Field-calibrated model of melt, refreezing, and runoff for polar ice caps : Application to Devon Ice Cap

Acknowledgments R.M.M. was supported by the Scottish Alliance for Geoscience, Environment and Society (SAGES). The field data collection contributed to the validation of the European Space Agency Cryosat mission and was supported by the Natural Sciences and Engineering Research Council, Canada, the Meteorological Service of Canada (CRYSYS program), the Polar Continental Shelf Project (an agency of Natural Resources Canada), and by UK Natural Environment Research Council consortium grant NER/O/S/2003/00620. Support for D.O.B. was provided by the Canadian Circumpolar Institute and the Climate Change Geoscience Program, Earth Sciences Sector, Natural Resources Canada (ESS contribution 20130371). Thanks are also due to the Nunavut Research Institute and the communities of Resolute Bay and Grise Fjord for permission to conduct fieldwork on Devon Ice Cap. M.J. Sharp, A. Gardner, F. Cawkwell, R. Bingham, S. Williamson, L. Colgan, J. Davis, B. Danielson, J. Sekerka, L. Gray, and J. Zheng are thanked for logistical support and field assistance during the data collection. We thank Ruzica Dadic, two other anonymous reviewers, and the Editor, Bryn Hubbard, for their helpful comments on an earlier version of this paper and which resulted in significant improvements.Peer reviewedPublisher PD

Some aspects of the thermophysiology of the skink Leiolopisma Zelandica.

The original aim of this study was to characterise some aspects of the thermophysiology of a terrestrial vertebrate ectotherm which is physiologically adapted to tolerate and to be active over a wide range of body temperatures including low temperatures. The intention was to investigate the physiological performances of a eurythermic lizard over as wide a temperature range as was biologically and technically practicable and at different levels of organisation (organismal, organ and tissue). The small eurythermic skink Leiolopisma zelandica was chosen because of its abundance locally. Preliminary experiments indicated that certain physiological responses of the intact animal could be determined over the range -5° to 40° C. During the course of this investigation, information about the general biology and thermal relations of L. zelandica was also obtained, In addition, a large number of experiments were conducted at the temperature extremes of this species to explore physiological and behavioural responses to high and low temperatures. The bulk of the work on the thermophysiology of whole animals and tissues has been written up as two manuscripts in a style suitable for publication (Section 1, Papers A and B). A second section was erected to contain more thorough accounts of the biology, thermal relations and responses to temperature extremes of L. zelandica (Section 2, Parts A and B). Because most of the thermophysiological work was presented in the more concise format of a manuscript, it was necessary to elaborate in appendices on pertinent information regarding equipment and procedures. Data presented graphically in Papers A and B are tabulated in the final appendix. This approach to thesis presentation has necessitated some duplication of information within the thesis so that the Papers could be relatively autonomous. Since, at the time of thesis submission, Papers A and B have not been sent to editors, a compromise was made between the traditional form of a dissertation and the manuscript style. Consequently, a certain amount of redaction is anticipated

Silica in a Mars analog environment: Ka'u Desert, Kilauea Volcano, Hawaii

Airborne Visible/Near-Infrared Imaging Spectrometer (AVIRIS) data acquired over the Ka'u Desert are atmospherically corrected to ground reflectance and used to identify the mineralogic components of relatively young basaltic materials, including 250–700 and 200–400 year old lava flows, 1971 and 1974 flows, ash deposits, and solfatara incrustations. To provide context, a geologic surface units map is constructed, verified with field observations, and supported by laboratory analyses. AVIRIS spectral end-members are identified in the visible (0.4 to 1.2 μm) and short wave infrared (2.0 to 2.5 μm) wavelength ranges. Nearly all the spectral variability is controlled by the presence of ferrous and ferric iron in such minerals as pyroxene, olivine, hematite, goethite, and poorly crystalline iron oxides or glass. A broad, nearly ubiquitous absorption feature centered at 2.25 μm is attributed to opaline (amorphous, hydrated) silica and is found to correlate spatially with mapped geologic surface units. Laboratory analyses show the silica to be consistently present as a deposited phase, including incrustations downwind from solfatara vents, cementing agent for ash duricrusts, and thin coatings on the youngest lava flow surfaces. A second, Ti-rich upper coating on young flows also influences spectral behavior. This study demonstrates that secondary silica is mobile in the Ka'u Desert on a variety of time scales and spatial domains. The investigation from remote, field, and laboratory perspectives also mimics exploration of Mars using orbital and landed missions, with important implications for spectral characterization of coated basalts and formation of opaline silica in arid, acidic alteration environments

Dynamical description of vesicle growth and shape change

We systematize and extend the description of vesicle growth and shape change using linear nonequilibrium thermodynamics. By restricting the study to shape changes from spheres to axisymmetric ellipsoids, we are able to give a consistent formulation which includes the lateral tension of the vesicle membrane. This allows us to generalize and correct a previous calculation. Our present calculations suggest that, for small growing vesicles, a prolate ellipsoidal shape should be favored over oblate ellipsoids, whereas for large growing vesicles oblates should be favored over prolates. The validity of this prediction is examined in the light of the various assumptions made in its derivation.Comment: 6 page