Sea Ice Modelling in the Pikialasorsuaq: Parameters Sensitivities and Future Prospects

  • Author / Creator
    Buchart, Liam
  • In northern Baffin Bay, of the Canadian Arctic, resides Pikialasorsuaq. Pikialasorsuaq mean \enquote{great upwelling} in Greenlandic. Also known as the North Water Polynya, polynya are regions of open water surrounded by thick pack ice. The open water generates conditions which enhance primary productivity throughout the year, and are capable supporting large marine life, making Pikialasorsuaq one of the most important ocean ecosystems on the planet. Local communities rely on the polynya for hunting, fishing, and transportation due to its open water when the rest of the region is covered in ice. The polynya forms when an ice bridge blocks ice flowing through Nares Strait in winter, prevailing winds push ice away from the bridge leaving open water.

    Climate warming threatens this region. As ice thins it may move through Nares Strait more easily. Greenland melt is expected to increase and enhance the stratification. Changes to the amount of ice and stratification of the region are then predicted to have significant impacts on the wildlife and humans which call it home. The modelling of Pikialasorsuaq is a difficult task due to the complex set of dynamics which form it. Improve
    ments are required to better simulate the polynya currently and in the future.

    I start with presenting sensitivity experiments with a high resolution sea ice model to access the importance of parameters involved in ice dynamics and mechanical redistribution. Tidal constituents, ice density, ice shear strength, ice compressive strength, and vertical resolution are modified to test their relative impact on resolving Pikialasorsuaq as well as Arctic Ocean, basin-scale sea ice. Parameter perturbation experiments impact basin-scale ice thickness and are capable of producing sea ice velocity and volume fluxes consistent with an ice bridge in Nares Strait.

    A small member ensemble is used to look at the potential impact of climate change on Pikialasorsuaq. Extending from 1981-2070 changes to sea ice, ocean, and biogeochemical variables are analyzed in the context of polynya formation and maintenance. Two different warming scenarios are used in the ensemble to provide and upper and lower limit on the expected changes of the coming decades. Ice concentration and thickness diminish while the upper layers of the region become more fresh and the lower layers more saline. The surface and lower layers are found to warm significantly.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.