Development of Ice-Shelf Estuaries Promotes Fractures and Calving.

Area of Science:

• Glaciology
• Climate Science
• Hydrology

Background:

• Global warming increases surface meltwater on ice shelves.
• Efficient meltwater evacuation is crucial to prevent ice-shelf collapse.

Purpose of the Study:

• To observe the evolution of a surface river into an ice-shelf estuary.
• To identify similar estuary formations on other ice shelves.
• To understand the impact of these estuaries on ice-shelf stability and calving.

Main Methods:

• Field observations of surface river evolution into an estuary.
• Analysis of ice-shelf fracturing patterns.
• Identification of estuary channels and their correlation with calving events.

Main Results:

• Observed a surface river evolving into an estuary on the Petermann Ice Shelf.
• Identified a second estuary at the Ryder Ice Shelf.
• Documented flow reversal and persistent seawater within the Petermann estuary.
• Found linear fractures initiating at the calving front and propagating upstream along estuary channels.
• Linked estuary channels to past rectilinear calving events.

Conclusions:

• Surface hydrology processes, including estuary formation, can promote fracturing and enhance calving.
• Increased surface melting will enhance fluvial incision, promoting estuary development and longitudinal fracturing.
• Estuary development may lead to increased calving and accelerate ice loss and global sea-level rise, potentially impacting Antarctica within 50 years.