Arctic Tundra Surface Energy Budget - assessing the status and informing predictions
SNSF, December 2018 – November 2022
Prof Dr. Gabriela Schaepman-Strub email
Raleigh Grysko, PhD candidate email
Dr. Jacqueline Oehri, Postdoc email
Elena Plekhanova, PhD candidate email
This project aims to assess drivers of energy fluxes of the arctic land surface and their impacts on the carbon and water cycle. One of the drivers investigated is the predicted increase in summer precipitation and its impact on permafrost thaw and, in collaboration with the URPP GCB, on vegetation composition and plant traits. The Arctic land has warmed up to 5°C in the 20'th century and substantial warming and increased precipitation are predicted for the 21st century. Such climatic changes impact the energy, water, and carbon cycle. To date, there is a very strong research bias towards the carbon cycle, while the carbon budget will strongly depend on the fate of the energy and water fluxes. A tight coupling of these three cycles exists through the short- and longwave radiation absorption and its partitioning into sensible, latent, and ground heat flux. This project aims to 1) strengthen the understanding of the relevance of the energy budget on the state and future of the Arctic system across scientific disciplines, 2) assess the status of the energy fluxes and identify their drivers through synthesizing existing pan-arctic data, 3) address how an increase or decrease of soil moisture affects the surface energy budget.
Following a mechanistic approach, we will perform detailed radiative and turbulent flux measurements in an experiment (in the northeast Siberian tundra, a severely underrepresented Arctic region and ecosystem with respect to global experiments and observations) with a precipitation addition and drought treatment, complemented by a mechanistic model. Through the combined experimental and modelling framework, we will contribute mechanistic understanding of future summer precipitation changes onto Arctic ecosystems and related energy flux changes. In the long term, the proposed research is expected to significantly impact the representation of major drivers and feedbacks of the Arctic terrestrial energy fluxes in land surface models - a prerequisite for an improved prediction of the Arctic system, its coupling at global scale.