Dynamic Surface Hydrology

Dynamic Surface Hydrology

Supraglacial hydrological features, including lakes, streams and slush, form as a result of atmospherically forced melting at the ice sheet surface. They are important in the context of ice shelf stability for two main reasons: First, they are an important indicator that the ice shelf has reached, or is near to, it’s limit of viability with respect to atmospheric forcing. This is because they form on ice shelves where the firn layer is thin, saturated or rendered impermeable by the refreezing of meltwater into solid ice slabs (potentially by slush that formed in previous years). Second, lakes in particular can contribute to instability directly, by inducing fractures in the ice shelf when they fill and drain. This can potentially contribute to iceberg calving and is thought to be the mechanism for the complete collapse of the Larsen B Ice Shelf in 2002.

Examples of  random forest based classification of supraglacial hydrology in the Watson River Region of the Greenland Ice Sheet from Sentinel-2 satellite imagery. True colour images are shown in figures a, c, e and g, while b, d, f, and h are the same images with the regions classified as surface water overlaid in red.

Summary of dynamic surface hydrology datasets planned within 5DAIS:

• The 5DAIS dataset will be based on Sentinel-2 optical satellite imagery data.
• Temporal sampling will be determined during the project consolidation phase, but is expected to be a monthly icesheet wide product with the possibility of fortnightly or finer for selected ROIs. All ice shelves will be mapped from slightly inland of the grounding line to the margin .
• Lake and stream mapping will be validated against previously-published lakes products for WAIS for 2017 and EAIS for 2017 and products generated for GVIIS and for the Amundsen Sea Embayment through the Digital Twin Antarctica project. Slush mapping will be validated against previously published estimates.