Sea Level Rise Seminar, 2020-09-29: Rebecca Jackson

Sea Level Rise Seminar, 2020-09-29
Presenter: Rebecca Jackson
Title: Melting and mixing at the termini of tidewater glaciers

Overview: Around the globe, glaciers and ice sheets are shrinking and contributing to sea level rise. Projections of sea level are hindered by our limited understanding of the ocean’s role in driving glacier mass loss. With growing evidence that ocean warming can trigger glacier retreat, submarine melting lies at the crux of ocean-glacier interactions. However, at the termini of tidewater glaciers, we lack observations of submarine melting or the oceanic processes that control melt. Instead, many studies rely on untested theory and parameterizations to estimate submarine melt rates. These frameworks hinge on buoyant plumes, whose small-scale dynamics can modulate both the ocean’s impact on the glacier via submarine melting and the glacier’s impact on the ocean via buoyancy forcing. In this talk, I will present data collected near the terminus of LeConte Glacier, Alaska to probe the standard theory for plume-driven melt. In the first half, I will present surveys from autonomous kayaks that reveal ubiquitous meltwater intrusions along the terminus and suggest a mechanism to explain melt rates that are significantly higher than standard theory predicts. In the second half, the bulk freshwater fluxes from submarine melt and subglacial discharge are evaluated across a wide range of conditions in seven field campaigns in order to test the theoretical relationship between these two sources of freshwater. Modifications to the standard melt parameterizations are explored, in an effort to work towards an updated representation of melt in ocean-glacier models.

Видео Sea Level Rise Seminar, 2020-09-29: Rebecca Jackson канала NASA Goddard Institute for Space Studies