Distributed energy balance modeling of South Cascade Glacier, Washington and assessment of model uncertainty
Faron S. Anslow, S. Hostetler, W. R. Bidlake, P.U. Clark
2008, Journal of Geophysical Research F: Earth Surface (113)
We have developed a physically based, distributed surface energy balance model to simulate glacier mass balance under meteorological and climatological forcing. Here we apply the model to estimate summer ablation on South Cascade Glacier, Washington, for the 2004 and 2005 mass balance seasons. To arrive at optimal mass balance simulations,...
Surface albedo observations at Gusev Crater and Meridiani Planum, Mars
J.F. Bell III, M.S. Rice, J. R. Johnson, T.M. Hare
2008, Journal of Geophysical Research E: Planets (113)
During the Mars Exploration Rover mission, the Pancam instrument has periodically acquired large-scale panoramic images with its broadband (739??338 nm) filter in order to estimate the Lambert bolometric albedo of the surface along each rover's traverse. In this work we present the full suite of such estimated albedo values measured...
Determining Titan's spin state from Cassini RADAR images
B.W. Stiles, Randolph L. Kirk, R. D. Lorenz, S. Hensley, E. Lee, S.J. Ostro, M.D. Allison, P.S. Callahan, Y. Gim, L. Iess, Del Marmo, G. Hamilton, W.T.K. Johnson, R.D. West
2008, Astronomical Journal (135) 1669-1680
For some 19 areas of Titan's surface, the Cassini RADAR instrument has obtained synthetic aperture radar (SAR) images during two different flybys. The time interval between flybys varies from several weeks to two years. We have used the apparent misregistration (by 10-30 km) of features between separate flybys to construct...
Alaska Melilotus invasions: Distribution, origin, and susceptibility of plant communities
J.S. Conn, K.L. Beattie, M.A. Shephard, M.L. Carlson, I. Lapina, M. Hebert, R. Gronquist, R. Densmore, M. Rasy
2008, Arctic, Antarctic, and Alpine Research (40) 298-308
Melilotus alba and M. officinalis were introduced to Alaska in 1913 as potential forage crops. These species have become naturalized and are now invading large, exotic plant-free regions of Alaska. We determined distributions of M. alba and M. officinalis in Alaska from surveys conducted each summer from 2002 to 2005....
Structure, stratigraphy, and origin of Husband Hill, Columbia Hills, Gusev Crater, Mars
T.J. McCoy, M. Sims, M.E. Schmidt, L. Edwards, L.L. Tornabene, L.S. Crumpler, B. A. Cohen, L.A. Soderblom, D.L. Blaney, S. W. Squyres, R. E. Arvidson, J.W. Rica, E. Treguier, C. d’Uston, J. A. Grant, H.Y. McSween, M.P. Golombek, A. F. C. Haldemann, P.A. de Souza
2008, Journal of Geophysical Research E: Planets (113)
The strike and dip of lithologic units imaged in stereo by the Spirit rover in the Columbia Hills using three-dimensional imaging software shows that measured dips (15-32??) for bedding on the main edifice of the Columbia Hill are steeper than local topography (???8-10??). Outcrops measured on West Spur are conformable...
Paleoclimatic significance of chemical weathering in loess-derived paleosols of subarctic central Alaska
D.R. Muhs, T. A. Ager, G. Skipp, J. Beann, J. Budahn, J. P. McGeehin
2008, Arctic, Antarctic, and Alpine Research (40) 396-411
Chemical weathering in soils has not been studied extensively in high-latitude regions. Loess sequences with modern soils and paleosols are present in much of subarctic Alaska, and allow an assessment of present and past chemical weathering. Five sections were studied in detail in the Fairbanks, Alaska, area. Paleosols likely date...
Relative abundance of mesopredators and size of oak patches in the cross-timbers ecoregion
M.R. Disney, E. C. Hellgren, C.A. Davis, David M. Leslie Jr., David M. Engle
2008, Southwestern Naturalist (53) 214-223
Mesopredators (e.g., raccoon Procyon lotor, Virginia opossum Didelphis virginiana, striped skunk Mephitis mephitis) have received considerable attention because of links to population declines in birds via increased nest predation, especially in landscapes fragmented by anthropogenic forces. Relationships of abundance of mesopredators to size of habitat patches have received less attention...
A reference data set of hillslope rainfall-runoff response, Panola Mountain Research Watershed, United States
Meerveld H. J. Tromp-van H. J., A.L. James, Jeffery J. McDonnell, N.E. Peters
2008, Water Resources Research (44)
Although many hillslope hydrologic investigations have been conducted in different climate, topographic, and geologic settings, subsurface stormflow remains a poorly characterized runoff process. Few, if any, of the existing data sets from these hillslope investigations are available for use by the scientific community for model development and validation or conceptualization...
Climatically driven loss of calcium in steppe soil as a sink for atmospheric carbon
A.G. Lapenis, G.B. Lawrence, S.W. Bailey, B.F. Aparin, A.I. Shiklomanov, N.A. Speranskaya, M.S. Torn, M. Calef
2008, Global Biogeochemical Cycles (22)
During the last several thousand years the semi-arid, cold climate of the Russian steppe formed highly fertile soils rich in organic carbon and calcium (classified as Chernozems in the Russian system). Analysis of archived soil samples collected in Kemannaya Steppe Preserve in 1920, 1947, 1970, and fresh samples collected in...
Analytical and numerical analyses of an unconfined aquifer test considering unsaturated zone characteristics
A.F. Moench
2008, Water Resources Research (44)
A 7-d, constant rate aquifer test conducted by University of Waterloo researchers at Canadian Forces Base Borden in Ontario, Canada, is useful for advancing understanding of fluid flow processes in response to pumping from an unconfined aquifer. Measured data include not only drawdown in the saturated zone but also volumetric...
Mangrove production and carbon sinks: A revision of global budget estimates
S. Bouillon, A.V. Borges, E. Castaneda-Moya, K. Diele, T. Dittmar, N.C. Duke, E. Kristensen, S.-Y. Lee, C. Marchand, J. J. Middelburg, V. H. Rivera-Monroy, T. J. Smith III, R.R. Twilley
2008, Global Biogeochemical Cycles (22)
Mangrove forests are highly productive but globally threatened coastal ecosystems, whose role in the carbon budget of the coastal zone has long been debated. Here we provide a comprehensive synthesis of the available data on carbon fluxes in mangrove ecosystems. A reassessment of global mangrove primary production from the literature...
Hydrothermal origin of halogens at Home Plate, Gusev Crater
M.E. Schmidt, S. W. Ruff, T.J. McCoy, W. H. Farrand, J. R. Johnson, Ralf Gellert, D. W. Ming, R.V. Morris, N. Cabrol, K.W. Lewis, Christian Schroeder
2008, Journal of Geophysical Research E: Planets (113)
In the Inner Basin of the Columbia Hills, Gusev Crater is Home Plate, an 80 m platform of layered elastic rocks of the Barnhill class with microscopic and macroscopic textures, including a bomb sag, suggestive of a phreatomagmatic origin. We present data acquired by the Spirit Mars Exploration Rover by...
Wind-driven particle mobility on Mars: Insights from Mars Exploration Rover observations at "El Dorado" and surroundings at Gusev Crater
R. Sullivan, R. Arvidson, J.F. Bell, Ralf Gellert, M. Golombek, R. Greeley, Kenneth E. Herkenhoff, J. Johnson, S. Thompson, P. Whelley, J. Wray
2008, Journal of Geophysical Research E: Planets (113)
The ripple field known as 'El Dorado' was a unique stop on Spirit's traverse where dust-raising, active mafic sand ripples and larger inactive coarse-grained ripples interact, illuminating several long-standing issues of Martian dust mobility, sand mobility, and the origin of transverse aeolian ridges. Strong regional wind events endured by Spirit...
Deep drilling into the Chesapeake Bay impact structure
G. S. Gohn, C. Koeberl, K.G. Miller, W.U. Reimold, J.V. Browning, C.S. Cockell, J. Wright Horton Jr., T. Kenkmann, A.A. Kulpecz, D.S. Powars, W. E. Sanford, M.A. Voytek
2008, Science (320) 1740-1745
Samples from a 1.76-kilometer-deep corehole drilled near the center of the late Eocene Chesapeake Bay impact structure (Virginia, USA) reveal its geologic, hydrologic, and biologic history. We conducted stratigraphic and petrologic analyses of the cores to elucidate the timing and results of impact-melt creation and distribution, transient-cavity collapse, and ocean-water...
Diurnal and vertical variability of the sensible heat and carbon dioxide budgets in the atmospheric surface layer
P. Casso-Torralba, J. V. -G. de Arellano, F. Bosveld, M.R. Soler, A. Vermeulen, C. Werner, E. Moors
2008, Journal of Geophysical Research D: Atmospheres (113)
The diurnal and vertical variability of heat and carbon dioxide (CO2) in the atmospheric surface layer are studied by analyzing measurements from a 213 in tower in Cabauw (Netherlands). Observations of thermodynamic variables and CO2 mixing ratio as well as vertical profiles of the turbulent fluxes are used to retrieve...
Genetic characterization of Hawaiian isolates of Plasmodium relictum reveals mixed-genotype infections
S.I. Jarvi, M.E.M. Farias, C. T. Atkinson
2008, Biology Direct (3)
Background: The relatively recent introduction of a highly efficient mosquito vector and an avian pathogen (Plasmodium relictum) to an isolated island ecosystem with nai??ve, highly susceptible avian hosts provides a unique opportunity to investigate evolution of virulence in a natural system. Mixed infections can significantly contribute to the uncertainty in...
Iron isotope fractionation during magmatic differentiation in Kilauea Iki lava lake
F.-Z. Teng, N. Dauphas, Rosalind Tuthill Helz
2008, Science (320) 1620-1622
Magmatic differentiation helps produce the chemical and petrographic diversity of terrestrial rocks. The extent to which magmatic differentiation fractionates nonradiogenic isotopes is uncertain for some elements. We report analyses of iron isotopes in basalts from Kilauea Iki lava lake, Hawaii. The iron isotopic compositions (56Fe/54Fe) of late-stagemeltveins are 0.2 permil...
Sediment and nutrient delivery from thermokarst features in the foothills of the North Slope, Alaska: Potential impacts on headwater stream ecosystems
W.B. Bowden, M.N. Gooseff, A. Balser, A. Green, B. J. Peterson, J. Bradford
2008, Journal of Geophysical Research G: Biogeosciences (113)
Permafrost is a defining characteristic of the Arctic environment. However, climate warming is thawing permafrost in many areas leading to failures in soil structure called thermokarst. An extensive survey of a 600 km2 area in and around the Toolik Lake Natural Research Area (TLNRA) revealed at least 34 thermokarst features,...
Oceanic loading of wildfire-derived organic compounds from a small mountainous river
G.B. Hunsinger, Siddhartha Mitra, J.A. Warrick, C. R. Alexander
2008, Journal of Geophysical Research G: Biogeosciences (113)
Small mountainous rivers (SMRs) export substantial amounts of sediment into the world's oceans. The concomitant yield of organic carbon (OC) associated with this class of rivers has also been shown to be significant and compositionally unique. We report here excessively high loadings of polycyclic aromatic hydrocarbons (PAHs), lignin, and levoglucosan,...
Mars Exploration Rover Navigation Camera in-flight calibration
J.M. Soderblom, J.F. Bell III, J. R. Johnson, J. Joseph, M.J. Wolff
2008, Journal of Geophysical Research E: Planets (113)
The Navigation Camera (Navcam) instruments on the Mars Exploration Rover (MER) spacecraft provide support for both tactical operations as well as scientific observations where color information is not necessary: large-scale morphology, atmospheric monitoring including cloud observations and dust devil movies, and context imaging for both the thermal emission spectrometer and...
The formation conditions of chondrules and chondrites
C. M. O’D. Alexander, Jeffrey N. Grossman, D.S. Ebel, F.J. Ciesla
2008, Science (320) 1617-1619
Chondrules, which are roughly millimeter-sized silicate-rich spherules, dominate the most primitive meteorites, the chondrites. They formed as molten droplets and, judging from their abundances in chondrites, are the products of one of the most energetic processes that operated in the early inner solar system. The conditions and mechanism of chondrule...
Evaluating the potential effectiveness of compensatory mitigation strategies for marine bycatch
M. Finkelstein, V. Bakker, D.F. Doak, B. Sullivan, R. Lewison, W.H. Satterthwaite, P.B. McIntyre, S. Wolf, D. Priddel, J.M. Arnold, R.W. Henry, P. Sievert, J. Croxall
2008, PLoS ONE (3)
Conservationists are continually seeking new strategies to reverse population declines and safeguard against species extinctions. Here we evaluate the potential efficacy of a recently proposed approach to offset a major anthropogenic threat to many marine vertebrates: incidental bycatch in commercial fisheries operations. This new approach, compensatory mitigation for marine bycatch...
MGS-TES thermal inertia study of the Arsia Mons Caldera
Glen E. Cushing, Timothy N. Titus
2008, Journal of Geophysical Research E: Planets (113)
Temperatures of the Arsia Mons caldera floor and two nearby control areas were obtained by the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES). These observations revealed that the Arsia Mons caldera floor exhibits thermal behavior different from the surrounding Tharsis region when compared with thermal models. Our technique compares...
Hydrothermal processes at Gusev Crater: An evaluation of Paso Robles class soils
A. S. Yen, R.V. Morris, B. C. Clark, Ralf Gellert, A.T. Knudson, S. Squyres, D. W. Mittlefehldt, D. W. Ming, R. Arvidson, T. McCoy, M. Schmidt, J. Hurowitz, R. Li, J. R. Johnson
2008, Journal of Geophysical Research E: Planets (113)
The Mars Exploration Rover Spirit analyzed multiple occurrences of sulfur-rich, light-toned soils along its traverse within Gusev Crater. These hydrated deposits are not readily apparent in images of undisturbed soil but are present at shallow depths and were exposed by the actions of the rover wheels. Referred to as 'Paso...
Evaluating transition-metal catalysis in gas generation from the Permian Kupferschiefer by hydrous pyrolysis
M. D. Lewan, M.J. Kotarba, D. Wieclaw, A. Piestrzynski
2008, Geochimica et Cosmochimica Acta (72) 4069-4093
Transition metals in source rocks have been advocated as catalysts in determining extent, composition, and timing of natural gas generation (Mango, F. D. (1996) Transition metal catalysis in the generation of natural gas. Org. Geochem.24, 977–984). This controversial hypothesis may have important implications concerning gas generation in unconventional shale-gas accumulations....
