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Portland State University

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Climatic changes

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Articles 31 - 60 of 60

Full-Text Articles in Physical Sciences and Mathematics

Evaluating Simplistic Methods To Understand Current Distributions And Forecast Distribution Changes Under Climate Change Scenarios: An Example With Coypu (Myocastor Coypus), Catherine S. Jarnevich, Nicholas E. Young, Trevor R. Sheffels, Jacoby Carter, Mark D. Sytsma, Colin Talbert Jan 2017

Evaluating Simplistic Methods To Understand Current Distributions And Forecast Distribution Changes Under Climate Change Scenarios: An Example With Coypu (Myocastor Coypus), Catherine S. Jarnevich, Nicholas E. Young, Trevor R. Sheffels, Jacoby Carter, Mark D. Sytsma, Colin Talbert

Environmental Science and Management Faculty Publications and Presentations

Invasive species provide a unique opportunity to evaluate factors controlling biogeographic distributions; we can consider introduction success as an experiment testing suitability of environmental conditions. Predicting potential distributions of spreading species is not easy, and forecasting potential distributions with changing climate is even more difficult. Using the globally invasive coypu (Myocastor coypus [Molina, 1782]), we evaluate and compare the utility of a simplistic ecophysiological based model and a correlative model to predict current and future distribution. The ecophysiological model was based on winter temperature relationships with nutria survival. We developed correlative statistical models using the Software for Assisted Habitat Modeling …


Psu Green Building Summer Internship Final Presentation, 2017, Campus Sustainability Office Jan 2017

Psu Green Building Summer Internship Final Presentation, 2017, Campus Sustainability Office

Campus Sustainability Office Publications, Reports and Presentations

RESEARCH QUESTION: Is duct cleaning beneficial in terms of energy efficiency and overall occupant comfort?


Campus Sustainability Office Annual Report, 2016-2017, Campus Sustainability Office Jan 2017

Campus Sustainability Office Annual Report, 2016-2017, Campus Sustainability Office

Campus Sustainability Office Publications, Reports and Presentations

The Campus Sustainability Office 2016-2017 annual report.


Analysis Of Impacts To Ecosystem Services Of Tree Replacement - Recommendations For Broadway Arboretum Phase One, Kim Brown, Joaquin Moore, Jeffrey J. Gerwing Jan 2017

Analysis Of Impacts To Ecosystem Services Of Tree Replacement - Recommendations For Broadway Arboretum Phase One, Kim Brown, Joaquin Moore, Jeffrey J. Gerwing

Campus Sustainability Office Publications, Reports and Presentations

The Broadway Arboretum Project is a coordinated effort between the Campus Planning Office (CPO), Campus Sustainability Office (CSO), and the Facilities and Property Management team (FPM) that seeks to increase diversity and resilience of PSU’s urban forest by replacing the existing trees lining Broadway Ave. between I-405 and SW Market Street (currently consisting of almost entirely a single variety, Norway Maple) with a variety of trees that showcase those currently approved by the City for street tree planting while also providing a testing ground for additional varieties that might by resilient to the challenges of growing and surviving in Portland’s …


Multiple New-Particle Growth Pathways Observed At The Us Doe Southern Great Plains Field Site, Anna L. Hodshire, Michael J. Lawler, Jun Zhao, John Ortega, Coty Jen, Taina Yli-Juuti, Jared F. Brewer, Jack K. Kodros, Kelley C. Barsanti, Dave R. Hanson, Peter H. Mcmurry, James N. Smith, Jeffery R. Pierce Jul 2016

Multiple New-Particle Growth Pathways Observed At The Us Doe Southern Great Plains Field Site, Anna L. Hodshire, Michael J. Lawler, Jun Zhao, John Ortega, Coty Jen, Taina Yli-Juuti, Jared F. Brewer, Jack K. Kodros, Kelley C. Barsanti, Dave R. Hanson, Peter H. Mcmurry, James N. Smith, Jeffery R. Pierce

Civil and Environmental Engineering Faculty Publications and Presentations

New-particle formation (NPF) is a significant source of aerosol particles into the atmosphere. However, these particles are initially too small to have climatic importance and must grow, primarily through net uptake of low volatility species, from diameters ∼ 1 to 30–100 nm in order to potentially impact climate. There are currently uncertainties in the physical and chemical processes associated with the growth of these freshly formed particles that lead to uncertainties in aerosol-climate modeling. Four main pathways for new-particle growth have been identified: condensation of sulfuric-acid vapor (and associated bases when available), condensation of organic vapors, uptake of organic acids …


How Landscape Ecology Informs Global Land-Change Science And Policy, Audrey L. Mayer, Brian Buma, Amélie Davis, Sara A. Gagné, E. Louise Loudermilk, Robert M. Scheller, Fiona K.A. Schmiegelow, Fiona Majorin, Yolanda F. Wiersma, Janet Franklin Apr 2016

How Landscape Ecology Informs Global Land-Change Science And Policy, Audrey L. Mayer, Brian Buma, Amélie Davis, Sara A. Gagné, E. Louise Loudermilk, Robert M. Scheller, Fiona K.A. Schmiegelow, Fiona Majorin, Yolanda F. Wiersma, Janet Franklin

Environmental Science and Management Faculty Publications and Presentations

Landscape ecology is a discipline that explicitly considers the influence of time and space on the environmental patterns we observe and the processes that create them. Although many of the topics studied in landscape ecology have public policy implications, three are of particular concern: climate change; land use–land cover change (LULCC); and a particular type of LULCC, urbanization. These processes are interrelated, because LULCC is driven by both human activities (e.g., agricultural expansion and urban sprawl) and climate change (e.g., desertification). Climate change, in turn, will affect the way humans use landscapes. Interactions among these drivers of ecosystem change can …


Carbon Sequestration In Managed Temperate Coniferous Forests Under Climate Change, Caren C. Dymond, Sarah Beukema, Craig R. Nitschke, K. David Coates, Robert M. Scheller Mar 2016

Carbon Sequestration In Managed Temperate Coniferous Forests Under Climate Change, Caren C. Dymond, Sarah Beukema, Craig R. Nitschke, K. David Coates, Robert M. Scheller

Environmental Science and Management Faculty Publications and Presentations

Management of temperate forests has the potential to increase carbon sinks and mitigate climate change. However, those opportunities may be confounded by negative climate change impacts. We therefore need a better understanding of climate change alterations to temperate forest carbon dynamics before developing mitigation strategies. The purpose of this project was to investigate the interactions of species composition, fire, management, and climate change in the Copper–Pine Creek valley, a temperate coniferous forest with a wide range of growing conditions. To do so, we used the LANDIS-II modelling framework including the new Forest Carbon Succession extension to simulate forest ecosystems under …


Utilizing Humidity And Temperature Data To Advance Monitoring And Prediction Of Meteorological Drought, Ali Behrangi, Paul C. Loikith, Eric J. Fetzer, Hai M. Nguyen, Stephanie L. Granger Nov 2015

Utilizing Humidity And Temperature Data To Advance Monitoring And Prediction Of Meteorological Drought, Ali Behrangi, Paul C. Loikith, Eric J. Fetzer, Hai M. Nguyen, Stephanie L. Granger

Geography Faculty Publications and Presentations

The fraction of land area over the Continental United States experiencing extreme hot and dry conditions has been increasing over the past several decades, consistent with expectation from anthropogenic climate change. A clear concurrent change in precipitation, however, has not been confirmed. Vapor pressure deficit (VPD), combining temperature and humidity, is utilized here as an indicator of the background atmospheric conditions associated with meteorological drought. Furthermore, atmospheric conditions associated with warm season drought events are assessed by partitioning associated VPD anomalies into the temperature and humidity components. This approach suggests that the concurrence of anomalously high temperature and low humidity …


Climate Change And Land Management Impact Rangeland Condition And Sage-Grouse Habitat In Southeastern Oregon, Megan K. Creutzburg, Emilie B. Henderson, David R. Conklin Apr 2015

Climate Change And Land Management Impact Rangeland Condition And Sage-Grouse Habitat In Southeastern Oregon, Megan K. Creutzburg, Emilie B. Henderson, David R. Conklin

Environmental Science and Management Faculty Publications and Presentations

Contemporary pressures on sagebrush steppe from climate change, exotic species, wildfire, and land use change threaten rangeland species such as the greater sage-grouse (Centrocercus urophasianus). To effectively manage sagebrush steppe landscapes for long-term goals, managers need information about the potential impacts of climate change, disturbances, and management activities. We integrated information from a dynamic global vegetation model, a sage-grouse habitat climate envelope model, and a state-and-transition simulation model to project broad-scale vegetation dynamics and potential sage-grouse habitat across 23.5 million acres in southeastern Oregon. We evaluated four climate scenarios, including continuing current climate and three scenarios of global …


Fire Modulates Climate Change Response Of Simulated Aspen Distribution Across Topoclimatic Gradients In A Semi-Arid Montane Landscape, Jian Yang, Peter J. Weisberg, Douglas J. Shinneman, Thomas E. Dilts, Susan L. Earnst, Robert M. Scheller Feb 2015

Fire Modulates Climate Change Response Of Simulated Aspen Distribution Across Topoclimatic Gradients In A Semi-Arid Montane Landscape, Jian Yang, Peter J. Weisberg, Douglas J. Shinneman, Thomas E. Dilts, Susan L. Earnst, Robert M. Scheller

Environmental Science and Management Faculty Publications and Presentations

Content Changing aspen distribution in response to climate change and fire is a major focus of biodiversity conservation, yet little is known about the potential response of aspen to these two driving forces along topoclimatic gradients.

Objective This study is set to evaluate how aspen distribution might shift in response to different climate-fire scenarios in a semi-arid montane landscape, and quantify the influence of fire regime along topoclimatic gradients.

Methods We used a novel integration of a forest landscape succession and disturbance model (LAN DIS-II) with a fine-scale climatic water deficit approach to simulate dynamics of aspen and associated conifer …


Glacier Status And Contribution To Streamflow In The Olympic Mountains, Usa, Jon L. Riedel, Steve Wilson, William Baccus, Michael Larrabee, T.J. Fudge, Andrew G. Fountain Feb 2015

Glacier Status And Contribution To Streamflow In The Olympic Mountains, Usa, Jon L. Riedel, Steve Wilson, William Baccus, Michael Larrabee, T.J. Fudge, Andrew G. Fountain

Geology Faculty Publications and Presentations

The Olympic Peninsula, Washington, USA, currently holds 184 alpine glaciers larger than 0.01 km² and their combined area is 30.2 ± 0.95km². Only four glaciers are >1km² and 120 of the others are -¹ (1900–80) to 0.54 km² a-¹ (1980–2009). Thinning rates on four of the largest glaciers averaged nearly 1ma-¹ from 1987 to 2010, resulting in estimated volume losses of 17–24%. Combined glacial snow, firn and ice melt in the Hoh watershed is in the range 63–79 ± 7 × 106m3, or 9–15% of total May–September streamflow. In the critical August–September …


The Effects Of Global Change Upon United States Air Quality, Rodrigo Gonzalez-Abraham, Serena H. Chung, Jeremy C. Avise, Brian Lamb, Eric P. Salathé Jr., Christopher G. Nolte, Dan Loughlin, Alex Guenther, Christine Wiedinmyer, Tiffany Duhl, Yang Zhang, David G. Streets Jan 2015

The Effects Of Global Change Upon United States Air Quality, Rodrigo Gonzalez-Abraham, Serena H. Chung, Jeremy C. Avise, Brian Lamb, Eric P. Salathé Jr., Christopher G. Nolte, Dan Loughlin, Alex Guenther, Christine Wiedinmyer, Tiffany Duhl, Yang Zhang, David G. Streets

Civil and Environmental Engineering Faculty Publications and Presentations

To understand more fully the effects of global changes on ambient concentrations of ozone and particulate matter with aerodynamic diameter smaller than 2.5 μm (PM2.5) in the United States (US), we conducted a comprehensive modeling effort to evaluate explicitly the effects of changes in climate, biogenic emissions, land use and global/regional anthropogenic emissions on ozone and PM2.5 concentrations and composition. Results from the ECHAM5 global climate model driven with the A1B emission scenario from the Intergovernmental Panel on Climate Change (IPCC) were downscaled using the Weather Research and Forecasting (WRF) model to provide regional meteorological fields. We …


Predicted Effects Of Gypsy Moth Defoliation And Climate Change On Forest Carbon Dynamics In The New Jersey Pine Barrens, Alec M. Kretchun, Robert M. Scheller, Melissa S. Lucash, Kenneth L. Clark, John Hom, Steve Van Tuyl Aug 2014

Predicted Effects Of Gypsy Moth Defoliation And Climate Change On Forest Carbon Dynamics In The New Jersey Pine Barrens, Alec M. Kretchun, Robert M. Scheller, Melissa S. Lucash, Kenneth L. Clark, John Hom, Steve Van Tuyl

Environmental Science and Management Faculty Publications and Presentations

Disturbance regimes within temperate forests can significantly impact carbon cycling. Additionally, projected climate change in combination with multiple, interacting disturbance effects may disrupt the capacity of forests to act as carbon sinks at large spatial and temporal scales. We used a spatially explicit forest succession and disturbance model, LANDIS-II, to model the effects of climate change, gypsy moth (Lymantria dispar L.) defoliation, and wildfire on the C dynamics of the forests of the New Jersey Pine Barrens over the next century. Climate scenarios were simulated using current climate conditions (baseline), as well as a high emissions scenario (HadCM3 A2 …


Climate Change Effects On Northern Great Lake (Usa) Forests: A Case For Preserving Diversity, Matthew Joshua Duveneck, Robert M. Scheller, Mark A. White, Stephen D. Handler, Catherine Ravenscroft Feb 2014

Climate Change Effects On Northern Great Lake (Usa) Forests: A Case For Preserving Diversity, Matthew Joshua Duveneck, Robert M. Scheller, Mark A. White, Stephen D. Handler, Catherine Ravenscroft

Environmental Science and Management Faculty Publications and Presentations

Under business as usual (BAU) management, stresses posed by climate change may exceed the ability of Great Lake forests to adapt. Temperature and precipitation projections in the Great Lakes region are expected to change forest tree species composition and productivity. It is unknown how a change in productivity and/or tree species diversity due to climate change will affect the relationship between diversity and productivity. We assessed how forests in two landscapes (i.e., northern lower Michigan and northeastern Minnesota, USA) would respond to climate change and explored the diversityproductivity relationship under climate change. In addition, we explored how tree species diversity …


A Data Set Of Worldwide Glacier Length Fluctuations, Paul W. Leclercq, Johannes Oerlemans, Hassan J. Basagic, Christina Bushueva, A. J. Cook, Raymond Le Bris Jan 2014

A Data Set Of Worldwide Glacier Length Fluctuations, Paul W. Leclercq, Johannes Oerlemans, Hassan J. Basagic, Christina Bushueva, A. J. Cook, Raymond Le Bris

Geology Faculty Publications and Presentations

Glacier fluctuations contribute to variations in sea level and historical glacier length fluctuations are natural indicators of past climate change. To study these subjects, longterm information of glacier change is needed. In this paper we present a data set of global long-term glacier length fluctuations. The data set is a compilation of available information on changes in glacier length worldwide, including both measured and reconstructed glacier length fluctuations. All 471 length series start before 1950 and cover at least four decades. The longest record starts in 1535, but the majority of time series start after 1850. The number of available …


Impacts Of Fire And Climate Change On Long-Term Nitrogen Availability And Forest Productivity In The New Jersey Pine Barrens, Melissa S. Lucash, Robert M. Scheller, Alec M. Kretchun, Kenneth L. Clark, John Hom Jan 2014

Impacts Of Fire And Climate Change On Long-Term Nitrogen Availability And Forest Productivity In The New Jersey Pine Barrens, Melissa S. Lucash, Robert M. Scheller, Alec M. Kretchun, Kenneth L. Clark, John Hom

Environmental Science and Management Faculty Publications and Presentations

Increased wildfires and temperatures due to climate change are expected to have profound effects on forest productivity and nitrogen (N) cycling. Forecasts about how wildfire and climate change will affect forests seldom consider N availability, which may limit forest response to climate change, particularly in fire-prone landscapes. The overall objective of this study was to examine how wildfire and climate change affect long-term mineral N availability in a fire-prone landscape. We employed a commonly used landscape simulation model (LANDIS-II) in the New Jersey Pine Barrens, a landscape characterized by frequent small fires and fire-resilient vegetation. We found that fire had …


Carbon Dynamics In The Future Forest: The Importance Of Long-Term Successional Legacy And Climate–Fire Interactions, E. Louise Loudermilk, Robert M. Scheller, Peter J. Weisberg, Jian Yang, Thomas E. Dilts, Sarah L. Karam, Carl Skinner Oct 2013

Carbon Dynamics In The Future Forest: The Importance Of Long-Term Successional Legacy And Climate–Fire Interactions, E. Louise Loudermilk, Robert M. Scheller, Peter J. Weisberg, Jian Yang, Thomas E. Dilts, Sarah L. Karam, Carl Skinner

Environmental Science and Management Faculty Publications and Presentations

Understanding how climate change may influence forest carbon (C) budgets requires knowledge of forest growth relationships with regional climate, long-term forest succession, and past and future disturbances, such as wildfires and timber harvesting events. We used a landscape-scale model of forest succession, wildfire, and C dynamics (LANDIS-II) to evaluate the effects of a changing climate (A2 and B1 IPCC emissions; Geophysical Fluid Dynamics Laboratory General Circulation Models) on total forest C, tree species composition, and wildfire dynamics in the Lake Tahoe Basin, California, and Nevada. The independent effects of temperature and precipitation were assessed within and among climate models. Results …


Climate Change And Fire Management In The Mid-Atlantic Region, Kenneth L. Clark, Nicholas Skowronski, Heidi Renninger, Robert M. Scheller Oct 2013

Climate Change And Fire Management In The Mid-Atlantic Region, Kenneth L. Clark, Nicholas Skowronski, Heidi Renninger, Robert M. Scheller

Environmental Science and Management Faculty Publications and Presentations

In this review, we summarize the potential impacts of climate change on wildfire activity in the mid­-Atlantic region, and then consider how the beneficial uses of prescribed fire could conflict with mitigation needs for climate change, focusing on patters of carbon (C) sequestration by forests in the region. We use a synthesis of field studies, eddy flux tower measurements, and simulation studies to evaluate how the use of prescibed fire affects short-and long-term forest C dynamics. Climate change may create weather conditions more conducive to wildfire activity, but successional changes in forest composition, altered gap dynamics, reduced understory and forest …


Portland State University Solid Waste Assessment Report, Moonrose Doherty, Brittany Ann Brannon, Eric T. Crum Jun 2013

Portland State University Solid Waste Assessment Report, Moonrose Doherty, Brittany Ann Brannon, Eric T. Crum

Campus Sustainability Office Publications, Reports and Presentations

In January of 2013, the Campus Sustainability Office (CSO) of Portland State University (PSU) contacted Community Environmental Services (CES) with the request to conduct a landfill-bound waste assessment for the University’s 50-acre downtown campus, located in Portland, Oregon. CES is a research and service unit within the Center for Urban Studies at Portland State University. PSU is a state university that was founded in 1946, is home to Oregon’s largest undergraduate and graduate enrollment, and is the only public university in the state located in a major metropolitan city. Portland State is world-renowned for its sustainability initiatives, and has had …


Climate Action Progress, 2013, Campus Sustainability Office Jan 2013

Climate Action Progress, 2013, Campus Sustainability Office

Campus Sustainability Office Publications, Reports and Presentations

In 2010, Portland State University (PSU) adopted the University’s first Climate Action Plan (CAP) as part of the American College and University President’s Climate Commitment (ACUPCC). The CAP calls for climate neutrality by 2040 and identifies emission reduction targets in the following areas: Buildings & Energy, Materials, Travel, Commuting, Education & Research, and EcoDistrict Development. This report serves as an assessment of progress to date and provides: an updated carbon emissions profile, a snapshot of progress on individual actions, a summary of efforts contributing to CAP goals, and suggestions regarding next steps.


Divergent Carbon Dynamics Under Climate Change In Forests With Diverse Soils, Tree Species, And Land Use Histories, Robert M. Scheller, Alec M. Kretchun, Steve Van Tuyl, Kenneth L. Clark, Melissa S. Lucash, John Hom Nov 2012

Divergent Carbon Dynamics Under Climate Change In Forests With Diverse Soils, Tree Species, And Land Use Histories, Robert M. Scheller, Alec M. Kretchun, Steve Van Tuyl, Kenneth L. Clark, Melissa S. Lucash, John Hom

Environmental Science and Management Faculty Publications and Presentations

Accounting for both climate change and natural disturbances—which typically result in greenhouse gas emissions—is necessary to begin managing forest carbon sequestration. Gaining a complete understanding of forest carbon dynamics is, however, challenging in systems characterized by historic over-utilization, diverse soils and tree species, and frequent disturbance. In order to elucidate the cascading effects of potential climate change on such systems, we projected forest carbon dynamics, including soil carbon changes, and shifts in tree species composition as a consequence of wildfires and climate change in the New Jersey pine barrens (NJPB) over the next 100 years. To do so, we used …


Land Cover, Climate, And The Summer Surface Energy Balance In Phoenix, Az, And Portland, Or, Ariane Middel, Anthony J. Brazel, Patricia Gober, Soe Win Myint, Heejun Chang, Jiunn-Der Duh Nov 2012

Land Cover, Climate, And The Summer Surface Energy Balance In Phoenix, Az, And Portland, Or, Ariane Middel, Anthony J. Brazel, Patricia Gober, Soe Win Myint, Heejun Chang, Jiunn-Der Duh

Institute for Sustainable Solutions Publications and Presentations

Changes in land use and land cover alter the local energy balance and contribute to distinct urban climates. This paper presents a local-scale above-canopy study of intra-urban land cover mixes in two cities to analyse the relative effects of surface morphology and local climate on the surface energy balance (SEB). The study is conducted for urban areas in Phoenix, Arizona, and Portland, Oregon, cities with distinct climates but similarly warm and dry summers. A Local-Scale Urban Meteorological Parameterization Scheme (LUMPS) is used to analyse the relative contributions of local weather extremes and land cover variations on the urban energy balance. …


How Defining Planetary Boundaries Can Transform Our Approach To Growth, W. L. Steffen, Johan Rockström, Robert Costanza May 2011

How Defining Planetary Boundaries Can Transform Our Approach To Growth, W. L. Steffen, Johan Rockström, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

The article focuses on the importance to identify safe boundaries based on the fundamental characteristics of our planet to address the growing threats of climate change. It highlights the rapid transition of the planet from the stable Holocene state to an unknown future state of significantly different conditions. In addition, climate change, biodiversity loss and phosphorus production were already transgressed by humanity and require innovative frameworks and effective solutions.


Quantifying Uncertainty In Urban Flooding Analysis Considering Hydro-Climatic Projection And Urban Development Effects, Il-Won Jung, Heejun Chang, Hamid Moradkhani Jan 2011

Quantifying Uncertainty In Urban Flooding Analysis Considering Hydro-Climatic Projection And Urban Development Effects, Il-Won Jung, Heejun Chang, Hamid Moradkhani

Geography Faculty Publications and Presentations

How will the combined impacts of land use change, climate change, and hydrologic modeling influence changes in urban flood frequency and what is the main uncertainty source of the results? Will such changes differ by catchment with different degrees of current and future urban development? We attempt to answer these questions in two catchments with different degrees of urbanization, the Fanno catchment with 84% urban land use and the Johnson catchment with 36% urban land use, both located in the Pacific Northwest of the US. Five uncertainty sources – general circulation model (GCM) structures, future greenhouse gas (GHG) emission scenarios, …


Portland State University Climate Action Plan, 2010, Fletcher Beaudoin, Noelle Studer-Spevak Jan 2010

Portland State University Climate Action Plan, 2010, Fletcher Beaudoin, Noelle Studer-Spevak

Campus Sustainability Office Publications, Reports and Presentations

In June 2007, Portland State University (PSU) joined this effort by signing the American College and University Presidents Climate Commitment (ACUPCC). The commitment challenged PSU to form a committee to oversee climate efforts, track carbon emissions, and develop a Climate Action Plan (CAP) to move toward carbon neutrality. This document fulfills the final requirement for ACUPCC and supports regional climate goals of partner agencies, such as those described in the 2009 City of Portland and Multnomah County Climate Action Plan.


Winter Precipitation Intensity And Enso/Pdo Variability In The Willamette Valley Of Oregon, Sarah Praskievicz, Heejun Chang Jan 2009

Winter Precipitation Intensity And Enso/Pdo Variability In The Willamette Valley Of Oregon, Sarah Praskievicz, Heejun Chang

Geography Faculty Publications and Presentations

There is growing concern about the effects of inter-annual climatic variability, such as the El-Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), on regional hydrology and water resources. We analyzed patterns of wintertime precipitation intensity, using both simple intensity and number of heavy precipitation days per year, for eight stations in northwestern Oregon’s Willamette Valley for the period 1972–2006, and examined the separate and combined influence of ENSO and PDO on precipitation intensity. The analysis was accomplished using Kendall’s tau and analysis of variance (ANOVA) to determine differences in precipitation intensity among combinations of positive and negative ENSO …


Planetary Boundaries: Exploring The Safe Operating Space For Humanity, Johan Rockström, W. L. Steffen, Kevin Noone, Åsa Persson, F. Stuart Chapin Iii, Eric Lambin, Timothy M. Lenton, Marten Scheffer, Carl Folke, Hans Joachim Schellnhuber, Björn Nykvist, Cynthia A. De Wit, Terry Hughes, Sander Van Der Leeuw, Henning Rodhe, Sverker Sörlin, Peter K. Snyder, Robert Costanza, Uno Svedin, Malin Falkenmark, Louise Karlberg, Robert W. Corell, Victoria J. Fabry, James Hansen, Brian Walker, Diana Liverman, Katherine Richardson, Paul Crutzen, Jonathan Foley Jan 2009

Planetary Boundaries: Exploring The Safe Operating Space For Humanity, Johan Rockström, W. L. Steffen, Kevin Noone, Åsa Persson, F. Stuart Chapin Iii, Eric Lambin, Timothy M. Lenton, Marten Scheffer, Carl Folke, Hans Joachim Schellnhuber, Björn Nykvist, Cynthia A. De Wit, Terry Hughes, Sander Van Der Leeuw, Henning Rodhe, Sverker Sörlin, Peter K. Snyder, Robert Costanza, Uno Svedin, Malin Falkenmark, Louise Karlberg, Robert W. Corell, Victoria J. Fabry, James Hansen, Brian Walker, Diana Liverman, Katherine Richardson, Paul Crutzen, Jonathan Foley

Institute for Sustainable Solutions Publications and Presentations

Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems. We have identified nine planetary boundaries and, drawing upon current scientific understanding, we propose quantifications for seven of them. These seven are climate change (CO2 concentration …


Spatial Variability Of Methane Emissions From Rice Fields And Implications For Experimental Design, M. A. K. Khalil, Christopher Lee Butenhoff Aug 2008

Spatial Variability Of Methane Emissions From Rice Fields And Implications For Experimental Design, M. A. K. Khalil, Christopher Lee Butenhoff

Physics Faculty Publications and Presentations

It is observed that side by side plots in rice fields, managed by the same practices, produce methane emissions that are often different by factors of 2 to 4. Similarly on a given day when many plots are sampled, the emissions from one plot may differ from another by factors of 3-4 on average. These large variations must be taken into account if these data are extrapolated to larger scales such as countries or the world. In this paper we analyze and delineate the nature of this variability. We distinguish temporal and spatial variability and examine the effects of both …


Application Of Tree-Structured Regression For Regional Precipitation Prediction Using General Circulation Model Output, Xiangshang Li, David J. Sailor Nov 2000

Application Of Tree-Structured Regression For Regional Precipitation Prediction Using General Circulation Model Output, Xiangshang Li, David J. Sailor

Mechanical and Materials Engineering Faculty Publications and Presentations

This study presents a tree-structured regression (TSR) method to relate daily precipitation with a variety of free-atmosphere variables. Historical data were used to identify distinct weather patterns associated with differing types of precipitation events. Models were developed using 67% of the data for training and the remaining data for model validation. Seasonal models were built for each of 2 US sites: San Francisco, California, and San Antonio, Texas. The average correlation between observed and simulated daily precipitation data series is 0.75 for the training set and 0.68 for the validation set. Relative humidity was found to be the dominant variable …


Measurements Of Methane Emissions From Rice Fields In China, M. A. K. Khalil, R. A. Rasmussen, Martha J. Shearer, R. W. Dalluge, Lixin Ren, Chang-Lin Duan Oct 1998

Measurements Of Methane Emissions From Rice Fields In China, M. A. K. Khalil, R. A. Rasmussen, Martha J. Shearer, R. W. Dalluge, Lixin Ren, Chang-Lin Duan

Physics Faculty Publications and Presentations

Rice fields have always been regarded as one of the largest anthropogenic sources of atmospheric methane. Here we report the results of a 7-year study of methane emissions from rice fields in the Sichuan Province of China. In this region, there is one crop of rice per year, the fields are continuously flooded from transplanting to harvest, and there is heavy use of organic fertilizers. Emissions over the entire growing season were measured from each of up to 24 plots. Environmental variables were measured and relevant supporting data on the agricultural practices were recorded. The fields were studied under prevailing …