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Concept

Albédo géométrique

Publications associées (12)

Influence of sun cups on surface albedo of wet Alpine snowpack

Michael Lehning, Loïc Marcel Louis Brouet

In high elevation Alpine areas, characterised by high snow accumulation and radiation-driven melt processes, the formation of peculiar ablation features called sun cups can be observed. Sun cups likely influence the energy and mass balance of the wet snowp ...

2024

Shape Models of Lucy Targets (3548) Eurybates and (21900) Orus from Disk-integrated Photometry

Stephan Hellmich

We use our new light curves, along with historical data, to determine the rotation state, photometric properties, and convex shape models of the targets of the Lucy mission (3548) Eurybates and (21900) Orus. We determine a retrograde spin for both targets, ...

IOP Publishing Ltd2023

Improved Near-Surface Continental Climate in IPSL-CM6A-LR by Combined Evolutions of Atmospheric and Land Surface Physics

Etienne Gabriel Henri Vignon

This work is motivated by the identification of the land-atmosphere interactions as one of the key sources of uncertainty in climate change simulations. It documents new developments in related processes, namely, boundary layer/convection/clouds parameteri ...

2020

A new method to determine multi-angular reflectance factor from lightweight multispectral cameras with sky sensor in a target-less workflow applicable to UAV

Christoph Strecha, Manuel Simon Paul Cubero-Castan

A new physically based method to estimate hemispheric-directional reflectance factor (HDRF) from lightweight multispectral cameras that have a downwelling irradiance sensor is presented. It combines radiometry wilh photogrammetric computer vision to derive ...

ELSEVIER SCIENCE INC2019

A solar-based sustainable urban design: The effects of city-scale street-canyon geometry on solar access in Geneva, Switzerland

Jean-Louis Scartezzini, Jérôme Henri Kämpf, Nahid Mohajeri Pour Rayeni, Dan Assouline

Buildings commonly have the largest share in the energy demand of a country, but they also offer sites for the generation of solar energy. Here we develop a methodology to analyse the effects of street-canyon geometries on the solar access of street surfac ...

2019

Modeling the performance of cool pavements and the effect of their aging on outdoor surface and air temperatures

Flourentzos Flourentzou

Aiming at the improvement of a dense urban area's microclimatic conditions, this study examines by simulation means, the application of highly reflective materials as a mitigation strategy. However, as significant albedo changes may occur due to weathering ...

ELSEVIER SCIENCE BV2018

Carbon storage versus albedo change: radiative forcing of forest expansion in temperate mountainous regions of Switzerland

Michael Lehning, Marc Schneebeli Zeugin

In this study, we assess the climate mitigation potential from afforestation in a mountainous snow-rich region (Switzerland) with strongly varying environmental conditions. Using radiative forcing calculations, we quantify both the carbon sequestration pot ...

European Geosciences Union2015

Temporally Coherent Completion of Dynamic Shapes

Mark Pauly, Hao Li

We present a novel shape completion technique for creating temporally coherent watertight surfaces from real-time captured dynamic performances. Because of occlusions and low surface albedo, scanned mesh sequences typically exhibit large holes that persist ...

Association for Computing Machinery (ACM)2012

Relationship between high daily erythemal UV doses, total ozone, surface albedo and cloudiness: An analysis of 30 years of data from Switzerland and Austria

This work investigates the occurrence frequency of days with high erythemal UV doses at three stations in Switzerland and Austria (Davos, Hoher Sonnblick and Vienna) for the time period 1974-2003. While several earlier studies have reported on increases in ...

Elsevier2010

Albedo effect on radiative errors in air temperature measurements

Michael Lehning, Marc Parlange, Wolf Hendrik Huwald, Chad Higgins, Marc-Olivier Boldi

Most standard air temperature measurements are subject to significant errors mainly due to sensor heating by solar radiation, even when the measurement principle is accurate and precise. We present various air temperature measurements together with other m ...

American Geophysical Union2009

Specularities as an information source in the presence of texture

The appearance of real world objects is the result of the combination of their own texture and the light rays striking them before reaching our eyes, or our camera. This appearance therefore brings very rich information about the objects shapes, materials, ...

EPFL2009

Retrieving multiple light sources in the presence of specular reflections and texture

Pascal Fua

Recovering multiple point light sources from a sparse set of photographs in which objects of unknown texture can move is challenging. This is because both diffuse and specular reflections appear to slide across surfaces, which is a well known physical fact ...

Elsevier2008