Accumulation in coastal West Antarctic ice core records and the role of cyclone activity. Issue 17 (9th September 2017)

• Record Type: Journal Article
• Authors: Hosking, J. Scott; Fogt, Ryan; Thomas, Elizabeth R.; Moosavi, Vahid; Phillips, Tony; Coggins, Jack; Reusch, David
• Is Part Of: Geophysical research letters. Volume 44:Issue 17(2017)
• Page Start: 9084
• Page End: 9092
• Publication Date: 2017-09-09
• Subjects: cyclones -- West Antarctic -- ice cores -- SOMs -- accumulation; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL074722
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Cyclones are an important component of Antarctic climate variability, yet quantifying their impact on the polar environment is challenging. We assess how cyclones which pass through the Bellingshausen Sea affect accumulation over Ellsworth Land, West Antarctica, where we have two ice core records. We use self‐organizing maps (SOMs), an unsupervised machine learning technique, to group cyclones into nine SOM nodes differing by their trajectories (1980–2015). The annual frequency of cyclones associated with the first SOM node (SOM1, which generally originate from lower latitudes over the South Pacific Ocean) is significantly ( p < 0.001) correlated with annual accumulation, with the highest seasonal correlations ( p < 0.001) found during autumn. While significant ( p < 0.01) increases in vertically integrated water vapor over the South Pacific Ocean coincide with this same group of cyclones, we find no indication that this has led to an increase in moisture advection into, nor accumulation over, Ellsworth Land over this short time period. Key Points: Frequency of cyclones originating from lower latitudes over the South Pacific Ocean is highly correlated with Ellsworth Land accumulation Six of the top 10 precipitation events coincide with cyclones from lower latitudes during the autumn and winter seasons There are no trends in cyclone activity over the satellite record that can explain the observed accumulation trend over Ellsworth Land Plain Language Summary: Cyclones are an important component of Antarctic climate variability, yet quantifying their impact on the polar environment is challenging. We assess how cyclones which pass through the Bellingshausen Sea affect snowfall over Ellsworth Land, West Antarctica, where we have two ice core records. We use a novel machine learning technique to group cyclones differing by their pathways. The annual frequency of cyclones associated with cyclones which generally originate from lower latitudes over the South Pacific Ocean is significantly correlated with annual snowfall, with the highest seasonal correlations found during autumn. While significant increases in water vapor over the South Pacific Ocean coincide with this same group of cyclones, we find no indication that this has led to an increase in the transport of moisture into, nor accumulation over, Ellsworth Land over this short time period.