Search results for "satellite"
showing 10 items of 1031 documents
A photometric study of Be stars located in the seismology fields of COROT
2007
Context: In preparation for the COROT mission, an exhaustive photometric study of Be stars located in the seismology fields of the COROT mission has been performed. The very precise and long-time-spanned photometric observations gathered by the COROT satellite will give important clues of the origin of the Be phenomenon. Aims: The aim of this work is to find short-period variable Be stars located in the seismology fields of COROT and to study and characterise their pulsational properties. Methods: Light curves obtained at the Observatorio de Sierra Nevada together with data from Hipparcos and ASAS-3 of a total of 84 Be stars have been analysed in order to search for short-term variations. W…
Satelliittijärjestelmän linkkibudjettianalyysi
2013
Tutkielmassa selvitetään kirjallisuuskatsauksen avulla DVB-S ja DVB-RCS standardien mukaisten interaktiivisten satelliittijärjestelmien linkkibudjettia. Toisen sukupolven standardien eli DVB-S2 ja DVB-RCS2 mukaisten järjestelmien erityispiirteiden huomioiminen linkkibudjetin kannalta on tutkielman keskeinen teema. Tutkielma pyrkii antamaan selkeän kuvan satelliittijärjestelmän linkkibudjetista sekä tuomaan näkökulmia satelliittijärjestelmien jatkotutkimukseen ja suunnittelutyöhön. The link budget analysis of the satellite system. This paper discusses the link budget of the satellite systems based on DVB-S and DVB-RCS standards. Used method is literature review. The key theme is to study spe…
AsYouLikeHim: Images ofGalileoSince the17thCentury
2003
The Uses of Analogies in Seventeenth and Eighteenth Century Science
2011
The object of this paper is to look at the extent and nature of the uses of analogy during the first century following the so-called scientific revolution.Using the research tool provided by JSTOR we systematically analyze the uses of “analog” and its cognates (analogies, analogous, etc.) in the Philosophical Transactions of the Royal Society of London for the period 1665–1780. In addition to giving the possibility of evaluating quantitatively the proportion of papers explicitly using analogies, this approach makes it possible to go beyond the maybe idiosyncratic cases of Descartes, Kepler, Galileo, and other much studied giants of the so-called Scientific Revolution. As a result a classifi…
Coupling high-resolution satellite imagery with ALS-based canopy height model and digital elevation model in object-based boreal forest habitat type …
2014
We developed a classification workflow for boreal forest habitat type mapping. In object-based image analysis framework, Fractal Net Evolution Approach segmentation was combined with random forest classification. High-resolution WorldView-2 imagery was coupled with ALS based canopy height model and digital terrain model. We calculated several features (e.g. spectral, textural and topographic) per image object from the used datasets. We tested different feature set alternatives; a classification accuracy of 78.0 % was obtained when all features were used. The highest classification accuracy (79.1 %) was obtained when the amount of features was reduced from the initial 328 to the 100 most imp…
Aspecte i prefixació verbal en català antic
2021
The paper examines aspectual and selectional properties of Old Catalan prefixed verbs in comparison with their non prefixed counterparts. We ground our analysis on Talmy’s (1985, 2000) notion of verb framed and satellite framed languages and on Mateu (2002, 2003) and Mateu & Rigau (2002) theory of lexical structure, and we argue that telicity and other aspectual properties associated with prefixed verbs are by effects derived from the semantic value of the prefix together with the lexical structure they give rise to. Taking as a case in point the a- prefix of verbs such as «acórrer», we analyse the prefix as a path which relates a figure (the grammatical subject) to a ground (the argument i…
An Autonomous System to Take Angular Thermal-Infrared Measurements for Validating Satellite Products
2015
An autonomous system for field land surface temperature (LST) measurements taken at different observation angles was developed to be deployed easily at any conventional meteorological tower station. The system permits ground-truth data to be acquired on a continuous basis, and angularly scans land and sky hemispheres with a single thermal-infrared (TIR) radiometer. This paper describes the autonomous angular system and the methodology to assess ground-truth LST and relative-to-nadir emissivity data from system measurements. Ground-truth LSTs were used to validate satellite-retrieved LST products at two experimental sites (rice crop and shrubland areas). The relative-to-nadir emissivity valu…
Spatial and temporal variability of rainfall over the Republic of Djibouti from 1946 to 2017.
2021
20 pages; International audience; For the first time, the spatial and temporal variability of rainfall in the Republic of Djibouti is investigated using data from 14 weather stations over the period 1946–2017. Due to limited data availability, high-resolution long-term satellite rainfall products (CHIRPS, PERSIANN-CDR, TAMSATv3, ARC2) and ERA5 reanalysis also contribute to document time–space rainfall variability at monthly, seasonal and annual scales. Principal component analysis identifies two spatially coherent regions of rainfall variability in the east (coastal zone) and the west (inland zone) of the country. Annual rainfall amounts are everywhere very low (60–300 mm), but with contras…
SST Comparison of AVHRR and MODIS Time Series in the Western Mediterranean Sea
2020
La temperatura de la superficie del mar (SST) es un parámetro clave para comprender los procesos atmosféricos y oceánicos. Desde finales de la década de 1980, las imágenes de satélite infrarrojas se han utilizado para complementar los registros in situ para estudiar la variabilidad temporal y espacial de la SST. El radiómetro avanzado de muy alta resolución (AVHRR) del satélite de la Administración Nacional Oceánica y Atmosférica (NOAA) fue el primer sensor utilizado con éxito para calcular la SST después del desarrollo y validación del algoritmo de corrección atmosférica conocido como 'ventana dividida'. Más recientemente, el espectrorradiómetro de imágenes de resolución MODERADA (MODIS) a…
The Networked Utilisation of Satellite Images and Geospatial Technology in Journalism
2022
Satellite technology has become increasingly affordable and accessible in the past few decades. This has enabled many newsrooms to engage with genuinely remote journalism. This chapter explores the networked nature of satellite journalism and investigates its inclusion of experts and citizens outside newsrooms. Satellite journalism uses satellite-borne technology either as a (1) part of storytelling or (2) source of information. Academic research on the topic is scarce, so this chapter builds a base of knowledge on the contemporary practices, limitations and ethics—as well as directions of future development—of satellite journalism. By interviewing six journalists and one earth observation …