SWAT model application for the Vergara basin confirms that SWAT is a useful tool and can already be used to make a preliminary assessments of the potential impacts of land-use and climate changes on basin hydrology.     

Uptake from water and tissue distribution of neptunium-237 in crabs, shrimp and mussels

The uptake of ²³⁷Np has been followed in the tissues of mussels, shrimp and crabs exposed to the actinide in sea-water under controlled conditions. Bioaccumulation was observed in all tissues examined with the highest concentration factors noted in the external shells of the three species. Despite some incorporation of ²³⁷Np into internal tissues, it is noteworthy that after prolonged exposure 92–98% of the organisms' total ²³⁷Np content was associated with the non-edible shells. The general behaviour of this toxic transuranic element in invertebrate tissues appears to be very similar to that of plutonium.     

Field Survey of the 27 February 2010 Chile Tsunami

On 27 February 2010, a magnitude M _w?=?8.8 earthquake occurred off the coast of Chile??s Maule region causing substantial damage and loss of life. Ancestral tsunami knowledge from the 1960 event combined with education and evacuation exercises prompted most coastal residents to spontaneously evacuate after the earthquake. Many of the tsunami victims were tourists in coastal campgrounds. The international tsunami survey team (ITST) was deployed within days of the event and surveyed 800?km of coastline from Quintero to Mehuín and the Pacific Islands of Santa María, Mocha, Juan Fernández Archipelago, and Rapa Nui (Easter). The collected survey data include more than 400 tsunami flow depth, runup and coastal uplift measurements. The tsunami peaked with a localized runup of 29?m on a coastal bluff at Constitución. The observed runup distributions exhibit significant variations on local and regional scales. Observations from the 2010 and 1960 Chile tsunamis are compared.     

The origin of cleavage in the light of magnetic anisotropy investigations

The cleavage origin in rocks ranging from unmetamorphosed sediments, through slates to phyllites of the Nízký Jeseník Mts. (northern Moravia, Czechoslovakia), which show a range of deformation styles, from undeformed through fracture and slaty cleavage to the development of metamorphic foliation, was studied by means of magnetic anisotropy. These studies have shown that the fracture cleavage probably originated during a post-plastic rock deformation. Therefore the orientation of the fracture cleavage with respect to the strain-tensor components cannot be studied by means of magnetic anisotropy. The magnetic fabric of rocks with slaty cleavage was generated through componental movements during the ductile rock deformation. The slaty cleavage developed perpendicularly to the maximum shortening direction. In the rocks exhibiting macroscopically observable marks of slippage along the slaty cleavage, the slippage probably took place after the slaty cleavage developed, when the rock ductility was lower. The metamorphic foliation developed from the slaty cleavage in the course of continuous strain.     

Frequency of dry and wet spells in san salvador

Summary A study of the daily rainfall in San Salvador (El Salvador) has been made over a thirty year period 1918–47 in order to determine the dry and wet spells. It has been found that the extreme dry spells on the Pacific Coast of Central America last longer than in other climates, examined byHuttary. The occurrence of a dry spell in San Salvador lasting over half a year is being minutely examined, and the cause of its origin traced to orographic effects during northerly winds.

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Resumen Se estudiaron las observaciones diaras de la precipitación en San Salvador (El Salvador), realizadas en los aňos 1918–47. Resulta que en la costa Pacifica Centroamericana los períodos secos duran más que los períodos más largos en los climas estudiados porHuttary. Un período seco que duró más de medio aňo en San Salvador se analiza detenidamente, se supone que éste se habría originado en influencias orográficas efectivos cuando hay viento del norte.

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Dr.Heinz Dieterichs, Jefe meteorólogo en el Servicio Meteorológico Nacional de El Salvador,San Salvador (El Salvador, Central America).     

Variability of extreme precipitation in coastal river basins of the southern mexican Pacific region

Extreme wet and dry years (± 1 standard deviation, respectively), as well as the top 95 percentile (P95) of daily precipitation events, derived from tropical cyclone (TC) and nontropical cyclone (NTC) rainfall, were analyzed in coastal river basins in Southern Oaxaca, Mexico (Río Verde, Río Tehuantepec, and the Southern Coast). The study is based on daily precipitation records from 47 quality-controlled stations for the 1961 to 1990 period and TC data for the Eastern Tropical Pacific (EPAC). The aim of this study was to evaluate extreme (dry and wet) trends in the annual contribution of daily P95 precipitation events and to determine the relationship of summer precipitation with El Niño Southern Oscillation (ENSO) and the Pacifical Decadal Oscillation (PDO). A regionalization based on a rotated principal component analysis (PCA) was used to produce four precipitation regions in the coastal river basins. A significant negative correlation (significance at the 95% level) was only found with ONI in rainfall Region 3, nearest to the Gulf of Tehuantepec. Wet years, mainly linked to TC-derived P95 precipitation events, were associated with SST anomalies (≥?0.6°C) similar to weak La Niña and Neutral cool conditions, while dry years were associated with SST positive anomalies similar to Neutral warm conditions (≤?0.5°C). The largest contribution of extreme P95 precipitation derived from TCs to the annual precipitation was observed in Region 3. A significant upward trend in the contribution of TC-derived precipitation to the annual precipitation was found only in Region 1, low Río Verde.     

Magnetometer Array Study in North-Northeast Brazil: Conductivity Image Building and Functional Induction Modes

—Magnetovariational fields recorded by an array of magnetometers in the equatorial region of north-northeast Brazil are analyzed to infer the configuration of internal induced currents in and around the extensive intracratonic Parnaíba basin. Only nighttime magnetovariational fields were used because of the prevailing uniform source field conditions. For periods exceeding 40 min. the vertical fields at all inland sites are dominated by the effects of electric currents originating in the northeast, in the deep Atlantic Ocean. Below this period, although best developed in the 12–15 min. period range, the anomalous signatures are principally controlled by two distinct continental current paths. The first is associated with a N60°E trending graben-like structure in the southeastern part of the basin (named the Parnaíba Basin Conductivity Anomaly—PBCA) and the second appears as a subsurface sedimentary channel, from the NW corner of the array to the central part of the basin. This is named the LINK anomaly, as it connects the northwestern Marajó basin with the Parnaíba basin. While the PBCA is shown to highlight the importance of basement tectonics in the geological evolution of the Parnaíba basin, the LINK anomaly provides strong geophysical evidence of the direction of the sea intrusion into the region of the basin and possibly indicates the connectivity of the Parnaíba basin to the adjoining Amazon basin through the Marajó basin. Frequency and polarization dependence suggest that the induction response of individual structures is not determined by the local conductivity alone but also by their interconnectivity as well as by their linkage to the continental shelf and deep oceanic region.