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Cambridge NERC Doctoral Training Partnerships

Graduate Research Opportunities

Lead Supervisor: Louise Sime, British Antarctic Survey

Co-Supervisor: Rachael Rhodes, Earth Sciences & David Schroeder, University of Reading

Brief summary: 
The student will use the latest UK model HadGEM3 to simulate the past Arctic sea ice losses. They will investigate the importance of melt ponds for the past and future loss of Arctic sea ice.
Importance of the area of research concerned: 
The Last Interglacial (LIG), a warmer period 130,000–116,000 years before present, is a potential analogue for future climate change. Stronger summertime insolation at high northern latitudes drove Arctic land summer temperatures 4–5 °C higher than in the pre-industrial era. Climate model simulations previously failed to capture these elevated temperatures, because they were unable to correctly capture Arctic sea-ice changes. In 2020, Dr Sime and Dr Schroeder demonstrated that the latest version of the fully coupled UK Hadley Center climate model (HadGEM3) simulates a more accurate Arctic LIG climate, including elevated temperatures. We believe this is because of improved model physics, particularly a sophisticated sea-ice melt-pond scheme (Schroeder, et al.; 2014) which results in a complete simulated loss of Arctic sea ice in summer during the LIG. The veracity of these physics is crucial for understanding how and when the Arctic will be become ice free in future (Guarino, Sime, Schroeder, et al.; 2020). It is of huge importance to test these physics for other past periods of rapid sea ice change.
Project summary : 
The student will use the latest UK model HadGEM3 to simulate the LIG . They will investigate the importance of melt ponds for the past and future loss of Arctic sea ice. HadGEM3 is a fully coupled atmosphere–land–ocean–ice climate model. The student will ascertain the role of melt ponds for the Antarctic, Arctic climate change during the LIG and during other past periods of significant polar warmth and Arctic sea ice loss. These will be the past warm LIG and Holocene periods – and the super rapid sea ice losses that occurred during Dansgaard-Oeschger events (Sime, Hopcroft and Rhodes; 2019).
What will the student do?: 
The student will: 1. Run HadGEM3 and the sea-ice model CICE for the LIG, Holocene and Dansgaard-Oeschger time periods. 2. For each of these periods, ascertain the importance of role of melt ponds, snow-ice albedo changes, and other radiative feedbacks for the loss of the Arctic (and Antarctic) sea ice. 3. Look at how the observed sea ice response to solar variability compares to model responses to different solar forcings, and investigate how modern-day responses in decadal records compare to those observed in paleo-records. 4. Finally, the student may also use our HadGEM3 water isotope code to investigate how sea ice change should be imprinted on polar ice cores
References - references should provide further reading about the project: 
Guarino, M., Sime, L.C., Schroeder, D. et al. Sea-ice-free Arctic during the Last Interglacial supports fast future loss. Nat. Clim. Chang. (2020).
Sime, Louise , Hopcroft, Peter O., Rhodes, Rachael H.. (2019) Impact of abrupt sea ice loss on Greenland water isotopes during the last glacial period. Proceedings of the National Academy of Sciences of the United States of America, 116. 4099-4104. 10.1073/pnas.1807261116
Schroeder, D., Feltham, D. L., Flocco, D. & Tsamados, M. September Arctic sea-ice minimum predicted by spring melt-pond fraction. Nat. Clim. Change 4, 353–257 (2014).
You can find out about applying for this project on the British Antarctic Survey (BAS) page.
Dr Rachael Rhodes
Louise Sime
British Antarctic Survey Graduate Administrator