Recent Past Evolution of the Under-Ice Light at the Pan-Arctic Scale

Light availability for photosynthesis in the Arctic Ocean is largely affected by sea ice. Sea ice concentration and thickness, snow depth and microstructure and melt pond fraction and depth are the main physical drivers influencing the transmission of light into the ice-covered ocean. In response to the climate change, all these factors have drastically changed these last decades. In this project, I aim to study the consequences of these changes on the Arctic under ice light field. Under ice optical measurements led during several field campaigns have substantially largely contributed to better understand how light penetration is affected by sea ice, snow and melt ponds at a given location. However, a scale up to the Pan-Arctic level is needed to understand the recent evolution of the entire Arctic under-ice light field. Maps representing under ice light at the Pan-Arctic scale combined with satellite products and state-of-the-art parameterizations give new insights about the spatial variability of the under-ice light field;however, large uncertainties remain in both satellite products and the radiative transfer scheme. I aim to reduce these uncertainties by both improving the representation of light penetration in sea ice and snow and modeling key parameters of the surface state missing in satellite products.