Samples were collected from 2 meter snowpits in the accumulation zone of Canada, Commonwealth, and Rhone Glaciers in Taylor Valley, located in the McMurdo Dry Valleys region of Antarctica.

Snowpits were excavated to a depth of 2 meters at each location and samples were collected using a depth interval of approximately 3 cm utilizing clean sampling techniques. After excavation, the vertical surface was scraped in intervals to reveal a freshly exposed surface. Researchers wore non-particulating suits, clean polyethylene gloves, and used a plexiglass tray to collect the snow from a horizontal layer. Snow samples were transferred to wide-mouth Nalgene polycarbonate jars.

Before analysis, the samples were melted and transferred to 60 ml plastic bottles that had been cleaned with ultrapure water. The melted snow samples were stored at ~4 °C until analysis in the Crary Lab at McMurdo Station using methods outlined in Welch et al. 2010 (doi: 10.1017/S0954102010000702). In order to improve the detection limit for these low concentration samples, a 350 µl sample loop was used to inject a larger sample volume onto the chromatography columns. The samples were analyzed between 01/21/2001 and 02/11/2001.

Snow density was also measured in the field using a snow density kit obtained from the Berg Field Center, McMurdo Station, Antarctica.

Timeframe and geographic coordinates of sample collections were approximated based on the recollections of Kathy Welch and Thomas Nylen.