Atmospheric variability and precipitation in the Ross Sea region, Antarctica

• Main Author: Cohen, Lana
• Format: Thesis
• Language: unknown
• Published: 2013
• Subjects: Climatology (excl. Climate Change Processes); Meteorology; Antarctica; Climate; Precipitation; School: School of Geography; Environment and Earth Sciences; 040105 Climatology (excl. Climate Change Processes); 040107 Meteorology; 960202 Atmospheric Processes and Dynamics; 970104 Expanding Knowledge in the Earth Sciences; Degree Discipline: Geophysics; Degree Level: Doctoral; Degree Name: Doctor of Philosophy; Antarctic; Southern Ocean; The Antarctic; Ross Sea; West Antarctic Ice Sheet; Ross Ice Shelf; Pacific; Antarc*; Ice Sheet; Ice Shelf
• Online Access: https://doi.org/10.26686/wgtn.17006209.v1; https://figshare.com/articles/thesis/Atmospheric_variability_and_precipitation_in_the_Ross_Sea_region_Antarctica/17006209

Understanding how atmospheric variability in the Pacific sector of Antarctica drives precipitation is essential for understanding current and past climate changes on the West Antarctic Ice Sheet and the Ross Ice Shelf. Precipitation plays a key role in the Antarctic climate system (via mass balance of ice sheets) and is necessary for understanding past climates (via snow and ice proxies). However precipitation is difficult to measure and model and its variability in these regions is still not well understood. This thesis compiles three separate but inter-related studies which provide further understanding of the atmospheric variability of the Ross Sea region and its role in driving precipitation. Synoptic classifications over the Southern Ocean in the Pacific sector of Antarctica (50°S–Antarctic coast, 150°E–90°W) are derived from NCEP reanalysis data (1979–2011), producing a set of six synoptic types for the region. These six types describe the atmospheric variability of the Ross and Amundsen Seas region for the past 33 years and show how hemispheric scale circulation patterns such as the El Niño-Southern Oscillation and the Southern Annular Mode are reflected in local precipitation and temperature on the Ross Ice Shelf. The synoptic types also provide understanding of how different source regions and transport pathways can influence precipitation on the Ross Ice Shelf, which is important for the interpretation of climate proxies. Because of the sparseness of in-situ meteorological measurements in Antarctica, many studies (including the two described above) rely on atmospheric reanalyses data. However, assessments of reanalyses precipitation have only been done on annual and longer timescales. An assessment of the ERA-Interim and NCEP-2 reanalyses precipitation data on synoptic timescales is developed using statistical, event-based analysis of snow accumulation data from automatic weather stations around the Ross Ice Shelf. The results show that there are important differences between the two reanalyses ...