The Influence of Sea-level Indicator Uncertainties on the LIG Highstand Oscillations

Abstract:

Paleoclimatic sea-level analysis is based upon the evaluation of sparse indirect observational data, the sea-level indicators, and models for sea-level fluctuations, with a wide range of complexity. Individual records of paleo sea-level depend not only upon the change in global ice volume, but also on the crustal deformation and gravity changes that are significant both near the glaciers and around the world. Understanding of these processes for the past is essential for interpreting the observations in order to generate better estimates for the future.

As part of the NERC-funded iGlass consortium, we use massive ensemble approaches to analyse sea-level changes during the last interglacial (LIG). Employing a bayesian statistical analysis, we compare the sea-level indicators to model-generated sea-level estimates. As a result we gain insight into the development of the ice sheets, the influence of the Earth deformation and the evolution of higher-than-present-day sea level during that period.

This contribution gives an overview of our sea-level analysis during the LIG. We focus on the uncertainties due to different selection and treatments of sea-level indicators. For example, some corals can have a large variation in depth habitat. We demonstrate that different methods of accounting for this range can influence the sea-level height estimate from the data. The analysis helps to answer questions of the effect of the uncertainties in the indicators, both in height as well as temporally, on features of the estimated global-average sea level. In particular, we address how well the data resolve sea-level oscillations during the LIG.