Light pollution in Spain. An european perspective

Using DMPS satellite night images taken in 2000 we have estimated the saturated surface in many European countries. The objective of this study is to compare the illumination conditions and its effects in light pollution. We have measured the surface of the saturated zone. We compare this parameter with the ratio of population density of the country. To avoid bias, normalize by dividing the area built in each country prior to the comparison. In this way only takes into account the surface that really makes sense to illuminate. We have gathered the official data on energy consumption in public lighting in Spain. After plotting the evolution along the years we found changes in the way this value is obtained in different provinces of Spain and we made a more pessimistic prediction for the present energy consumption

Orbits and emission spectra from the 2014 Camelopardalids

We have analysed the meteor activity associated with meteoroids of fresh dust trails of Comet 209P/LINEAR, which produced an outburst of the Camelopardalid meteor shower (IAU code #451, CAM) in 2014 May. With this aim, we have employed an array of high-sensitivity CCD video devices and spectrographs deployed at 10 meteor observing stations in Spain in the framework of the Spanish Meteor Network. Additional meteoroid flux data were obtained by means of two forward-scatter radio systems. The observed peak zenithal hourly rate was much lower than expected, of around 20 meteors h(-1). Despite of the small meteor flux in the optical range, we have obtained precise atmospheric trajectory, radiant and orbital information for 11 meteor and fireball events associated with this stream. The ablation behaviour and low tensile strength calculated for these particles reveal that Camelopardalid meteoroids are very fragile, mostly pristine aggregates with strength similar to that of the Orionids and the Leonids. The mineral grains seem to be glued together by a volatile phase. We also present and discuss two unique emission spectra produced by two Camelopardalid bright meteors. These suggest a non-chondritic nature for these particles, which exhibit Fe depletion in their composition

Evolution of the energy consumed by street lighting in Spain estimated with DMSP-OLS data

© Pergamon-Elsevier Science Ltd. This research was supported by an FPU grant (Formación de Profesorado Universitario) from the Spanish Ministry of Science and Innovation (MCINN) to Alejandro Sánchez de Miguel. This work has been partially funded by the Spanish MICINN (AYA2009-10368, AYA2012-30717, AYA2012-31277), by the Spanish program of International Campus of Excellence Moncloa (CEI) and by the Madrid Regional Government through the AstroMadrid Project (CAM S2009/ESP-1496, http://www.laeff.cabinta-csic.es/ projects/astromadrid/main/index.php). The support of the Spanish Network for Light Pollution Studies (Ministerio de Economía y Competitividad, Acción Complementaria AYA2011-15808-E) is acknowledged. Thanks goes also to Francisco Ocaña and Jessica Starkey for the critical review of this text.We present the results of the analysis of satellite imagery to study light pollution in Spain. Both calibrated and non-calibrated DMSP-OLS images were used. We describe the method to scale the non-calibrated DMSP-OLS images which allows us to use differential photometry techniques in order to study the evolution of the light pollution. Population data and DMSP-OLS satellite calibrated images for the year 2006 were compared to test the reliability of official statistics in public lighting consumption. We found a relationship between the population and the energy consumption which is valid for several regions. Finally the true evolution of the electricity consumption for street lighting in Spain from 1992 to 2010 was derived; it has been doubled in the last 18 years in most of the provinces. (C) 2013 Elsevier Ltd. All rights reserved,Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEMinisterio de Ciencia e Innovacion (MICINN)Comunidad de MadridCampus de Excelencia Internacional (CEI) Moncloa, Españapu

Statistical modelling and satellite monitoring of upward light from public lighting

In this work, we propose an approach to estimating the amount of light wasted by being sent towards the upper hemisphere from urban areas. This is a source of light pollution. The approach is based on a predictive model that provides the fraction of light directed skywards in terms of a small set of identified explanatory variables that characterise the urban landscape and its light sources. The model, built via the statistical analysis of a wide sample of basic urban scenarios to compute accurately the amount of light wasted at each of them, establishes an optimal linear regression function that relates the fraction of wasted flux to relevant variables like the kind of luminaires, the street fill factor, the street width, the building and luminaire heights and the walls and pavement reflectances. We applied this model to evaluate the changes in emissions produced at two urban nuclei in the Deltebre municipality of Catalonia. The results agree reasonably well with those deduced from the radiance measurements made with the VIIRS instrument onboard the Suomi-NPP Earth orbiting satellite

Análisis de la correlación entre los Puntos Kilométricos Nominales y Reales en la geometría de la línea ferroviaria

En trabajos anteriores hemos obtenido modelos de emisión de energía desde la superficie terrestre utilizando imágenes de los satélites ISS, DMSP y VIIRS. Se ha estudiado una correlación entre las mismas y las zonas geográficas de España e Italia. Estas zonas son bastante amplias, del orden de provincias. Con la utilización de los sensores a bordo del satélite VIIRS, es posible aumentar la resolución espacial y realizar estudios a nivel de término municipal e incluso de elementos aislados. Dentro de los trabajos de detección de emisiones desde diferentes partes de España, se plantea la posibilidad de utilizar recintos ferroviarios aislados como zonas de calibración. Estos recintos están lo suficientemente aislados y son lo suficientemente grandes como para aparecer individualmente en las imágenes de satélite, y su consumo eléctrico es conocido. Estas estructuras se localizan muchas veces por su posición kilométrica dentro de una línea. Como trabajo previo, es necesario llevar a cabo un análisis de la correlación entre los PK nominales y los reales de la infraestructura ferroviaria y de esta forma identificar su posición. A lo largo de la vida de un trazado ferroviario, este sufre variaciones que influyen en la posición que ocupan los postes kilométricos ubicados junto a la vía. Estos se encuentran marcando puntos hectométricos con el objeto de indicar al maquinista y personal que trabaja en la vía, dónde se encuentran en cada momento o dónde se sitúan las instalaciones. También suponen un punto de referencia para cualquier trabajo que se haga en la misma, lugar de las incidencias, de limitaciones de velocidad, etc. Las alteraciones en el trazado modifican la posición real de estos postes kilométricos, lo que hace que su posición geográfica no coincida con la que muestran. Por este motivo, si se necesita posicionar cualquier evento sobre la vía, a partir de sus coordenadas GPS, será necesario llevar a cabo una corrección, de forma que estén referidas a la posición nominal y que sea identificable por los afectados. De modo inverso, se tiene que aplicar esta corrección a los kilometrajes nominales, si se quieren representar sobre cartografía. En este trabajo se hace una comparación entre las posiciones reales y teóricas de los mismos, con el objeto de detectar dónde y en qué medida existe esta casuística y crear una correspondencia entre ambos valores. La fuente de datos para los PK se ha obtenido del Mapa Topográfico Nacional y de la Base Cartográfica Nacional 1:25:000. Las geometrías de los fenómenos de líneas se ha obtenido de la versión 12 de Tramificación Común de IDEAdif. Como resultado del trabajo, se ha introducido un nuevo campo en la información de cada PK del MTN25 para indicar la línea a la que pertenece y se ha desarrollado una metodología que permite la correlación entre una y otra kilometración. Se ha encontrado una correlación directa entre ambos valores en una línea dada, teniendo en cuenta los casos en los que se producen saltos de kilometración en ella. Palabras clave: Ferrocarril, GIS, Punto Kilométrico, Algoritm

CO^(12) mapping of the low-metallicity blue compact dwarf galaxy Markarian 86

We have mapped the CO^12 J = 1-0 and J = 2-1 line emission in Markarian 86, one of the most metal-deficient blue compact dwarf galaxies so far detected in CO^12. The CO^12 emission is distributed in a horseshoe-like structure that follows the locus of the most recent star formation regions. The minimum in molecular line emission corresponds to the position of an older, massive nuclear starburst. The H_2 mass of the galaxy [in the range of (0.4-5) x 10^7 M_⨀] and its morphology have been compared with the predictions of hydrodynamic simulations of the evolution of the interstellar medium surrounding a nuclear starburst. These simulations suggest that the physical conditions in the gas swept out by the starburst could have led to the formation of the ring of molecular gas reported here. This result provides an attractive scenario for explaining the propagation (in a galactic scale) of the star formation in dwarf galaxies

Zernike analysis of all-sky night brightness maps

All-sky night brightness maps (calibrated images of the night sky with hemispherical field-of-view (FOV) taken at standard photometric bands) provide useful data to assess the light pollution levels at any ground site. We show that these maps can be efficiently described and analyzed using Zernike circle polynomials. The relevant image information can be compressed into a low-dimensional coefficients vector, giving an analytical expression for the sky brightness and alleviating the effects of noise. Moreover, the Zernike expansions allow us to quantify in a straightforward way the average and zenithal sky brightness and its variation across the FOV, providing a convenient framework to study the time course of these magnitudes. We apply this framework to analyze the results of a one-year campaign of night sky brightness measurements made at the UCM observatory in Madrid