Toward a Better Understanding of Recent Warming of the Central West Antarctic Ice Sheet from Shallow Firn Cores

• Main Author: Williams, Jessica
• Format: Others
• Published: BYU ScholarsArchive 2013
• Subjects: climate variability; Antarctica; isotopes; ice core; Geology
• Online Access: https://scholarsarchive.byu.edu/etd/3939; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=4938&context=etd

Previous studies have shown significant warming through the 1990s in the West Antarctic Ice Sheet (WAIS); but the records used in those studies end in early 2000, preventing trend analysis into the latest decade. Fourteen new snowpits and firn cores were collected in 2010 and 2011, which have been combined with previous cores to extend the isotopic records over WAIS. Significance of these isotopic patterns across WAIS was determined and is used to re-evaluate the warming of the West Antarctic interior over recent decades. We find that isotopic records longer than 50 years are needed to assess climate trends due to decadal variability. When assessed over periods greater than 50 years, there is a statistically significant warming trend over central WAIS. However, the isotopes in the 2000s are anomalously low in the isotopic records, which challenge the recent suggestion that the warming trend is accelerating. We attribute the isotopic low over the most recent decade to the coupling effect of anomalously low temperatures over central WAIS and associated increase in sea ice in the adjacent seas. This work strongly indicates that decadal variability and likely climate trends are both driven, at least in part, by atmospheric variability in the tropics as well as at high latitudes.