Jean-Pierre Dedieu's research while affiliated with Centre D'Études Nordiques and other places

Publications (28)

Article
Full-text available
Changes in snowpack associated with climatic warming has drastic impacts on surface energy balance in the cryosphere. Yet, traditional monitoring techniques, such as punctual measurements in the field, do not cover the full snowpack spatial and temporal variability, which hampers efforts to upscale measurements to the global scale. This variability...
Article
Full-text available
Arctic vegetation cover has been increasing over the last 40 years, which has been attributed mostly to increases in temperature. Yet, the temporal dimension of this greening remains overlooked as it is often viewed as a monotonic trend. Here, using 11-year long rolling windows on 30 m resolution Landsat data, we examined the temporal variations in...
Article
Full-text available
In the Central Himalayas, glaciers and snowmelt play an important hydrological role, as they ensure the availability of surface water outside the monsoon period. To compensate for the lack of field measurements in glaciology and hydrology, high temporal and spatial resolution optical remotely sensed data are necessary. The French–Israeli VENµS Eart...
Preprint
Full-text available
Changes in snowpack associated with climatic warming has drastic impacts on surface energy balance in the cryosphere. Yet, traditional monitoring techniques, such as punctual measurements in the field, do not cover the full snowpack spatial and temporal variability, which hampers efforts to upscale measurements to the global scale. This variability...
Article
Full-text available
Optical sensors are increasingly sought to estimate the amount of chlorophyll a (chl_a) in freshwater bodies. Most, whether empirical or semi-empirical, are data-oriented. Two main limitations are often encountered in the development of such models. The availability of data needed for model calibration, validation, and testing and the locality of t...
Article
Full-text available
In the central part of the Hindu Kush Himalayan region, snowmelt is one of the main inputs that ensures the availability of surface water outside the monsoon period. A common approach for snowpack modeling is based on the degree day factor (DDF) method to represent the snowmelt rate. However, the important seasonal variability of the snow processes...
Presentation
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Background Scientific context • Rapidly increasing temperatures in the Arctic and decreasing snow cover duration have led to longer growing seasons affecting vegetation dynamics (treeline, shrubs advancing, ...). • Arctic greening trends are well documented (Fraser et al., 2011; Tremblay et al., 2012) and this knowledge is essential for understandi...
Conference Paper
Full-text available
Arctic snow cover dynamics exhibit strong changes in terms of extent and duration due to recent climate changeconditions (Mudryk et al., 2018; Lemke & Jacobi, 2011). In this context, innovative observation methods arehelpful for a better comprehension of the role of the snow for climate research and hydrology. The spatialvariability of snow propert...
Article
There is increasing interest in community-based environmental monitoring (CBEM) in Canada’s North in response to the rising impacts of resource exploitation and climate change, and with increased recognition of indigenous knowledge. IMALIRIJIIT, meaning those who study water in Inuktitut, is a CBEM program involving science land camps, capacity-bui...
Article
Full-text available
The characterization of snow extent is critical for a wide range of applications. Since 1966, snow maps at different spatial resolutions have been produced using various satellite sensor images. Nowadays, the most widely used products are likely those derived from Moderate-Resolution Imaging Spectroradiometer (MODIS) data, which cover the whole Ear...
Conference Paper
Full-text available
Arctic snow cover dynamics offer a changing face in terms of temporal duration and water equivalent, due to recent climate change conditions (Callaghan et al., 2011; Lemke & Jacobi, 2012). Indeed, the Arctic is now experiencing some of the most rapid and severe climate change on earth. In this context, innovative and improved methods are helpful to...
Article
Full-text available
Cet article présente une vue d’ensemble des avancées récentes en télédétection spatiale appliquée à l’étude des surfaces enneigées et englacées auxquelles la communauté scientifique française a participé. Qu’ils s’agissent de données satellitaires optique, radar, lidar ou gravimétrique, ces travaux sur la couverture nivale saisonnière ou pérenne, l...
Chapter
Aside from its impact on human activity in various regions around the world, snow also plays an important role in a range of environmental processes. In climatology, snow cover has the effect of lowering temperatures due to its high albedo which reflects between 40 and 95% of incident solar radiation and it can therefore be used as a barometer for...
Article
Full-text available
By looking for heroicness in biographical dictionaries we can place the hero, not as in isolated figure but as part of a larger pantheon that includes all the memorable figures who played a part in building the nation. Only by placing the heroic figure against this backdrop can we comprehend the factors that made them soar above other historical, s...
Article
The documentation generated by the offices of the Spanish Royal Exchequer under the Ancien Regime only tells part of the truth about the finances of the Monarchy. Firstly, the king possessed many more resources which are not accounted for in these sources or not expressed in the form of computable numbers in terms of revenue. Nor does it reflect th...
Article
By looking for heroicness in biographical dictionaries we can place the hero, not as in isolated figure but as part of a larger pantheon that includes all the memorable figures who played a part in building the nation. Only by placing the heroic figure against this backdrop can we comprehend the factors that made them soar above other historical, s...

Citations

... Contrary to the many aircraft models used, only three types of multispectral sensors were deployed in these studies: Parrot Sequoia (six times), MicaSense (CA, USA) RedEdge (three times), and Tetracam MCA-6 (Chatsworth, CA, USA) (one time). Additionally, the selection of hyperspectral sensors followed no trends across the four parameters and included a GER 1500 model by the Geophysical and Environmental Research corporation (Milbrook NY, USA) [104] OceanOptics (now OceanInsite) (Florida, USA) [43,110], ASIA (Marina Bay, Singapore) [121], Headwall (Bolton, MA, USA) [122], Resonon (Bozeman, MT, USA) [123], HyMap (Sydney, Australia) [124], and MicroHIS (Rijswijk, The Netherlands) [125]. Lastly, it was common for a few studies to modify RGB sensors to record Blue, Green, and NIR bands [44,111,112]. ...
... This is especially true in the field of snow monitoring [11]. For example, in the Everest region, MODIS (Moderate-Resolution Imaging Spectroradiometer) imagery has been used to help constrain the contributions of snow and ice to streamflow [12][13][14] and to track seasonal migration of the snow line [15]. A new technical step was reached in terms of spatio-temporal resolution with the Copernicus Sentinel platforms from ESA (European Space Agency), and the recent VENµS (Vegetation and Environment New Micro Satellite) program. ...
... A relationship was found between CPD and snowfall by Chang et al. (1996) and Leinss et al. (2014) which induces a propagation delay among horizontal and vertical phases due to horizontal alignments of fresh snow crystals. Recent studies focused on the boreal region (Leinss et al., 2014(Leinss et al., , 2016 or were applied in arctic regions with no or sparse vegetation (Dedieu et al., 2018), so the application of the CPD method in the arctic remains poorly documented. It could be hypothesized that the CPD can describe the entire snowpack in such cold and dry environments. ...
... Our finding that very few studies defined their usage of terms, with an absence of definitions for 71% of terms (10/14 terms), elucidates a major gap that is further confused by varied term use. The definitions of community-based differed, with emphasis on response to issues of common community concern (Gérin-Lajoie et al. 2018;Dawson et al. 2020) and a "robust" level of community involvement leading to knowledge co-production (Carter et al. 2019) ( Table 5). The term co-production and variations (co-produc*) also used alternate definitions, which referred to knowledge co-production as a process (Idrobo and Berkes 2012) and an outcome (Galappaththi et al. 2019). ...
... The OHMi Nunavik team is multidisciplinary. For example, the community-based water quality survey (Gérin-Lajoie et al. 2018) brings together ecologists, chemists, geographers, and remote sensing specialists. The academics also work in collaboration with an Environment Canada Laboratory, which conducts field sampling and analysis of water samples, as well as with the Nunavik Research Centre, which analyzes contaminants in fish specimens. ...
... All the processing was carried out using the Google Earth Engine (GEE) platform 58 . MODIS SCA products were extensively validated in different mountain areas in the last two decades, indicating an average accuracy of around 94.2% [59][60][61] . In mountain areas, the accuracies strongly depend on the illumination conditions and cloudiness. ...
... The seasonal snowmelt in the Himalayas is a primary source of fresh water to approximately one-sixth of the world's population (Mithen & Black 2011). The available water from snowmelt gets added to the discharge of the mountainous rivers Bernier et al. 2017), contributing to hydropower generation and rivercanal irrigation systems. In the mountainous regions, critical geohazards like avalanches and flash floods depend on the terrain conditions and the snow geophysical properties like the snow wetness/liquid water content and snow particle size (Schweizer et al. 2003;Weingartner et al. 2003;Wever et al. 2018). ...
... Le couvert nival est influencé par deux types de régimes de métamorphisme, soit celui de la neige mouillée (température au point de fusion), ou encore celui de la neige sèche (température < 0 °C ; Bernier et al., 2016 ;Madore, 2016;Colbeck, 1982). Ces régimes se mettent en place en fonction du gradient de température dans le couvert neigeux ainsi qu'en fonction de son contenu en eau liquide (Madore, 2016). ...