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- Keyword
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- Biogeochemistry -- Cold regions (3)
- McMurdo Dry Valleys (Antarctica) (3)
- Antarctica -- Environmental conditions (2)
- Glaciers -- Antarctica -- McMurdo Dry Valleys (2)
- Glaciers -- Antarctica -- Taylor Valley (2)
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- Ablation (Aerothermodynamics) (1)
- Antarctica -- McMurdo Dry Valleys (1)
- Atmospheric temperature -- Measurement (1)
- Biotic communities -- Antarctica (1)
- Climatic changes (1)
- Climatic changes -- Mathematical models (1)
- Columbia River (1)
- Coupled problems (Complex systems) (1)
- Desert ecology -- Antarctica -- McMurdo Dry Valleys (1)
- Floodplain ecology (1)
- Forest fires -- Environmental aspects -- Oregon (1)
- Glacial climates -- Antarctica (1)
- Glacial landforms -- Antarctica (1)
- Glaciers -- Environmental aspects (1)
- Glaciers -- Measurement (1)
- Glaciers -- Research (1)
- Glaciers -- Research -- United States (1)
- Glaciers -- United States -- Measurement (1)
- Hydrologic cycle -- Climatic factors -- Antarctica (1)
- Mass budget (Geophysics) (1)
- McMurdo Dry Valleys (Antarctica) -- Soil temperature -- Models (1)
- Meltwater -- Antarctica -- McMurdo Dry Valleys (1)
- Meltwater -- Antarctica -- Taylor Valley (1)
- Microbial ecology -- Antarctica (1)
- Nutrient cycles -- Antarctica --McMurdo Dry Valleys (1)
Articles 1 - 14 of 14
Full-Text Articles in Physical Sciences and Mathematics
Isotopic Signature Of Massive, Buried Ice In Eastern Taylor Valley, Antarctica: Implications For Its Origin, Christopher B. Gardner, Melisa A. Diaz, Devin F. Smith, Andrew G. Fountain, Joseph S. Levy, W. Berry Lyons
Isotopic Signature Of Massive, Buried Ice In Eastern Taylor Valley, Antarctica: Implications For Its Origin, Christopher B. Gardner, Melisa A. Diaz, Devin F. Smith, Andrew G. Fountain, Joseph S. Levy, W. Berry Lyons
Geography Faculty Publications and Presentations
The coastal regions of the McMurdo Dry Valleys, Antarctica, contain deposits of the Ross Sea Drift, sedimentary material left from the Ross Sea ice sheet from the advance of the West Antarctic ice sheet during the Last Glacial Maximum. Much of this deposit is ice-cored, but data on the stable isotopic composition of water from this ice, which may contain a valuable climate archive, are sparse or incomplete. Widespread thermokarstic ground subsidence in this “coastal thaw zone” of the McMurdo Dry Valleys suggests that these potential records are rapidly being lost due to the melting of ground ice and permafrost. …
Evaluating Cmip6 Model Fidelity At Simulating Non-Gaussian Temperature Distribution Tails, Arielle J. Catalano, Paul Loikith, J. David Neelin
Evaluating Cmip6 Model Fidelity At Simulating Non-Gaussian Temperature Distribution Tails, Arielle J. Catalano, Paul Loikith, J. David Neelin
Geography Faculty Publications and Presentations
Under global warming, changes in extreme temperatures will manifest in more complex ways in locations where temperature distribution tails deviate from Gaussian. Confidence in global climate model (GCM) projections of temperature extremes and associated impacts therefore relies on the realism of simulated temperature distribution tail behavior under current climate conditions. This study evaluates the ability of the latest state-of-the-art ensemble of GCMs from the Coupled Model Intercomparison Project phase six (CMIP6), to capture historical global surface temperature distribution tail shape in hemispheric winter and summer seasons. Comparisons with a global reanalysis product reveal strong agreement on coherent spatial patterns of …
Watershed Response To Climate Change And Fire-Burns In The Upper Umatilla River Basin, Usa, Kimberly Crystal Yazzie, Heejun Chang
Watershed Response To Climate Change And Fire-Burns In The Upper Umatilla River Basin, Usa, Kimberly Crystal Yazzie, Heejun Chang
Geography Faculty Publications and Presentations
This study analyzed watershed response to climate change and forest fire impacts in the upper Umatilla River Basin (URB), Oregon, using the precipitation runoff modeling system. Ten global climate models using Coupled Intercomparison Project Phase 5 experiments with Representative Concentration Pathways (RCP) 4.5 and 8.5 were used to simulate the effects of climate and fire-burns on runoff behavior throughout the 21st century. We observed the center timing (CT) of flow, seasonal flows, snow water equivalent (SWE) and basin recharge. In the upper URB, hydrologic regime shifts from a snow-rain-dominated to rain-dominated basin. Ensemble mean CT occurs 27 days earlier in …
The Influence Of Floodplain Restoration On Flow And Sediment Dynamics In An Urban River, Sangaralingam Ahilan, Mingfu Guan, Andrew Sleigh, Nigel G. Wright, Heejun Chang
The Influence Of Floodplain Restoration On Flow And Sediment Dynamics In An Urban River, Sangaralingam Ahilan, Mingfu Guan, Andrew Sleigh, Nigel G. Wright, Heejun Chang
Geography Faculty Publications and Presentations
A study of floodplain sedimentation on a recently restored floodplain is presented. This study uses a two-dimensional hydro-morphodynamic model for predicting flow and suspended-sediment dynamics in the downstream of Johnson Creek, the East Lents reach, where the bank of the river has been reconfigured to reconnect to a restored floodplain on a 0.26 km2 (26-ha) site. The simulation scenarios include 10-, 50-, 100- and 500-year event-based deposition modelling of flood events and long-term modelling using the 64 historical flood events between 1941 and 2014. Simulation results showed that the restored floodplain significantly attenuates the upstream flood peak by up …
Relationships Between Environmental Governance And Water Quality In A Growing Metropolitan Area Of The Pacific Northwest, Usa, Heejun Chang, Paul R. Thiers, Noelwah R. Netusil, J. Alan Yeakley, Gretchen Rollwagen-Bollens, Steve Bollens, Sonia Singh
Relationships Between Environmental Governance And Water Quality In A Growing Metropolitan Area Of The Pacific Northwest, Usa, Heejun Chang, Paul R. Thiers, Noelwah R. Netusil, J. Alan Yeakley, Gretchen Rollwagen-Bollens, Steve Bollens, Sonia Singh
Geography Faculty Publications and Presentations
We investigate relationships between environmental governance and water quality in two adjacent growing metropolitan areas in the western US. While the Portland, Oregon and Vancouver, Washington metro areas share many common biophysical characteristics, they have different land development histories and water governance structures, providing a unique opportunity for examining how differences in governance might affect environmental quality. We conceptualize possible linkages in which water quality influences governance directly, using monitoring efforts as a metric, and indirectly by using the change in the sale price of single-family residential properties. Governance may then influence water quality directly through riparian restoration resulting from …
Water Supply, Demand, And Quality Indicators For Assessing The Spatial Distribution Of Water Resource Vulnerability In The Columbia River Basin, Heejun Chang, Il-Won Jung, Angela L. Strecker, Daniel Wise, Martin Lafrenz, Vivek Shandas, Hamid Moradkhani, J. Alan Yeakley, Yangdong Pan, Robert Allen Bean, Gunnar Johnson, Mike Psaris
Water Supply, Demand, And Quality Indicators For Assessing The Spatial Distribution Of Water Resource Vulnerability In The Columbia River Basin, Heejun Chang, Il-Won Jung, Angela L. Strecker, Daniel Wise, Martin Lafrenz, Vivek Shandas, Hamid Moradkhani, J. Alan Yeakley, Yangdong Pan, Robert Allen Bean, Gunnar Johnson, Mike Psaris
Geography Faculty Publications and Presentations
We investigated water resource vulnerability in the US portion of the Columbia River basin (CRB) using multiple indicators representing water supply, water demand, and water quality. Based on the US county scale, spatial analysis was conducted using various biophysical and socio-economic indicators that control water vulnerability. Water supply vulnerability and water demand vulnerability exhibited a similar spatial clustering of hotspots in areas where agricultural lands and variability of precipitation were high but dam storage capacity was low. The hotspots of water quality vulnerability were clustered around the main stem of the Columbia River where major population and agricultural centres are …
A Dynamic Physical Model For Soil Temperature And Water In Taylor Valley, Antarctica, H. W. Hunt, Andrew G. Fountain, Peter T. Doran, Hassan J. Basagic
A Dynamic Physical Model For Soil Temperature And Water In Taylor Valley, Antarctica, H. W. Hunt, Andrew G. Fountain, Peter T. Doran, Hassan J. Basagic
Geography Faculty Publications and Presentations
We developed a simulation model for terrestrial sites including sensible heat exchange between the atmosphere and ground surface, inter- and intra-layer heat conduction by rock and soil, and shortwave and longwave radiation. Water fluxes included snowmelt, freezing/thawing of soil water, soil capillary flow, and vapour flows among atmosphere, soil, and snow. The model accounted for 96-99% of variation in soil temperature data. No long-term temporal trends in soil temperature were apparent. Soil water vapour concentration in thawed surface soil in summer often was higher than in frozen deeper soils, leading to downward vapour fluxes. Katabatic winds caused a reversal of …
Surface Energy Balance And Melt Thresholds Over 11 Years At Taylor Glacier, Antarctica, Matthew James Hoffman, Andrew G. Fountain, Glen E. Liston
Surface Energy Balance And Melt Thresholds Over 11 Years At Taylor Glacier, Antarctica, Matthew James Hoffman, Andrew G. Fountain, Glen E. Liston
Geography Faculty Publications and Presentations
In the McMurdo Dry Valleys, Victoria Land, Antarctica, melting of glacial ice is the primary source of water to streams, lakes, and associated ecosystems. To understand geochemical fluxes and ecological responses to past and future climates requires a physically based energy balance model. We applied a one-dimensional model to one site on Taylor Glacier using 11 years of daily meteorological data and seasonal ablation measurements. Inclusion of transmission of solar radiation into the ice was necessary to accurately model summer ablation and ice temperatures. Results showed good correspondence between calculated and measured ablation and ice temperatures over the 11 years. …
Temporal Variations In Physical And Chemical Features Of Cryoconite Holes On Canada Glacier, Mcmurdo Dry Valleys, Antarctica, Andrew G. Fountain, Thomas H. Nylen, Martyn Tranter, Elizabeth A. Bagshaw
Temporal Variations In Physical And Chemical Features Of Cryoconite Holes On Canada Glacier, Mcmurdo Dry Valleys, Antarctica, Andrew G. Fountain, Thomas H. Nylen, Martyn Tranter, Elizabeth A. Bagshaw
Geography Faculty Publications and Presentations
Cryoconite holes in the McMurdo Dry Valleys are ice-lidded, thus isolating the pools of water from the atmosphere and from potential surface melt. Hourly measurements of ice and water temperature and water electrical conductivity (EC) were recorded to broadly characterize the physical and chemical changes on daily to seasonal timescales. Overall, subsurface ice/water temperatures were typically several degrees warmer than air temperatures, underscoring the importance of subsurface solar heating. At no time was surface melt observed and the holes melted from within. Detailed differences in the timing and magnitude of both temperature and EC variations during melt-out and freezeup existed …
Hydrologic Response To Extreme Warm And Cold Summers In The Mcmurdo Dry Valleys, East Antarctica, Peter T. Doran, Christopher P. Mckay, Andrew G. Fountain, Thomas H. Nylen, Diane M. Mcknight, Chris Jaros, John E. Barrett
Hydrologic Response To Extreme Warm And Cold Summers In The Mcmurdo Dry Valleys, East Antarctica, Peter T. Doran, Christopher P. Mckay, Andrew G. Fountain, Thomas H. Nylen, Diane M. Mcknight, Chris Jaros, John E. Barrett
Geography Faculty Publications and Presentations
The meteorological characteristics and hydrological response of an extreme warm, and cold summer in the McMurdo Dry Valleys are compared. The driver behind the warmer summer conditions was the occurrence of down-valley winds, which were not present during the colder summer. Occurrence of the summer down-valley winds coincided with lower than typical mean sea level pressure in the Ross Sea region. There was no significant difference in the amount of solar radiation received during the two summers. Compared to the cold summer, glaciological and hydrological response to the warm summer in Taylor Valley included significant glacier mass loss, and 3- …
Biogeochemical Evolution Of Cryoconite Holes On Canada Glacier, Taylor Valley, Antarctica, Elizabeth A. Bagshaw, Martyn Tranter, Andrew G. Fountain, Kathleen A. Welch, Hassan J. Basagic, W. Berry Lyons
Biogeochemical Evolution Of Cryoconite Holes On Canada Glacier, Taylor Valley, Antarctica, Elizabeth A. Bagshaw, Martyn Tranter, Andrew G. Fountain, Kathleen A. Welch, Hassan J. Basagic, W. Berry Lyons
Geography Faculty Publications and Presentations
The cryoconite holes of the McMurdo Dry Valleys are simple, closed biogeochemical systems involving water, ice, mineral and organic debris, which serve as ecosystems for consortia of microorganisms. This study is the first to document the seasonal and annual chemical evolution of solutes in cryoconite holes. Samples of glacier ice, frozen cryoconite holes and those containing water were collected during the austral summer of 2005–2006. The isolation age was calculated from the excess Cl‾ in the holes, and varied from 0 to 5 years (a), consistent with the last hot summer when the cryoconite holes were open to the atmosphere. …
Biogeochemical Stoichiometry Of Antarctic Dry Valley Ecosystems, John E. Barrett, Ross A. Virginia, W. Berry Lyons, Diane M. Mcknight, John Charles Priscu, Peter T. Doran, Andrew G. Fountain, Diana H. Wall, D. L. Moorhead
Biogeochemical Stoichiometry Of Antarctic Dry Valley Ecosystems, John E. Barrett, Ross A. Virginia, W. Berry Lyons, Diane M. Mcknight, John Charles Priscu, Peter T. Doran, Andrew G. Fountain, Diana H. Wall, D. L. Moorhead
Geography Faculty Publications and Presentations
Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10–10⁶ years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated …
Snow-Patch Influence On Soil Biogeochemical Processes And Invertebrate Distribution In The Mcmurdo Dry Valleys, Antarctica, Michael N. Gooseff, John E. Barrett, Peter T. Doran, Andrew G. Fountain, W. Berry Lyons, Andrew N. Parsons, Dorota L. Porazinska, Ross A. Virginia, Diana H. Wall
Snow-Patch Influence On Soil Biogeochemical Processes And Invertebrate Distribution In The Mcmurdo Dry Valleys, Antarctica, Michael N. Gooseff, John E. Barrett, Peter T. Doran, Andrew G. Fountain, W. Berry Lyons, Andrew N. Parsons, Dorota L. Porazinska, Ross A. Virginia, Diana H. Wall
Geography Faculty Publications and Presentations
The McMurdo Dry Valleys is the largest of the ice-free areas in Antarctica. Precipitation events in excess of 1 cm of snow accumulation are rare. During the winter, snow is transported by strong katabatic winds blowing from the polar plateau, and deposited into the lee of topographic features (e.g., stream channels and other topographic depressions). At the start of the austral summer (early October), as much as 10% of the valley soils may be covered by distributed snow patches. Because liquid water is the primary driver of biological, physical, and chemical processes in this polar desert, quantifying fluxes of water …
A Strategy For Monitoring Glaciers, Andrew G. Fountain, Robert M. Krimmel, Dennis C. Trabant
A Strategy For Monitoring Glaciers, Andrew G. Fountain, Robert M. Krimmel, Dennis C. Trabant
Geography Faculty Publications and Presentations
Glaciers are important features in the hydrologic cycle and affect the volume, variability, and water quality of runoff. Assessing and predicting the effect of glaciers on water resources require a monitoring program to provide basic data for this understanding. The monitoring program of the U.S. Geological Survey employs a nested approach whereby an intensively studied glacier is surrounded by less intensively studied glaciers and those monitored solely by remote sensing. Ideally, each glacierized region of the United States would have such a network of glaciers. The intensively studied glacier provides a detailed understanding of the physical processes and their temporal …