Nutrient flux and budget in the Ebro estuary   总被引：1，自引：0，他引：1  

S. Falco  L.F. Niencheski  M. Rodilla  I. Romero  J. González del Río  J.P. Sierra  C. Mösso 《Estuarine, Coastal and Shelf Science》2010

The Ebro river flows to the Mediterranean coast of Spain. During its final stretch, the Ebro behaves in a similar way to a highly stratified estuary. This paper describes the transport of nutrients to the Ebro estuary, evaluates the general movement of nutrients in the estuarine region, using a mass balance approach, and estimates the amounts of nutrients discharged to the coastal environment. Given the strong saline stratification, this study only includes the surface layer that contains the continental freshwater. The annual nutrient budget for the Ebro estuary shows a net excess for nitrogen and phosphorus, while silicate almost attains equilibrium between addition and removal. There are several reasons for gains in nitrogen and phosphorous: a contribution of dissolved and particulate compounds in the freshwater (some of which are mineralized); a lower uptake of phytoplankton indicated by chlorophyll reduction in the estuary; an entrainment of the nutrient-rich upper part of the salt wedge; and, to a lesser extent, the impact of wastewater and agricultural water use. The biggest load discharged into the Mediterranean Sea by the Ebro is nitrogen, followed by silicate with over 10 000 tons of each deposited annually. Phosphorus is discharged at relatively low concentrations and with an annual load of about 200 t yr⁻¹.  相似文献   

Site formation processes at Donggutuo: a major Early Pleistocene site in the Nihewan Basin,North China     

Zhenxiu Jia  Shuwen Pei  Alfonso Benito‐Calvo  Dongdong Ma  Laura Sanchez‐Romero  Qi Wei 《第四纪科学杂志》2019,34(8):621-632

Understanding site formation processes is crucial for interpreting archaeological context patterns and hominin behaviour as these affect the preserved condition of a site and the integrity of archaeological remains. The fluvio‐lacustrine sequences in the Nihewan Basin of North China are rich sources of early Pleistocene archaeological sites, which offer an important opportunity to investigate human evolution and adapted behaviours in East Asia. Although many Palaeolithic sites have been reported from the Nihewan Basin, North China, few of them focus on site formation processes before interpreting the hominin behaviour patterns. Here, we present a site formation study of four archaeological layers (Layers 6D, 6C, 6B and 6A) in Trench 1 from the Donggutuo (namely DGT‐T1) site in the Nihewan Basin with an age of 1.1 Ma. Through the study of sedimentary contexts, spatial distributions of artefacts and fossils, intra‐assemblage category ratios, debitage size distributions, lithic abrasion, artifact orientation and planar dip, our results show that all the layers had been disturbed by low‐energy sheet wash across the lake shore setting, but to differing extents. The post‐depositional disturbance caused by water decreased from the lower to the upper layers, from Layer 6D to Layer 6A. This indicates that the archaeological remains in DGT‐T1 have not been subject to significant natural modifications and are thus suitable for studying early hominin behaviour in North China. Copyright © 2019 John Wiley & Sons, Ltd.  相似文献   

Recent trends in temperature and precipitation over the Balearic Islands (Spain)   总被引：1，自引：0，他引：1  

V. Homar  C. Ramis  R. Romero  S. Alonso 《Climatic change》2010,98(1-2):199-211

Changes in climatic parameters are often given in terms of global averages even though large regional variability is generally observed. The study of regional tendencies provides not only supplementary conclusions to more large-scale oriented results but is also of particular interest to local policy-makers and resource managers to have detailed information regarding sensible and influential climatic parameters. In this study, changes in precipitation for the Balearic Islands (Spain) have been analyzed using data from 18 rain gauges with complete daily time series during the period 1951–2006 and two additional sites where only monthly totals were available. Tendencies for maximum and minimum 2-m temperatures have also been derived using data from three thermometric stations with daily time series for the period 1976–2006. The thermometric stations are located at the head of the runways in the airports of the three major islands of the archipelago, where urbanization has arguably not had a relevant impact on the registered values. The annual mean temperature in the mid-troposphere and lower stratosphere has also been analyzed using the Balearics radiosonde data for the period 1981–2006. Results show there is a negative tendency for annual precipitation (163 mm per century) with 85% significance on the sign of the trend. An abrupt decrease in mean yearly precipitation of 65 mm is objectively detected in the time series around 1980. Additionally, the analysis shows that light and heavy daily precipitation (up to 4 mm and above 64 mm, respectively) increase their contribution to the total annual, while the share from moderate-heavy precipitations (16–32 mm) is decreasing. Regarding the thermometric records, minimum temperatures increased at a rate of 5.8°C per century during the 31 years and maximum temperatures also increased at a rate of 5.0°C per century, both having a level of statistical significance for the sign of the linear trend above 99%. Temperatures in the mid-troposphere decreased at a rate of ??5.4°C per century while a tendency of ??7.8°C per century is found in the lower stratosphere. The level of statistical significance for the sign of both the tropospheric and stratospheric linear trends is above 98% despite the great inter-annual variability of both series.  相似文献   

Unveiling the birth and evolution of the H ii region Sh2-173     

S. Cichowolski †  G. A. Romero  M. E. Ortega ‡  C. E. Cappa †  J. Vasquez § 《Monthly notices of the Royal Astronomical Society》2009,394(2):900-915

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Radar interferometry techniques for the study of ground subsidence phenomena: a review of practical issues through cases in Spain   总被引：5，自引：0，他引：5  

R. Tomás  R. Romero  J. Mulas  J. J. Marturià  J. J. Mallorquí  J. M. Lopez-Sanchez  G. Herrera  F. Gutiérrez  P. J. González  J. Fernández  S. Duque  A. Concha-Dimas  G. Cocksley  C. Castañeda  D. Carrasco  P. Blanco 《Environmental Earth Sciences》2014,71(1):163-181

Subsidence related to multiple natural and human-induced processes affects an increasing number of areas worldwide. Although this phenomenon may involve surface deformation with 3D displacement components, negative vertical movement, either progressive or episodic, tends to dominate. Over the last decades, differential SAR interferometry (DInSAR) has become a very useful remote sensing tool for accurately measuring the spatial and temporal evolution of surface displacements over broad areas. This work discusses the main advantages and limitations of addressing active subsidence phenomena by means of DInSAR techniques from an end-user point of view. Special attention is paid to the spatial and temporal resolution, the precision of the measurements, and the usefulness of the data. The presented analysis is focused on DInSAR results exploitation of various ground subsidence phenomena (groundwater withdrawal, soil compaction, mining subsidence, evaporite dissolution subsidence, and volcanic deformation) with different displacement patterns in a selection of subsidence areas in Spain. Finally, a cost comparative study is performed for the different techniques applied.  相似文献   

Sensitivity analysis of main variables present in flash flood processes. Application in two Spanish catchments: Arás and Aguilón   总被引：1，自引：0，他引：1  

Jesús Mateo Lázaro  José Ángel Sánchez Navarro  Alejandro García Gil  Vanesa Edo Romero 《Environmental Earth Sciences》2014,71(6):2925-2939

The program Simulation of Hydrological Extreme Events provides a set of functionalities that combined together allows constructing, manipulating, analyzing and comparing the hydrological processes involved in flash flood generation. The program makes use of existing databases of interest in hydrology and available in Spain, such as digital terrain models, coverage of rainfall or curve number. Two pilot watersheds from Spain were selected, Arás and Aguilón, where flash flood episodes have taken place. A sensitivity analysis of the flash flood episodes in response to changes in the main hydrological processes involved has been made, such as spatial and temporal distribution of rainfall, soil moisture status and water flow through channel network. In this work, we found that the antecedent moisture condition is the most influential factor in the magnitude of flash floods produced by the same amount of rain. The temporal distribution of the storm represents the second characteristic in order of relevance. In addition, terrain morphology (specially the slope) is found to be decisive in the results differences obtained.  相似文献   

Preface     

K. S. Cheng  Gustavo E. Romero 《Astrophysics and Space Science》2005,297(1-4):ix-x

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Status of the Connection between Unidentified Egret Sources and Supernova Remnants: The Case of Cta 1     

Diego F. Torres  Thomas M. Dame  Gustavo E. Romero 《Astrophysics and Space Science》2005,297(1-4):393-398

In this paper we briefly comment on the observational status of the possible physical association between unidentified EGRET sources and supernova remnants (SNRs) in our Galaxy. We draw upon recent results presented in the review by Torres et al. (2003), concerning molecular gas in the vicinity of all 19 SNRs found to be positionally coincident with EGRET sources at low Galactic latitudes. In addition, we present new results regarding the supernova remnant CTA 1. Our findings disfavor the possibility of a physical connection with the nearby (in projection) EGRET source. There remains possible, however, that the compact object produced in the supernova explosion be related with the observed γ-ray flux.  相似文献   

The Binary Black Hole Scenario for the BL Lacertae Object AO 0235＋16     

G.E.Romero  S.E.Nuza 《中国天文和天体物理学报》2003,3(6):513-525

Recent analysis of the long term radio light curve of the extremely variable BL Lacertae object AO 0235+16 by Raiteri et al. have revealed the presence of recurrent outbursts with a period of ～ 5.7±0.5 yr. Periodicity analysis of the optical light curve also shows evidence for a shorter period. Here we discuss whether such a behavior can be explained by a binary black hole model where the accretion disk of one of the supermassive black holes is precessing due to the tidal effects of the companion. We estimate the mass of the accreting hole and analyze constraints on the secondary mass and the orbital parameters of the system. It is possible to provide a viable interpretation of the available multiwavelength data.  相似文献   

Reply to “Discussion of “From saturated to unsaturated conditions and vice versa” by M. Lloret-Cabot et al. (DOI 10.1007/s11440-017-0577-6)” by S. Qi et al. (DOI 10.1007/s11440-017-0625-2)     

Martí Lloret-Cabot  Simon J. Wheeler  Jubert A. Pineda  Enrique Romero  Daichao Sheng 《Acta Geotechnica》2018,13(2):493-495

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