noaa-icecore-18536 EPICA Dronning Maud Land Ice Core 1cm Electric Conductivity Measurements (ECM) Schwander, J.; Flückiger, J.; Stauffer, B.; Zumbrunnen, O. EPICA Dronning Maud Land Ice Core 1cm Electric Conductivity Measurements (ECM) 2015-05-01 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/18536 Investigator J. Schwander Investigator J. Flückiger Investigator B. Stauffer Investigator O. Zumbrunnen earth science paleoclimate ice cores depth,null,null,meter,null,ice cores,null,null,N,null earth science paleoclimate ice cores electrical conductivity,bulk ice,null,nanosiemens,null,ice cores,null,null,N,null earth science paleoclimate ice core physical properties geoscientificInformation 140000 cal yr BP 1260 cal yr BP Complete -75 -75 .07 .07 2892 2892 Continent Antarctica EPICA Dronning Maud Land>LATITUDE -75>LONGITUDE .07 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Eisen, Olaf; Wilhelms, Frank; Steinhage, Daniel; Schwander, Jakob 2006 Journal of Glaciology 52 177 299-310 10.3189/172756506781828674

We present a technique that modifies and extends down-hole target methods to provide absolute measures of uncertainty in radar-reflector depth of origin. We use ice-core profiles to model wave propagation and reflection, and then cross-correlate the model results with radio-echo sounding (RES) data to identify the depth of reflector events. Stacked traces recorded with RES near the EPICA drill site in Dronning Maud Land, Antarctica, provide reference radargrams, and dielectric properties along the deep ice core form the input data to a forward model of wave propagation that produces synthetic radargrams. Cross-correlations between synthetic and RES radargrams identify differences in propagation wave speed. They are attributed to uncertainties in pure-ice permittivity and are used for calibration. Removing conductivity peaks results in the disappearance of related synthetic reflections and enables the unambiguous relation of electric signatures to RES features. We find that (i) density measurements with gamma-attenuation or dielectric profiling are too noisy below the firn-ice transition to allow clear identification of reflections, (ii) single conductivity peaks less than 0.5 m wide cause the majority of prominent reflections beyond a travel time of about 10 mu s (~900 m depth) and (iii) some closely spaced conductivity peaks within a range of 1-2 m cannot be resolved within the RES or synthetic data. Our results provide a depth accuracy to allow synchronization of age-depth profiles of ice cores by RES, modeling of isochronous internal structures, and determination of wave speed and of pure-ice properties. The technique successfully operates with dielectric profiling and electrical conductivity measurements, suggesting that it can be applied at other ice cores and drill sites. STUDY NOTES: Electrical conductivity measurements (ECM) at 1cm. resolution.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml2015ecm1cm.txt Data File; EPICA Dronning Maud Land 1cm ECM USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11