Snow and Avalanche Research

Global solar spectrum and total global irradiance

Solar and atmospheric measurement

Solar Induced chlorophyll Fluorescence

The FloX is specifically designed to passively measure chlorophyll fluorescence under natural light conditions. Therefore the design is optimized to achieve maximum efficiency in terms of: Signal to Noise Ratio, Spectral Resolution and quick acquisition time. The core of the system is the spectrometer covering the Red/Near Infrared region (650 – 800 nm). This is the spectral range where chlorophyll fluorescence is emitted and where the two atmospheric oxygen absorption bands (O2B and O2A, at 689 nm and 760 nm respectively) are used to measure it. Upward and downward channels of the FloX allow to measure the solar irradiance and the reflected radiance from the canopy. In order to keep a stable level of dark current the spectrometers are embedded in a temperature controlled housing. The signal-to-noise is maximized thanks to accurate automatic optimization of the signal of both channels and a high performance optical light throughput.

Field Spectroradiometer - Hyperspectral

The RoX is designed for long term measurements of solar radiance, reflected radiance and reflectance. Its robustness and flexibility make the RoX suitable for several application (e.g. vegetation monitoring, water quality, snow and ice properties). The core of the system is the spectrometer covering the Visible/Near Infrared region (300- 950 nm). Upward and downward channels of RoX allow to sequentially measure the solar irradiance and the reflected radiance from the canopy.

NIR reflectance box

The NoX automatic Field spectrometer is a new JB product. It allows measuring from Visible up to the Near Infrared region (1650 nm). Its low power consumption and rugged case makes it suitable for installation in harsh enviroments: from the poles to the equator. From vegetation to snow the NoX is suitable for researches where the NIR range makes the difference. The NIR reflectance box (NoX) is an unique instrument, enabling the continuous observation of Up-welling and Down-welling radiance in the visible near infrared region. It measures spectral data of high resolution (approximately 3 nm), yet is built to withstand the hazards of a permanent outdoor installation.

Aerial Spectroradiometer

The AirRoX is a heavily customized spectroscopy system prototype that consist of a full range spectrometer fully integrated into a quadcopter drone. This project started with the question of taking hyperspectral measurements of hard to access areas in the Antarctic shelf ice to understand albedo of various snow and ice covers. In this scenario, the drone, equipped with the spectrometer flies above the ice and collects measurements over previously defined waypoints. Along with the spectrometer a camera is triggered to accurately determine the surface that was surveyed. The payload triggering is fully integrated with the drones flight controller including a stabilizing gimbal mount. As the payload, including camera, spectrometer and gimbal weighs less than 700 g, the medium sized drone achieved a take off weight of 4900 g offering flight times beyond 30 minutes. A stationary RoX spectroscopy system is used to gather irradiance measurement parallel to the airborne spectra of reflected radiance.

UAV-BASED SUN-INDUCED CHLOROPHYLL FLUORESCENCE

AIRFLOX is a non-imaging spectrometer package consisting of two independent optical systems Dual channel module for the fluorescence range (650 nm – 800 nm) and Dual channel module for the VIS-NIR range (400 nm – 1000 nm) operating independently and in parallel. Our AIRFLOX payload will be approximately 4 Kg and can be easily mounted to drones capable to lift 6 Kg. Fiber optics needs to be attached to the UAV platform using a gimbal.

Liquid Water Content of snow

Measuring LWC over a perfectly controlled snow sample volume. Based on capacitance technology and a concentric electrode design, this device offers reliable LWC measurements over a perfectly controlled snow sample volume. A reliable method based on the dielectric permittivity of snow in the MHz range. This technology is developed in collaboration with Météo-France, relies on the relation between the liquid water content, the density and the permittivity of snow in the MHz range. The technique was validated against the well-established calorimetry method.

Specific surface area (SSA) of snow

Based on optical and laser technologies, it provides instantaneous measurements of snow SSA in the field. The instrument is perfectly adapted to alpine and polar conditions, withstanding temperatures as low as -40 °C (-40 °F). The IceCube can work for any kind of snow, from melt-freeze crusts to fresh snow. The working principle relies on the relation between the infrared reflectance and the specific surface area of snow. The device illuminates a snow sample, collects the reflected light and infers the reflectance of the snow. This reflectance is then converted into SSA using a radiative transfer model and calibration using the well-established methane adsorption method. Thanks to its sample-based technique, the instrument guarantees that no stray light can affect the measurement and the instrument therefore provides accurate results in no time.

Snow Depth Measurement Station

Monitor snowfall in real time with little installation effort. Application cases: Real time snowfall notification - Snow water equivalent estimation for hydroelectricity - Avalanche forecast. The collected information provides a better knowledge of the spatial and temporal variability of snow. Temperature: • Range: -40/+65 °C • Accuracy: ± 0.8 °C • Resolution: 0.1 °C Snow depth: • Range: 50 cm to 5 m • Accuracy: ± 10 mm • Resolution: 1 mm Temperature-compensated acoustic snow gauge

Portable and autonomous station for tracking the glacier mass loss

The SmartStake station allows you to monitor ice ablation on a glacier with high accuracy over long periods of time. Designed as a convenient and efficient replacement for the classical stakes, the instrument allows a much more detailed analysis of the ablation phenomenon, thanks to a very high monitoring rate and an enhanced accuracy. The SmartStake station is supported by the WGMS and the Kilian Jornet Foundation as part of their joint work to monitor glaciers and show their importance for our planet.