Fast-flowing ice streams transport ice from the interior of the Antarctic Ice Sheet to the ocean. Understanding how ice-stream tributaries evolve is crucial for predicting the ice sheet’s response to climate change. This map, approximately 1000 km across, shows the pattern of flow convergence on the Siple-Coast Ice Streams in West Antarctica, computed from surface velocities measured by satellite-based interferometric radar. Blue and bronze colours signify converging and diverging flows, respectively. Black indicates streaming flow where the ice speed exceeds 50 metres per year. From left to right are the four major ice-stream systems of MacAyeal, Bindschadler, Whillans, and Mercer. Flow speeds on their main trunks reach several hundred metres per year. Visible above the centre of the image is the remnant flow of the Kamb Ice Stream, which stagnated 200 years ago.

This map shows that ice streams capture ice from the slow interior and interstream ridges (white areas) in a complex manner. These findings highlight the role of nonlinear ice rheology in ice-stream formation and help elucidate the mechanisms controlling the spatial dynamics of ice-stream networks.

Dr Ng is from the Department of Geography, University of Sheffield, UK. The image was made by using the computational results of his publications.