Assessment of errors and uncertainty patterns in GIA modeling

During the last decade many efforts have been devoted to the assessment of global sea level rise and to the determination of the mass balance of continental ice sheets. In this context, the important role of glacial-isostatic adjustment (GIA) has been clearly recognized. Yet, in many cases only one "preferred" GIA model has been used, without any consideration of the possible errors involved.

Lacking a rigorous assessment of systematic errors in GIA modeling, the reliability of the results is uncertain. GIA sensitivity and uncertainties associated with the viscosity models have been explored in the literature. However, at least two major sources of errors remain. The first is associated with the ice models, spatial distribution of ice and history of melting (this is especially the case of Antarctica), the second with the numerical implementation of model features relevant to sea level modeling, such as time-evolving shorelines and paleo coastlines.

In this study we quantify these uncertainties and their propagation in GIA response using a Monte Carlo approach to obtain spatio-temporal patterns of GIA errors. A direct application is the error estimates in ice mass balance in Antarctica and Greenland due to GIA. GIA errors are also important in the far field of previously glaciated areas and in the time evolution of global indicators.

In this regard we also account for other possible errors sources which can impact global indicators like the sea level history related to GIA.