Interactions between changing weather patterns and the Antarctic cryosphere in the Ross Sea Region.

• Main Author: Dale, Ethan R.
• Format: Other/Unknown Material
• Language: English
• Published: University of Canterbury 2020
• Subjects: Antarctic; Ross Ice Shelf; Ross Island; Ross Sea; Terra Nova Bay; The Antarctic; Antarc*; Antarctica; Ice Shelf; Sea ice
• Online Access: https://hdl.handle.net/10092/100089; https://doi.org/10.26021/8698

In this thesis the sensitivity of the cryosphere to changing weather patterns in the Ross Sea is investigated. The focus is on the production and persistence of sea ice and precipitation events over the Ross Ice Shelf (RIS). Changes are expected as a result of climate variability, and the change in the occurrence of storms and other severe weather patterns in Antarctica and in the Ross Sea. The influence of strong wind events on the sea ice concentration within the Ross Sea Polynya (RSP) is studied. Sea ice concentration within the RSP was observed to show a rapid decrease in response to strong wind events. Following a strong wind event, the RSP was found to remain open for an extended period of time, persisting beyond the end of the strong wind event. Sea ice drift within the Ross Sea was observed to be influenced by strong wind events with cyclonic drift anomalies being observed during periods of strong winds. A comparison of ERA-Interim reanalysis wind speeds and observed Automatic Weather Station (AWS) wind speeds east of Ross Island revealed that, despite strong correlations between the two data sets, ERA-Interim considerably underestimates wind speeds. Data from a Controlled Meteorological balloon flight within the atmospheric boundary layer over the Ross Sea in November 2017 is presented. The flight lasted 70 hours and passed over both the Terra Nova Bay and Ross Sea polynyas whilst making 31 vertical soundings. Balloon observations of temperature, humidity, and wind velocity were compared to co-located predictions made by the Antarctic Mesoscale Prediction System (AMPS); the two data sets were gener- ally found to agree. The wind direction predictions made by AMPS were found to be least accurate in the vicinity of complex topography and during periods of low wind speed. The upward heat and moisture fluxes from the RSP were investigated. Lagrangian and Eulerian derivatives of potential temperature and water mixing ratios were calculated using Lagrangian back trajectories within the AMPS field. This allow ...