Five millennia of surface temperatures and ice core bubble characteristics from the WAIS Divide deep core, West Antarctica

• Published in: Paleoceanography
• Main Authors: Fegyveresi, John M., Alley, Richard B., Fitzpatrick, Joan J., Cuffey, Kurt M., McConnell, Joseph R., Voigt, Donald E., Spencer, Matthew K., Stevens, Nathan T.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2016
• Subjects: Antarctic; West Antarctic Ice Sheet; West Antarctica; Antarc*; Antarctica; ice core; Ice Sheet
• Online Access: http://hdl.handle.net/11714/6208; https://doi.org/10.1002/2015PA002851

Bubble number densities from the West Antarctic Ice Sheet (WAIS) Divide deep core in West Antarctica record relatively stable temperatures during the middle Holocene followed by late Holocene cooling. We measured bubble number density, shape, size, and arrangement on new samples of the main WAIS Divide deep core WDC06A from similar to 580m to similar to 1600 depth. The bubble size, shape, and arrangement data confirm that the samples satisfy the requirements for temperature reconstructions. A small correction for cracks formed after core recovery allows extension of earlier work through the brittle ice zone, and a site-specific calibration reduces uncertainties. Using an independently constructed accumulation rate history and a steady state bubble number density model, we determined a temperature reconstruction that agrees closely with other independent estimates, showing a stable middle Holocene, followed by a cooling of similar to 1.25 degrees C in the late Holocene. Over the last similar to 5 millennia, accumulation has been higher during warmer times by similar to 12%degrees C-1, somewhat stronger than for thermodynamic control alone, suggesting dynamic processes.