Climate logging with a new rapid optical technique at siple dome

R.C. Bay; P.B. Price; G.D. Clow; A. J. Gow

doi:10.1029/2001gl013763

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Climate logging with a new rapid optical technique at siple dome

R.C. Bay·P.B. Price·G.D. Clow·A. J. Gow

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Abstract

The dust logger design is based on a decade of experience in the use of light sources to measure optical properties of deep Antarctic ice. Light is emitted at the top of the instrument by side-directed LEDs, scattered or absorbed by dust in the ice surrounding the borehole, and collected in a downhole-pointing photomultiplier tube (PMT) a meter below. With this method the ice is sampled at ambient pressure in a much larger volume than is the case in a core study, and the entire length can be logged in one day. In ice in which scattering is dominated by bubbles, the absorption from dust impurities is perceived as a drop in signal, whereas in bubble-free ice the scattering from dust increases the light collected. We report on results obtained in Siple Dome Hole A in December 2000. The instrument measured increases in dust concentration extending over many meters during glacial maxima, as well as narrow spikes due to ??? 1 cm thick ash and dust bands of volcanic origin. Monte Carlo simulation is employed to clarify data analysis and predict the capabilities of future designs.

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R.C. Bay, P.B. Price, G.D. Clow, A. J. Gow. 2001-12-15. Climate logging with a new rapid optical technique at siple dome. https://doi.org/10.1029/2001gl013763

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