The Marginal Ice Zone (MIZ) seawater property dynamics of the Southern Ocean below Southern Africa using animal-borne observations

• Main Author: De Kock, Wade
• Other Authors: Vichi, Marcello
• Format: Master Thesis
• Language: English
• Published: University of Cape Town 2018
• Subjects: Oceanography; Austral; Indian; Southern Ocean; Elephant Seals; Sea ice; Southern Elephant Seals
• Online Access: http://hdl.handle.net/11427/29614; https://open.uct.ac.za/bitstream/11427/29614/1/thesis_sci_2018_de_kock_wade.pdf

The Marginal Ice Zone (MIZ) in the Southern Ocean is a dynamic area shown to vary seasonally in width and extent northward. Remote sensing is the only tool available to give a large-scale picture of sea-ice conditions but it is important to note that only surface properties are visible in remote sensing products. Little is known about the hydrographical properties of the Atlantic Sector of the Southern Ocean in the austral winter as it is difficult to obtain shipboard observations. Using observations from southern elephant seals, it is possible to analyse properties such as salinity and temperature within the MIZ. These properties may then be related to observations of sea ice concentration obtained by remote sensing to qualitatively describe their relationships. This work provides an example of how data from selected seal observations and satellite data can be used operationally to define the hydrography of the MIZ, focusing on the years 2005 to 2009. Results show that the properties of the underlying water in the MIZ appear to be fairly constant in the region of 15°W to 45°E for the months of July and August. A warmer pool of water is evident in the east of this region. Based on what is known about the physics of the region and what is seen spatially regarding changes in temperature and salinity, the warm pool may be brought about by eddies along the South West Indian Ridge. Results also show that surface concentrations of sea ice may have an effect on the underlying properties of the water. A more detailed description of the characteristics and features in the MIZ may further help to understand key processes in the region. Changes in subsurface temperature and salinity may influence the formation of ice. This may in turn influence large to mesoscale processes in both the ocean and atmosphere. Understanding how these physical properties change and what may cause them to change can help further understanding of larger scale processes.