Using satellite remote sensing to evaluate and calibrate hydrological monitoring in Norway

The Norwegian Water Resources and Energy Directorate (NVE) is responsible for operating the Varsom forecasting service issuing forecasts covering a number of natural hazards in Norway, including flooding, avalanches and lake ice coverage. Additionally, NVE is monitoring glacier lakes that have a risk for glacier lake outburst floods (GLOFs). This responsibility requires multi-modal data gathering, ranging from permanent hydrological stations and field observers digging snow pits, to analysis of country-wide satellite-borne radar and optical imaging.

In this study we demonstrate how satellite remote sensing allow us to detect hazardous events and monitor hydrological conditions. Our infrastructure utilizes publicly available satellite data from Copernicus. We process the data  through a central platform built on Apache Airflow for job monitoring, GRASS and Actinia for spatial processing and Docker for parallelization. Using this platform we have built a number of products that identifies and digitizes objects, as well as time series analysis of various hydrological data. The platform can output these products to existing public datasets, like the Norwegian national landslide and avalanche database, as well as to purpose-built solutions, like our time-series database, which will make spatially aggregated time series publicly available.

Examples of using satellite data operationally include automated detection of avalanches making it possible to validate the details of a published avalanche bulletin of a high avalanche danger episode in the spring of 2023. Snow coverage monitoring of important watersheds during the same period allowed us to get confidence in the validity of our models and resulting assessment of the risk of melting season floodings.

In addition to use cases where satellite observations give us complementary information, we use the data in areas where there is few or no other available source of information. The best example of this is the monitoring of formation and drainage of glacier lakes, where optical imaging and manual digitizing has been the go-to solution for a long time. We are now developing automated products using Sentinel-1 and Sentinel-2 data to aid mapping and monitoring

The satellite products produced at NVE provide richer information of snow, ice and hydrologic condtitions. Products are being made publicly available.