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Earth Sciences

2018

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Articles 1 - 30 of 44

Full-Text Articles in Geography

Coupling Between Land–Ocean–Atmosphere And Pronounced Changes In Atmospheric/Meteorological Parameters Associated With The Hudhud Cyclone Of October 2014, Akshansa Chauhan, Rajesh Kumar, Ramesh P. Singh Dec 2018

Coupling Between Land–Ocean–Atmosphere And Pronounced Changes In Atmospheric/Meteorological Parameters Associated With The Hudhud Cyclone Of October 2014, Akshansa Chauhan, Rajesh Kumar, Ramesh P. Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

India is vulnerable to all kinds of natural hazards associated with land, ocean, biosphere, atmosphere, and snow/glaciers. These natural hazards impact large areas and the population living in the affected regions. India is surrounded by ocean on three sides and is vulnerable to cyclonic activities. Every year cyclones hit the east and west coasts of India, affecting the population living along the coasts and infrastructure and inland areas. The extent of the affected inland areas depends on the intensity of the cyclone. On 12 October 2014, a strong cyclone “Hudhud” hit the east coast of India that caused a high …


Land Use And Land Cover Changes, And Environment And Risk Evaluation Of Dujiangyan City (Sw China) Using Remote Sensing And Gis Techniques, Biswajit Nath, Zheng Niu, Ramesh P. Singh Dec 2018

Land Use And Land Cover Changes, And Environment And Risk Evaluation Of Dujiangyan City (Sw China) Using Remote Sensing And Gis Techniques, Biswajit Nath, Zheng Niu, Ramesh P. Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

Understanding of the Land Use and Land Cover (LULC) change, its transitions and Landscape risk (LR) evaluation in earthquake-affected areas is important for planning and urban sustainability. In the present study, we have considered Dujiangyan City and its Environs (DCEN), a seismic-prone area close to the 2008 Wenchuan earthquake (8.0 Mw) during 2007–2018. Five different multi-temporal data sets for the years 2007, 2008, 2010, 2015, and 2018 were considered for LULC mapping, followed by the maximum likelihood supervised classification technique. The individual LULC maps were further used in four time periods, i.e., 2007–2018, 2008–2018, 2010–2018, and 2015–2018, to evaluate the …


Investigating Smoke Aerosol Emission Coefficients Using Modis Active Fire And Aerosol Products – A Case Study In The Conus And Indonesia, Xiaoman Lu, Xiaoyang Zhang, Fangjun Li, Mark Cochrane Dec 2018

Investigating Smoke Aerosol Emission Coefficients Using Modis Active Fire And Aerosol Products – A Case Study In The Conus And Indonesia, Xiaoman Lu, Xiaoyang Zhang, Fangjun Li, Mark Cochrane

Global Land Surface Season Data Sets

This data set is in relation to the paper of the same title, which has been submitted to the Journal of Geophysical Research: Biogeosciences.

Instructions for viewing the data in “Readme.txt”





Keeping Pace With Relative Sea Level Rise: Marsh Platform Monitoring Shows Minimal Sediment Deficit Along The Louisiana Coast, Kelly Marie Sanks Dec 2018

Keeping Pace With Relative Sea Level Rise: Marsh Platform Monitoring Shows Minimal Sediment Deficit Along The Louisiana Coast, Kelly Marie Sanks

Graduate Theses and Dissertations

Recent reports estimate that the marshes of the Mississippi Delta receive just 30% of the sediment necessary to sustain current land area1. An extensive monitoring campaign by the USGS and LCPRA provides direct measurements of sediment accumulation, subsidence rates, and deposit characteristics along the coast over the past 10 years2, allowing us to directly evaluate this sediment balance. By interpolating bulk density, organic fraction, and vertical accretion rates from 273 sites, a direct measurement of organic and inorganic sediment accumulation can be made. Results show that a total of 82 MT/year of sediment is delivered to the coast. Using a …


Timing And Formation Of Linear Dunes South Of The Niobrara River Valley, North-Central Nebraska Sand Hills, Ashley K. Larsen Dec 2018

Timing And Formation Of Linear Dunes South Of The Niobrara River Valley, North-Central Nebraska Sand Hills, Ashley K. Larsen

Department of Geography: Dissertations, Theses, and Student Research

The Nebraska Sand Hills is a vast (7500 square kilometer) area of grass-stabilized sand dunes. Larger dunes in the Nebraska Sand Hills formed primarily during the Late Pleistocene, but many underwent widespread reactivation during the Holocene. Recent Optically Stimulated Luminescence (OSL) dating indicates that the last major phase of reactivation in the Sand Hills was during the Medieval Warm Period, approximately 800 years ago. Nevertheless, many questions about the evolution of the dunes remain unanswered, particularly regarding the formation of linear dunes in portions of the Sand Hills.

This study seeks to understand more about the formation of linear dunes …


Assessing The Cooling Effects Of Urban Vegetation On Urban Heat Mitigation In Selected U.S. Cities, Qiuyan Yu Nov 2018

Assessing The Cooling Effects Of Urban Vegetation On Urban Heat Mitigation In Selected U.S. Cities, Qiuyan Yu

USF Tampa Graduate Theses and Dissertations

Urban Heat Island (UHI) is a growing problem worldwide. Mitigation of UHI is necessary for cities to adapt to climate change and enhance sustainable development at a city scale. Cooling cities with urban vegetation management is a sustainable solution for urban heat mitigation. Urban vegetation influences urban microclimate through the shading effect, surface roughness, and evapotranspiration. The differences in horizontal and vertical structures of urban vegetation determine the shading effect, surface roughness, and evapotranspiration. Enhancing the cooling effect of urban vegetation requires a comprehensive understanding of how vegetation structure affects UHI. The effects of horizontal structure on land surface temperature …


Rates Of Planimetric Change In A Proglacial Gravel-Bed Braided River: Field Measurement And Physical Modeling, Lara Middleton, Peter Ashmore, Pauline Leduc, Darren Sjogren Oct 2018

Rates Of Planimetric Change In A Proglacial Gravel-Bed Braided River: Field Measurement And Physical Modeling, Lara Middleton, Peter Ashmore, Pauline Leduc, Darren Sjogren

Geography & Environment Publications

Planimetric change was measured on daily hydrographs over two meltwater seasons using time-lapse images of the proglacial, gravel, braided, Sunwapta River, Canada. Significant planimetric change occurred on 10-15 days per year. Area of planimetric change correlated with peak and total daily meltwater hydrograph discharge. A clear threshold discharge can be identified below which no planform activity occurs, an intermediate range over which change occurs conditionally, and a peak flow range at which significant change always occurs. Field conditions were reproduced in a physical model in a laboratory flume. Photogrammetric DEMs of bed morphology and measurements of bedload output were made …


Improving International Development Evaluation Through Geospatial Data And Analysis, Malte Lech, Juha Ilari Uitto, Sven Harten, Geeta Batra, Anupam Anand Oct 2018

Improving International Development Evaluation Through Geospatial Data And Analysis, Malte Lech, Juha Ilari Uitto, Sven Harten, Geeta Batra, Anupam Anand

International Journal of Geospatial and Environmental Research

Increasing availability of new types of data strengthens geospatial research in different scientific fields and opens up opportunities to better measure results and evaluate the impacts of development interventions. This article presents examples where geospatial approaches have been applied in evaluations and thus demonstrate the potential use in informing policy design through scientifically sound evidence as well as learning.

The authors illustrate innovative ways of employing geospatial data and analysis in impact evaluations of international development cooperation. These interventions are concerned with topics such as biodiversity conservation, land degradation, sustainable use of natural resources, and disaster risk management. Recent methodological …


Evolution Of Grain Size Distributions And Bed Mobility During Hydrographs In Gravel-Bed Braided Rivers, Sarah Peirce, Peter Ashmore, Pauline Leduc Sep 2018

Evolution Of Grain Size Distributions And Bed Mobility During Hydrographs In Gravel-Bed Braided Rivers, Sarah Peirce, Peter Ashmore, Pauline Leduc

Geography & Environment Publications

Evolution of bed material mobility and bedload grain size distributions under a range of discharges is rarely observed in braiding in gravel-bed rivers. Yet, the changing of bedload grain size distributions with discharge is expected to be different from laterally stable, threshold, channels on which most gravel bedload theory and observation are based. Here, simultaneous observations of flow, bedload transport rate, and morphological change were made in a physical model of a gravel-bed braided river to document the evolution of grain size distributions and bed mobility over three experimental event hydrographs. Bedload transport rate and grain size distributions were measured …


Using Drones To Generate New Data For Conservation Insights, Paul Lorah, Alice Ready, Emma Rinn Aug 2018

Using Drones To Generate New Data For Conservation Insights, Paul Lorah, Alice Ready, Emma Rinn

International Journal of Geospatial and Environmental Research

Human impact on the environment is driving a decline in biodiversity that heightens the need for informed management of conservation lands. Unmanned aerial vehicles (UAVs), also known as drones, are an increasingly cost-effective tool for generating high-quality data used to map landscape features, analyze land cover change and assess the effectiveness of conservation efforts. Traditional sources of remotely sensed data such as satellites and aircraft can be costly, inflexible and unable to detect fine-scale surface variation. This paper explores the advantages (and challenges) of analyzing data collected by drones to generate useful conservation management insights. We focus on three key …


Learner Requirements And Geospatial Literacy Challenges For Making Meaning With Google Earth, Lynn A. Moorman, Susan Crichton Jul 2018

Learner Requirements And Geospatial Literacy Challenges For Making Meaning With Google Earth, Lynn A. Moorman, Susan Crichton

International Journal of Geospatial and Environmental Research

This research contributes an educational research perspective to teaching and learning with geospatial technologies. This work considers the literacy of a geospatial text that is readily accessible to students, but often assumed to be intuitive to read– dynamic scalable satellite imagery, which often serves as base maps for common navigation, GIS, and virtual globe applications. Within the context of a STEM project, Grades 5 and 6 students were observed and interviewed to identify knowledge and skills that were required to make meaning of Google Earth imagery. A qualitative methodological approach incorporating a thinkaloud data collection protocol was followed to stay …


Improving Spatial Thinking Through Experiential-Based Learning Across International Higher Education Settings, Kyle C. Flynn Jul 2018

Improving Spatial Thinking Through Experiential-Based Learning Across International Higher Education Settings, Kyle C. Flynn

International Journal of Geospatial and Environmental Research

Research in geographic education has a strong focus on the improvement of spatial thinking. For Millennials, spatial thinking curriculum could benefit from the inclusion of experiential-based learning activities. However, as universities are faced with larger class sizes, new approaches need to be incorporated by the instructors to offer improved learning environments. Courses introducing basic geography skills often incorporate lessons concerned with spatial thinking and global perspectives. Thus, the instruction of geographic tools such as Global Positioning Systems (GPS), longitude, latitude, and remote sensing offer prime opportunities for experiential-based learning in geographic pedagogy. This research aimed to employ a low-cost experiential-based …


Forewarned Is Forearmed: Review Of Curbing Catastrophe: Natural Hazards And Risk Reduction In The Modern World By Timothy H. Dixon (2017), Jason Makansi Jul 2018

Forewarned Is Forearmed: Review Of Curbing Catastrophe: Natural Hazards And Risk Reduction In The Modern World By Timothy H. Dixon (2017), Jason Makansi

Numeracy

Timothy H. Dixon. 2017. Curbing Catastrophe: Natural Hazards and Risk Reduction in the Modern World. (New York, NY: Cambridge University Press) 300 pp. ISBN 978-1108113663.

Curbing Catastrophe for the most part lives up to what is claimed in the foreword: “…a compelling account of recent and historical disasters, both natural and human-caused, drawing on common themes and providing a holistic understanding of hazards, disasters, and mitigation for anyone interested in this important and topical subject.” This is a pretty thorough treatment of an extraordinarily complex subject, and the gaps identified in this review should be considered explications more than …


Geography Education, Spatial Thinking, And Geospatial Technologies: Introduction To The Special Issue, Injeong Jo, Jung Eun Hong Jul 2018

Geography Education, Spatial Thinking, And Geospatial Technologies: Introduction To The Special Issue, Injeong Jo, Jung Eun Hong

International Journal of Geospatial and Environmental Research

This special issue contains six papers on the development of students’ knowledge, skills, and practice of geospatial thinking in a variety of educational contexts. Each of the papers addresses an aspect of the research gap that deserves timely attention in the field, focusing on curriculum design, pedagogical approaches, exemplary resources or tools, and strategies to move forward for the promotion of geospatial teaching and learning. We encourage continued research efforts to accumulate knowledge about curriculum, instruction, and assessment, as well as teachers’ professional development that can help students become 21st-century citizens equipped with geospatial literacy. Further research is recommended on …


A Comparative Study On Coastal Zone Changes And Anthropogenic Impacts Between Tampa Bay, Usa, And Xiangshan Harbor, China, During The Last 30 Years, Qiandong Guo Jun 2018

A Comparative Study On Coastal Zone Changes And Anthropogenic Impacts Between Tampa Bay, Usa, And Xiangshan Harbor, China, During The Last 30 Years, Qiandong Guo

USF Tampa Graduate Theses and Dissertations

Currently, the U.S. and China are the two largest national economic entities in the world. However, it is noticeable that the two countries have considerably different strategies for economic development, environmental protection and land supply in coastal zones. In order to understand the coastline dynamics, land use land cover (LULC) changes and land management policies in the U.S. and China, a case study of the Tampa Bay (TB) watershed, Florida, U.S., and Xiangshan Harbor (XH), Zhejiang Province, China was conducted. The two areas possess similar humid subtropical climate and dense population, but experienced different anthropogenic impacts. TB sat at a …


International Energy Geopolitics, Bert Chapman Jun 2018

International Energy Geopolitics, Bert Chapman

Libraries Faculty and Staff Presentations

Overview of international energy geopolitical trends. Emphasizes the importance of the Persian Gulf, South China Sea, East China Sea, Russia, and the Arctic to U.S. and international economic and strategic developments. Stresses the continuing importance of fossil fuels in domestic and international energy consumption, the variety of energy sources being used by various global regions, the potential for military conflict over access to natural resources, and how emerging energy leaders will determine global energy, environmental, and international security developments.


Changing Snow Seasonality In The Highlands Of Kyrgyzstan, Monika Tomaszewska, Geoffrey Henebry May 2018

Changing Snow Seasonality In The Highlands Of Kyrgyzstan, Monika Tomaszewska, Geoffrey Henebry

NASA Land-Cover Land-Use Change Data Sets

Few studies have examined changing snow seasonality in Central Asia. Here, we analyzed changes in the seasonality of snow cover across Kyrgyzstan (KGZ) over 14 years from 2002/03–2015/16 using the most recent version (v006) of MODIS Terra and Aqua 8 day snow cover composites (MOD10A2/MYD10A2).We focused on three metrics of snow seasonality—first date of snow, last date of snow, and duration of snow season—and used nonparametric trends tests to assess the significance and direction of trends. We evaluated trends at three administration scales and across elevation. We used two techniques to assure that our identification of significant trends was not …


Gis Modeling Of The Prominent Geohazards In Arkansas, Kyle Walker Rowden May 2018

Gis Modeling Of The Prominent Geohazards In Arkansas, Kyle Walker Rowden

Graduate Theses and Dissertations

The State of Arkansas is prone to numerous geohazards. This thesis is a twofold study of prominent geohazards in Arkansas: the first fold includes a novel triggerless approach for mass wasting susceptibility modeling applied to the Boston Mountains in NW Arkansas, and the second fold is a GIS-based regression modeling of the extreme weather patterns at the state level. Each study fold is presented in this thesis as a separate chapter embracing a published peer-reviewed paper. In the first paper, I have used the analytical hierarchy process to assign preliminary statistical weights to the most cogent variables influencing mass wasting …


An Assessment Of Atmospheric And Meteorological Factors Regulating Red Sea Phytoplankton Growth, Wenzhao Li, Hesham El-Askary, Mohamed A. Qurban, Emmanouil Proestakis, Michael J. Garay, Olga V. Kalishnikova, Vassilis Amiridis, Antonis Gkikas, Eleni Marinou, Thomas Piechota, K. P. Manikandan Apr 2018

An Assessment Of Atmospheric And Meteorological Factors Regulating Red Sea Phytoplankton Growth, Wenzhao Li, Hesham El-Askary, Mohamed A. Qurban, Emmanouil Proestakis, Michael J. Garay, Olga V. Kalishnikova, Vassilis Amiridis, Antonis Gkikas, Eleni Marinou, Thomas Piechota, K. P. Manikandan

Mathematics, Physics, and Computer Science Faculty Articles and Research

This study considers the various factors that regulate nutrients supply in the Red Sea. Multi-sensor observation and reanalysis datasets are used to examine the relationships among dust deposition, sea surface temperature (SST), and wind speed, as they may contribute to anomalous phytoplankton blooms, through time-series and correlation analyses. A positive correlation was found at 0–3 months lag between chlorophyll-a (Chl-a) anomalies and dust anomalies over the Red Sea regions. Dust deposition process was further examined with dust aerosols’ vertical distribution using satellite lidar data. Conversely, a negative correlation was found at 0–3 months lag between SST anomalies …


The Variability In The Morphological Active Width: Results From Physical Models Of Gravel‐Bed Braided Rivers, Sarah Peirce, Pauline Leduc, Peter Ashmore Apr 2018

The Variability In The Morphological Active Width: Results From Physical Models Of Gravel‐Bed Braided Rivers, Sarah Peirce, Pauline Leduc, Peter Ashmore

Geography & Environment Publications

The morphological active width, defined as the lateral extent of bed-material displacement over time, is a fundamental parameter in multi-threaded gravel-bed rivers, linking complex channel dynamics to bedload transport. Here, results are presented from 5 constant discharge experiments, and three event hydrographs, covering a range of flow strengths and channel configurations for which morphological change, bedload transport rates, and stream power were measured in a physical model. Changes in channel morphology were determined via differencing of photogrammetrically-derived digital elevation models (DEMs) of the model surface generated at regular intervals over the course of ~115 hours of experimental runs. Independent measures …


Assessing Land Deformation And Sea Encroachment In The Nile Delta, Egypt, Esayas Gebremichael Apr 2018

Assessing Land Deformation And Sea Encroachment In The Nile Delta, Egypt, Esayas Gebremichael

Research and Creative Activities Poster Day

Persistent scatterer interferometric analyses were conducted on a stack of 84 Envisat ASAR scenes spanning 7 years (2004 to 2010) over the entire Nile Delta of Egypt and surroundings to monitor the ongoing spatial and temporal land deformation, identify the factors controlling the deformation, and model the interplay between sea level rise and land subsidence to identify areas and populations threatened by sea encroachment by the end of the 21st century. Findings include: (1) general patterns of subsidence in the northern delta, near-steady (none) subsidence in the southern delta, separated by a previously mapped flexure zone undergoing uplift; (2) high …


Place: A Dynamic Geospatial Data Repository, Eleta Exline, Hannah Hamalainen Apr 2018

Place: A Dynamic Geospatial Data Repository, Eleta Exline, Hannah Hamalainen

PLACE Project

Poster presented at University of Massachusetts and New England Area Librarian e-Science Symposium, University of Massachusetts Medical School, Worcester, Massachusetts, April 5, 2018


Cuando La Vida Era Tranquila: Land Use And Livelihood Changes Following The Construction Of The Chan 75 Dam In Nance Del Risco, Bocas Del Toro, Patrick Mckenzie Apr 2018

Cuando La Vida Era Tranquila: Land Use And Livelihood Changes Following The Construction Of The Chan 75 Dam In Nance Del Risco, Bocas Del Toro, Patrick Mckenzie

Independent Study Project (ISP) Collection

The Ngobe are Panama’s most populous indigenous group. While the Ngobe that live in the comarca have land and resource rights, those that live immediately outside of it do not. This issue has been exacerbated by the creation of Palo Seco Forest Reserve which has removed all land rights from the Ngobe living within it. In order to meet its growing demand for energy, Panama is expanding its hydroelectric sector. One such hydroelectric dam built by AES is Chan 75. However, Chan 75 has had a controversial history, especially regarding its treatment of the Ngobe people of the corregimiento Nance …


Remote Sensing And Spatial Metrics For Quantifying Seagrass Landscape Changes: A Study On The 2011 Indian River Lagoon Florida Seagrass Die-Off Event, René Dieter Baumstark Mar 2018

Remote Sensing And Spatial Metrics For Quantifying Seagrass Landscape Changes: A Study On The 2011 Indian River Lagoon Florida Seagrass Die-Off Event, René Dieter Baumstark

USF Tampa Graduate Theses and Dissertations

Florida’s seagrasses are ecologically important marine environments which have suffered major degradation caused by increasing anthropogenic pressures. A 2011 seagrass die-off event caused by an algal bloom in the Florida Indian River Lagoon (IRL) was particularly severe with a majority of seagrass lost in areas such as the Banana River. An understanding of how this coastal marine environment changed is an important step toward better managing resources for conservation. Modern tools and methods provide new opportunities to study these changes at the landscape scale, a scale that informs on the larger more comprehensive state of a system. Classified satellite imagery …


Understanding 1-D Vertical Flux Dynamics In A Low-Gradient Stream: An Assessment Of Stage As A Control Of Vertical Hyporheic Exchange, Frances Claire Harris Mar 2018

Understanding 1-D Vertical Flux Dynamics In A Low-Gradient Stream: An Assessment Of Stage As A Control Of Vertical Hyporheic Exchange, Frances Claire Harris

Theses and Dissertations

Little Kickapoo Creek (LKC) is a low-gradient, third-order perennial stream with headwaters in Bloomington, IL. The objective of this study is to characterize vertical one-dimensional (1-D) flux rates in the top 150 cm of the streambed, test the viability of a heat tracing method in a low-gradient area, and determine the relationship between stage and 1-D vertical flux rates. In 2009, six wells were installed along the thalweg of the stream in a 25-meter stretch spaced at 5-meter intervals. Each well recorded temperature at five separate depths logging at 15-minute0 intervals from February 2009 to March 2010: 30, 60, 90, …


Predicting Potential Fire Severity Using Vegetation, Topography And Surface Moisture Availability In A Eurasian Boreal Forest Landscape, Lei Fang, Jian Yang, Megan White, Zhihua Liu Mar 2018

Predicting Potential Fire Severity Using Vegetation, Topography And Surface Moisture Availability In A Eurasian Boreal Forest Landscape, Lei Fang, Jian Yang, Megan White, Zhihua Liu

Forestry and Natural Resources Faculty Publications

Severity of wildfires is a critical component of the fire regime and plays an important role in determining forest ecosystem response to fire disturbance. Predicting spatial distribution of potential fire severity can be valuable in guiding fire and fuel management planning. Spatial controls on fire severity patterns have attracted growing interest, but few studies have attempted to predict potential fire severity in fire-prone Eurasian boreal forests. Furthermore, the influences of fire weather variation on spatial heterogeneity of fire severity remain poorly understood at fine scales. We assessed the relative importance and influence of pre-fire vegetation, topography, and surface moisture availability …


Glacier Inventories And Change In Glacier National Park, Melissa Carrie Brett Mar 2018

Glacier Inventories And Change In Glacier National Park, Melissa Carrie Brett

Dissertations and Theses

Glacier National Park, in northwestern Montana, is a unique and awe-inspiring national treasure that is often used by the media and public-at-large as a window into the effects of climate change. An updated inventory of glaciers and perennial snowfields (G&PS) in the Park, along with an assessment of their change over time, is essential to understanding the role that glaciers are playing in the environment of this Park. Nine inventories between 1966 and 2015 were compiled to assess area changes of G&PS. Over that 49-year period, total area changed by nearly -34 ± 11% between 1966 and 2015. Volume change, …


Variation Of Groundwater Divides During Wet And Dry Years In The Wolf River Basin, Northeastern Wisconsin, Susan A. Borchardt Mar 2018

Variation Of Groundwater Divides During Wet And Dry Years In The Wolf River Basin, Northeastern Wisconsin, Susan A. Borchardt

International Journal of Geospatial and Environmental Research

Groundwater divides and surface-water divides do not always coincide, and groundwater divides are not as easy to detect as surface-water divides. Groundwater divides are also dynamic, moving in response to environmental and anthropogenic stresses. This study will investigate how different hydrological stresses can change the size and shape of the study basin and whether the stresses together mitigate or intensify the basin’s response. This study looks at three factors that may affect the size and shape of the Wolf River basin: annual precipitation, soil permeability, and the presence of high-capacity wells. This study examined four groundwater basins that represent the …


Expanding The "Active Layer", Peter Ashmore, Sarah Peirce, Pauline Leduc Feb 2018

Expanding The "Active Layer", Peter Ashmore, Sarah Peirce, Pauline Leduc

Geography & Environment Publications

Church and Haschenburger (2017) make helpful distinctions around the issue of defining the active layer, with which we agree. We propose expanding discussion and definition of the ”active layer” in fluvial bedload transport to include the concept of the “morphological active layer”. This is particularly applicable to laterally unstable rivers (such as braided rivers) in which progressive morphological change over short time periods is the process by which much of the bedload transport occurs. The morphological active layer is also distinguished by variable lateral and longitudinal extent continuity over a range of flows and transport intensity. We suggest that the …


Validating Geospatial Regression Models With Bootstrapping, Lam T. Tran, Phoebe Tran Feb 2018

Validating Geospatial Regression Models With Bootstrapping, Lam T. Tran, Phoebe Tran

International Journal of Geospatial and Environmental Research

Spatial statistical models have been used extensively in many geospatial and environmental studies over several decades. While being very important, the issues of testing and validation in spatial statistical models are rarely investigated carefully in spatial environmental studies. Often strict theoretical asymptotic assumptions used in those models are left unexplored or unanswered in many studies. This study is to explore if bootstrapping is capable of providing more realistic statistical inference for spatial regression models while dealing with several common issues with spatial data, such as spatial dependence and unknown heteroscedasticity. With experiments on both simulated and real-world datasets, the study …