Our Work
Current Projects
State-dependent ice-sheet resonance under Cenozoic and future climates
Hub Contributors: Nick Golledge, Dan Lowry
Ice sheets respond to climatic changes over a wide range of periodicities (frequencies). On orbital timescales, geological evidence suggests that ice sheet volume and area appear to 'resonate' with insolation forcings at approximately 100kyr, 41kyr, and 23kyr frequencies. Temporal uncertainties in proxy-based reconstructions, however, mean that it is often necessary to assume that the way a ice mass resonates to environmental changes of a particular frequency is invariant. When we test these assumptions with model simulations, however, the results indicate that the style of ice sheet resonance is dependent both on the frequency of the insolation forcing, and on the background climate state experienced by the ice sheet.
Ice-sheet model intercomparison project phase 6 (ISMIP6)
Hub Contributors: Nick Golledge, Dan Lowry
Uncertainties related to ice-sheet contributions to future sea-level rise can be better quantified if multiple models are used to simulate the same period, and with the same forcing climatologies. To that end, ISMIP6 simulated both the Greenland and Antarctic ice sheets over the current century using climate forcings from both CMIP5 & 6. We contributed to both intercomparisons, using model configurations we had developed and refined over many years. We continue to work on related simulations, for example the new ISMIP2300 experiments that investigate multi-centennial changes in the Antarctic Ice Sheet. The results of the original initiatives were published in a series of papers:
- Payne, A.J. and 62 others incl. Golledge, N. and Lowry, D. (2021) Future sea level under CMIP5 and CMIP6 scenarios from the Greenland and Antarctic ice sheets. Geophysical Research Letters, doi: 10.1029/2020GL091741.
- Edwards, T.L. and 83 others incl. Golledge, N. and Lowry, D. (2021). Projected land ice contributions to 21st century sea level rise. Nature, 593, 74-82.
- Seroussi, H. and 46 others, incl. Golledge, N. and Lowry, D. (2020). ISMIP6 Antarctica: a multi-model ensemble of the Antarctic ice sheet evolution over the 21st century. The Cryosphere, 14, 3033-3070
- Goelzer, H. et al., and 41 others, incl. Golledge, N. and Lowry, D. (2020) The future sea-level contribution of the Greenland ice sheet: a multi-model ensemble study of ISMIP6. The Cryosphere, 14, 3071-3096
Graph theory and statistical mechanics approaches to climate and ice sheet science
Hub Contributors Nick Golledge and Béatrice Désy, with collaborator Markus Luczak-Roesch
Conventional techniques for understanding the time evolution of global climate and ice sheets often employs process-based models that solve long chains of differential equations to calculate how these systems evolve through a series of incremental changes. Yet such approaches have certain drawbacks, such as being computationally expensive, and prone to smoothing errors. In some cases it is preferable to approach the matter differently, and look at the statistical properties of a system and how these properties change through time. To that end, we are currently exploring a suite of related projects that investigate scale-invariant ice sheet flow, multi-fractal fluctuations in climate records, and network theory-based assessments of how environmental changes cascade through the global climate system.
Atmosphere-ocean interactions
Hub Contributors Alena Malyarenko, Alexandra Gossart, Mario Krapp, and Nikhil Hale
The broad aim of this project is to study past, present and future ocean-atmosphere-sea ice interactions at regional scale over the Ross Sea. We have developed a new, coupled model setup that is physically consistent in the representation of ocean/atmosphere/sea ice interactions for polar climates (Malyarenko et al, 2021 *as a link to publications*). The model couples the MITgcm ocean component to the PWRF atmosphere part using the Earth System Modeling Framework (ESMF). The grid of the models are at approximately 10 km horizontal resolution on a polar stereographic grid and contain 210 x 240 grid cells and 61 model levels in the atmosphere and 70 in the ocean.
Antarctic surface mass balance and surface melt
Hub Contributors: Nick Golledge, Yaowen Zheng, and Alexandra Gossart
The aim of this project is to study the variability, both spatially and temporally, of surface mass balance and melt at the surface of the Antarctic ice sheet. Surface melt is important because it impacts the health of the firn layer and plays a role in surface mass balance. Additionally, it can also play a role in ice shelf hydrofracturing and instability. Several tools are used to estimate melt over Antarctica and encompass, among other things, spaceborne observations, temperature-melt dependence models and surface energy balance models.
Hub Publications
Malyarenko, A., Gossart, A., Sun, R., & Krapp, M. (2023). Conservation of heat and mass in P-SKRIPS version 1: The coupled atmosphere–ice–ocean model of the Ross Sea. Geoscientific Model Development, 16(11), 3355–3373. https://doi.org/10.5194/gmd-16-3355-2023
Siegert, M., & Golledge, N. R. (2022). Advances in numerical modelling of the Antarctic ice sheet. In Antarctic Climate Evolution (pp. 199–218). Elsevier. https://doi.org/10.1016/B978-0-12-819109-5.00006-2
Levy, R. and 25 more including Golledge, N. (2022). Antarctic environmental change and ice sheet evolution through the Miocene to Pliocene – a perspective from the Ross Sea and George V to Wilkes Land Coasts. In Antarctic Climate Evolution (pp. 389–521). Elsevier. https://doi.org/10.1016/B978-0-12-819109-5.00014-1
Will, M., Krapp, M., Stock, J. T., & Manica, A. (2021). Different environmental variables predict body and brain size evolution in Homo. Nature Communications, 12(1), 4116. https://doi.org/10.1038/s41467-021-24290-7
Lowry, D. P., Krapp, M., Golledge, N. R., & Alevropoulos-Borrill, A. (2021). The influence of emissions scenarios on future Antarctic ice loss is unlikely to emerge this century. Communications Earth & Environment, 2(1), 221. https://doi.org/10.1038/s43247-021-00289-2
Krapp, M., Beyer, R. M., Edmundson, S. L., Valdes, P. J., & Manica, A. (2021). A statistics-based reconstruction of high-resolution global terrestrial climate for the last 800,000 years. Scientific Data, 8(1), 228. https://doi.org/10.1038/s41597-021-01009-3
Golledge, N., & Lowry, D. P. (2021). Is the marine ice cliff hypothesis collapsing? Science, 372(6548), 1266–1267. https://doi.org/10.1126/science.abj3266
Golledge, N., and 12 others including Lowry, D. (2021). Retreat of the Antarctic Ice Sheet During the Last Interglaciation and Implications for Future Change. Geophysical Research Letters, 48(17). https://doi.org/10.1029/2021GL094513
Edwards, T. L. and 83 others including Golledge, N. and Lowry, D. (2021). Projected land ice contributions to twenty-first-century sea level rise. Nature, 593(7857), 74–82. https://doi.org/10.1038/s41586-021-03302-y
Ashley, K. E. and 18 others including Golledge, N. and Lowry, D. (2021). Mid-Holocene Antarctic sea-ice increase driven by marine ice sheet retreat. Climate of the Past, 17(1), 1–19. https://doi.org/10.5194/cp-17-1-2021
Stevens, C., Hulbe, C., Brewer, M., Stewart, C., Robinson, N., Ohneiser, C., & Jendersie, S. (2020). Ocean mixing and heat transport processes observed under the Ross Ice Shelf control its basal melting. Proceedings of the National Academy of Sciences, 117(29), 16799–16804. https://doi.org/10.1073/pnas.1910760117
Goelzer, H. and 41 others including Golledge, N. and Lowry, D. (2020). The future sea-level contribution of the Greenland ice sheet: A multi-model ensemble study of ISMIP6. The Cryosphere, 14(9), 3071–3096. https://doi.org/10.5194/tc-14-3071-2020