This session is intended to attract a broad range of ice-sheet and glacier modelling contributions, welcoming applied and theoretical contributions. Theoretical topics that are encouraged are higher-order mechanical models, data inversion and assimilation, representation of other earth sub-systems in ice-sheet models, and the incorporation of basal processes and novel constitutive relationships in these models.
Applications of newer modelling themes to ice-sheets and glaciers past and present are particularly encouraged, in particular those considering ice streams, rapid change, grounding line motion and ice-sheet model intercomparisons.
Ice sheet and glacier surface mass balance and atmospheric interaction
Understanding the impacts of climate change on ice sheets and glaciers requires accurate surface mass balance. The interaction of ice sheets and glaciers with the atmosphere means that coupled atmosphere-ocean modes and large-scale weather patterns, meso-scale circulations over mountains, and local-scale energy and mass exchanges in the near-surface boundary layer can control the surface mass balance. Surface processes including melt-albedo feedbacks and firn densification introduce further complexity in determining surface mass balance. The Ice Sheets Model Intercomparison Project (ISMIP6), part of the Climate Model Intercomparison Project (CMIP6), aims to constrain the total mass balance contribution of ice sheets and glaciers to sea level rise. In this context, accurate estimates of surface mass balance from both models and observations are crucial, and so intercomparisons of models are currently underway.
This session focuses on (i) novel field- and remotely-sensed advances in measuring the surface energy balance and surface mass balance and (ii) process-based modelling that improves our understanding of glacier and ice sheet surface mass balance and atmospheric interaction. We invite contributions from a broad range of theoretical, numerical or observational studies that explore historic, recent and projected changes to glacier and ice sheet surface mass balance and atmospheric interaction. The range of topics includes but is not limited to: surface energy balance; improvements to satellite SMB retrievals; firn densification; future atmospheric circulation impacts; changes in cloudiness; and the impact of impurities upon albedo. We particularly welcome contributions which focus on improvements to process understanding that will lead to better SMB estimates in the future.
Ice sheets play an active role in the climate system by amplifying, pacing, and potentially driving global climate change over a wide range of time scales. The impact of interactions between ice sheets and climate include changes in atmospheric and ocean temperatures and circulation, global biogeochemical cycles, the global hydrological cycle, vegetation, sea level, and land-surface albedo, which in turn cause additional feedbacks in the climate system. This session will present data and modelling results that examine ice sheet interactions with other components of the climate system over several time scales. Among other topics, issues to be addressed in this session include ice sheet-climate interactions from glacial-interglacial to millennial and centennial time scales, the role of ice sheets in Cenozoic global cooling and the mid-Pleistocene transition, reconstructions of past ice sheets and sea level, the current and future evolution of the ice sheets, and the role of ice sheets in abrupt climate change.
Ice shelves and tidewater glaciers - dynamics, interactions, observations, modelling
Ice shelves and tidewater glaciers are sensitive elements of the climate system. Sandwiched between atmosphere and ocean, they are vulnerable to changes in either. The recent disintegration of ice shelves such as Larsen B and Wilkins on the Antarctic Peninsula, current thinning of the ice shelves in the Amundsen Sea sector of West Antarctica, and the recent accelerations of many of Greenland's tidewater glaciers provide evidence of the rapidity with which those systems can respond. Changes in marine-terminating outlets appear to be intimately linked with acceleration and thinning of the ice sheets inland of the grounding line, with immediate consequences for global sea level. Studies of the dynamics and structure of the ice sheets' marine termini and their interactions with atmosphere and ocean are the key to improving our understanding of their response to climate forcing and of their buttressing role for ice streams. The main themes of this session are the dynamics of ice shelves and tidewater glaciers and their interaction with the ocean, atmosphere and the inland ice, including grounding line dynamics. The session includes studies on related processes such as calving, ice fracture, rifting and mass balance, as well as theoretical descriptions of mechanical and thermodynamic processes. We seek contributions both from numerical modelling of ice shelves and tidewater glaciers, including their oceanic and atmospheric environments, and from observational studies of those systems, including glaciological and oceanographic field measurements, as well as remote sensing and laboratory studies.
The state-of-the-art in ice coring sciences (StatICS)
The half-century since the first deep ice core drilling at Camp Century, Greenland, has seen extensive innovation in methods of ice sample extraction, analysis and interpretation. Ice core sciences include isotopic diffusion analysis, multiple-isotope systematics, trace gases and their isotopic compositions, ice structure and physical properties, high-resolution analysis of major and trace impurities, and studies of DNA and radiochemistry in ice, among many others. Many climate and geochemical proxies have been identified from ice cores, with ongoing effort to extend their application and refine their interpretation. Great challenges remain in the field of ice coring sciences, including the identification of suitable sites for recovery of million-year-old ice; spatial integration of climate records (e.g. PAGES groups Antarctica2k and Iso2k); and deeper understanding of glaciological phenomena such as streaming flow, folding of layers and basal ice properties. This session welcomes all contributions reporting the state-of-the-art in ice coring sciences, including drilling and processing, dating, analytical techniques, results and interpretations of ice core records from polar ice sheets and mid- and low-latitude glaciers, remote and autonomous methods of surveying ice stratigraphy, and related modelling research.
Novel and quantitative methods for reconstructing continental palaeoenvironments and palaeohydrology
In recent decades, quantitative methods have become increasingly important in the field of palaeoenvironmental, palaeoclimatic and palaeohydrological reconstruction, due to the need for comparison between different records and to provide boundary conditions for computational modelling. Continental environmental archives (e.g. speleothems, lakes, land snails, rivers, or peatlands) are often highly temporally resolved (subdecadal to seasonal) and may provide more direct information about atmospheric and hydrological processes than marine archives. The wide variety of archive types available on land also allows for intercomparison and ground-truthing of results from different techniques and different proxies, and multi-proxy reconstructions from the same archive can disentangle local and supra-regional environmental conditions. This approach is particularly useful for the reconstruction of hydrological dynamics, which are challenging to reconstruct due to their high spatial variability, signal buffering, nonlinearities and uncertainties in the response of available paleoclimate archives and proxies. For example, climate-independent factors such as land cover change can affect the local to regional water availability recorded in proxies.
This session aims to highlight recent advances in the use of innovative and quantitative proxies to reconstruct past environmental change on land. We present studies of various continental archives, including but not limited to carbonates (caves, paleosols, snails), sediments (lakes, rivers, alluvial fans), and biological proxies (tree rings, fossil assemblages, plant biomarkers). We particularly include studies involving the calibration of physical and chemical proxies that incorporate modern transfer functions, forward modeling and/or geochemical modeling to predict proxy signals, and quantitative estimates of past temperature and palaeohydrological dynamics. We also include reconstructions of temperature and hydrologic variability over large spatial scales and paleoclimate data assimilation. This session will provide a forum for discussing recent innovations and future directions in the development of terrestrial palaeoenvironmental proxies on seasonal to multi-millennial timescales.
This session aims to highlight recent advances in the use of innovative and quantitative proxies to reconstruct past environmental change on land. We welcome studies of any continental archive, including but not limited to carbonates (caves, paleosols, snails), sediments (lakes, rivers, alluvial fans), ice, and biological proxies (tree rings, fossil assemblages, plant biomarkers). We particularly encourage studies involving the calibration of physical and chemical proxies that incorporate modern transfer functions, forward modeling and/or geochemical modeling to predict proxy signals, and quantitative estimates of past temperature and precipitation amounts. We also welcome reconstructions of temperature and hydrologic variability over large spatial scales, including paleoclimate data assimilation studies. This session will provide a forum for discussing recent innovations and future directions in the development of terrestrial palaeoenvironmental proxies on seasonal to multi-millennial timescales.
Glaciers and volcanoes interact in a number of ways, including instances where volcanic/geothermal activity alters glacier dynamics or mass balance, via subglacial eruptions or the deposition of supraglacial tephra. Glaciers can also impact volcanism, for example by directly influencing mechanisms of individual eruptions resulting in the construction of distinct edifices. Glaciers may also influence patterns of eruptive activity when mass balance changes adjust the load on volcanic systems. However, because of the remoteness of many glacio-volcanic environments, these interactions remain poorly understood.
In these complex settings, hazards associated with glacier-volcano interaction can vary from lava flows to volcanic ash, lahars, pyroclastic flows or glacial outburst floods. These can happen consecutively or simultaneously and affect not only the earth, but also glaciers, rivers and the atmosphere. As accumulating, melting, ripping or drifting glaciers generate signals as well as degassing, inflating/ deflating or erupting volcanoes, the challenge is to study, understand and ultimately discriminate these potentially coexisting signals. We wish to fully include geophysical observations of current and recent events with geological observations and interpretations of deposits of past events.
We invite contributions that deal with the mitigation of the hazards associated with ice-covered volcanoes, that improve the understanding of signals generated by ice-covered volcanoes, or studies focused on volcanic impacts on glaciers and vice versa. Research on recent activity is especially welcomed. This includes geological observations e.g. of deposits in the field or remote-sensing data, together with experimental and modelling approaches. We also invite contributions on past activity and glaciovolcanic deposits. We aim to bring together scientists from volcanology, glaciology, seismology, geodesy, hydrology, geomorphology and atmospheric science in order to enable a broad discussion and interaction.