| Summary: | This data set, when complete, will contain the following: 1) 14CO, 14CO2 and 14CH4 data from measurements in firn air, firn matrix and shallow ice (to 130 m) at Greenland Summit. 2) Supporting firn air trace gas measurements for firn model tuning 3) Noble gas isotope measurements in firn air 4) high-resolution measurements of CH4 and air content in the lock-in zone 5) Measurements of [CO] and CO stable isotopes in firn air These data were used to improve understanding of the production of carbon-14 in glacial firn and ice by cosmic rays, and the subsequent loss of such carbon-14 by diffusion through the ice grains into the air contained in the firn followed by diffusion in the firn air out to the atmosphere. This information adds value to studies of past atmospheric methane sources, potential carbon-14 dating of ice cores, and potential application of carbon-14 in ice as a tracer of past cosmic ray flux variations. In addition, these data inform the potential use of carbon monoxide’s carbon-14 composition in ice cores and firn air as a proxy for the past oxidizing and cleansing capability of the atmosphere.
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