Abstract
Current volcanic reconstructions based on ice core analysis have
significantly improved over the past few decades by incorporating
multiple-core analyses with a high temporal resolution from different parts
of the polar regions into a composite common volcanic eruption record.
Regional patterns of volcanic deposition are based on composite records,
built from cores taken at both poles. However, in many cases only a single
record at a given site is used for these reconstructions. This assumes that
transport and regional meteorological patterns are the only source of the
dispersion of the volcanic products. Here we evaluate the local-scale
variability of a sulfate profile in a low-accumulation site (Dome C,
Antarctica), in order to assess the representativeness of one core for such a
reconstruction. We evaluate the variability with depth, statistical
occurrence, and sulfate flux deposition variability of volcanic eruptions
detected in five ice cores, drilled 1 m apart from each other. Local-scale
variability, essentially attributed to snow drift and surface roughness at
Dome C, can lead to a non-exhaustive record of volcanic events when a single
core is used as the site reference, with a bulk probability of 30 % of
missing volcanic events and close to 65 % uncertainty on one volcanic
flux measurement (based on the standard deviation obtained from a five-core
comparison). Averaging n records reduces the uncertainty of the deposited
flux mean significantly (by a factor 1∕ √ n); in the case of five cores,
the uncertainty of the mean flux can therefore be reduced to 29 %.
Citation
ID:
187412
Ref Key:
gautier2016climatevariability