987 resultados para Orbiting astronomical observatories.


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Accurate age models are a tool of utmost important in paleoclimatology. Constraining the rate and pace of past climate change are at the core of paleoclimate research, as such knowledge is crucial to our understanding of the climate system. Indeed, it allows for the disentanglement of the various drivers of climate change. The scarcity of highly resolved sedimentary records from the middle Eocene (Bartonian - Lutetian Stages; 47.8 - 37.8 Ma) has led to the existence of the "Eocene astronomical time scale gap" and hindered the establishment of a comprehensive astronomical time scale (ATS) for the entire Cenozoic. Sediments from the Newfoundland Ridge drilled during Integrated Ocean Drilling Program (IODP) Expedition 342 span the Eocene gap at an unprecedented stratigraphic resolution with carbonate bearing sediments. Moreover, these sediments exhibit cyclic lithological changes that allow for an astronomical calibration of geologic time. In this study, we use the dominant obliquity imprint in XRF-derived calcium-iron ratio series (Ca/Fe) from three sites drilled during IODP Expedition 342 (U1408, U1409, U1410) to construct a floating astrochronology. We then anchor this chronology to numerical geological time by tuning 173-kyr cycles in the amplitude modulation pattern of obliquity to an astronomical solution. This study is one of the first to use the 173-kyr obliquity amplitude cycle for astrochronologic purposes, as previous studies primarily use the 405-kyr long eccentricity cycle as a tuning target to calibrate the Paleogene geologic time scale. We demonstrate that the 173-kyr cycles in obliquity's amplitude are stable between 40 and 50 Ma, which means that one can use the 173-kyr cycle for astrochronologic calibration in the Eocene. Our tuning provides new age estimates for magnetochron reversals C18n.1n - C21r and a stratigraphic framework for key sites from Expedition 342 for the Eocene. Some disagreements emerge when we compare our tuning for the interval between C19r and C20r with previous tuning attempts from the South Atlantic. We therefore present a revision of the original astronomical interpretations for the latter records, so that the various astrochronologic age models for the middle Eocene in the North- and South-Atlantic are consistent.

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In 2001 we started as part of the EU FP5 project Greenveins monitoring of insect communities in the normal landscape of Saxony-Anhalt (Germany), which is dominated by agricultural use. We selected four landscape sites of 4x4 km and recorded insects using combined flight traps, combining the ideas of window and yellow pan traps (see Duelli et al., 1999). Traps consist of a yellow funnel (25 cm diameter) filled with water (preserving agent added) and two perspex windows mounted in a way that they are crossed in the center. Within each square km of a site one trap was placed at ecotones between semi-natural habitats and agricultural fields (16 traps per site). Traps were operated in late spring-early summer (three sampling rounds) and late summer (three sampling rounds). Follow-up sampling started in 2010 as long-term monitoring within the TERENO project (www.tereno.net), contributing to the LTER network (Long-Term Ecosystem Research) in Germany (www.lter-d.de) and internationally as well (www.lter-europe.net). Metadata about the sites and related activities and data sets can be found in the DEIMS Repository for Research Sites and Datasets (https://data.lter-europe.net/deims/). In 2010 another two landscapes were added and yearly sampled in the same way. Due to long processing time of trapped insects data of follow-up years will be available about 18 months after trapping.

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Thesis (Ph.D.)--University of Washington, 2016-08

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This document is summarizing a major part of the work performed by the FP7-JERICO consortium, including 27 partner institutions, during 4 years (2011-2015). Its objective is to propose a strategy for the European coastal observation and monitoring. To do so we give an overview of the main achievements of the FP7-JERICO project. From this overview, gaps are analysed to draw some recommendations for the future. Overview, gaps and recommendation are addressed at both Hardware and Software levels of the JERICO Research Infrastructure. The main part of the document is built upon this analysis to outcome a general strategy for the future, giving priorities to be targeted and some possible funding mechanisms, but also upon discussions held in dedicated JERICO strategy workshops. This document was initiated in 2014 by the coordination team but considering the fact that an overview of the entire project and its achievement were needed to feed this strategy deliverable it couldn’t ended before the end of FP7-JERICO, April 2015. The preparation of the JERICO-NEXT proposal in summer 2014 to answer an H2020 call for proposals pushed the consortium ahead, fed deep thoughts about this strategy but the intention was to not propose a strategy only bounded by the JERICO-NEXT answer. Authors are conscious that writing JERICO-NEXT is even drawing a bias in the thoughts and they tried to be opened. Nevertheless, comments are always welcome to go farther ahead. Structure of the document The Chapter 3 introduces the need of sustained coastal observatories, from different point of view including a short description of the FP7-JERICO project. In Chapter 4, an analysis of the JERICO coastal observatory Hardware (platforms and sensors) in terms of Status at the end of JERICO, identified gaps and recommendations for further development is provided region by region. The main challenges that remain to be overcome is also summarized. Chapter 5 is dedicated the JERICO infrastructure Software (calibration, operation, quality assessment, data management) and the progress made through JERICO on harmonization of procedures and definition of best practices. Chapter 6 provides elements of a strategy towards sustainable and integrated coastal observations for Europe, drawing a roadmap for cost-effective scientific-based consolidation of the present infrastructure while maximizing the potential arising from JERICO in terms of innovation, wealth-creation, and business development. After reading the chapter 3, for who doesn’t know JERICO, any chapter can be read independently. More details are available in the JERICO final reports and its intermediate reports; all are available on the JERICO web site (www.jerico-FP7.eu) as well as any deliverable. Each chapter will list referring JERICO documents. A small bibliographic list is available at the end of this deliverable.

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The South Atlantic Magnetic Anomaly (SAMA) is one of the most outstanding anomalies of the geomagnetic field. The SAMA secular variation was obtained and compared to the evolution of other anomalies using spherical harmonic field models for the 1590-2005 period. An analysis of data from four South American observatories shows how this large scale anomaly affected their measurements. Since SAMA is a low total field anomaly, the field was separated into its nondipolar, quadrupolar and octupolar parts. The time evolution of the non-dipole/total, quadrupolar/total and octupolar/total field ratios yielded increasingly high values for the South Atlantic since 1750. The SAMA evolution is compared to the evolution of other large scale surface geomagnetic features like the North and the South Pole and the Siberia High, and this comparison shows the intensity equilibrium between these anomalies in both hemispheres. The analysis of non-dipole fields in historical period suggests that SAMA is governed by (i) quadrupolar field for drift, and (ii) quadrupolar and octupolar fields for intensity and area of influence. Furthermore, our study reinforces the possibility that SAMA may be related to reverse fluxes in the outer core under the South Atlantic region.

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O presente artigo analisa os resultados obtidos num minicurso sobre o Sol e sua dinâmica realizado no Observatório Astronômico do Centro de Divulgação Científica e Cultural (CDCC) pertencente à Universidade de São Paulo (USP) na cidade de São Carlos para alunos do ensino fundamental. As atividades foram desenvolvidas na recente inaugurada, Sala Solar. Ela é dedicada ao estudo do Sol, enfatizando a observação de manchas solares e do espectro do Sol. A metodologia adotada no minicurso consistiu em pequenos experimentos, observações e diálogos expositivos. Isto incentivou os estudantes a tomarem decisões, fazerem questionamentos e refletirem gerando pensamentos mais críticos e produzindo um maior número de conexões entre o real e o abstrato que contribuiu para níveis de maior complexidade conceitual verificados durante entrevistas semiestruturadas e nas respostas ao questionário final.

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A hydrodynamic characterization of the Itapocu river and Barra Velha lagoon estuarine system was carried out with the objective of evaluating how the current regime in this area is affected by astronomical and meteorological tides and the river discharge. Meteorological, water level and current velocity and direction data were gathered hourly during a twenty-day period, from 22-July until 10-August, 2004. Current meters were positioned at the inlet, at the entrance of the north and south lagoons and at the lower estuary of the river along with a tide gauge. The estuarine system showed distinct current behavior among the different sectors within the estuary, responding to the different forcings. The strongest currents were observed at the inlet while the weakest values were observed at the northern lagoon, a location that showed little dynamic. The general flow was ebb-dominated flux, in response to fluvial discharge, even during local wind water set-up event.

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Searches for field horizontal-branch (FHB) stars in the halo of the Galaxy in the past have been carried out by several techniques, such as objective-prism surveys and visual or infrared photometric surveys. By choosing adequate color criteria, it is possible to improve the efficiency of identifying bona fide FHB stars among the other objects that exhibit similar characteristics, such as main-sequence A-stars, blue stragglers, subdwarfs, etc. In this work, we report the results of a spectroscopic survey carried out near the south Galactic pole intended to validate FHB stars originally selected from the HK objective-prism survey of Beers and colleagues, based on near-infrared color indices. A comparison between the stellar spectra obtained in this survey with theoretical stellar atmosphere models allows us to determine T(eff), log g, and [Fe/H] for 13 stars in the sample. Stellar temperatures were calculated from measured (B-V)(o), when this measurement was available (16 stars). The color index criteria adopted in this work are shown to correctly classify 30% of the sample as FHB, 25% as non-FHB (main-sequence stars and subdwarfes), whereas 40% could not be distinguished between FHB and main-sequence stars. We compare the efficacy of different color criteria in the literature intended to select FHB stars, and discuss the use of the Mg II 4481 line to estimate the metallicity.

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The first known plan of the city of Sao Paulo, made in 1810 by Rufino Felizardo e Costa, is analyzed with emphasis on the cartographic and astronomical details: the precision, scale, magnetic declination, and orientation in relation to the north, the prime meridian, the precision of the coordinates (latitude and longitude) and others. An analytic methodology is followed, observing the plan and formulating questions. To answer then, resources of modern technologies are employed (digital cartography, GPS) as well as knowledge of the history of cartography. The work is justified by the fact that there are no cartographic studies about this important document.

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Doppler images in Balmer, He I, He II and C II lines, and simultaneous I-band photometry of the polar MR Ser are presented and analyzed. The Balmer and Helium Doppler tomograms, of this bright polar at high mass transfer state show the emission from the accretion flow and the heated surface of the companion star. As a result of a comparison between the Doppler tomograms, the ionization structure of the flow could be constrained. The highest ionization region was found in the vicinity of the magnetospheric radius. Photoionization modeling of the accretion column indicates that the Balmer and Helium emission line production in this system can be explained only by the central soft X-ray illumination. The orbital ephemeris of MR Ser has been revised.