The Origin of Snow

April 10, 2022

The 2022 snow sampling campaign has come to an end. Many thanks to our citizen scientists for participating in the ISLAS project! We have now returned the samples to our research partner at the University of Bergen. 

What is the ISLAS project? 

ISLAS stands for ISotopic Links to Atmospheric water’s Sources. This project was initiated in 2019 by Professor Harald Sodemann, a meteorologist from the University of Bergen, Norway. The project’s objective is to better understand how water fluxes move across the atmosphere, where water evaporates, how long it remains in the atmosphere and where it precipitates. Ultimately, this study will help improve the weather forecast models, and the prediction of future climate. 

A combination of measurements 

During Easter, citizen scientists have sampled snow for the project in Northern Norway, Sweden and Finland. In parallel, many professional scientists have participated in the project too. From Kiruna (Sweden), Andenes (Norway) and Ny Ålesund (Svalbard, Norway), weather balloons were launched from several locations while ground stations ran high-resolution paired measurements of water vapor and precipitation. Additionally, isotope measurements were done at low altitude over the sea ice during an intense aircraft campaign. 

Climate change influences the water cycle and the origin of snow

The global atmosphere can be considered as a stable reservoir for water vapor. New water vapor continuously enters the atmosphere through changes originating from the ocean and land surface, and is removed by precipitation (i.e., snow and rain). In the long term, this  stable system is in mass balance. The virtual reservoir reflects the timescale of how long water vapor stays in the atmosphere. However, with climate change, the Earth’s atmosphere is getting warmer and the duration of water vapor changes. This residence time changes depending on the region. In some parts the water vapor will be stored for longer periods of time.

In other places it doesn’t even have the time to really accumulate.  Exactly how things are changing is still to be explored further, and one of ISLAS’ goals is to bring some answers to that question. For the time being, the hydrological cycle, with its feedbacks related to water vapor and clouds, is still the largest source of uncertainty in weather prediction and climate models. In ISLAS, researchers use stable isotopes to determine the origin of snow (i.e. where water evaporated originally), and the residence time of water vapor in the atmosphere. If you wonder what a stable isotope is, this video by Harald Sodemann is for you.