PhD defence: Spectral snow albedo in a regional climate model: application to the Greenland and Antarctic ice sheets

Climate change has always played a major role on Earth. An important part of the climate system are the ice sheets of Greenland and Antarctica. Crucial for the development of an ice sheet is the reflectivity of sunlight, or albedo, at the surface.

To better understand the climate system (and therefore also the albedo) of the past, present and future, we use climate models. There is still room for improvements in such models, however, as the description of some processes is rather simple, like the albedo. The goal of this research is to implement a new snow albedo scheme in the climate model RACMO2, and analyze its impact on the development of the major ice sheets. In this thesis, we present the steps taken, discuss the new physical processes and evaluate the results.

We show that the determined albedo and climate in RACMO2 for the Greenland ice sheet now match better with in situ and satellite observations. An important improvement is that absorption of sunlight beneath the surface leads to higher snow temperatures. For the Antarctic ice sheet, sensitivity experiments illustrate that the modeled temperature and snowmelt are exceptionally sensitive to changes in the snowpack.

To summarize, the introduction of new physical processes and the implementation of a new snow albedo scheme in RACMO2 has led to many new insights and a positive impact on the quality of model simulations. With this research we hope to contribute to improved future climate projections of the Greenland and Antarctic ice sheets.