Enthalpy balance theory unifies diverse glacier surge behaviour

Abstract

It is commonly asserted that there are two distinct classes of glacier surges: slow, long-duration ‘Svalbard-type’ surges, triggered by a transition from cold- to warm-based conditions (thermal switching), and fast, shorter-duration ‘Alaska-type’ surges triggered by a reorganisation of the basal drainage system (hydraulic switching). This classification, however, reflects neither the diversity of surges in Svalbard and Alaska (and other regions), nor the fundamental dynamic processes underlying all surges. We argue that enthalpy balance theory offers a framework for understanding the spectrum of glacier surging behaviours while emphasising their essential dynamic unity. In this paper, we summarise enthalpy balance theory, illustrate its potential to explain so-called ‘Svalbard-type’ and ‘Alaska-type’ surges using a single set of principles, and show examples of a much wider range of glacier surge behaviour than previously observed. We then identify some future directions for research, including strategies for testing predictions of the theory against field and remote sensing data, and priorities for numerical model development.

Glacier Surge as a Trigger for the Fastest Delta Growth in the Arctic

“…To understand the signi cance of the meltwater release event implied by rapid delta formation, it is useful to consider the controls on water storage and release during the whole surge cycle. Velocity uctuations during surges of Svalbard glaciers commonly display correlations with air temperature, re ecting routing of surface meltwater to the bed through crevassed ice (Benn et al, 2019b(Benn et al, , 2023Sevestre et al, 2018). This can be clearly seen in Fig.…”

“…Such summer slowdowns are common on both surging and non-surging glaciers, and re ect the development of e cient conduit systems in response to high meltwater in ux (e.g. Bartholomew et al, 2012;Benn et al, 2023;Mair et al, 2003;Meier et al, 1994).…”