11 research outputs found

    Aerial mapping and multi-sensors approaches from remote sensing applied to the roman archaeological heritage

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    This report details the preliminary results of the research focused on Roman archaeological heritage in the Middle Ebro Valley (Spain). The principal objective of this project was to obtain several different readings by means of a UAV equipped with different sensors. Firstly, it has been possible to obtain accurate maps, 3D models and digital elevation models of the site. Secondly, it has been possible to investigate and define archaeological remains still underground, via a new methodology which utilises visible and near-infrared wavelengths

    Thinning of the Monte Perdido Glacier in the Spanish Pyrenees since 1981

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    This paper analyzes the evolution of the Monte Perdido Glacier, the third largest glacier in the Pyrenees, from 1981 to the present. We assessed the evolution of the glacier''s surface area by analysis of aerial photographs from 1981, 1999, and 2006, and changes in ice volume by geodetic methods with digital elevation models (DEMs) generated from topographic maps (1981 and 1999), airborne lidar (2010) and terrestrial laser scanning (TLS, 2011, 2012, 2013, and 2014) data. We interpreted the changes in the glacier based on climate data from nearby meteorological stations. The results indicate that the degradation of this glacier accelerated after 1999. The rate of ice surface loss was almost three times greater during 1999-2006 than during earlier periods. Moreover, the rate of glacier thinning was 1.85 times faster during 1999-2010 (rate of surface elevation change = -8.98 ± 1.80 m, glacier-wide mass balance = -0.73 ± 0.14 m w.e. yr-1) than during 1981-1999 (rate of surface elevation change = -8.35 ± 2.12 m, glacier-wide mass balance = -0.42 ± 0.10 m w.e. yr-1). From 2011 to 2014, ice thinning continued at a slower rate (rate of surface elevation change = -1.93 ± 0.4 m yr-1, glacier-wide mass balance = -0.58 ± 0.36 m w.e. yr-1). This deceleration in ice thinning compared to the previous 17 years can be attributed, at least in part, to two consecutive anomalously wet winters and cool summers (2012-2013 and 2013-2014), counteracted to some degree by the intense thinning that occurred during the dry and warm 2011-2012 period. However, local climatic changes observed during the study period do not seem sufficient to explain the acceleration of ice thinning of this glacier, because precipitation and air temperature did not exhibit statistically significant trends during the study period. Rather, the accelerated degradation of this glacier in recent years can be explained by a strong disequilibrium between the glacier and the current climate, and likely by other factors affecting the energy balance (e.g., increased albedo in spring) and feedback mechanisms (e.g., heat emitted from recently exposed bedrock and debris covered areas)

    Toward an Ice-Free Mountain Range: Demise of Pyrenean Glaciers During 2011-2020

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    [EN]Pyrenean glaciers are the largest in southern Europe. Their survival is threatened by climate change, highlighting the significance of their study. This research presents an assessment of changes in the glacierized area and thickness of Pyrenean glaciers from 2011 to 2020, using high-resolution optical satellite, airborne lidar and UAV images. The total glacierized area has shrunk by 23.2% and thickness has decreased on average by 6.3 m. These two variables show no correlation for individual glaciers. Although climatic conditions do not vary much among glaciers, their evolution was heterogeneous during the study period. The smaller glaciers (10 ha) have a more homogeneous response. This can be attributed to the generally larger influence of local topography on the response of the smaller Pyrenean glaciers. There is no sign of slowdown in glacier shrinkage respect to previous decades.This work was supported by the Interreg-POCTEFA project OPCC ADAPYR and Spanish Ministry of Economy and Competitiveness project "CGL2017-82216-R." J. Revuelto is supported by the Grant IJC2018-036260-I. I. Vidaller is supported by the Grant FPU18/04978 and is studying the PhD program in the University of Zaragoza. E. Izagirre and I. Rico are supported by the Grant PPGI19/02 (UPV/EHU) and the Consolidated Research Group IT1029-16 (Basque Country Government). E. Berthier acknowledges support from the French Space Agency (CNES)

    Valores recomendados del factor de correccion por humedad, k_h, para la determinacion de la exposicion mediante camaras de cavidad en la energia del "6"0Co

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    Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

    Nuevas magnitudes ICRU para la vigilancia radiologica ambiental e individual. Calibracion de dosimetros personales usando haces externos de fotones

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    Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

    Toward an Ice‐Free Mountain Range: Demise of Pyrenean Glaciers During 2011–2020

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    International audienceGlacier mass balance evolution depends on snow accumulation and snow, firn and ice melt during the cold and warm seasons respectively and is thus considered a reliable indicator of climate fluctuations (Braithwaite & Hughes, 2020). The Little Ice Age (LIA, between the 14th and 19th centuries) represents the last global advance phase for the majority of mountain glaciers around the world (Solomina et al., 2016). Since then, the decline of glaciers has been almost continuous, only interrupted by short stabilization periods (Zemp et al., 2015). Several studies identify the 1980s as a "tipping point in global glacier evolution," followed by accelerated glacier shrinkage (Beniston et al., 2018; Huss & Hock, 2018). Very small glaciers (<0.5 km 2) predominate in number in the northern hemisphere mountain ranges at temperate latitudes, since more than 80% of glaciers in these mountains are beneath this area threshold (Huss & Fischer, 2016). Shrinkage of very small glaciers occurred more rapidly by the late 20 th and early 21 st centuries than in earlier decades (Bahr & Radić, 2012; Parkes & Marzeion, 2018). This fast shrinkage is explained by their generally low accumulation area ratio, which is mainly driven by the observed globa
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