Utility of Larsen-C Ice Shelf Firn Cores for Climate Reconstruction in Other Antarctic Regions
Board Location: #127
Discipline: Computer Sciences and Information Management
Session: 3
Saneru A Williams - University of Maryland College Park
Co-Author(s): Orion Schomber, University of South Forida, St. Petersburg, FL; Brad Rosemheim, University of South Florida, St. Petersburg FL; Noel Gourmelen, University of Leeds, School of Earth and Environment, Leeds, United Kingdom; Andrew Shepherd, University of Leeds, School of Earth and Environment, Leeds, United Kingdom; Amber Leeson, University of Leeds, School of Earth and Environment, Leeds, United Kingdom; Elizabeth Williams, Tulane University, Department of Earth and Environmental Sciences, New Orleans, Louisiana; Alvaro Fernandez, Tulane University, Department of Earth and Environmental Sciences, New Orleans, Louisiana.
The Antarctic Peninsula (AP) is the most climatically sensitive region in Antarctica and has
experienced rapid ice shelf disintegration over the past 50 years. The Larsen C ice shelf (LCIS) is
the largest remaining ice shelf on the AP, but sparse in situ instrumental measurements limit the
accuracy of climate models of ice sheet stability. However, the ice and firn comprising the LCIS
may hold valuable and underutilized data to characterize the sensitivities of the LCIS. This study
used three short firn cores (~30 m each) from the LCIS to assess whether or not isotope data
could be used to reconstruct short-term climate records. Stable oxygen (δ18O) and hydrogen
(δ2H) isotope records in the firn cores were used to identify water-equivalent mass accumulation
and vertical accumulation rates when sampled in 10cm intervals. We used spectral analysis in the
distance domain of the isotope data to identify which alternative sampling rates were able to identify an annual signal in the isotope data. Using rectangular interpolation to emulate lower-
resolution sampling of these ice cores, we found sample rates exceeding 20cm (5 measurements per annual cycle, approximately) diminished the annual isotopic signal significantly. Higher
frequency sampling emulated by linear interpolation does not change the results of spectral
analysis, nor does it emulate sampling the ice cores at a higher resolution, however higher
frequency sampling would potentially be cost and effort prohibitive for discrete, rather than
continuous, sampling methods. Given that the LCIS is a region of high firn accumulation rates, it
may be the exception rather than the rule, we can apply our assessment to other areas with lower
accumulation rates to ascertain which areas may be conducive to similar analysis. Based upon
these results, we suggest that areas with at least 0.55 m/yr of snow accumulation could be valid
to examine the most efficient sample rate for future AP climate analyses derived from firn cores.
Funder Acknowledgement(s): Authors extend thanks and acknowledgement for funding and support from the NSF Grant # OCE-2244285, NSF REU Site: Making Waves: Science Communication and Interdisciplinary Ocean Research Experiences at US, College of Marine Science. Author would like to thank Drs. Ana Arellano and Jennifer Collins and graduate assistants/REU coordinators, Natalia Lopez Figueroa and Brooke Page, for their support during the summer. We would also like to thank and US Department of Journalism and Digital Communications for their support in Science Communication (Drs. Mark Walters and Stephen Song)
Faculty Advisor: Brad, E. Rosenheim., brosenheim@usf.edu
Role: Utilized mathematical interpolation to simulate different sample rates other than 10cm intervals on Larsen C ice shelf firn core isotope data to see the effect it has on the isotopic signal.