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81.
The Imaging Magnetograph eXperiment (IMaX) for?the?Sunrise Balloon-Borne Solar Observatory 总被引:1,自引:0,他引:1
V. Mart��nez?Pillet J. C. del Toro Iniesta A. ��lvarez-Herrero V. Domingo J. A. Bonet L. Gonz��lez?Fern��ndez A. L��pez?Jim��nez C. Pastor J. L. Gasent?Blesa P. Mellado J. Piqueras B. Aparicio M. Balaguer E. Ballesteros T. Belenguer L. R. Bellot?Rubio T. Berkefeld M. Collados W. Deutsch A. Feller F. Girela B. Grauf R. L. Heredero M. Herranz J. M. Jer��nimo H. Laguna R. Meller M. Men��ndez R. Morales D. Orozco?Su��rez G. Ramos M. Reina J. L. Ramos P. Rodr��guez A. S��nchez N. Uribe-Patarroyo P. Barthol A. Gandorfer M. Knoelker W. Schmidt S. K. Solanki S. Vargas?Dom��nguez 《Solar physics》2011,268(1):57-102
The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the Sunrise balloon-borne solar observatory in June 2009 for almost six days over the Arctic Circle. As a polarimeter, IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual-beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mÅ. IMaX uses the high-Zeeman-sensitive line of Fe i at 5250.2 Å and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15??C?0.18 arcsec range over a 50×50 arcsec field of view. Time cadences vary between 10 and 33 s, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are 4 G for longitudinal fields and 80 G for transverse fields per wavelength sample. The line-of-sight velocities are estimated with statistical errors of the order of 5??C?40 m?s?1. The design, calibration, and integration phases of the instrument, together with the implemented data reduction scheme, are described in some detail. 相似文献
82.
83.
Maria Fernanda Alvarez Margarita Luisa Osterrieth Julio Luis del Río 《Environmental Earth Sciences》2012,65(2):505-515
Organic matter is a fundamental factor in the biogeochemical cycle of carbon; it influences the chemical, physical, and biological
properties of the soil. The aim of this paper is to determine the organic fractions in the three predominant morphologies
of aggregates found in Typical Argiudolls of the Buenos Aires southeastern area and to link them to different soil uses, as
possible indicators of soil quality. The study was carried out in the basin de Los Padres Pound (General Pueyrredón, Buenos Aires). We analyzed the first 5 cm of mollic epipedons of plots with different soil uses: (a)
cultivated plots, (b) pine and eucalyptus forests, (c) pastures, and (d) a natural plot in the de Los Padres Pound Reserve as a reference. The percentage of soil organic carbon (SOC), light organic carbon (LOC), fulvic acids (FA), humic acids (HA),
and humins (H) in elongated, quadrangular and spherical aggregates were determined. The results show slight variations in
SOC (7.2–8.6%) in the spherical aggregates of all the plots and a greater variability in elongated and quadrangular aggregates
(5.6–10% and 6.9–13.6%, respectively). HA are minimal in the agroecosystems with extreme values of 0.02% in the spherical
aggregates of cultivated plots, and maximal in the elongated and quadrangular aggregates of natural plots (0.3–0.5%). Fulvic
acids display a similar behavior, while H decrease slightly with the morphologies and the different practices. The substantial
decrease of humic substances in cultivated plots translates into a lower biologic activity; this, in turn, influences the
aggregation, thus lowering the structural stability of these plots, which have been under agro-horticultural management for
more than 50 years. 相似文献
84.
María del Carmen Blanco Juan Darío Paoloni Hector Morrás Carmen Fiorentino Mario Eduardo Sequeira Nilda N. Amiotti Oscar Bravo Silvana Diaz Martín Espósito 《Environmental Earth Sciences》2012,66(7):2075-2084
Excessive arsenic concentrations above the Argentinean and WHO guidelines for drinking water (10 μg L−1) affects shallow aquifers of the southern Pampean Plain (Argentina) hosted in the Pampean and the Post Pampean formations
(loess and reworked loess; Plio-Pleistocene–Holocene). Health problems related to high As concentrations in drinking waters
are known as Endemic Regional Chronic Hydroarsenicism. Hydrochemistry of shallow groundwaters and soil geochemistry were investigated
aiming to (1) understand the partition of As in the solid phase and its relationship with unacceptable As concentrations in
waters, (2) identify the provision source of As to groundwaters. Only 5% of the samples had As concentrations <10 μg L−1; in 27% As concentrations ranged from 10 to 50 μg L−1 and in 58% it reached 60–500 μg L−1. The coarse fraction (50–2,000 μm) hosts about 27% of the total As in the solid phase, being positively correlated to Ba
(p < 0.01; r
2 = 0.93). About 70% is included in the <2 μm fraction and had positive correlations of As–Fe (p < 0.05; r
2 = 0.85) and As–Cr (p < 0.05; r
2 = 0.68). Soils and sediment sand fractions of vadose zones are the primary sources of As in shallow groundwater while adsorption–desorption
processes, codisolution–coprecipitation, and evaporation during the dry seasons raise As concentrations in waters exceeding
the guideline value for drinking water. 相似文献
85.
86.
E. Abraham H.F. del Valle F. Roig L. Torres J.O. Ares F. Coronato R. Godagnone 《Journal of Arid Environments》2009,73(2):144-153
The compilation of published results on the geography of the Monte Desert biome of Argentina that we present here offers a review of its boundaries and ecotones, and of its biophysical and socio-economic characteristics. In relation to socio-ecological issues, the focus is on a case study in the province of Mendoza. An analysis is presented about the ecological-economic issues and the sustainable investment policies in rangelands of the Patagonian Monte. In addition, this biome is compared with other South American arid biomes and their North American counterparts. We identified some gaps in the current knowledge, especially at a mesoscale level, where studies on Monte borders are deemed necessary as well as explicit boundary criteria for ecosystem differentiation. Also the ecological-economic relations and feedbacks between livestock herbivory, soil erosion and market behaviour should be considered within the framework of wider socio-ecological research. 相似文献
87.
A.L. Carrera M.J. Mazzarino M.B. Bertiller H.F. del Valle E.M. Carretero 《Journal of Arid Environments》2009,73(2):192-201
In arid and semiarid ecosystems, primary productivity and nutrient cycling are directly related to the amount and seasonal distribution of precipitation. However, depending on morphological, phenological, physiological, and biochemical traits, plants may influence the quality and quantity of organic matter inputs to the soil and thus the biomass and activity of the soil biota responsible for carbon and nitrogen dynamics. In this paper, we review the available knowledge on plant functional traits and their impacts on ecosystem processes such as N and C cycling throughout the Monte Phytogeographical Province. We address the mechanisms of N conservation, the quantity and quality of leaf litterfall and root traits of the dominant plant life forms and their effects on decomposition processes, soil organic matter accretion, and soil-N immobilization and mineralization. We conclude that plant functional traits affect ecosystem processes in the Monte Phytogeographical Province since the chemistry of senesced leaves and root biomass exerts an important control on organic matter decomposition and N availability in soil. 相似文献
88.
Vicente G. Ruiz de Argandoa Lope Calleja ngel Rodríguez-Rey Luis Miguel Surez del Río Carmen Celorio 《Engineering Geology》2009,103(3-4):69-75
X-ray Computed Tomography (X-ray CT) has been used to study the petrophysical characteristics of a Jurassic sandstone from Asturias (Northern Spain) used as building stone in several monuments in the region. CT monitoring of water capillarity tests has made it possible to visualize the movement of water inside the samples, to relate this movement with texture characteristics, and to measure the height reached in successive images, thereby determining the capillary penetration coefficient; based on this coefficient, the effective capillary pore radius has also been estimated. An advantage of the use of CT is that, as the information comes from the sample interior, border effects that can be generated in the external faces can be avoided.The CT was also used to visualize how a commercial organosilicon consolidant penetrates inside the rock by means of capillarity, a usual way of consolidant application in stone restoration processes. The coefficient of capillary penetration of the product, determined on the basis of the measurements made on the tomographic images, is 53% less than that of water. The influence of rock texture characteristics on the capillarity both of the consolidant and the water was also observed.The samples underwent CT water capillarity studies before and after the consolidant application, proving that the treatment improves the rock's hydric properties. The coefficient of capillary penetration decreased by 24% following the application of the consolidant, whereas the effective pore radius decreased by more than 40%. 相似文献
89.
R. Bermejo J. Carpio J. I. Díaz P. Galán del Sastre 《Pure and Applied Geophysics》2008,165(6):1025-1047
We present a finite element algorithm of a climate diagnostic model that takes as a climate indicator the atmospheric sea-level
temperature. This model belongs to the category of energy balance models introduced independently by the climatologists M.I.
Budyko and W.D. Sellers in 1969 to study the influence of certain geophysical mechanisms on the Earth climate. The energy
balance model we are dealing with consists of a two-dimensional nonlinear parabolic problem on the 2-sphere with the albedo
terms formulated according to Budyko as a bounded maximal monotone graph in The numerical model combines the first-order Euler implicit time discretization scheme with linear finite elements for space
discretization, the latter is carried out for the special case of a spherical Earth and uses quasi-uniform spherical triangles
as finite elements. The numerical formulation yields a nonlinear problem that is solved by an iterative procedure. We performed
different numerical simulations starting with an initial datum consisting of a monthly average temperature field, calculated
from the temperature field obtained from 50 years of simulations, corresponding to the period 1950–2000, carried out by the
Atmosphere General Circulation Model HIRLAM. 相似文献
90.
Romo-Morales Diana Moreno-Rodríguez Verónica Molina-Freaner Francisco Valencia-Moreno Martín Ruiz Joaquín Minjárez-Osorio Christian Hernández-Mendiola Ernesto del Rio-Salas Rafael 《Natural Resources Research》2020,29(4):2773-2786
Natural Resources Research - Mining is an important activity in Mexico; however, despite its economic benefits, it carries potential environmental risks, including mine spills. On August 6,... 相似文献