Tundra Energy Fluxes under Drought and Extreme Summer Rainfall Scenarios

The Arctic is undergoing amplified climate change and forecasts predict increased warming and precipitation in the future. How changes in temperature and precipitation affect the partitioning of the Arctic land surface energy budget is not clear, despite the importance of both the Arctic region and the surface energy budget in earth system processes at local, regional, and global scales.We will investigate the Arctic tundra energy budget and the relative importance of biotic and abiotic drivers. Specifically, we are experimentally testing effects of changing summer precipitation on the partitioning of the surface energy budget by simulating precipitation-based climate extremes – extreme drought and extreme precipitation totals.We will present a literature-based synthesis of the expected impact of drought and extreme rainfall on the energy budget components of the tundra land surface and a description of the experimental design and treatments. The experiment has been established at a long-term Siberian tundra test site (71°N, 147°E). Extreme drought (precipitation) is being simulated by removing (adding) a predetermined fraction of ambient precipitation from (to) the test plots. Control plots, where ambient precipitation is not modified, are used as a baseline. Plot selection, soil sampling, and installation of below-ground sensors were performed during the past two summers, while setup of shelters and water-addition installations were completed early July 2019.With our results on energy budget behavior change under future summer precipitation scenarios, we expect to inform mechanistic and statistic modeling of species distributions, ecosystem functions, and climate feedback in the Arctic tundra.