Thomas Laepple

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A new radioscopic imaging technique has been developed to measure firn density in unprecedented resolution and accuracy even when the porosity is low or the geometry of a core or piece of core is not perfect. The technique is based on an X-ray microfocus computer tomograph (ICE-CT) designed especially for ice-core applications. Applied on an archive piece(More)
The temperature variability simulated by climate models is generally consistent with that observed in instrumental records at the scale of global averages, but further insight can also be obtained from regional analysis of the marine temperature record. A protocol is developed for comparing model simulations to observations that account for observational(More)
The Milankovitch theory states that global climate variability on orbital timescales from tens to hundreds of thousands of years is dominated by the summer insolation at high northern latitudes. The supporting evidence includes reconstructed air temperatures in Antarctica that are nearly in phase with boreal summer insolation and out of phase with local(More)
The variability of sea surface temperatures (SSTs) at multidecadal and longer timescales is poorly constrained, primarily because instrumental records are short and proxy records are noisy. Through applying a new noise filtering technique to a global network of late Holocene SST proxies, we estimate SST variability between annual and millennial timescales.(More)
Significant discrepancies exist between the detrended variability of late-Holocene marine temperatures inferred from Mg/Ca and Uk37 proxies, with the former showing substantially more centennial-scale variation than the latter. Discrepancies exceed that attributable to differences in location and persist across various calibrations, indicating that they are(More)
15 Arctic climate has experienced major changes over the past millennia that are not fully 16 understood in terms of their controls and seasonality. Stable-data from ice wedges in 17 permafrost provide unique information on past winter climate. Recently, an ice-wedge 18 record from the Lena River Delta suggested for the first time that Siberian winter 19(More)
One possible method for predicting landfalling hurricane numbers is to first predict the number of hurricanes in the basin and then convert that prediction to a prediction of landfalling hurricane numbers using an estimated proportion. Should this work better than just predicting landfalling hurricane numbers directly? We perform a basic statistical(More)
Temporal variations of the radionuclide Be are broadly synchronous across the globe and thus provide a powerful tool to synchronize ice core chronologies from different locations. We compared the Be record of the Akademii Nauk (AN) ice core (Russian Arctic) for the time period CE 1590–1950 to the Be records of two well-dated Greenland ice cores (Dye3 and(More)
Along a traverse through North Greenland in May 2015 we collected snow cores up to 2 m depth and analyzed their density and water isotopic composition. A new sampling technique and an adapted algorithm for comparing data sets from different sites and aligning stratigraphic features are presented. We find good agreement of the density layering in the(More)
Temporal variations of the radionuclide Be are broadly synchronous across the globe and thus provide a powerful tool to synchronize ice core chronologies from different locations. We compared the Be record of the Akademii Nauk (AN) ice core (Russian Arctic) for the time period CE 1590–1950 to the Be records of two well-dated Greenland ice cores (Dye3 and(More)