Sea Ice Retrievals and data Assimilation in NOrway

Sjøisen i Arktis er i stadig bevegelse som følge av endringer i temperatur og vind. Vi bruker satellittbilder fra en rekke satellitter for å kartlegge hvor sjøisen befinner seg hver dag. I likhet med værvarslene man finner på yr, kan også sjøisens bevegelser de kommende dagene varsles ved hjelp av datamodeller. Det er vanskeligere å varsle sjøis enn vind eller regn, og dette var motivasjonen for SIRANO-prosjektet med dets 3 spesifikke forskningsmål. I SIRANO fokuserer vi på området rundt Svalbard og Barentshavet. Vi vil: 1) bedre utnytte hver tilgjengelige satellitt for seg; 2) utnytte satellittene bedre sammen; og 3) bruke satellittene bedre sammen med datamodeller (via dataassimilasjon) for å forbedre sjøisvarslingen. I mars 2023 organiserte vi en stor konferanse om sjøisvarsling i Oslo (https://iicwg-da-11.met.no/).

The Sea Ice Retrievals and data Assimilation in NOrway (SIRANO) project is a research collaboration between the Norwegian Meteorological Institute (MET) and UiT - the Arctic University of Norway. In the Arctic, around Svalbard and in the Barents Sea, sea-ice moves every day, because the temperature and wind change. We use pictures from many satellites to tell where the sea-ice is every day. We also use computer models to tell where sea-ice will be in the next couple of days (like the weather forecast on Yr, but for sea-ice). But it is more difficult to predict sea-ice than wind and rain, and we need to do some research to make better sea-ice forecasts. In our project, we will perform this new research. Three things that must be improved are: 1) to use satellites better individually, each on their own; 2) to use the satellites better all together; and 3) to use the satellites better together with the forecast models. The main difficulty is to combine pictures from several very different satellites. For example, a type of satellite we want to use (Synthetic Apperture Radars) sees many details, but the pictures are hard to understand by a computer algorithm, and there are data gaps. Another type of satellites (MicroWave Radiometers) does not see the small details, but can easily be interpreted by computer algorithms and takes many images a day. How can we build a third satellite picture, that will combine the pictures from these two satellites well? This is one of the questions we must answer. When we are done with our research, Norway will have new methods to use satellites and computer models to tell you where the sea-ice is, and where it is moving to. This is very useful for ships sailing or fishing around Svalbard, and for the Search and Rescue teams if there is an accident. It will also improve the weather forecasts we prepare for Yr.