Do Inner Greenland's Melt Rate Dynamics Approach Coastal Ones?

TL;DR

This paper uses Bayesian Langevin estimation to analyze Greenland's melt rate dynamics, revealing destabilizing trends and nonlinear behaviors that suggest inland melt may be approaching coastal instability, driven by atmospheric fluctuations.

Contribution

It introduces a nonlinear Bayesian Langevin estimation approach to better understand Greenland melt dynamics, highlighting the importance of nonlinear modeling over linear methods.

Findings

Increased fast-scale melt amplitudes since 1970s.

Inland melt dynamics may become less stable, approaching coastal melt.

Nonlinear drift is essential for accurate modeling of melt dynamics.

Abstract

The Greenland Ice Sheet may be nearing a tipping point, transitioning to permanent melting. This article analyses two melt rate time series using the Bayesian Langevin estimation (BLE), providing further evidence for destabilizing melt dynamics, along with new insights from the method's nonlinear parameterisation. Comparing the results for Western Central Greenland and the Nuussuaq peninsula suggests that inland melt dynamics may approach less stable coastal dynamics on slow and fast scales. Both datasets show a significant increase in fast-scale amplitudes since the 1970s, possibly driven by large-scale atmospheric fluctuations. Additionally, the BLE's nonlinear drift proves crucial for obtaining these results, as a linear Ornstein-Uhlenbeck process fails to capture these dynamics due to the oversimplification of a strictly positive autocorrelation function.