Dating the Siple Dome (Antarctica) ice core by manual and computer interpretation of annual layering

Taylor, Kendrick C.; Alley, Richard B.; Meese, D. A.; Spencer, Matthew K.; Brook, E.; Dunbar, Nelia W.; Finkel, Robert C.; Gow, Anthony J.; Kurbatov, Andrei V.; Lamorey, G.; Mayewski, Paul Andrew; Meyerson, E. A.; Nishiizumi, K.; Zielinski, Gregory A.

doi:10.3189/172756504781829864

Cited by 93 publications

(79 citation statements)

References 24 publications

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“…A low imprecision of 0-0.5 % or an age uncertainty of approximately 1-2 yr over a period of 200 yr results in minimal relative estimation error and maximal confidence on the similarity peak position for the time series similarity functionŝ S. If a similarity analysis for real-world data sets covering a time span of 100 000 yr was desired, this would amount to an "allowed" age error of 500 yr at a mean time series resolution of 500 yr, which is a lower than what is usually found (Taylor et al, 2004). Thus, the resolution desired in the analysis is necessarily dependent on age uncertainty -only if that is lower, or comparable, would an analysis of such short time series with full consideration of age uncertainties be feasible.…”

Section: Discussionmentioning

confidence: 91%

Similarity estimators for irregular and age-uncertain time series

Rehfeld

Kurths

2014

Clim. Past

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Abstract. Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many data sets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear.In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age-uncertain time series. We compare the Gaussian-kernel-based cross-correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series.In the linear test case, coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55 % (in the linear case) to 53-42 % (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5 % of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity contributes less, particularly for the adapted Gaussian-kernel-based estimators and the event synchronization function. The introduced link strength concept summarizes the hypothesis test results and balances the individual strengths of the estimators: while gXCF is particularly suitable for short and irregular time series, gMI and the ESF can identify nonlinear dependencies. ESF could, in particular, be suitable to study extreme event dynamics in paleoclimate records. Programs to analyze paleoclimatic time series for significant dependencies are included in a freely available software toolbox.

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Section: Discussionmentioning

confidence: 91%

Similarity estimators for irregular and age-uncertain time series

Rehfeld

Kurths

2014

Clim. Past

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“…Additionally, time series of ammonium, bromine, lead, acidity, and conductivity were included, if the interpretation of the above parameters were not clear. For the few sections of problematic core quality that could not be measured at DRI (bad core breaks, broken cores), the annual interpretation relied on electrical conductivity measurements (ECM) and dielectric profiling (DEP) performed before shipment to DRI [Moore, 1993;Taylor et al, 2004;Taylor, Alley, Lamorey, and Mayewski, 1997]. The quality of those measurements is good, and the poor quality of most sections was only a result of the shipment process.…”

Section: Ice Core Datingmentioning

confidence: 99%

A new bipolar ice core record of volcanism from WAIS Divide and NEEM and implications for climate forcing of the last 2000 years

et al. 2013

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Volcanism is a natural climate forcing causing short‐term variations in temperatures. Histories of volcanic eruptions are needed to quantify their role in climate variability and assess human impacts. We present two new seasonally resolved, annually dated non‐sea‐salt sulfur records from polar ice cores—WAIS Divide (WDC06A) from West Antarctica spanning 408 B.C.E. to 2003 C.E. and NEEM (NEEM‐2011‐S1) from Greenland spanning 78 to 1997 C.E.—both analyzed using high‐resolution continuous flow analysis coupled to two mass spectrometers. The high dating accuracy allowed placing the large bi‐hemispheric deposition event ascribed to the eruption of Kuwae in Vanuatu (previously thought to be 1452/1453 C.E. and used as a tie‐point in ice core dating) into the year 1458/1459 C.E. This new age is consistent with an independent ice core timescale from Law Dome and explains an apparent delayed response in tree rings to this volcanic event. A second volcanic event is detected in 1453 C.E. in both ice cores. We show for the first time ice core signals in Greenland and Antarctica from the strong eruption of Taupo in New Zealand in 232 C.E. In total, 133 volcanic events were extracted from WDC06A and 138 from NEEM‐2011‐S1, with 50 ice core signals—predominantly from tropical source volcanoes—identified simultaneously in both records. We assess the effect of large bipolar events on temperature‐sensitive tree ring proxies. These two new volcanic records, synchronized with available ice core records to account for spatial variability in sulfate deposition, provide a basis for improving existing time series of volcanic forcing.

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“…In this study we used ice samples from the Siple Dome deep ice core (SDMA) drilled from 1997 to 1999 on the Siple Coast, West Antarctica (81.65 • S, 148.81 • W; 621 m elevation) (Taylor et al, 2004). The SDMA samples were collected and cut at National Ice Core Laboratory (NICL, Denver, Colorado, USA) from January to February of 2013.…”

Section: Methodsmentioning

confidence: 99%

Atmospheric methane control mechanisms during the early Holocene

et al. 2017

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Abstract. Understanding processes controlling the atmospheric methane (CH 4 ) mixing ratio is crucial to predict and mitigate future climate changes in this gas. Despite recent detailed studies of the last ∼ 1000 to 2000 years, the mechanisms that control atmospheric CH 4 still remain unclear, partly because the late Holocene CH 4 budget may be comprised of both natural and anthropogenic emissions. In contrast, the early Holocene was a period when human influence was substantially smaller, allowing us to elucidate more clearly the natural controls under interglacial conditions more clearly. Here we present new high-resolution CH 4 records from Siple Dome, Antarctica, covering from 11.6 to 7.7 thousands of years before 1950 AD (ka). We observe four local CH 4 minima on a roughly 1000-year spacing, which correspond to cool periods in Greenland. We hypothesize that the cooling in Greenland forced the Intertropical Convergence Zone (ITCZ) to migrate southward, reducing rainfall in northern tropical wetlands. The inter-polar difference (IPD) of CH 4 shows a gradual increase from the onset of the Holocene to ∼ 9.5 ka, which implies growth of boreal source strength following the climate warming in the northern extratropics during that period.

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Dating the Siple Dome (Antarctica) ice core by manual and computer interpretation of annual layering

Cited by 93 publications

References 24 publications

Similarity estimators for irregular and age-uncertain time series

Similarity estimators for irregular and age-uncertain time series

A new bipolar ice core record of volcanism from WAIS Divide and NEEM and implications for climate forcing of the last 2000 years

Atmospheric methane control mechanisms during the early Holocene

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