East Antarctic surface mass balance in the Anthropocene: observations and multiscale modelling
The climate of the high latitudes of the Southern Hemisphere has changed considerably over the last decades, but the origin and long-term relevance of those changes are not well understood, in particular because the short instrumental records do not allow documenting the full range of variability of the Southern Hemisphere climate system. Furthermore, the Antarctic climate system is very complex with strong interactions between the ice sheet, atmosphere, ocean and sea ice. Within this complex system small scale variations often have large scale consequences, while regional processes are partly controlled by large scale dynamics. Therefore it is crucial to link the dynamics that affect Antarctica at different spatial and temporal scales in order to make progress in our understanding, and increase the confidence in the future projections for Antarctica. Within this framework, we propose to study the surface mass balance (SMB) in the Princess Ragnhild Coast (PRC) region.
The project has two main objectives. Firstly, we aim to understand the local processes responsible for SMB variability in the PRC region and to document the changes during the last 300 years. Secondly, we will establish links between local, regional, and large scale processes to determine the origin of the variability of the surface mass balance. This will allow determining if the mass gain observed in a recent ice core record collected close to PRC is representative for larger areas and if the changes are the result of anthropogenic forcing and/or linked to the natural variability of oceanic and atmospheric circulation. Finally, the representation of the variability of East Antarctic surface mass balance in Earth System Models will be assessed and the implications for future surface mass balance projections will be analysed.
The analyses will be based on i) new meteorological data and ice core records, ii) compilations of existing proxy records and instrumental data, iii) detailed characterization of the spatio-temporal properties of the data and iv) regional and global model outputs from existing and new simulations. This combined observations-modelling approach, which will focus specifically on data analysis and assimilation, will allow studying the interactions between different temporal and spatial scales.
The project consists of 4 main work packages (WP). The first one is devoted to the collection, analysis and interpretation of 2 new ice core records in the Princess Ragnhild Coast region, close to Princess Elisabeth Station and new meterologocical observations characterizing local-scale variations. The spatial variability will be further documented with complementary shallow ice cores (ca. 15 m) across the Roi Baudouin Ice Shelf, which is connecting the ice rises. In the second work package, the processes responsible for surface mass variations will be analyzed using local and regional model simulations over the recent past, aided by in situ weather station, snow radar data and statistical post-processing approaches. In work package 3, the links between local and regional scale processes, on the one hand, and the large scales processes represented by global reanalysis and global climate model data, on the other hand, will be studied. The corresponding analyses will address both the last 30 years, when most instrumental data are available, and the last 300 years, to determine the long-term temporal variability and trends. Finally, in WP4 the performance of CMIP5 and CMIP6 simulations will be assessed, improving the confidence in future projections of surface mass balance and thus sea level.
The partners form an unique interdisciplinary network with expertise covering the entire spatio-temporal spectrum under study: we have specialists in the collection and interpretation of multi-parametric ice core properties in Antarctica, regional and global climate modelling, and Earth System Dynamics. The proposed framework will allow tightening the interactions between the different groups and integrating the various methodological approaches. This will improve the comparison between observations and model results. Moreover, it will stress the added value of combining (new) data with model dynamics and pre-existing information.
Expected Results and Potential Impact
The main expected impact of our research is a better estimate and understanding of the surface mass balance in East Antarctica, linking small scale and large scale process as well as a wide range of timescales, which is a high priority for the scientific community. A better understanding of those processes and thus of the global climate dynamics, will further increase the credibility of policies devoted to mitigate the impact of climate changes. Additionally, surface mass balance is connected to sea level rise and our results will help to refine future projections and inform assessments devoted to policy makers. We also intend to engage the general public in outreach activities to stimulate the interest on the unique and attractive environment of Antarctica by blogging about our plans, developments, results, and fieldwork adventures, by displaying continuous, real-time weather station data, by maintaining an account on Twitter to share our results on social media and by making conferences in Universities, schools and societies.
Dr. Stéphane Vannitsem, supervisor at RMIB
Former RMI collaborators within this project:
Dr. Lesley De Cruz
Dr. Nicolas Ghilain