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Articles 91 - 120 of 384
Full-Text Articles in Geography
A Process-Model Perspective On Recent Changes In The Carbon Cycle Of North America, Guillermo Murray-Tortarolo, Benjamin Poulter, Rodrigo Vargas, Daniel Hayes, Anna M. Michalak, Christopher A. Williams, Lisamarie Windham-Myers, Jonathan A. Wang, Kimberly P. Wickland, David Butman, Hanqin Tian, Stephen Sitch, Pierre Friedlingstein, Mike O’Sullivan, Peter Briggs, Vivek Arora, Danica Lombardozzi, Atul K. Jain, Wenping Yuan, Roland Séférian, Julia Nabel, Andy Wiltshire, Almut Arneth, Sebastian Lienert, Sönke Zaehle, Vladislav Bastrikov, Daniel Goll, Nicolas Vuichard, Anthony Walker, Etsushi Kato, Xu Yue, Zhen Zhang
A Process-Model Perspective On Recent Changes In The Carbon Cycle Of North America, Guillermo Murray-Tortarolo, Benjamin Poulter, Rodrigo Vargas, Daniel Hayes, Anna M. Michalak, Christopher A. Williams, Lisamarie Windham-Myers, Jonathan A. Wang, Kimberly P. Wickland, David Butman, Hanqin Tian, Stephen Sitch, Pierre Friedlingstein, Mike O’Sullivan, Peter Briggs, Vivek Arora, Danica Lombardozzi, Atul K. Jain, Wenping Yuan, Roland Séférian, Julia Nabel, Andy Wiltshire, Almut Arneth, Sebastian Lienert, Sönke Zaehle, Vladislav Bastrikov, Daniel Goll, Nicolas Vuichard, Anthony Walker, Etsushi Kato, Xu Yue, Zhen Zhang
Geography
Continental North America has been found to be a carbon (C) sink over recent decades by multiple studies employing a variety of estimation approaches. However, several key questions and uncertainties remain with these assessments. Here we used results from an ensemble of 19 state-of-the-art dynamic global vegetation models from the TRENDYv9 project to improve these estimates and study the drivers of its interannual variability. Our results show that North America has been a C sink with a magnitude of 0.37 ± 0.38 (mean and one standard deviation) PgC year−1 for the period 2000–2019 (0.31 and 0.44 PgC year−1 in each …
Chinese Neoglobalization In East Africa: Logics, Couplings And Impacts, Pádraig R. Carmody, James T. Murphy
Chinese Neoglobalization In East Africa: Logics, Couplings And Impacts, Pádraig R. Carmody, James T. Murphy
Geography
The most significant case of transnational state capitalism today is China's Belt and Road Initiative (BRI) which seeks to expand/extend the country's geoeconomic and geopolitical integrations globally. We conceptualise the BRI as manifest principally through industrial offshoring, infrastructure investments and exports from China. These vectors articulate with particular places, forming transnational couplings that shape development outcomes. We examine the BRI's couplings and their development implications in the East African countries of Djibouti, Ethiopia and Kenya where China has engaged significantly. We demonstrate the contingent manner of BRI's variegations; its pragmatism, flexibility, and limitations as a hegemonic or developmental project.
Linking Tree Cover Change To Historical Management Practices In Urban Parks, Sabine Nix, Lara A. Roman, Marc Healy, John Rogan, Hamil Pearsall
Linking Tree Cover Change To Historical Management Practices In Urban Parks, Sabine Nix, Lara A. Roman, Marc Healy, John Rogan, Hamil Pearsall
Geography
Context: Urban tree canopy (UTC) in parks is shaped by complex interactions between social and ecological processes over decades. To understand UTC change in parks, it is critical to identify and characterize the unique set of social processes that drive long-term change. Objectives: We sought to uncover the feedbacks between social processes and long-term UTC changes in parks of a post-industrial city that experienced substantial population loss and park disinvestment. Methods: Our mixed-methods approach involved quantifying spatiotemporal UTC changes and connecting those changes to historical management practices for three parks in Philadelphia, PA (US). We delineated UTC using aerial imagery …
What Makes Wildfires Destructive In California?, Alexandra D. Syphard, Jon E. Keeley, Mike Gough, Mitchell Lazarz, John Rogan
What Makes Wildfires Destructive In California?, Alexandra D. Syphard, Jon E. Keeley, Mike Gough, Mitchell Lazarz, John Rogan
Geography
As human impacts from wildfires mount, there is a pressing need to understand why structures are lost in destructive fires. Despite growing research on factors contributing to structure loss, fewer studies have focused on why some fires are destructive and others are not. We characterized overall differences between fires that resulted in structure loss (“destructive fires”) and those that did not (“non-destructive wildfires”) across three California regions. Then, we performed statistical analyses on large fires only (≥100 ha) to distinguish the primary differences between large destructive large fires and large non-destructive fires. Overall, destructive fires were at least an order …
Applying Landscape Fragmentation Analysis To Icescape Environments: Potential Impacts For The Pacific Walrus (Odobenus Rosmarus Divergens), Anthony Himmelberger, K E. Frey, Florencia Sangermano
Applying Landscape Fragmentation Analysis To Icescape Environments: Potential Impacts For The Pacific Walrus (Odobenus Rosmarus Divergens), Anthony Himmelberger, K E. Frey, Florencia Sangermano
Geography
Sea-ice cover across the Arctic has declined rapidly over the past several decades owing to amplified climate warming. The Pacific walrus (Odobenus rosmarus divergens) relies on sea-ice floes in the St. Lawrence Island (SLI) and Wainwright regions of the Bering and Chukchi seas surrounding Alaska as a platform for rest, feeding and reproduction. Lower concentrations of thick ice floes are generally associated with earlier seasonal fragmentation and shorter annual persistence of sea-ice cover, potentially affecting the life history of the Pacific walrus. In this study, 24 Landsat satellite images were classified into thick ice, thin ice or open water to …
Probabilistic Tracking Of Annual Cropland Changes Over Large, Complex Agricultural Landscapes Using Google Earth Engine, Sitian Xiong, Priscilla Baltezar, Morgan A. Crowley, Michael Cecil, Stefano C. Crema, Eli Baldwin, Jeffrey A. Cardille, Lyndon Estes
Probabilistic Tracking Of Annual Cropland Changes Over Large, Complex Agricultural Landscapes Using Google Earth Engine, Sitian Xiong, Priscilla Baltezar, Morgan A. Crowley, Michael Cecil, Stefano C. Crema, Eli Baldwin, Jeffrey A. Cardille, Lyndon Estes
Geography
Cropland expansion is expected to increase across sub-Saharan African (SSA) countries in the next thirty years to meet growing food needs across the continent. These land transformations will have cascading social and ecological impacts that can be monitored using novel Earth observation techniques that produce datasets complementary to national cropland surveys. In this study, we present a flexible Bayesian data synthesis workflow on Google Earth Engine (GEE) that can be used to fuse optical and synthetic aperture radar data and demonstrate its ability to track agricultural change at national scales. We adapted the previously developed Bayesian Updating of Land Cover …
New Political Ecologies Of Renewable Energy, Sarah Knuth, Ingrid Behrsin, Anthony Levenda, James Mccarthy
New Political Ecologies Of Renewable Energy, Sarah Knuth, Ingrid Behrsin, Anthony Levenda, James Mccarthy
Geography
The critique of fossil fuel regimes has been a foundational concern for the field of political ecology, in its drives to expose the injustices and harms of energy extractivism and its early warnings of the climate crisis. However, it is increasingly evident that renewable energy sources and their infrastructures will carry their own costs and trade-offs, and that critique, resistance and alternative movement-building are needed to forge a truly just renewable energy transition. This theme issue underlines the many ways in which political ecology is well-positioned to lead critical and engaged scholarship in support of energy/climate justice. In this introduction …
Emerging Hot Spot Analysis To Indicate Forest Conservation Priorities And Efficacy On Regional To Continental Scales: A Study Of Forest Change In Selva Maya 2000-2020, Nicholas Cuba, Laura A. Sauls, Anthony J. Bebbington, Denise Humphreys Bebbington, Avecita Chicchon, Pilar Delpino Marimón, Oscar Diaz, Susanna Hecht, Susan Kandel, Tracey Osborne, Rebecca Ray, Madelyn Rivera, John Rogan, Viviana Zalles
Emerging Hot Spot Analysis To Indicate Forest Conservation Priorities And Efficacy On Regional To Continental Scales: A Study Of Forest Change In Selva Maya 2000-2020, Nicholas Cuba, Laura A. Sauls, Anthony J. Bebbington, Denise Humphreys Bebbington, Avecita Chicchon, Pilar Delpino Marimón, Oscar Diaz, Susanna Hecht, Susan Kandel, Tracey Osborne, Rebecca Ray, Madelyn Rivera, John Rogan, Viviana Zalles
Geography
Despite the importance of preserving contiguous tropical forest areas to maintain biodiversity and terrestrial carbon stocks, methodological challenges continue to hinder broad-scale analysis of threats to these forests. Emerging Hot Spot Analysis (EHSA) is a spatial-statistical method that conveys complex information about the temporal dynamics of deforestation across a range of moderate to coarse spatial scales. Using Global Forest Change (GFC) data as inputs, EHSA produces spatially comprehensive, gridded outputs that represent a standardized, reproduceable way to instantiate contiguous forest tracts as spatial objects. Doing so allows aggregation of other GFC-derived values and analysis of alternative geographic configurations besides sub-national …
Albedo Changes Caused By Future Urbanization Contribute To Global Warming, Zutao Ouyang, Pietro Sciusco, Tong Jiao, Sarah Feron, Cheyenne Lei, Fei Li, Ranjeet John, Peilei Fan, Xia Li, Christopher A. Williams, Guangzhao Chen, Chenghao Wang, Jiquan Chen
Albedo Changes Caused By Future Urbanization Contribute To Global Warming, Zutao Ouyang, Pietro Sciusco, Tong Jiao, Sarah Feron, Cheyenne Lei, Fei Li, Ranjeet John, Peilei Fan, Xia Li, Christopher A. Williams, Guangzhao Chen, Chenghao Wang, Jiquan Chen
Geography
The replacement of natural lands with urban structures has multiple environmental consequences, yet little is known about the magnitude and extent of albedo-induced warming contributions from urbanization at the global scale in the past and future. Here, we apply an empirical approach to quantify the climate effects of past urbanization and future urbanization projected under different shared socioeconomic pathways (SSPs). We find an albedo-induced warming effect of urbanization for both the past and the projected futures under three illustrative scenarios. The albedo decease from urbanization in 2018 relative to 2001 has yielded a 100-year average annual global warming of 0.00014 …
A Modified Vegetation Photosynthesis And Respiration Model (Vprm) For The Eastern Usa And Canada, Evaluated With Comparison To Atmospheric Observations And Other Biospheric Models, Sharon M. Gourdji, Anna Karion, Israel Lopez-Coto, Subhomoy Ghosh, Kimberly L. Mueller, Yu Zhou, Christopher A. Williams, Ian T. Baker, Katharine D. Haynes, James R. Whetstone
A Modified Vegetation Photosynthesis And Respiration Model (Vprm) For The Eastern Usa And Canada, Evaluated With Comparison To Atmospheric Observations And Other Biospheric Models, Sharon M. Gourdji, Anna Karion, Israel Lopez-Coto, Subhomoy Ghosh, Kimberly L. Mueller, Yu Zhou, Christopher A. Williams, Ian T. Baker, Katharine D. Haynes, James R. Whetstone
Geography
Atmospheric CO2 measurements from a dense surface network can help to evaluate terrestrial biosphere model (TBM) simulations of Net Ecosystem Exchange (NEE) with two key benefits. First, gridded CO2 flux estimates can be evaluated over regional scales, not possible using flux tower observations at discrete locations for model evaluation. Second, TBM ability to explain atmospheric CO2 fluctuations due to the biosphere can be directly tested, an important objective for anthropogenic emissions monitoring using atmospheric observations. Here, we customize the Vegetation Photosynthesis and Respiration Model (VPRM) for an eastern North American domain with strong biological activity upwind of urban areas. Parameters …
Modeling The Spatial Distribution Of The Current And Future Ecosystem Services Of Urban Tree Planting In Chicopee And Fall River, Massachusetts, R. Moody, N. Geron, M. Healy, J. Rogan, Deborah Martin
Modeling The Spatial Distribution Of The Current And Future Ecosystem Services Of Urban Tree Planting In Chicopee And Fall River, Massachusetts, R. Moody, N. Geron, M. Healy, J. Rogan, Deborah Martin
Geography
Mature urban tree canopy cover disrupts the local effects of urban heat islands and provides important ecosystem services such as energy savings through evaporation and shading, pollution removal, storm runoff control, and carbon sequestration. Sustainable urban tree canopy relies on the planting of juvenile trees. Typically, tree planting programs are only evaluated by the number of trees planted and there is a lack of analysis of juvenile trees post-planting. This study examines the value and distribution of energy savings provided by juvenile trees and how that value changes considering predicted tree growth and mortality by 2050. Using i-Tree Eco software, …
Contested Landscapes, Disputed Realities: An Investigation Of Socio-Environmental Conflict From Mining In Northern Ecuador: An Honors Thesis, Ian F. Hirons
Student Works
For decades, Ecuador has been one of the preeminent petrostates in South America. However, in response to recent drops in global demand and pricing for oil products, the country has made serious commitments to further develop its mineral resources. By opening a new natural resource sector, Ecuador has firmly cemented itself as a primarily extractivist nation. In the process, the national government has frequently come into conflict with activist and community groups who protest the encroachment of extractive industry. This thesis explores the various dimensions of socio-environmental conflict created by large-scale mining projects in northern Ecuador with specific attention to …
Ownership Is A Habit Of Mind: How Community Land Trusts Expose Key Consensual Fictions Of Urban Property, Deborah Martin
Ownership Is A Habit Of Mind: How Community Land Trusts Expose Key Consensual Fictions Of Urban Property, Deborah Martin
Geography
Community land trusts (“CLTs”) have garnered attention as a novel,
non-state organizational mechanism for enabling permanently
affordable homeownership. In canonical form, they separate
a home from the land upon which it sits, holding the land in trust
and selling the home for its value without the land. Additionally,
CLTs use ground lease restrictions to constrain the resale process
and enforce long-term reproduction of affordability. Herein, we
argue that given the “actually existing” character of CLT practices,
the legal vocabulary CLTs use is not most directly nor most accu-
rately descriptive. The nature of the present intervention is empha-
tically not …
The Monadnock Volume 62, 2021, Clark University Geographical Society
The Monadnock Volume 62, 2021, Clark University Geographical Society
The Monadnock (Clark Geographical Society)
Volume 62 of The Monadnock. The Monadnock was the alumni magazine of the Clark University Geographical Society (1927-1985) (2014-present).
Beyond Biomass To Carbon Fluxes: Application And Evaluation Of A Comprehensive Forest Carbon Monitoring System, Yu Zhou, Christopher A. Williams, Natalia Hasler, Huan Gu, Robert Kennedy
Beyond Biomass To Carbon Fluxes: Application And Evaluation Of A Comprehensive Forest Carbon Monitoring System, Yu Zhou, Christopher A. Williams, Natalia Hasler, Huan Gu, Robert Kennedy
Geography
Accurate quantification of forest carbon stocks and fluxes over regions is needed to monitor forest resources as they respond to changes in climate, disturbance and management, and also to evaluate contributions of forest sector to the regional and global carbon balances. In previous work we introduced a national forest carbon monitoring system (NFCMS) that combines forest inventory data, satellite remote sensing of stand biomass and forest disturbances, and an ecosystem carbon cycle model to assess contemporary forest carbon dynamics at a 30 m resolution. In this study, we evaluate the NFCMS estimates of biomass and carbon fluxes with available data …
Encoding A Categorical Independent Variable For Input To Terrset’S Multi-Layer Perceptron, Emily Evenden, Robert Gilmore Pontius
Encoding A Categorical Independent Variable For Input To Terrset’S Multi-Layer Perceptron, Emily Evenden, Robert Gilmore Pontius
Geography
The profession debates how to encode a categorical variable for input to machine learning algorithms, such as neural networks. A conventional approach is to convert a categorical variable into a collection of binary variables, which causes a burdensome number of correlated variables. TerrSet’s Land Change Modeler proposes encoding a categorical variable onto the continuous closed interval from 0 to 1 based on each category’s Population Evidence Likelihood (PEL) for input to the Multi-Layer Perceptron, which is a type of neural network. We designed examples to test the wisdom of these encodings. The results show that encoding a categorical variable based …
The Total Operating Characteristic From Stratified Random Sampling With An Application To Flood Mapping, Zhen Liu, Robert Gilmore Pontius
The Total Operating Characteristic From Stratified Random Sampling With An Application To Flood Mapping, Zhen Liu, Robert Gilmore Pontius
Geography
The Total Operating Characteristic (TOC) measures how the ranks of an index variable distinguish between presence and absence in a binary reference variable. Previous methods to generate the TOC required the reference data to derive from a census or a simple random sample. However, many researchers apply stratified random sampling to collect reference data because stratified random sampling is more efficient than simple random sampling for many applications. Our manuscript derives a new methodology that uses stratified random sampling to generate the TOC. An application to flood mapping illustrates how the TOC compares the abilities of three indices to diagnose …
A Near-Real-Time Approach For Monitoring Forest Disturbance Using Landsat Time Series: Stochastic Continuous Change Detection, Su Ye, John Rogan, Zhe Zhu, J. Ronald Eastman
A Near-Real-Time Approach For Monitoring Forest Disturbance Using Landsat Time Series: Stochastic Continuous Change Detection, Su Ye, John Rogan, Zhe Zhu, J. Ronald Eastman
Geography
Forest disturbances greatly affect the ecological functioning of natural forests. Timely information regarding extent, timing and magnitude of forest disturbance events is crucial for effective disturbance management strategies. Yet, we still lack accurate, near-real-time and high-performance remote sensing tools for monitoring abrupt and subtle forest disturbances. This study presents a new approach called ‘Stochastic Continuous Change Detection (S-CCD)’ using a dense Landsat data time series. S-CCD improves upon the ‘COntinuous monitoring of Land Disturbance (COLD)’ approach by incorporating a mathematical tool called the ‘state space model’, which treats trends and seasonality as stochastic processes, allowing for modeling temporal dynamics of …
Toward The Development Of Deep Learning Analyses For Snow Avalanche Releases In Mountain Regions, Yunzhi Chen, Wei Chen, Omid Rahmati, Fatemeh Falah, Dominik Kulakowski, Saro Lee, Fatemeh Rezaie, Mahdi Panahi, Aref Bahmani, Hamid Darabi, Ali Torabi Haghighi, Huiyuan Bian
Toward The Development Of Deep Learning Analyses For Snow Avalanche Releases In Mountain Regions, Yunzhi Chen, Wei Chen, Omid Rahmati, Fatemeh Falah, Dominik Kulakowski, Saro Lee, Fatemeh Rezaie, Mahdi Panahi, Aref Bahmani, Hamid Darabi, Ali Torabi Haghighi, Huiyuan Bian
Geography
Snow avalanches impose a considerable threat to infrastructure and human safety in snow bound mountain areas. Nevertheless, the spatial prediction of snow avalanches has received little research attention in many vulnerable parts of the world, particularly in developing countries. The present study investigates the applicability of a stand alone convolutional neural network (CNN) model, as a deep learning approach, along with two metaheuristic algorithms including grey wolf optimization (CNN-GWO) and imperialist competitive algorithm (CNN-ICA) in snow avalanche modelling in the Darvan watershed, Iran. The analysis was based on thirteen potential drivers of avalanche occurrence and an inventory map of previously …
Effects Of Bark Beetle Outbreaks On Forest Landscape Pattern In The Southern Rocky Mountains, U.S.A., Kyle C. Rodman, Robert A. Andrus, Cori L. Butkiewicz, Teresa B. Chapman, Nathan S. Gill, Brian J. Harvey, Dominik Kulakowski, Niko J. Tutland, Thomas T. Veblen, Sarah J. Hart
Effects Of Bark Beetle Outbreaks On Forest Landscape Pattern In The Southern Rocky Mountains, U.S.A., Kyle C. Rodman, Robert A. Andrus, Cori L. Butkiewicz, Teresa B. Chapman, Nathan S. Gill, Brian J. Harvey, Dominik Kulakowski, Niko J. Tutland, Thomas T. Veblen, Sarah J. Hart
Geography
Since the late 1990s, extensive outbreaks of native bark beetles (Curculionidae: Scolytinae) have affected coniferous forests throughout Europe and North America, driving changes in carbon storage, wildlife habitat, nutrient cycling, and water resource provisioning. Remote sensing is a cru-cial tool for quantifying the effects of these disturbances across broad landscapes. In particular, Landsat time series (LTS) are increasingly used to characterize outbreak dynamics, including the presence and severity of bark beetle-caused tree mortality, though broad-scale LTS-based maps are rarely informed by detailed field validation. Here we used spatial and temporal information from LTS products, in combination with extensive field data …
The Atmospheric Carbon And Transport (Act)-America Mission, Kenneth J. Davis, Edward V. Browell, Sha Feng, Thomas Lauvaux, Michael D. Obland, Sandip Pal, Bianca C. Baier, David F. Baker, Ian T. Baker, Zachary R. Barkley, Kevin W. Bowman, Yu Yan Cui, A. Scott Denning, Joshua P. Digangi, Jeremy T. Dobler, Alan Fried, Tobias Gerken, Klaus Keller, Bing Lin, Amin R. Nehrir, Caroline P. Normile, Christopher W. O'Dell, Lesley E. Ott, Anke Roiger, Andrew E. Schuh, Colm Sweeney, Yaxing Wei, Brad Weir, Ming Xue, Christopher A. Williams
The Atmospheric Carbon And Transport (Act)-America Mission, Kenneth J. Davis, Edward V. Browell, Sha Feng, Thomas Lauvaux, Michael D. Obland, Sandip Pal, Bianca C. Baier, David F. Baker, Ian T. Baker, Zachary R. Barkley, Kevin W. Bowman, Yu Yan Cui, A. Scott Denning, Joshua P. Digangi, Jeremy T. Dobler, Alan Fried, Tobias Gerken, Klaus Keller, Bing Lin, Amin R. Nehrir, Caroline P. Normile, Christopher W. O'Dell, Lesley E. Ott, Anke Roiger, Andrew E. Schuh, Colm Sweeney, Yaxing Wei, Brad Weir, Ming Xue, Christopher A. Williams
Geography
The Atmospheric Carbon and Transport (ACT)-America NASA Earth Venture Suborbital Mission set out to improve regional atmospheric greenhouse gas (GHG) inversions by exploring the intersection of the strong GHG fluxes and vigorous atmospheric transport that occurs within the midlatitudes. Two research aircraft instrumented with remote and in situ sensors to measure GHG mole fractions, associated trace gases, and atmospheric state variables collected 1,140.7 flight hours of research data, distributed across 305 individual aircraft sorties, coordinated within 121 research flight days, and spanning five 6-week seasonal flight campaigns in the central and eastern United States. Flights sampled 31 synoptic sequences, including …
Atmospheric Carbon And Transport – America (Act-America) Data Sets: Description, Management, And Delivery, Y. Wei, R. Shrestha, S. Pal, T. Gerken, S. Feng, J. Mcnelis, D. Singh, M. M. Thornton, A. G. Boyer, M. A. Shook, G. Chen, B. C. Baier, Z. R. Barkley, J. D. Barrick, J. R. Bennett, E. V. Browell, J. F. Campbell, L. J. Campbell, Y. Choi, J. Collins, J. Dobler, M. Eckl, A. Fiehn, A. Fried, J. P. Digangi, R. Barton-Grimley, H. Halliday, T. Klausner, S. Kooi, J. Kostinek, T. Lauvaux, B. Lin, Christopher A. Williams
Atmospheric Carbon And Transport – America (Act-America) Data Sets: Description, Management, And Delivery, Y. Wei, R. Shrestha, S. Pal, T. Gerken, S. Feng, J. Mcnelis, D. Singh, M. M. Thornton, A. G. Boyer, M. A. Shook, G. Chen, B. C. Baier, Z. R. Barkley, J. D. Barrick, J. R. Bennett, E. V. Browell, J. F. Campbell, L. J. Campbell, Y. Choi, J. Collins, J. Dobler, M. Eckl, A. Fiehn, A. Fried, J. P. Digangi, R. Barton-Grimley, H. Halliday, T. Klausner, S. Kooi, J. Kostinek, T. Lauvaux, B. Lin, Christopher A. Williams
Geography
The ACT-America project is a NASA Earth Venture Suborbital-2 mission designed to study the transport and fluxes of greenhouse gases. The open and freely available ACT-America data sets provide airborne in situ measurements of atmospheric carbon dioxide, methane, trace gases, aerosols, clouds, and meteorological properties, airborne remote sensing measurements of aerosol backscatter, atmospheric boundary layer height and columnar content of atmospheric carbon dioxide, tower-based measurements, and modeled atmospheric mole fractions and regional carbon fluxes of greenhouse gases over the Central and Eastern United States. We conducted 121 research flights during five campaigns in four seasons during 2016–2019 over three regions …
Joint Co2 Mole Fraction And Flux Analysis Confirms Missing Processes In Casa Terrestrial Carbon Uptake Over North America, Sha Feng, Thomas Lauvaux, Christopher A. Williams, Kenneth J. Davis, Yu Zhou, Ian Baker, Zachary R. Barkley, Daniel Wesloh
Joint Co2 Mole Fraction And Flux Analysis Confirms Missing Processes In Casa Terrestrial Carbon Uptake Over North America, Sha Feng, Thomas Lauvaux, Christopher A. Williams, Kenneth J. Davis, Yu Zhou, Ian Baker, Zachary R. Barkley, Daniel Wesloh
Geography
Terrestrial biosphere models (TBMs) play a key role in the detection and attribution of carbon cycle processes at local to global scales and in projections of the coupled carbon-climate system. TBM evaluation commonly involves direct comparison to eddy-covariance flux measurements. We use atmospheric CO2 mole fraction ([CO2]) measured in situ from aircraft and tower, in addition to flux-measurements from summer 2016 to evaluate the Carnegie-Ames-Stanford-Approach (CASA) TBM. WRF-Chem is used to simulate [CO2] using biogenic CO2 fluxes from a CASA parameter-based ensemble and CarbonTracker version 2017 (CT2017) in addition to transport and CO2 boundary condition ensembles. The resulting “super ensemble” …
Climate Impacts Of U.S. Forest Loss Span Net Warming To Net Cooling, Christopher A. Williams, Huan Gu, Tong Jiao
Climate Impacts Of U.S. Forest Loss Span Net Warming To Net Cooling, Christopher A. Williams, Huan Gu, Tong Jiao
Geography
Storing carbon in forests is a leading land-based strategy to curb anthropogenic climate change, but its planetary cooling effect is opposed by warming from low albedo. Using detailed geospatial data from Earth-observing satellites and the national forest inventory, we quantify the net climate effect of losing forest across the conterminous United States. We find that forest loss in the intermountain and Rocky Mountain West causes net planetary cooling but losses east of the Mississippi River and in Pacific Coast states tend toward net warming. Actual U.S. forest conversions from 1986 to 2000 cause net cooling for a decade but then …
Assessment Of Empirical And Semi-Analytical Algorithms Using Modis-Aqua For Representing In-Situ Chromophoric Dissolved Organic Matter (Cdom) In The Bering, Chukchi, And Western Beaufort Seas Of The Pacific Arctic Region, Melishia I. Santiago, Karen E. Frey
Assessment Of Empirical And Semi-Analytical Algorithms Using Modis-Aqua For Representing In-Situ Chromophoric Dissolved Organic Matter (Cdom) In The Bering, Chukchi, And Western Beaufort Seas Of The Pacific Arctic Region, Melishia I. Santiago, Karen E. Frey
Geography
We analyzed a variety of satellite-based ocean color products derived using MODIS-Aqua to investigate the most accurate empirical and semi-analytical algorithms for representing in-situ chromophoric dissolved organic matter (CDOM) across a large latitudinal transect in the Bering, Chukchi, and western Beaufort Seas of the Pacific Arctic region. In particular, we compared the performance of empirical (CDOM index) and several semi-analytical algorithms (quasi-analytical algorithm (QAA), Carder, Garver-Siegel-Maritorena (GSM), and GSM-A) with field measurements of CDOM absorption (aCDOM) at 412 nanometers (nm) and 443 nm. These algorithms were compared with in-situ CDOM measurements collected on cruises during July 2011, 2013, 2014, 2015, …
Field-Scale Soil Moisture Bridges The Spatial-Scale Gap Between Drought Monitoring And Agricultural Yields, Noemi Vergopolan, Sitian Xiong, Lyndon Estes, Niko Wanders, Nathaniel W. Chaney, Eric F. Wood, Megan Konar, Kelly Caylor, Hylke E. Beck, Nicolas Gatti, Tom Evans, Justin Sheffield
Field-Scale Soil Moisture Bridges The Spatial-Scale Gap Between Drought Monitoring And Agricultural Yields, Noemi Vergopolan, Sitian Xiong, Lyndon Estes, Niko Wanders, Nathaniel W. Chaney, Eric F. Wood, Megan Konar, Kelly Caylor, Hylke E. Beck, Nicolas Gatti, Tom Evans, Justin Sheffield
Geography
Soil moisture is highly variable in space and time, and deficits (i.e., droughts) play an important role in modulating crop yields. Limited hydroclimate and yield data, however, hamper drought impact monitoring and assessment at the farm field scale. This study demonstrates the potential of using field-scale soil moisture simulations to support highresolution agricultural yield prediction and drought monitoring at the smallholder farm field scale. We present a multiscale modeling approach that combines HydroBlocks a physically based hyper-resolution land surface model (LSM) with machine learning. We used HydroBlocks to simulate root zone soil moisture and soil temperature in Zambia at 3 …
Natural Climate Solutions For Canada, C. Ronnie Drever, Susan C. Cook-Patton, Fardausi Akhter, Pascal H. Badiou, Gail L. Chmura, Scott J. Davidson, Raymond L. Desjardins, Andrew Dyk, Joseph E. Fargione, Max Fellows, Ben Filewod, Margot Hessing-Lewis, Susantha Jayasundara, William S. Keeton, Timm Kroeger, Tyler J. Lark, Edward Le, Sara M. Leavitt, Marie Eve Leclerc, Tony C. Lemprière, Juha Metsaranta, Brian Mcconkey, Eric Neilson, Guillaume Peterson St-Laurent, Danijela Puric-Mladenovic, Sebastien Rodrigue, Raju Y. Soolanayakanahally, Seth A. Spawn, Maria Strack, Carolyn Smyth, Naresh Thevathasan, Mihai Voicu, Christopher A. Williams
Natural Climate Solutions For Canada, C. Ronnie Drever, Susan C. Cook-Patton, Fardausi Akhter, Pascal H. Badiou, Gail L. Chmura, Scott J. Davidson, Raymond L. Desjardins, Andrew Dyk, Joseph E. Fargione, Max Fellows, Ben Filewod, Margot Hessing-Lewis, Susantha Jayasundara, William S. Keeton, Timm Kroeger, Tyler J. Lark, Edward Le, Sara M. Leavitt, Marie Eve Leclerc, Tony C. Lemprière, Juha Metsaranta, Brian Mcconkey, Eric Neilson, Guillaume Peterson St-Laurent, Danijela Puric-Mladenovic, Sebastien Rodrigue, Raju Y. Soolanayakanahally, Seth A. Spawn, Maria Strack, Carolyn Smyth, Naresh Thevathasan, Mihai Voicu, Christopher A. Williams
Geography
Alongside the steep reductions needed in fossil fuel emissions, natural climate solutions (NCS) represent readily deployable options that can contribute to Canada's goals for emission reductions. We estimate the mitigation potential of 24 NCS related to the protection, management, and restoration of natural systems that can also deliver numerous co-benefits, such as enhanced soil productivity, clean air and water, and biodiversity conservation. NCS can provide up to 78.2 (41.0 to 115.1) Tg CO2e/year (95% CI) of mitigation annually in 2030 and 394.4 (173.2 to 612.4) Tg CO2e cumulatively between 2021 and 2030, with 34% available at ≤CAD 50/Mg CO2e. Avoided …
Brazil, Big Hydro, And A Beautiful Monster: “Green” Energy Generation In The Xingu River Basin, Ian F. Hirons
Brazil, Big Hydro, And A Beautiful Monster: “Green” Energy Generation In The Xingu River Basin, Ian F. Hirons
Student Works
Brazil is quickly becoming an influential actor on the world stage of geopolitics. The nation has achieved global economic and environmental recognition due to the extensive development of its hydrological resources in the form of hydroelectric power plants. As the world’s second greatest generator of hydroelectricity, Brazil has proven a staunch adherence to building dams in the large-scale. Though these dams have brought electricity to millions of people across the country, the socio-ecological toll inflicted by their construction has been devastating to natural biomes and local inhabitants. This article traces Brazil’s proclivity for large-scale hydropower to four motivational categories often …
Unfamiliar Territory: Emerging Themes For Ecological Drought Research And Management, Shelley D. Crausbay, Julio Betancourt, John Bradford, Jennifer Cartwright, William C. Dennison, Jason Dunham, Carolyn A.F. Enquist, Abby G. Frazier, Kimberly R. Hall, Jeremy S. Littell, Charles H. Luce, Richard Palmer, Aaron R. Ramirez, Imtiaz Rangwala, Laura Thompson, Brianne M. Walsh, Shawn Carter
Unfamiliar Territory: Emerging Themes For Ecological Drought Research And Management, Shelley D. Crausbay, Julio Betancourt, John Bradford, Jennifer Cartwright, William C. Dennison, Jason Dunham, Carolyn A.F. Enquist, Abby G. Frazier, Kimberly R. Hall, Jeremy S. Littell, Charles H. Luce, Richard Palmer, Aaron R. Ramirez, Imtiaz Rangwala, Laura Thompson, Brianne M. Walsh, Shawn Carter
Geography
Novel forms of drought are emerging globally, due to climate change, shifting teleconnection patterns, expanding human water use, and a history of human influence on the environment that increases the probability of transformational ecological impacts. These costly ecological impacts cascade to human communities, and understanding this changing drought landscape is one of today's grand challenges. By using a modified horizon-scanning approach that integrated scientists, managers, and decision-makers, we identified the emerging issues in ecological drought that represent key challenges to timely and effective responses. Here we review the themes that most urgently need attention, including novel drought conditions, the potential …
Refugee Housing In Worcester: A Neighborhood Case Study Of Bell Hill, Tyler Seth Maren
Refugee Housing In Worcester: A Neighborhood Case Study Of Bell Hill, Tyler Seth Maren
Sustainability and Social Justice
This paper examines refugee resettlement practices at the neighborhood level, asking what neighborhood characteristics are conducive to achieving positive integration and housing stability outcomes. Using data from a quantitative study of refugee resettlement case files from Ascentria Care Alliance as a foundation, this research takes the form of an analysis of the Bell Hill neighborhood in Worcester, MA, a major resettlement destination. Using Ascentria data, secondary data sources such as US Census data and the Worcester Assessor’s Database, and site visits, this paper constructs a profile of Bell Hill along four major dimensions: community characteristics, housing, social infrastructure, and physical …