Hauteurs de neige et équivalent-eau du manteau neigeux d'un glacier artique : du terrain à l'interpolation, confrontation de méthodes (exemple du Loven Est, Spitsberg 79°N

National audience

Modélisation multiscalaire de phénomènes spatiaux : optimisation d'échelles d'analyse et typologies emboîtées dans le contexte d'un risque épidémiologique

ACTN; National audience; Echinococcus multilocularis est un parasite responsable chez l'homme d'une maladie grave : l'échinococcose alvéolaire. Les œufs du parasi te, agent pathogène, sont présents dans les fèces de renard et peuvent survivre plusieur s mois dans l'environnement. La dispersion du parasite est fonction des besoins et de l'u tilisation de l'espace des campagnols, hôtes intermédiaires, et des renards, hôtes définiti fs. La manière dont ces derniers appréhendent leurs domaines vitaux est liée au paysage et aux di sponibilités en habitat et en nourriture qu'il recèle. Le risque épidém iologique lié à la maladie a conduit, en France et en Europe, à la mise en place de programmes …

Recent climate change observed in Svalbard since fourty years in Ny Alesund (79°N)

International audience

Probabilité d'apparition d'un phénomène parasitaire et choix de modèles de régression logistique

Epidemiological processes are now using spatial statistics and modelling tools. The main objective of most health risks studies consists in identifying potential contamination sources and factors capable of explaining their localization. Health data often prove binary (typically presence/absence) and specific methods such as binary logistic regression have to be used. This method's output consists in a probability for the pathogen of interest. A posterior classification of each sample is then conducted using a probability threshold. The method used to maximize this threshold is called the ROC curve which consists in giving a representation of the behaviour of the model and then to choose th…

The spatio-temporal dynamic of agricultural areas, from Antiquity to modern period (ArchaeDyn Project)

International audience

Les nuées dynamiques floues appliquées au développement dune typologie paysagère

International audience; Un programme d'épidémiosurveillance actuellement en cours vise à évaluer la présence du parasite Echinococcus multilocularis en France. Contrairement aux hypothèses écologiques initiales, le parasite et ses hôtes ne semblent pas privilégier certains modes d'occupation du sol plus que d'autres. L'objectif de ce travail consiste à identifier dans un premier temps les contextes paysagers au sein desquels la présence parasitaire est confirmée puis, dans un second temps, à mettre en évidence un gradient dans les prévalences spécifiques à chacun de ces contextes. Les nuées dynamiques floues ont permis d'optimiser et de critiquer la typologie paysagère établie. La hiérarchi…

Modéliser et représenter la vulnérabilité paysagère dans un contexte épidémiologique : les hôtes intermédiaires d'Echinococcus multilocularis

A multivariate approach of the factors impacting a small arctic glacier, Austre Lovén-Spitsberg

International audience; Arctic glaciers are good indicators of the ongoing climate change as their dynamics are strongly linked to it. This study is focused on the Austre Lovén glacier, on the Brøgger peninsula in Spitsbergen (Svalbard, 79°N). The aim is to understand how contrasted climate and snow conditions over the course of a year can lead to multiple consequences, sometimes unexpected, on mass balance. In 2014, a negative budget was expected, but data analysis has shown the first positive mass balance in 7 years. The objective here is to (i) identify and qualify the combination of factors affecting an arctic glacier mass balance. Three primary indicators seem to display the greatest i…

PRISM - Permafrost, Rock, Ice and Snow monitoring in the Austre Lovén glacier basin (Spitsberg)

International audience

Arctic Glacier hydrosystems as natural sensors for recent Climatic variations (Loven East Glacier, Svalbard, 79° N", hydro-loven-Flows)

Evolution of prodeltas : a print of glacier melting processes

International audience; Coastal evolution in meters from 1966 to 2016 Prodeltas evolution in meters from 1966 to 2012 from side scan mosaics the Shoreline evolution measured by calculation between reference points Ice evolution than processes control coastal high-latitudes and how they will Coastal evolution in meters from 1966 to 2016 Question 1 : What are the effects of the glacier retreat on the hydrographic network ? First results show a decrease of the drainage density and the width of the active band which conducts to a clear concentration of the hydrographic ntework. Question 2 : What is the Kongsfjorden line evolution ? Coastal areas supplied by the hydrographic network become small…

Monitoring snow cover dynamics on an arctic hydrosystem using field measurements, remote and in situ sensing (Austre Lovenbreen, Spitsberg, 79°N)

International audience

Data issues in a moving environment: remote and in situ tools to monitor glacier dynamics and their hydrological consequences in the Austre Lovènbreen basin

COM; International audience; The precise quantification of glacier movements over time is one of the goals of glaciology. Understanding how and where ice is appearing, melting, and what happens once it’s gone are at the core of the Hydro - Se nsor - FlOWS program (IPY #16, IPEV 304, ANR 0310) that just ended and will be one of the aspects of the new Cryo - Sensors program. Obtaining a precise digital elevation model (DEM) of a glacier surface is not straightforward. When using old datasets, caution should be applied to the interpretation made of the results as the variability tends to increase. Recent monitoring techniques (DGPS, airborne Lidar) do provide a higher level of accuracy but s…

Monitoring the snow cover on the slopes of a polar glacier basin using terrestrial laser scanning

COM; International audience

Echinococcus multilocularis in urban and rural foxes of the Czech Republic

International audience

Understanding links between snow cover and mass balance using a dense monitoring network in a small Arctic glacier basin (Austre Lovénbreen, Svalbard 79°N)

COM; International audience; Glacier ice is the result of successive transformations of snow. All glaciers are therefore strongly linked with seasonal snowfalls. The frequency of snowfalls, the quantities involved, and the quality of snow all have an influence on the dynamics of glaciers. Snow cover is the prime source of new ice, but it also has a protective role in ablation areas of glaciers. From an hydrological point of view, snow also constitutes an important part of the outflows of glacier basins. A monitoring protocol based on a network of stakes and complemented with regular snow drilling campaigns has been carried out for 5 years on the Austre Lovénbreen (Spistbergen, 79 N). Overal…

A terrestrial laser scanning survey to derive snow volume and water equivalent on the slopes of Austre Lovén glacier basin (Svalbard - 79°N)

COM; International audience; Steep slopes represent 35% of Austre Lovén glacier basin, a small valley glacier in Svalbard (79°N). Slopes and their dynamics do have an important impact on polar glaciers. They also are of high hydrological importance in the water budget of basins. One major issue in studying slopes is the fact that they are hard to instrument and both equipment and staff have to deal with the steepness of the field and the exposure to avalanches and rock fall. In order to minimize this exposure without giving up the required spatial and temporal precision, terrestrial laser scanning (TLS) is used. A monitoring program is now starting using TLS. TLS allows for remote high qual…

Évaluation de l'influence des facteurs climatiques sur le bilan de masse du glacier Austre Loven (Spitsberg, 79°N) par une approche multivariée

Arctic is a region where a quick warming is ongoing. Effects are particularly visible on glaciers of which dynamics is very sensitive to climate change. The goal of this study is to identify and rank the main climatological and nivological factors influencing the mass balance of a small arctic glacier in Svalbard using a statistical approach. To highlight spatial differences, cartography were then used. Results show that positive degree-days play an important role in explaining mass balance contrary to liquid precipitations that had a marginal effect over the studied period (2007-2014). Moreover, years with very different climatic conditions can lead to a similar mass balance.

Confidence maps: a tool to evaluate archaeological data's relevance in spatial analysis

L'article est disponible en ligne sur Virtual Library Propylaeum : http://archiv.ub.uni-heidelberg.de/propylaeumdok/volltexte/2010/551/pdf/08_05_ostir_et_al_confidence.pdf; International audience

Snowcover Survey on an Alpine Type Glacier in High Latitude (Austre Lovénbreen, Svalbard, 79°N)

International audience

Le choix de descripteurs paysagers en tant qu'indicateurs d'un risque épidémiologique

National audience; Echinococcus multilocularis (Em) est un parasite responsable chez l'homme d'une maladie grave : l'échinococcose alvéolaire. La contamination humaine peut se produire par ingestion accidentelle d'œufs du parasite. Un programme européen d'épidémiosurveillance, EchinoRisk, est actuellement en cours. En France, ce programme, mené conjointement par l'ERZ (Entente interdépartementale de lutte contre la rage et autres zoonoses) et l'AFSSA (Agence française de sécurité sanitaire des aliments), a permis jusqu'à présent de collecter 5 820 échantillons localisés de fèces de renards. À ce jour, 2 305 échantillons ont été analysés parmi lesquels 62 ont révélé la présence du parasite. …

Spatial variability of snow cover in the slopes of a small arctic glacier catchment using Lidar data

International audience; In the Arctic, because glaciers are subject to dramatic changes due to climate shift, a major concern is to estimate the contribution of glacier basins outflows to sea level rise. Snow on the Austre Lovénbreen (a small alpine type glacier in Spitsbergen – 4,6km 2) has been well studied since 2007 thanks to a good measurement network and numerous field campaigns. It has been possible to estimate the runoff coming from the glacier itself. However, the glacier covers only 43% of the Austre Lovén catchment. Of the remaining 57%, 23% are constituted by the moraine area, and 34 % are the surrounding slopes, which are also important snow storages. This paper focusing on slo…

Géographie de la santé et épidémiologie spatiale

International audience

Investigating snowcover volumes and icings dynamics in the moraine of an Arctic catchment using UAV/ photogrammetry and LiDAR

International audience; Means for assessing the contribution of the terminal moraine into the water budget of an Arctic glacier is investigated: on the one hand the terminal moraine represents a significant fraction (22%)of the catchment area of the glacier under investigation – Austre Lovenbreen, in the Brøgger peninsula, Spitsbergen – and on the other hand icings formation (or aufeis) each winter illustrates the contribution of subglacial water flow. While over the glacier, with a smooth surface readily interpolated, the winter and summer mass balances are assessed with only a few sparsely distributed stakes, such an approach is not valid with the rough topography of the glacier moraine: …

Five consecutive years of mass balance observations to understand glacier reaction to present climate change (Austre Lovénbreen, Svalbard 79°N)

COM; International audience; Since 2008, mass balance is measured on the Austre Lovénbreen (Spitsbergen, Norway, 79 N) as part of the Hydro-Sensor-FlOWS program. The observations are made at a very fine scale: on the 4.5 km 2 glacier, mass balance is measured each September with 36 stakes. Snow cover is measured at the end of April. 20 air-temperature loggers give hourly data on the thermal state of the glacier. In addition automatic cameras provide 3 pictures per day. These pictures are used to determine whether ice is visible or snow covered all over the glacier. Climate parameters provided by the nearby Ny-Alesund weather station are also used. The influence of climatic parameters on mas…

Area, volume and freshwater flux inferred from the change in geometry of a high Arctic glacier since the 1960s (Austre Lovénbreen, Svalbard)

International audience

High time and space resolution analysis of Austre Lovén glacier seasonal and interannual dynamics (Svalbard - 79°N)

COM; International audience; Austre Lovén glacier is a small valley glacier in Svalbard. It has been retreating since the little ice age. Over the last five years, an extensive monitoring program has been conducted in this glacier basin. A network of 36 ablation stakes has been distributed at regular intervals over the 4.5 km² glacier surface. Mass balance measurements were complemented with regular snow drilling campaigns aiming at understanding the links between microclimatic parameters and glacier evolution. In addition, 20 automatic temperature loggers have been recording hourly data. 6 cameras provided 3 pictures a day covering most of the glacier surface and giving an accurate account…

Witnessing and measuring the impacts of cryosphere changes in the High Arctic

International audience

Echinococcus multilocularis in France: First results

International audience

Measurements of the intensity of the agrarian exploitation by spatial analysis of the ancient field system well-preserved by the forest cover

International audience