Origins of water beneath Mars' south polar ice cap

Dr Neil Arnold, in collaboration with Dr Matt Balme and Dr Frances Butcher (a former undergraduate in the Department of Geography here in Cambridge) of the Open University, and Dr Susan Conway of the University of Nantes, France, have published a paper in the Journal of Geophysical Research: Planets investigating the location of the recently-detected water layer beneath part of Mars' south polar ice cap.

Mars' present‐day ice deposits are generally assumed to be frozen throughout given its very cold climate, but new evidence from orbital radar data suggests a possible present‐day ~20km‐wide area of liquid water beneath Mars' south polar ice cap. Subglacial lakes are common on Earth, and their locations have been successfully predicted from ice surface topography and ice thickness using theories for subglacial water flow. This paper uses surface topography and ice thickness data for Mars' south polar ice cap to calculate the theoretical locations of possible subglacial lakes beneath the ice cap, and compares these with the location of the observed possible present‐day area of liquid water. The observed patch of possible liquid water does not coincide with the predicted lake locations however, which the paper interprets as implying that the liquid water is most likely to be an isolated patch of liquid, possibly caused by locally raised geothermal heating, rather than the liquid forming a "true", topographically constrained, subglacial lake.

SPRI Emeritus Professor, Philip Gibbard, awarded the Digby McLaren Medal

Congratulations to SPRI Emeritus Professor Philip Gibbard, who was awarded the Digby McLaren Medal, at the International Commission on Stratigraphy's STRATI 2019 Congress in Milano, Italy on 4th July 2019.

The Medal is awarded to honour a significant body of internationally important contributions to stratigraphy sustained over a number of years. Contributions can be in research (through publication of papers, monographs or books) or in education (through development of influential educational material or resources. It is expected that a major proportion of the work will have been published in an international language.

Past water flow beneath Pine Island and Thwaites glaciers

A team of researchers at the Scott Polar Research Institute along with collaborators at the British Antarctic Survey, Lamont‑Doherty Earth Observatory, and Victoria University of Wellington have published a paper investigating subglacial water flow beneath Pine Island and Thwaites glaciers in West Antarctica.

The study combines geomorphological mapping and numerical modelling of water flow beneath the West Antarctic Ice Sheet 20,000 years ago. The authors find that water discharged from a system of subglacial lakes carved out huge channels beneath the glaciers over several glacial cycles. The results are reported in the journal The Cryosphere.

The team includes PhD student James Kirkham, Professor Julian Dowdeswell, Dr Neil Arnold and Dr Kelly Hogan and Dr Robert Larter at the British Antarctic Survey.

Rapid melting of the world’s largest ice shelf linked to solar heat in the ocean

A study conducted at the Scott Polar Research Institute links melting of the world's largest ice shelf to solar heating of the ocean surface. The findings may have important implications for the stability of ice shelf.

In a study of Antarctica's Ross Ice Shelf, which covers an area roughly the size of France, the team spent several years building up a record of how the north-west sector of this vast ice shelf interacts with the ocean beneath it. Their results, reported in the journal Nature Geoscience, show that the ice is melting much more rapidly than previously thought due to inflowing warm water.

Glaciers and surface winds in a Himalayan valley

PhD student, Emily Potter, with supervisors Ian Willis (SPRI), Andrew Orr (BAS) and colleagues have published their latest research in the Journal of Geophysical Research, which has also been featured as an Editors' Highlight in EOS.

The work uses field measurements and a regional climate model to determine the patterns and causes of wind acceleration around the Khumbu Valley, Nepal, and how they change over diurnal cycles, and between the monsoon and dry seasons.

It confirms strong daytime up-valley winds and weak nighttime winds in both seasons, and shows that pressure gradient forces are the dominant cause of wind acceleration, but that turbulence and advection are important too. The forcing terms are highly variable across the valley, and also strongly influenced by the presence of glaciers. When glaciers are removed from the model in the monsoon run, the wind continues much further up the valley, showing how local valley winds might respond to future glacier shrinkage.

This work will help the development of regional climate models in the Hindu-Kush Karakoram Himalaya, which are crucial for predicting future precipitation and glacier melt in the region.