From mid-March until mid-April an international team of experts from Japan, France, Switzerland, Italy, and Finland gathered at the FMI Arctic Space Centre in Sodankylä, Finnish Lapland, to participate to the SnowAPP campaign. The team included professor Teruo Aoki from the Arctic Environment Research Center of the Japanese National Institute of Polar Research; senior scientist Masashi Niwano from the Meteorological Research Institute of the Japanese Meteorological Agency; professor Ghislain Picard and Master student Ines Ollivier from the Institut des Géosciences de l’Environnement (IGE) of the University of Grenoble, France; PhD student Amy Mcfarlane from the WSL Institute for Snow and Avalanche Research (SLF), Switzerland; Research fellow Marco Pasian and PhD student Pedro Fidel Espin Lopez from the Microwave Laboratory at the University of Pavia, Italy; Professor Ziti Jiao and PhD student Jing Guo from Beijing Normal University, China, Research manager Jouni Peltoniemi from the Finnish Geospatial Research Institute, as well as several colleagues from the Finnish Meteorological Institute from Helsinki and Sodankylä.

Sodankylä is located in Finnish Lapland. (67.37 °N, 26.63 °E)

The goal of the campaign was to measure in detail the snow properties and the elecromagnetic signals reflected and emitted by the snow from visible/infrared wavelengths down to microwave wavelengths. Ground-based, continuously-measuring spectro-albedometers, microwave radiometers, and radars were deployed on a flat, open, snow-covered wetland area, where simultaneous manual measurements of snow micro- and macro-properties are performed.

Why are these snow measurements important? Because global warming is changing the snow budget on the Earth, with large impacts on ecosystems, changing fresh water availability, and on all human activities carried out in regions that are seasonally snow covered. Monitoring snow is more and more crucial for freshwater management, mitigation of climate changes, adaptation to new climate conditions, and risk assessments (such as avalanches, floods, and land instability consequent to the thaw of permafrost).

In-situ snow observations are sparse; vast snow-covered areas are hardly accessible, and therefore snow monitoring mostly relies on satellite snow observations. However, these have large errors and spatial-temporal gaps, also related to the operational limitations of the single satellite sensors. The unique set of observations collected during the campaign will be used to develop a new model of the interaction of electromagnetic radiation with the snow, which will be then enable an improved retrieval of snow properties from the combination of optical and microwave satellite observations. Furthermore, the model will be used to improve the simulation of snow surface albedo in numerical weather prediction and climate models, which will lead to an improved simulation of weather and climate.

The campaign was funded by the Academy of Finland project SnowAPP (“Modelling of the Snow microphysical-radiative interaction and its APPlications”) and by INTAROS. Senior scientist Roberta Pirazzini is the principal investigator of the SnowAPP field campaign and of the FMI contribution to the INTAROS project, while senior scientist Petri Räisänen is the principal investigator of the SnowAPP project.