Calibration of the δ¹⁸O isotopic paleothermometer for central Greenland, using borehole temperatures

Abstract

We suggest that calibrations of isotopic paleothermometers using borehole temperatures are a useful paleoclimate tool, because they are independent of spatial gradients and include the effects of prehistoric temperatures over ice sheets.

Experimental observation of transient <i>δ</i><sup>18</sup>O interaction between snow and advective airflow under various temperature gradient conditions

“…Dansgaard, 1964;Lorius et al, 1979;Grootes et al, 1994;Petit et al, 1999;Johnsen et al, 2001;EPICA Members, 2004). However, the processes that influence the isotopic composition of precipitation at high latitudes are complex, making direct inference of palaeotemperatures from the isotopic record difficult (Cuffey et al, 1994;Jouzel et al, 1997Jouzel et al, , 2003Hendricks et al, 2000). Several factors affect the vapour and snow isotopic composition, which give rise to ice-core isotopic composition, starting from the process of evaporation in the source region, transportation of the air mass to the top of the ice sheet and post-depositional processes (Craig and Gordon, 1964;Merlivat and Jouzel, 1979;Johnsen et al, 2001;Ciais and Jouzel, 1994;Jouzel and Merlivat, 1984;Jouzel et al, 2003;Helsen et al, 2005Helsen et al, , 2006Helsen et al, , 2007Cuffey and Steig, 1998;Krinner and Werner, 2003).…”

Spatial and temporal variability in the stable isotope systematics of modern precipitation in China: implications for paleoclimate reconstructions

“…This database includes mean monthly N 18 O p , ND, precipitation amount, surface temperature, and vapor pressure values for 29 sites in China, although many of these records are discontinuous. To prevent inter-annual variability in stable isotope systematics from biasing our results, we chose to focus our study on 10 (Fig. 2).…”

“…Recent studies have suggested that the transfer function, dN 18 O p /dT, may exhibit signi¢-cant temporal and spatial variability. Cu¡ey et al [9,10], for example, used borehole temperature pro¢les from ice cores in Greenland as an independent paleothermometer to demonstrate that the temporal N 18 O p /T s relationship may be as much as a factor of two weaker than the modern spatial relationship commonly used in paleotem-perature reconstructions. In addition, Fricke and O'Neil [11] have shown that the slope of the N 18 O p^T relationship is somewhat dependent on climate mode.…”

The Younger Dryas Termination and North Atlantic Deep Water Formation: Insights from climate model simulations and Greenland Ice Cores

“…In this model, the Younger Dryas ended when the Atlantic salt conveyor reestablished itself and warm surface waters were again advected to high latitudes in the North Atlantic. In addition to the drainage diversion there is substantial evidence for a large iceberg discharge from [Cuffey et al, 1994) and from the glacial maximum ( 0.33 per mil per øC [Cuffey et al, 1995]). No direcct calibration was obtained for the Younger Dryas because its borehole-temperature signal has largely diffused away, although the isotopic data do contain temperature information [Cuffey et al, 1994[Cuffey et al, , 1995.…”