Permafrost Rock Ice and Snow Monitoring of slopes using terrestrial laser scanning in the Austre Loven glacier basin (Svalbard). – PRISM

Three main goals were achieved in this project, requiring 8 field trips with the logistic support of the French polar Institute (Institut Paul-Emile Victor – IPEV). International cooperations with Austrian and Chinese researchers contributed to strengthen the works of the PRISM team.
The first goal was to measure precisely the snow cover on slopes, on the glacier, and on periglacial spaces. Repeat measurements allowed to quantify precisely snow dynamics and to understand its influence on the hydrological and glaciological balance of the glacier basin.
The second goal revealed the geomorphological evolution of the glacier basin. The high spatial resolution of laser data revealed rock movements and showed the amplitude of ongoing evolutions caused by glacier retreat and climatic evolutions.
Eventually the third goal was to target ice evolutions. It showed clearly the ongoing glacier retreat and its consequences.

Laser measurements proved very appropriate to reveal all major phenomena the arctic cryosphere is subject to. The wealth of data produced allowed the team to go much further than the initial objectives. The evaluation of the snow cover in the most remote and inaccessible areas is one of the highlights of this project. Morphological evolutions of the glacier basin were also revealed at a very high resolution. Lastly, glacier retreat, in addition to classic ablation stakes measurements, was made visible at spatial and time resolution rarely achieved in this region.

These results were presented to the international research community on the occasion of international conferences. In the field, direct collaborations emerged with Austrian and Chinese colleagues. The PRISM team gained international visibility and is now identified as the French partner in research groups on arctic glaciology, especially in Svalbard. It also has to be noted that the Austre Lovén glacier basin is now an observatory recognized by national and international (WGMS) institutions.

The main goals of the PRISM project were to highlight cryosphere processes. The data acquisition protocol established proved successful. Terrestrial laser is an appropriate tool to obtain high resolution digital elevation models. From a practical point of view, the most recent Lidar equipments now function with batteries which makes fieldwork much easier. Constraints such as glacier travel and a harsh climate led the team to adapt its working conditions. The time allowed in the field was definitely a plus in the success of the missions undertaken in Svalbard.
The latest equipment is now lighter allowing for the transportation of it to high points in the glacier basin which are more favorable to laser scanning. This was tested during the last fieldwork missions of the PRISM project.
New scientific collaborations have been undertaken with Austrian and Chinese colleagues. The French Polar Instiute IPEV is still supporting our team and this is a sign of the recognition of our work.
The PRISM project contributed to reinforcing the status of long-term observatory for the Austre Lovén glacier. This status is recognized at the national (IR OZCAR) and international (World Glacier Monitoring Service) levels.

The PRISM project led to the publication of scientific papers. One PhD thesis is ongoing working on laser data acquired in the framework of the project. Our works have been presented in various international conferences. The results we obtained also serve as teaching material for our students in geography and engineering. Different public science events were also the occasion to put our works in the light. In the field we also had the occasion to present our project to the French Minister of Environment in august 2016.

In a global change perspective, high latitude regions happen to be an important observatory where current dynamics are
observed. Studying slopes in polar environments is the main focus of the PRISM project. This project specifically aims at
understanding, monitoring, and modeling the spatial dimension of slope dynamics in glacier basins. These dynamics do
have a key role in the physical and hydrological behavior of polar glaciers. Slopes are impacted by permafrost melting,
snow cover and glacier constraints. The combination of this factors leads to processes that are far from well documented.
Acquiring data in slopes is not a straightforward task. To quantify precisely the processes occurring in slopes requires data
both spatially and temporally precise enough. Difficulties associated with slopes access do forbid in most case direct field
monitoring of slopes. Remote sensing, for obvious steepness of slopes reasons is not adapted either. Only Terrestrial Laser Scanner (TLS) techniques do seem to allow for fine grain observations at adapted time steps. The study field of the
PRISM project is the Austre Lovenbreen glacier basin located in Svalbard (79°N). This glacier has been studied by French
and foreign scientists since the 60’s. The amount of data hence already available will be used to criticize and validate the
results of this project and will provide valuable contextual elements. These will be helpful to model the evolution of slopes
over time and to extrapolate results to the whole glacier basin. The project is organized in three different tasks. Snow
dynamics will be evaluated by measuring the volume of snow laying on slopes. A high resolution spatial model of slopes at
both the yearly maximum and minimum of the snow cover will help us derive the corresponding volumes. In the meantime,
other data acquisition phases will focus on the short term evolutions of the snow cover therefore highlighting processes
such as snow avalanches and melting. Whenever possible, these measures will be associated with manual measures of
snow height and water equivalent and with automatic temperature loggers data. Rock and permafrost dynamics will also
be monitored using TLS. This tool provides sufficient detail to assess rockfalls, rockslides, and slope movements. These
events are related to the microclimatic context. Permafrost suffers from surface temperatures and rain precipitations
effects. Rock dynamics are also linked to physical characteristics of slopes (steepness, orientation, nature of the rocks).
The spatial approach of rock dynamics developed here will be coupled with temperature measures in the slopes. All rockrelated
parameters do play a role in glacier issues as the glacier is receiving and transporting most of the rock material
coming from the slopes. The last task of the project is focusing on glacier-slope interface and ice dynamics. Snow
accumulations (névés) at the bottom of slopes will be located and quantified. A distinction between new slope-related ice
and old glacier ice will be established. The annual variations of the slopes’ base will be monitored using a fine modeling of
this contact area. TLS data will grant us the possibility to follow precisely these dynamics. These processes will be
observed in different strategic places in the glacier basin such as accumulation and ablation zones, steep or low-angle
slopes, corresponding to different interface configurations.