June Data in Focus: SITES Water high frequency lake temperature profile monitoring

02 June 2023

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.  

SITES has three Thematic Programs that strengthen the collaboration within the network of stations in remote sensing, water monitoring and aquatic mesocosms. The Thematic Programs facilitate comparison between climate zones, landscape elements and management systems and offer open data from long-term monitoring and experimental installations.

This month the SITES Water Thematic Program is featured, which builds a unique long-term and well-coordinated measurement program where hydrological, physical, chemical, and biological parameters within lakes and streams are measured at seven SITES stations. As part of SITES Water, lake platforms are equipped with automated high frequency sensors that measures weather and climate variables above the lake (e.g. air temperature, humidity, wind speed) as well as physical variables within the lake (e.g. temperature, oxygen). The lake water temperature is measured at different depths, i.e. lake profile, which allows for the thermal structure of the lake over the year to be determined. The thermal structure of a lake plays an important role in the biogeochemical cycling and subsequent greenhouse gas emissions from the lake.

Link to Data: https://meta.fieldsites.se/objects/iHSmt3sLan6AhIm_DO5tV1h6

Image removed.
Photo and graphic: Roberto Lo Monaco

The graph shows sub-hourly water temperature at different depths in lake Erssjön over the year in 2020. Early in the year, the water temperature at different depths in the lake was similar but as air temperatures warmed in the spring, a thermal stratification formed, where the warm surface water of the lake disconnected from the cooler bottom water. As the air temperatures cooled in the fall, the lake mixed and the water temperatures in the lake at different depths became similar again. The photo shows the lake platform on Erssjön, which is equipped with meteorological sensors above the lake and in situ aquatic sensors below the lake.