Low velocity impact experiments (0.14 to l km/ s) carried out in polycrystalline water ice targets at 257 and 81 K resulted in interactions which can be assigned to four fragmentation classes, cratering, erosion, disruption, and total fragmentation. Specific kinetic energies for the transitions between these classes range from l x 105 to 7 x 105 ergs/g for 81 K ice and from 3 x 105 to 2 x 106 e...

The mode of formation of gullies on Mars, very young erosional–depositional landforms consisting of an alcove, channel, and fan, is one of the most enigmatic problems in martian geomorphology. Major questions center on their ages, geographic and stratigraphic associations, relation to recent ice ages, and, if formed by flowing water, the sources of the water to cause the observed erosion/deposi...

In July 2011, the observation of a massive phytoplankton bloom underneath a sea ice-covered region of the Chukchi Sea shifted the scientific consensus that regions of the Arctic Ocean covered by sea ice were inhospitable to photosynthetic life. Although the impact of widespread phytoplankton blooms under sea ice on Arctic Ocean ecology and carbon fixation is potentially marked, the prevalence o...

Recent studies indicate that the glaciers and ice caps in Queen Elizabeth Islands (QEI), Canada have experienced an increase in ice mass loss during the last two decades, but the contribution of ice dynamics to this loss is not well known. We present a comprehensive mapping of ice velocity using a suite of satellite data from year 1991 to 2015, combined with ice thickness data from NASA Operati...

We develop a modeling framework to describe the accumulation of terrestrial cosmogenic 3He in Antarctic debris-covered glaciers. The framework helps quantify the expected range in cosmogenic-nuclide inventories for measured clasts at the surface of supraglacial debris. We first delineate the physical factors that impact clast movement within, and on top of, debris-covered glaciers, including th...

We present the Potsdam Parallel Ice Sheet Model (PISM-PIK), developed at the Potsdam Institute for Climate Impact Research to be used for simulations of large-scale ice sheet-shelf systems. It is derived from the Parallel Ice Sheet Model (Bueler and Brown, 2009). Velocities are calculated by superposition of two shallow stress balance approximations within the entire ice covered region: the sha...

The radiative impact of water ice clouds on the atmosphere of Mars is analyzed via a reanalysis of Mars Climate Sounder (MCS) temperature and ice opacity profiles. Polar hood clouds only have a small radiative impact, while tropical clouds increase diurnally averaged temperatures at the 10 Pa level by ∼10–15 K. Cloud radiative heating strengthens the meridional overturning circulation, increasi...

Assessing the impact of glaciation on Earth's surface requires understanding glacial erosion processes. Developing erosion theories is challenging because of the complex nature of the erosion processes and the difficulty of examining the ice/bedrock interface of contemporary glaciers. We demonstrate that the glacial erosion rate is proportional to the ice-sliding velocity squared, by quantifyin...

To realize a penetrator mission for icy objects in the solar system, a fundamental study on the penetration dynamics into ice has been made. In the experiments, projectiles of the mass about 2.5 g were tested for the target made from water ice by the ballistic range at the impact velocity 100-350 m/s, and the behavior of the projectile and target was observed by the high-speed video camera. Unl...