The Role of Uncertainty in Estimating Lead/Lag Relationships in Marine Sedimentary Archives: A Case Study From the Tropical Pacific

Abstract

Understanding the mechanisms behind any changes in the climate system often requires establishing the timing of events imprinted on the geological record. However, these proxy records are prone to large uncertainties, which may preclude meaningful conclusions about the relative timing of events. In this study, we put forth a framework to estimate the uncertainty in phase relationships inferred from marine sedimentary records. The novelty of our method lies in the accounting of the various sources of uncertainty inherent to paleoclimate reconstruction and timing analysis. Specifically, we use a Monte Carlo process allowing sampling of possible realizations of the time series as functions of uncertainties in time, the climate proxy, and the identification of the termination timing. We then apply this technique to 15 published sea surface temperature records from the equatorial Pacific to evaluate whether we observed any significant changes in the termination timing between the east and the west. We find that the uncertainty on the relative timing estimates is on the order of several thousand years and mainly stems from age model uncertainty (90%). However, even small differences in mean termination timings can be detected with a sufficiently large number of samples. Improvements in the dating of sediment records provide an opportunity to reduce uncertainty in studies of this kind.

Deglacial carbon cycle changes observed in a compilation of 127 benthic <i>δ</i><sup>13</sup>C time series (20–6 ka)

“…For age models generated either by δ 18 O alignment or radiocarbon dating, the amount of age uncertainty depends on the time resolution of the δ 18 O or 14 C data, respectively. A comparison of 15 low-latitude Pacific cores found that 14 C-based age uncertainty is comparable to, if not greater than, the uncertainty associated with δ 18 O alignments by HMM-Match (Khider et al, 2017).…”

Astronomical tunings of the Oligocene–Miocene transition from Pacific Ocean Site U1334 and implications for the carbon cycle

“…We note, however, that these records show variable ratios of productivity to dissolution as the main source of variance in the data. Future additional testing of phase uncertainties could include statistical approaches, such as Monte Carlo simulations (Khider et al, 2017).…”

Modern, Preindustrial, and Past (Last 25 ka) Carbon Isotopic (δ13C) Variability in the Surface Waters of the Southwest Pacific

“…To determine the main long‐term trends in the δ 13 C DIC equivalent data for each region, we combined downcore δ 13 C G . bulloides TC data sets from the same region (e.g., BoP and NCR) using a Monte Carlo simulation in the program R, which considers the analytical and chronological errors to provide a statistically robust long‐term trend (Khider et al, ). For the analytical error for δ 13 C G .…”

“…Planktic δ 13 C are typically noisy and hard to interpret. To determine the main long-term trends in the δ 13 C DIC equivalent data for each region, we combined downcore δ 13 C G.bulloidesTC data sets from the same region (e.g., BoP and NCR) using a Monte Carlo simulation in the program R, which considers the analytical and chronological errors to provide a statistically robust long-term trend (Khider et al, 2017). For the analytical error for δ 13 C G.bulloides we used ±0.05‰ and all δ 13 C are reported with respect to the Vienna Peedee Belemite (vpdb) standard Schiraldi et al, 2014).…”