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171.
Ana Valdeolmillos‐Rodríguez Miriam Dorado‐Valiño Maria Blanca Ruiz‐Zapata Ana María Alonso‐Zarza 《第四纪科学杂志》2011,26(1):128-140
The Middle Pleistocene palaeoclimate and palaeoenvironment evolution of the Las Tablas de Daimiel wetlands is described using a combination of sedimentology, pollen and δ13C and δ18O isotopic records of Unit B of core LT‐199906. This unit mostly contains fluvial and palustrine sediments. U/Th and amino acid racemization (AAR) dating and a comparison of the δ18O curve of Unit B with oceanic records suggests that Unit B spans the period from the end of Marine Isotope Stage (MIS) 10 (340 ka) to the first stages of MIS 7 (ca. 210 ka). MIS 9 was characterised by a regional vegetation dominated by Cupressaceae, with Pinus as a tree element. The water level was high and temperatures were very probably higher than during the Holocene. MIS 8 and the first substages of MIS 7 (7e, 7d and 7c) were dominated by xerophilous steppe vegetation in lowlands (elevations around 610 m above sea level) near to the wetland. At higher altitudes, far away from the wetland, there were fewer Pinus than in MIS 9, and a greater presence of warm, temperate and cool climate tree elements. The aquatic system in MIS 9 became shallower, with eutrophication and the accumulation of organic matter occurring; temperatures were similar to or lower than those of the Holocene. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
172.
Devis-Morales Andrea Rodríguez-Rubio Efraín Montoya-Sánchez Raúl Andrés 《Ocean Dynamics》2021,71(2):251-277
Ocean Dynamics - The three-dimensional transport of sediments released by the main rivers in the Colombian Caribbean basin is investigated using numerical model simulations. Different types of... 相似文献
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174.
Solar Physics - We analyzed the temporal variation of energetic particles measured by the Low Energy Telescope (LET), the Kiel Electron Telescope (KET), and the High Energy Telescope (HET)... 相似文献
175.
Nieves R. Brisaboa Miguel R. Luaces M. Andrea Rodríguez 《International journal of geographical information science》2014,28(1):56-82
An inconsistency measure can be used to compare the quality of different data sets and to quantify the cost of data cleaning. In traditional relational databases, inconsistency is defined in terms of constraints that use comparison operators between attributes. Inconsistency measures for traditional databases cannot be applied to spatial data sets because spatial objects are complex and the constraints are typically defined using spatial relations. This paper proposes an inconsistency measure to evaluate how dirty a spatial data set is with respect to a set of integrity constraints that define the topological relations that should hold between objects in the data set. The paper starts by reviewing different approaches to quantify the degree of inconsistency and showing that they are not suitable for the problem. Then, the inconsistency measure of a data set is defined in terms of the degree in which each spatial object in the data set violates topological constraints, and the possible representations of spatial objects are points, curves, and surfaces. Finally, an experimental evaluation demonstrates the applicability of the proposed inconsistency measure and compares it with previously existing approaches. 相似文献
176.
O. E. Malandraki N. Agueda A. Papaioannou K.-L. Klein E. Valtonen B. Heber W. Dr?ge H. Aurass A. Nindos N. Vilmer B. Sanahuja A. Kouloumvakos S. Braune P. Preka-Papadema K. Tziotziou C. Hamadache J. Kiener V. Tatischeff E. Riihonen Y. Kartavykh R. Rodríguez-Gasén R. Vainio 《Solar physics》2012,281(1):333-352
Solar energetic particle (SEP) events are a key ingredient of solar?Cterrestrial physics both for fundamental research and space weather applications. Multi-satellite observations are an important and incompletely exploited tool for studying the acceleration and the coronal and interplanetary propagation of the particles. While STEREO uses for this diagnostic two identical sets of instrumentation, there are many earlier observations carried out with different spacecraft. It is the aim of the SEPServer project to make these data and analysis tools available to a broad user community. The consortium will carry out data-driven analysis and simulation-based data analysis capable of deconvolving the effects of interplanetary transport and solar injection from SEP observations, and will compare the results with the electromagnetic signatures. The tools and results will be provided on the web server of the project in order to facilitate further analysis by the research community. This paper describes the data products and analysis strategies with one specific event, the case study of 13 July 2005. The release time of protons and electrons are derived using data-driven and simulation-based analyses, and compared with hard X-ray and radio signatures. The interconnection of the experimental and the simulation-based results are discussed in detail. 相似文献
177.
Pere Anadón Andrea Moscariello Julio Rodríguez-Lázaro M. L. Filippi 《Journal of Paleolimnology》2006,35(3):593-616
Stable isotopes and trace-element contents of ostracod (Candona neglecta) valves mostly from the Holocene portion of two assembled cores from Petit Lac (Lake Geneva, Switzerland-France) were analysed
in order to depict the geochemical record of post-glacial environmental changes of this lake. Additional stable isotope and
trace element data from the gastropod Bithynia tentaculata (shells and opercula) from some intervals of these cores, as well as previous data from bulk carbonate from the lower part
of the studied intervals were also considered. Mg/Ca and Sr/Ca molar ratios for the Holocene lake water have been estimated
from evaluations of the partitioning coefficients for Mg and Sr for C. neglecta and B. tentaculata taking into account the modern-lake water composition. This study shows an overall gentle trend to higher δ18O values in C. neglecta valves from the Boreal interval (mean −8.44‰) to the upper part of the core (mean −8.11‰). This trend is superimposed to
higher frequency oscillations of stable isotope values and trace element ratios, especially through the upper Older Atlantic
and the Subboreal. The overall isotopic oxygen trend includes several shifts in δ18O of about 1‰. These shifts are interpreted as major regional-global climate changes that have also been observed in other
coeval δ18O and pollen records which reflect the Holocene climate variability in other European basins. Especially well-defined peaks
in some episodes like Older Atlantic (~8200 yr BP), Younger Atlantic – Subboreal transition (~5600 yr BP) and early Subatlantic
(~ 2500 yr BP) correspond to well-recognized events in globally-distributed records. Some of these shifts are correlated with
pulses in the lake-level curve of the Lake Geneva.
An erratum to this article is available at . 相似文献
178.
179.
The tidal exchange of ammonia-nitrogen, nitrate-nitrogen, total nitrogen, total phosphorus, and total organic carbon between coastal lagoons and the marine environment were determined. Constituent measurements were made in Huizache-Caimanero Lagoon in Northwest Mexico over 24-h sampling periods during both dry and wet seasons. The exchange of these nutrients was also compared to exchanges in estuarine marshes of other latitudes. High exchange rates were found to be associated to extreme climatic events. 相似文献
180.