The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.
During the month of January most of Sweden is snow and ice-covered, although the duration and intensity of snow and ice has been declining over time due to ongoing climate change. The SITES calendar post for January displays this trend, as ice cover duration on Lake Erken over the past 80 years has been declining. At Erken Laboratory, visual observations of Lake Erken’s ice cover began in the 1940s and continues today, now with the assistance of a monitoring camera on Malma Island. This long-term ice-covered record is one of the most comprehensive in the world.
The graph displays the total number of lake ice cover days, i.e. days between the start of continuous ice coverage (> 75% of lake surface ice-covered) and the ice break-up of the observed lake area, over time on Lake Erken between 1941 to 2021. The photo shows Malma Island, where the lake monitoring camera as well as other monitoring sensors are located, and with the Erken Laboratroy in the very background.