Popular Scientific Presentation
Loess and dust deposits. Deposits of wind-blown mineral dust cover large areas of land and form deep sedimentary layers termed loess that cover 10% of the world’s continents. Loess is one of our most important past climate records, reaching back 10s of millions of years, and we focus on the study of its composition in order to reconstruct long records of climate and identify the sources of dust activity, a major driver in climate change. We also use radiogenic dating techniques such as luminescence to accurately pinpoint the age of these deposits. One major research focus in Uppsala is using loess to understand the evolution of the Asian monsoon, a system that sustains 2/3rds of the world’s population.
Ice cores. An important branch of s modern glaciological research focuses on retrieving records of past climate, environmental conditions and air pollution by drilling ice cores from ice sheets and ice fields. The cores are analysed in the field, or sampled later for more detailed analytical work. The biology, chemistry and physics of ice cores reveal climatic and environmental changes in the regions from where ice cores are taken. In Uppsala we presently focus on the study of ice cores from Canada, Greenland and Svalbard.
Glacier mass balance. Another important aspect of glaciers is their mass balance. Mass balance is the net sum of snow accumulation and ice loss through ablation. Since both accumulation and ablation is related to the climate, mass balance is a good indicator of the impact of climate change on glaciers. Studying the relationship between climate and mass balance provides information about the future response of glaciers responses global warming. Mass balance can be studied in many different ways. In the Nordic excellence centre SVALI we also work with climate and weather models together with field data to better understand regional variations in mass balance, in order to make future projections of changes in ice sheets volume. We work primarily with the atmospheric model WRF, and integrate better melting models in earth science models (ESM).
Ice dynamics is the the mechanical properties and dynamical behaviour of glacial flow. Important for the flow of glaciers is the conditions at its base, where melt water acts like a lubricant and accelerate the flow. This makes our understanding of ice dynamics important for assessing the glaciers’ response to climate change and their contribution to sea-level changes. The knowledge of ice dynamics is also crucial in order to understand the chronology of an ice core, and the flux of ice through a glaciated landscape and the reshaping of the landscape.
Numerical modelling. Ice that discharge into the Ocean from large ice sheets as well as from glaciers and ice caps is substantially contributing to global sea level rise. To understand the present and future contribution of ice to this rise we need to understand how glacier dynamics and glacier-climate coupling and feedback mechanisms operate. Numerical modelling is a valuable tool to understand these complex interactions. Using full stokes models allows a realistic description of the processes involved in ice flow and enables future projections to some extent. The future rate of increase in the velocity of outlet glaciers or ice streams is a major unknown today and modelling such processes is a great challenge.