Radiative transfer modelling; Land surface energy budget; Shortwave radiation partitioning; Climate change; Tundra ecosystems
Juszak I., Eugster W., Heijmans M.M.P.D., Schaepman-Strub G. (2016), Contrasting radiation and soil heat fluxes in Arctic shrub and wet sedge tundra, in Biogeosciences
, 13, 4049-4064.
Myers-Smith I.H., ... Schaepman-Strub G. et al. (2015), Climate sensitivity of shrub growth across the tundra biome, in Nature Climate Change
, 5, 887-891.
Juszak Inge, Erb Angela M., Maximov Trofim C., Schaepman-Strub Gabriela (2014), Arctic shrub effects on NDVI, summer albedo and soil shading, in REMOTE SENSING OF ENVIRONMENT
, 153, 79-89.
Budishchev A., Mi Y., van Huissteden J., Belelli-Marchesini L., Schaepman-Strub G., Parmentier F. J. W., Fratini G., Gallagher A., Maximov T. C., Dolman A. J. (2014), Evaluation of a plot-scale methane emission model using eddy covariance observations and footprint modelling, in BIOGEOSCIENCES
, 11(17), 4651-4664.
Juszak Inge, Iturrate-Garcia Maitane, Gastellu-Etchegorry Jean-Philippe, Schaepman Michael, Maximov Trofim, Schaepman-Strub Gabriela, Drivers of shortwave radiation fluxes in Arctic tundra across scales, in Remote Sensing of Environment
Iturrate-Garcia Maitane, Interactive effects between plant functional types and soil factors on tundra species diversity and community composition, in Ecology and Evolution
Climate change in the Arctic is more extensive and faster than expected. Changes in the physical system will lead to vegetation shifts, such as shrub encroachment as can already be observed in many regions of the Arctic. The vegetation changes will ultimately feedback to the climate system through altering energy and carbon fluxes. Two examples of feedbacks driven by altered shortwave energy fluxes are a decreasing albedo but increasing soil shading with increasing shrub growth; and changes in species competition through shifts of light available for photosynthesis within the canopy. Changes in energy fluxes are closely linked to the carbon cycle through processes such as productivity, nutrient availability influenced by soil temperature, greenhouse gas exchange with the atmosphere (e.g. methane emissions), and potential release of large carbon stocks currently locked in the permafrost. The longterm goal of the applicant is to contribute to the understanding, quantification, and simplified, yet accurate parameterization of the permafrost-biosphere-atmosphere interactions through energy fluxes in the Arctic, from local to regional scales. She co-supervised a PhD in NE Siberia working on observational and experimental evidence on the effects of shrubs on energy fluxes. It is now proposed to extend this work to all major vegetation types occurring at the site. Methodologically, this work will expand previous mainly observational-based methods with 3-dimensional modelling. This project will - for the first time - simulate shortwave radiation fluxes for selected tundra vegetation types based on a sophisticated 3D radiative transfer model (DART) in combination with in situ validation measurements. The model allows testing sensitivities of the shortwave energy fluxes (albedo, vertical profile of radiation, and transmitted radiation at the ground level) between the biosphere and atmosphere, as a function of vegetation composition and structure, sun angle, as well as irradiance conditions. Through this study, we expect to find a simplified parameterization of shortwave energy fluxes in tundra vegetation, as well as contribute to a more accurate prediction of vegetation feedbacks under future climate change scenarios. The results of the project will contribute to an increased accuracy of shortwave energy budget predictions and their feedback on permafrost and climate in the vulnerable Arctic system.