We present an analysis of two concentrically-fractured depressions on Mars, one in northern Hellas and the second in Galaxias Fossae. Volumetric measurements indicate that ∼2.4 km 3 and ∼0.2 km 3 of material was removed in order to form the North Hellas and Galaxias depressions. The removed material is inferred to be predominantly water ice. Calorimetric estimates suggest that up to ∼10 3 –10 5...

The impact of climatic change along the Antarctica Peninsula has been widely debated in light of atmospheric/oceanic warming and increases in glacial melt over the past half century. Particular concern exists over the impact of these changes on marine ecosystems, not only on primary producers but also on higher trophic levels. Here we present a record detailing of the historical controls on the...

Concentric crater fill (CCF) occurs in the interior of impact craters in midto high latitudes on Mars and is interpreted to have formed by glacial ice flow and debris covering. We use the characteristics and orientation of deposits comprising CCF, the thickness of pedestal deposits in midto high-latitude pedestal craters (Pd), the volumes of the current polar caps, and information about regiona...

[1] Understanding the history of ice caps on Mars could reveal important information about Martian geologic and climatic history. To do this, an ice reconstruction model is needed that operates over complex topography and can be constrained with a limited number of free parameters. In this study we developed a threshold-sliding model for ice cap morphology based on the classic model of Nye late...

The emergence of rapid Arctic warming in recent decades has coincided with unusually cold winters over Northern Hemisphere continents. It has been speculated that this “Warm Arctic, Cold Continents” trend pattern is due to sea ice loss. Here we use multiple models to examine whether such a pattern is indeed forced by sea ice loss specifically and by anthropogenic forcing in general. While we sh...

A general circulation model of the Martian Atmosphere is coupled with a 3-dimensional polythermal ice-sheet model of the polar ice caps. With this combination a series of experiments is carried out to investigate the impact of long-term obliquity change on the Martian north polar ice cap (NPC). The behaviour of the NPC is tested under obliquities of y 1⁄4 15 , 25 and 35 . With increasing obliqu...

Sea-ice conditions and kinematics are studied in the Palmer Long-Term Ecological Research (PAL LTER) study region west of the Antarctic Peninsula. Remote sensing data from ERS-1 Synthetic Aperture Radar (SAR) and Scatterometer (EScat) and from DMSP SSM/I, are used to study the influence of synoptic weather systems on sea-ice characteristics during July-August 1992. Weather records from Palmer S...

Introduction: High latitude ground ice on Mars was inferred in the shallow subsurface by hydrogen measurements using Mars Odyssey’s Gamma Ray Spectrometer (GRS) [1]. However, at mid to low latitudes, GRS found only small quantities of hydrogen, consistent with hydrated minerals. Recent observations have shown new small craters [2], and some in the mid-latitudes have exposed water ice at a depth...

Dynamic impact responses and brain tissue deformations from helmeted centric and non-centric headform impacts were assessed with respect to suggested concussive injury thresholds from the literature. Results from six commercially available ice hockey helmets were compared statistically. It is proposed that the current centric impact standards for ice hockey helmets measuring linear acceleration...