USAP-DC

Satellite observations show expanding Antarctic sea ice over the last three decades. Increasing Antarctic sea ice seems unexpected when compared to observations of rising global temperatures or shrinking Arctic sea ice. Computer models of global climate also predict Antarctic sea ice to shrink instead of grow. Several hypotheses have been suggested to explain the contradiction between what scientists expect to see based on computer models and physical intuition and the growth that is recorded in observations. This study will examine the hypothesis that sea ice expansion can be explained by sea ice motion, where sea ice moves in such a way as to promote an increase in overall coverage. Researchers will use several different types of computer models, ranging in complexity, to better understand the physical processes of sea ice motion and how the sea ice motion interacts with the larger atmosphere-ocean system. The team will transfer their research to the classroom by hosting a week-long teacher workshop. Teachers will learn how scientists use computer models to test hypotheses and then develop and test tools for use in the classroom. Five middle and high school teachers will participate and become part of the UC San Diego STEM Success Initiative master science teacher network. The project will support a graduate student and a postdoctoral researcher. Sea ice motion has recently emerged as one of the candidates to explain the Antarctic sea ice expansion but a systematic investigation of how sea ice motion influences sea ice concentration has not been presented to date. Researchers will conduct a process-oriented study of the relationship between sea ice motion and Antarctic sea ice extent using a hierarchy of models. The hierarchy will consist of (i) an idealized single-column model of sea ice evolution, (ii) an idealized latitudinally-varying global model of sea ice and climate, (iii) an atmospheric global climate model (GCM) above a slab ocean that includes sea ice motion, (iv) a comprehensive GCM, and (v) model output from the suite of current comprehensive GCMs. The range of model complexities will help researchers better understand the relationship between sea ice motion and sea ice extent by allowing them to identify important processes that are robust across the model hierarchy.

Person	Role
Eisenman, Ian	Investigator and contact
Wagner, Till	Co-Investigator

Antarctic Ocean and Atmospheric Sciences

Award # 1643445

USAP-1643445_1

None in the Database

Repository	Title (link)	Format(s)	Status
GitHub	Model code, model output fields, etc	Not Provided	exists

1. S. Sun, I. Eisenman, and A. Stewart (2018). Does Southern Ocean surface forcing shape the global ocean overturning circulation? Geophysical Research Letters 45, 2413-2423. (doi:10.1002/2017GL076437)
2. S. Sun, I. Eisenman, L. Zanna, and A. Stewart (2020). Surface constraints on the depth of the Atlantic Meridional Overturning Circulation: Southern Ocean versus North Atlantic. Journal of Climate 33, 3125-3149. (doi:10.1175/JCLI-D-19-0546.1)
3. S. Sun and I. Eisenman (2021). Observed Antarctic sea ice expansion reproduced in a climate model after correcting biases in sea ice drift velocity. Nature Communications 12, 1060. (doi:10.1038/s41467-021-21412-z)
4. T.J.W. Wagner, I. Eisenman, and H. Mason (2021). How sea ice drift influences sea ice extent and volume. Submitted.
5. Si, Y., Stewart, A., & Eisenman, I. (2021). Coupled ocean/sea ice dynamics of the Antarctic Slope Current driven by topographic eddy suppression and sea ice momentum redistribution. (doi:10.1002/essoar.10507558.1)
6. England, M. R., Eisenman, I., Lutsko, N. J., & Wagner, T. J. W. (2021). The Recent Emergence of Arctic Amplification. Geophysical Research Letters, 48(15). (doi:10.1029/2021gl094086)
7. England, M. R., Wagner, T. J. W., & Eisenman, I. (2020). Modeling the breakup of tabular icebergs. Science Advances, 6(51), eabd1273. (doi:10.1126/sciadv.abd1273)
8. Wagner, T. J. W., Dell, R. W., Eisenman, I., Keeling, R. F., Padman, L., & Severinghaus, J. P. (2018). Wave inhibition by sea ice enables trans-Atlantic ice rafting of debris during Heinrich events. Earth and Planetary Science Letters, 495, 157–163. (doi:10.1016/j.epsl.2018.05.006)
9. Beer, E., Eisenman, I., & Wagner, T. J. W. (2020). Polar Amplification Due to Enhanced Heat Flux Across the Halocline. Geophysical Research Letters, 47(4). (doi:10.1029/2019gl086706)
10. Sun, S., Eisenman, I., & Stewart, A. L. (2018). Does Southern Ocean Surface Forcing Shape the Global Ocean Overturning Circulation? Geophysical Research Letters, 45(5), 2413–2423. (doi:10.1002/2017gl076437)
11. Sun, S., Thompson, A. F., & Eisenman, I. (2020). Transient Overturning Compensation between Atlantic and Indo-Pacific Basins. Journal of Physical Oceanography, 50(8), 2151–2172. (doi:10.1175/jpo-d-20-0060.1)
12. Sun, S., Eisenman, I., Zanna, L., & Stewart, A. L. (2020). Surface Constraints on the Depth of the Atlantic Meridional Overturning Circulation: Southern Ocean versus North Atlantic. Journal of Climate, 33(8), 3125–3149. (doi:10.1175/jcli-d-19-0546.1)
13. Bonan, D. B., Schneider, T., Eisenman, I., & Wills, R. C. J. (2021). Constraining the Date of a Seasonally Ice‐Free Arctic Using a Simple Model. Geophysical Research Letters, 48(18). (doi:10.1029/2021gl094309)
14. England, M. R., Polvani, L. M., & Sun, L. (2020). Robust Arctic warming caused by projected Antarctic sea ice loss. Environmental Research Letters, 15(10), 104005. (doi:10.1088/1748-9326/abaada)
15. Evan, A., & Eisenman, I. (2021). A mechanism for regional variations in snowpack melt under rising temperature. Nature Climate Change, 11(4), 326–330. (doi:10.1038/s41558-021-00996-w)
16. Lester, C. W., Wagner, T. J. W., McNamara, D. E., & Cape, M. R. (2020). The Influence of Meltwater on Phytoplankton Blooms Near the Sea-Ice Edge. (doi:10.1002/essoar.10504088.2)
17. Roach, L.A., I. Eisenman, T.J. Wagner, E. Blanchard-Wrigglesworth, and C.M. Bitz, 2022: Asymmetry in the seasonal cycle of Antarctic sea ice due to insolation, Nature Geosciences. 15, 277-281. (doi:10.1038/s41561-022-00913-6)
18. Wagner, T. J. W., Eisenman, I., Ceroli, A. M., & Constantinou, N. C. (2022). How Winds and Ocean Currents Influence the Drift of Floating Objects. Journal of Physical Oceanography, 52(5), 907–916. (doi:10.1175/jpo-d-20-0275.1)
19. Castagno, A. P., Wagner, T. J. W., Cape, M. R., Lester, C. W., Bailey, E., Alves‐de‐Souza, C., York, R. A., & Fleming, A. H. (2023). Increased sea ice melt as a driver of enhanced Arctic phytoplankton blooming. Global Change Biology. Portico. (doi:10.1111/gcb.16815)