With recent observations of diminishing summer Arctic sea ice extent, the hypothesis of a “tipping point” in summer ice cover has been the focus of a number of studies. This view suggests that as summer Arctic sea ice cover retreats it will reach a critical point after which the ice–albedo effect will cause the summer ice cover to disappear altogether. We have examined the heuristic argument be...

The low-temperature proton-ordered counterparts for ice-Ih, ice-III, ice-VI and ice-VII are investigated by first principle methods in conjunction with a graph enumeration technique. Two experimentally well calibrated disorder/order transitions, ice-Ih/ice-XI and ice-VII/ice-VIII, are used to validate the methodology we used herein and in both cases our approach is able to reproduce major exper...

Liquid water present in polycrystalline ice at the interstices between ice crystals results in a network of liquid-filled veins and nodes within a solid ice matrix, making ice a low porosity porous media. Here we used nuclear magnetic resonance (NMR) relaxation and time dependent self-diffusion measurements developed for porous media applications to monitor three dimensional changes to the vein...

[1] This study investigates the effects of cloud condensation nuclei (CCN) and ice nuclei (IN) on ice formation in mixed-phase clouds using an adiabatic parcel model. The simulations with lower updrafts represent mixed-phase stratiform clouds, and those with higher updrafts represent deep convective clouds. Increasing CCN concentration can lead to more ice crystals with smaller sizes, but does ...

Understanding the dynamic behaviour of ice in glaciers, polar ice caps, sea ice and the icy planets of the Solar System is a major challenge, especially in a time of changing climate, amplified at the poles and exciting new space exploration. This theme issue of the Philosophical Transactions of the Royal Society A highlights some of the recent advances in the observations, analyses, theories, ...

in the early days of aviation, at the advent of thermal ice protection system development, aircraft designers believed that in fighting in-flight icing, the critical variables were the mass of supercooled water that an airplane would transit and the temperature. The measure of mass is liquid water content (LWC). Droplet size of supercooled water, which influences potential icing severity, is me...

1Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, PO Box 60 12 03, Potsdam, Germany. 2Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany. 3British Antarctic Survey, Cambridge, UK. 4Lamont–Doherty Earth Observatory, Columbia University, New York, NY, USA. *e-mail: [email protected] Floating ice shelves, which fringe ...

The winter expansion of the sea ice surrounding Antarctica and the subsequent retreat of the ice in summer may be linked with the wind stress acting on the Southern Ocean in conjunction with the heat exchange in open water regions within the ice fields.

The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data ...