Katelyn Johnson

Head and shoulders shot of PhD student Katelyn Johnson

Contact

Phone: 04 463 5233 x 8373
Email: Katelyn.Johnson@vuw.ac.nz
Office: CO 522

Qualifications

BSc Texas A&M University (2010); MSc The Ohio State University (2012)
PhD Candidate in Ice Core Climatology

PhD thesis

Title

Holocene ice-ocean interactions in the Ross Sea and Adélie Land regions using ice and sediment cores.

Supervisors

Project Aim and Description

The IPCC identifies the West Antarctic Ice Sheet (WAIS) as an area of particular concern for rapid deglaciation and subsequent sea-level rise, since paleoclimate evidence suggests the WAIS has collapsed under conditions similar to those forecast by the end of the century. The Ross Ice Shelf (RIS) serves as a main drainage system and buttresses the WAIS. For this reason, the Ross Sea region is of critical importance to understanding how climate change affected this area in the past, and how it may react in the future. Wind-driven changes in ocean currents, that act to transfer heat on to Antarctica’s continental shelf, are inferred to be the primary driver of groundline retreat following the Last Glacial Maximum.  Surface and bottom water freshening over the last several decades, as well as sea ice intensification, are suggested in part to be the consequence of current ice sheet retreat.  My research project aims to take advantage of two new atmospheric and marine records in the Ross Sea and Adélie Land regions to better constrain the ice-ocean interactions under stable and changing climate conditions.  The near annually resolved paleoclimate archives consist of an ice core from Roosevelt Island in the Ross Sea (RICE project), and an IODP core (U1357B) in the Adélie Basin - which is covered by surface waters sourced from the Ross Sea.  These proxies provide a unique opportunity to study the RIS calving line retreat, as well as the associated changes in polynya activity, surface water stratification and salinity, primary productivity, sea ice extent and atmospheric circulation over the past 12,000 years.