Sulfur deposition on the Greenland ice sheet : sources and implications of MSA and sulfate since 1900.
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Ice cores contain records of both local and global changes to atmospheric chemistry. Glaciochemical data from three newly acquired ice cores from the western portion of the Greenland Ice Sheet (GIS) were used to create high-resolution records of sulfate input, as methanesulfonic acid (MSA) and sulfate over the last century. Major ion and MSA signals were determined using ion chromatography. Our MSA record retains a consistent and robust seasonal signal and should be viable as a chemical proxy for the evolution of sea-ice extent in Disko Bay, which is adjacent to the ice sheet. We have used the MSA record to apply first-order dates to the GC-15 core. The GC-15 sulfate record shows several volcanic events. One possible eruption is from the Mount Pinatubo, which occurred in 1991. Our ion concentration records can be used to assess the relative importance of non-sea-salt inputs of major ions. A simple comparison between the three cores shows consistency of the seasonality of MSA, while there is no apparent seasonality in the sulfate comparison. However, there is a potential for location to be a determining factor of the magnitude of a MSA or sulfate concentration in each core. Further statistical analysis should be performed to determine similarities and differences between the three cores. The last 40m of the GC-15 core should also be processed.
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