Atmospheric methane across the Last Glacial Maximum and deglaciation from the GISP2, NEEM and WAIS Divide ice cores

This dataset includes measurements of atmospheric methane from samples from the NEEM, GISP2 and WAIS Divide ice cores. All measurements were made at the Oregon State University Ice Core and Quaternary Geochemistry Laboratory (Corvallis, OR) using an established analytical system. 433 samples from the NEEM ice core were measured between 1420 and 1560m depths. A measurement uncertainty ranging from 2.8 to 4.2 ppb, depending on the measurement year, was determined from replicate samples. 340 samples from the GISP2 ice core were measured between 1740 and 2060m depths. A measurement uncertainty ranging from 3.1 to 3.4 ppb, depending on the measurement year, was determined from replicate samples. All GISP2 and NEEM data were corrected for excess methane contamination using the established relationship between excess methane and Ca2+ (Lee et al., 2020). Both corrected and uncorrected data are included in the publication. 340 samples from the GISP2 ice core were measured between 1957 and 3081m depths. A measurement uncertainty ranging from 3.1 to 3.4 ppb, depending on the measurement year, was determined from replicate samples. Depths reflect the mid-points of the depth range of each samples, which is typically ~8cm. All replicate measurements are included in the dataset.