Pascal Sirguey
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View article: Performance of global canopy height models across varied New Zealand vegetation types
Performance of global canopy height models across varied New Zealand vegetation types Open
Background: Global canopy height models are becoming prolific yet require evaluation across New Zealand's diverse vegetation types to assess their accuracy and applicability. Accurate measurement of canopy height is crucial for estimating …
View article: An alternative to landslide volume-area scaling relationships: an ensemble approach adopting a difference model to estimate the total volume of landsliding triggered by the 2016 Kaikōura earthquake, New Zealand
An alternative to landslide volume-area scaling relationships: an ensemble approach adopting a difference model to estimate the total volume of landsliding triggered by the 2016 Kaikōura earthquake, New Zealand Open
Evaluating the influence of earthquakes on erosion, landscape evolution, and sediment-related hazards requires quantifying the number, location, and volume of co-seismic landslides following large earthquakes. Direct measurements of indivi…
View article: Spatial dynamics and drivers of recent changes in grass and shrub cover in submontane grassland plant communities
Spatial dynamics and drivers of recent changes in grass and shrub cover in submontane grassland plant communities Open
Shrub encroachment into grassland ecosystems has been increasingly observed and documented worldwide in recent years. A grass–shrub transition can affect the diversity, abundance and functional integrity of grassland plant communities and …
View article: Unprecedented Winter Rainfall Initiates Large Snow Avalanche and Mass Movement Cycle in New Zealand's Southern Alps/Kā Tiritiri o te Moana
Unprecedented Winter Rainfall Initiates Large Snow Avalanche and Mass Movement Cycle in New Zealand's Southern Alps/Kā Tiritiri o te Moana Open
An exceptional July 2022 winter storm brought 550 mm of precipitation to the Southern Alps of New Zealand. A series of alpine mass movements occurred during the storm, including a widespread snow avalanche cycle, debris flows, and erosion …
View article: Accurate quantification of sediment conveyance following the 2016 Kaikōura earthquake, New Zealand
Accurate quantification of sediment conveyance following the 2016 Kaikōura earthquake, New Zealand Open
Evaluating the influence of earthquakes on erosion, landscape evolution and sediment-related hazards requires quantifying the volume and velocity of post-seismic sediment cascades. However, accurate estimates of post-earthquake sediment tr…
View article: Applying a distributed mass-balance model to identify uncertainties in glaciological mass balance on Brewster Glacier, New Zealand
Applying a distributed mass-balance model to identify uncertainties in glaciological mass balance on Brewster Glacier, New Zealand Open
A distributed mass-balance model is used over a 10-year period for the re-analysis of a glaciological mass-balance time series obtained from Brewster Glacier, New Zealand. Mass-balance modelling reveals glaciological mass balance has been …
View article: Reconstruction of Annual Glacier Mass Balance from Remote Sensing-Derived Average Glacier-Wide Albedo
Reconstruction of Annual Glacier Mass Balance from Remote Sensing-Derived Average Glacier-Wide Albedo Open
Annual mass balance is an important reflection of glacier status that is also very sensitive to climate fluctuations. However, there is no effective and universal albedo-based method for the reconstruction of annual mass balance due to the…
View article: The impact of terrain model source and resolution on snow avalanche modeling
The impact of terrain model source and resolution on snow avalanche modeling Open
Natural hazard models need accurate digital elevation models (DEMs) to simulate mass movements on real-world terrain. A variety of platforms (terrestrial, drones, aerial, satellite) and sensor technologies (photogrammetry, lidar, interfero…
View article: Differential effects of topography on the timing of the growing season in mountainous grassland ecosystems
Differential effects of topography on the timing of the growing season in mountainous grassland ecosystems Open
Grasslands in mountainous areas often show distinct responses in the timing of their growing season in relation to topographical variation. However, it is unclear which factors of topography (elevation, aspect, and slope) affect which phas…
View article: Comment on nhess-2022-97
Comment on nhess-2022-97 Open
Natural hazard models need accurate digital elevation models (DEMs) to simulate mass movements on three-dimensional terrain. A variety of platforms (terrestrial, drones, aerial, satellite) and sensor technologies (photogrammetry, LiDAR, in…
View article: Southern Alps equilibrium line altitudes: four decades of observations show coherent glacier–climate responses and a rising snowline trend
Southern Alps equilibrium line altitudes: four decades of observations show coherent glacier–climate responses and a rising snowline trend Open
An end of summer snowline (EOSS) photographic dataset for Aotearoa New Zealand contains over four decades of equilibrium line altitude (ELA) observations for more than 50 index glaciers. This dataset provides an opportunity to create a cli…
View article: The impact of terrain model source and resolution on snow avalanche modelling
The impact of terrain model source and resolution on snow avalanche modelling Open
Natural hazard models need accurate digital elevation models (DEMs) to simulate mass movements on three-dimensional terrain. A variety of platforms (terrestrial, drones, aerial, satellite) and sensor technologies (photogrammetry, LiDAR, in…
View article: Using Vector Agents to Implement an Unsupervised Image Classification Algorithm
Using Vector Agents to Implement an Unsupervised Image Classification Algorithm Open
Unsupervised image classification methods conventionally use the spatial information of pixels to reduce the effect of speckled noise in the classified map. To extract this spatial information, they employ a predefined geometry, i.e., a fi…
View article: Recent trends in the timing of the growing season in New Zealand’s natural and semi-natural grasslands
Recent trends in the timing of the growing season in New Zealand’s natural and semi-natural grasslands Open
We investigate the temporal dynamics of shifts in phenological responses of a range of key stages of the growing season in New Zealand’s three indigenous grassland types over the last 16 years (2001–2016). A near-daily Normalized Differenc…
View article: Topographical effects on the timing of growing season in alpine grasslands
Topographical effects on the timing of growing season in alpine grasslands Open
Context: It is important to understand the responses of alpine vegetation to recent anthropogenic climate change. The mountainous landscapes with high climatic heterogeneity are good locations to investigate the effects of microclimatic va…
View article: Intercomparison of photogrammetric platforms for spatially continuous snow depth mapping
Intercomparison of photogrammetric platforms for spatially continuous snow depth mapping Open
Snow depth has traditionally been estimated based on point measurements collected either manually or at automated weather stations. Point measurements, though, do not represent the high spatial variability in snow depths present in alpine …
View article: Variability in glacier albedo and links to annual mass balance for the gardens of Eden and Allah, Southern Alps, New Zealand
Variability in glacier albedo and links to annual mass balance for the gardens of Eden and Allah, Southern Alps, New Zealand Open
The gardens of Eden and Allah (GoEA) are two of New Zealand's largest ice fields. However, their remote location and protected conservation status have limited access and complicated monitoring and research efforts. To improve our understa…
View article: Intercomparison of photogrammetric platforms for spatially continuous snow depth mapping
Intercomparison of photogrammetric platforms for spatially continuous snow depth mapping Open
Snow depth has traditionally been estimated based on point measurements collected either manually or at automated weather stations. Point measurements, though, do not represent the high spatial variability of snow depths present in alpine …
View article: Variability of glacier albedo and links to annual mass balance for theGardens of Eden and Allah, Southern Alps, New Zealand
Variability of glacier albedo and links to annual mass balance for theGardens of Eden and Allah, Southern Alps, New Zealand Open
The Gardens of Eden and Allah (GoEA) are two of New Zealand's largest icefields. However, their remote location and protected conservation status has limited access and complicated monitoring and research efforts. As a result, the behaviou…
View article: Characterising spatio-temporal variability in seasonal snow cover at a regional scale from MODIS data: the Clutha Catchment, New Zealand
Characterising spatio-temporal variability in seasonal snow cover at a regional scale from MODIS data: the Clutha Catchment, New Zealand Open
A 16-year series of daily snow-covered area (SCA) for 2000–2016 is derived from MODIS imagery to produce a regional-scale snow cover climatology for New Zealand's largest catchment, the Clutha Catchment. Filling a geographic gap in observa…
View article: The Influence of Weather Systems in Controlling Mass Balance in the Southern Alps of New Zealand
The Influence of Weather Systems in Controlling Mass Balance in the Southern Alps of New Zealand Open
The recent advance of some fast‐responding glaciers in New Zealand demonstrates that regional variability in atmospheric circulation can counteract the effects of global warming. Until recently, a key challenge in quantifying how weather s…
View article: Charactersing spatio-temporal variability in seasonal snow cover at a regional scale from MODIS data: The Clutha Catchment, New Zealand
Charactersing spatio-temporal variability in seasonal snow cover at a regional scale from MODIS data: The Clutha Catchment, New Zealand Open
A 16-year series of daily snow covered area (SCA) for 2000–2016 is derived from MODIS imagery to produce a regional scale snow cover climatology for New Zealand's largest catchment, the Clutha Catchment. Filling a geographic gap in observa…
View article: The unprecedented coupled ocean-atmosphere summer heatwave in the New Zealand region 2017/18: drivers, mechanisms and impacts
The unprecedented coupled ocean-atmosphere summer heatwave in the New Zealand region 2017/18: drivers, mechanisms and impacts Open
During austral summer (DJF) 2017/18, the New Zealand region experienced an unprecedented coupled ocean-atmosphere heatwave, covering an area of 4 million km2. Regional average air temperature anomalies over land were +2.2 °C, and sea surfa…
View article: Corrigendum: Inexpensive Aerial Photogrammetry for Studies of Whales and Large Marine Animals
Corrigendum: Inexpensive Aerial Photogrammetry for Studies of Whales and Large Marine Animals Open
Corrigendum: Inexpensive Aerial Photogrammetry for Studies of Whales and Large Marine AnimalsStephen M. Dawson1*, Hamish Bowman2, Eva Leunissen1, Pascal Sirguey3 1Marine Science Department, University of Otago, New Zealand, 2Department of …
View article: An optimized method to calculate the geodetic mass balance of mountain glaciers
An optimized method to calculate the geodetic mass balance of mountain glaciers Open
Understanding the effects of climate on glaciers requires precise estimates of ice volume change over several decades. This is achieved by the geodetic mass balance computed by two means: (1) the digital elevation model (DEM) comparison (S…