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Full-Text Articles in Physical Sciences and Mathematics

Modeling The Effects Of Climate Change On Streamflow And Stream Temperature In The South Fork Of The Stillaguamish River, Katherine Mary Clarke Jan 2020

Modeling The Effects Of Climate Change On Streamflow And Stream Temperature In The South Fork Of The Stillaguamish River, Katherine Mary Clarke

WWU Graduate School Collection

The Stillaguamish River in northwest Washington State is an important regional water resource for local agriculture, industry, and First Nations tribes and a critical habitat for several threatened and endangered salmonid species, including the Chinook salmon. The river is currently subject to a temperature total maximum daily load, so it is important to understand how projected climate change will affect future stream temperatures and thus salmon populations. Snowpack is the main contributor to spring and summer streamflow and helps to mitigate stream temperatures as air temperatures rise through the summer in the South Fork of the Stillaguamish River. I used …


Crystal Mush Dynamics Of Mount St. Helens And Lassen Volcanic Center: Insights From Melt Inclusions And Titanium-In-Quartz Thermobarometry, Jeremy S. Rosen Jan 2020

Crystal Mush Dynamics Of Mount St. Helens And Lassen Volcanic Center: Insights From Melt Inclusions And Titanium-In-Quartz Thermobarometry, Jeremy S. Rosen

WWU Graduate School Collection

In order to better understand magma chamber dynamics at Lassen Volcanic Center (LVC) and Mount St. Helens (MSH) I examine quartz cathodoluminescent textures along with trace element abundances in quartz and compositions of quartz-hosted melt inclusions from multiple samples over a wide range of ages (LVC: 116 ka-1915; MSH: 272 ka to 84 ka). I use melt inclusion compositions to estimate quartz crystallization temperatures using zircon saturation thermometry and titanium abundances in quartz are used to estimate quartz crystallization pressures. When examined from core to rim within an individual grain, these data, along with internal CL-zoning textures reveal the dynamic …


Synthesis And Characterization Of Earth Abundant Metal Phosphide Photocatalysts For The Reverse Water Gas Shift Reaction, John D. Springer Jan 2020

Synthesis And Characterization Of Earth Abundant Metal Phosphide Photocatalysts For The Reverse Water Gas Shift Reaction, John D. Springer

WWU Graduate School Collection

This thesis work focuses on the synthesis and characterization of photocatalysts composed of metal phosphide nanoparticles on a titania (TiO2) support for the conversion of carbon dioxide (CO2) to carbon monoxide (CO) via the reverse water gas shift (RWGS) reaction. The CO product can be subsequently converted to solar fuels such as methanol (CH3OH), thus lowering the carbon footprint associated with the combustion of liquid fuels. The photocatalysts are composed of a tunable light absorber, indium-gallium phosphide (InxGa1-xP), and nickel phosphide (Ni2P) as a co-catalyst, on TiO2. The photocatalysts are characterized using diffuse reflectance ultraviolet-visible (UV-Vis) spectroscopy to determine band …


Incorporating Climate Change Predictions In Ecological Risk Assessment: A Bayesian Network Relative Risk Model For Chinook Salmon In The Skagit River Watershed, Eric J. Lawrence Jan 2020

Incorporating Climate Change Predictions In Ecological Risk Assessment: A Bayesian Network Relative Risk Model For Chinook Salmon In The Skagit River Watershed, Eric J. Lawrence

WWU Graduate School Collection

Climate change is expected to have widespread impacts on future ecosystem services in the Puget Sound and around the world. It is important that climate change be included in ecological risk assessment so that changing climate variables and potential interactive effects with chemical stressors can be taken into account. In this research, I focused on the question of how water temperature changes generated by climate change interact with organophosphate pesticide toxicity to affect Chinook salmon (Oncorhynchus tshawytscha) population size in the Skagit River, WA. To answer this question, I conducted an ecological risk assessment using the Bayesian network …


Carbodiimides: Templates For Covalent Adaptable Networks And Post Polymerization Modification, Alberto J Melchor Bañales Jan 2020

Carbodiimides: Templates For Covalent Adaptable Networks And Post Polymerization Modification, Alberto J Melchor Bañales

WWU Graduate School Collection

The global increase in plastic waste has negatively impacted the environment, human health, and economy. Plastics that lack recyclability, such as thermosets are some of the main culprits. To help address this issue, reactive functional groups can be incorporated in macromolecules, enabling straightforward post-polymerization modification (PPM) that can enhance their ability to be recycled. This thesis studied carbodiimides as a reactive functional group for facile PPM with amines through a catalyst-free transformation to N,Nʹ,Nʺ-trisubstituted guanidines. Small molecule studies showed that N,Nʹ,Nʺ-trisubstituted guanidines underwent a reversible thermal exchange reaction without a catalyst. The newly found thermal exchange reaction, termed thermal guanidine …


Bio-Preservation Potential Of Sediment In Eberswalde Crater, Mars, Cory Hughes Jan 2020

Bio-Preservation Potential Of Sediment In Eberswalde Crater, Mars, Cory Hughes

WWU Graduate School Collection

Within Eberswalde crater, Mars, is one of the most well-preserved river delta deposits identified within Mars’ rock record, and visually traceable from the deposit, is the partially-intact watershed that fed the paleo-lake that once resided within the crater basin. Aqueous alteration minerals, smectite clays and opaline silica, have been previously identified within the deposit, however the origin of those minerals is not well understood. Through analysis of topographic and hyperspectral data, we seek to ascertain the origin and provenance of these minerals to better understand their formative conditions and formation age. We will also assess Eberswalde crater’s potential as a …


Can Arbuscular Mycorrhizal Fungi Protect Rubus Idaeus From The Effects Of Soil-Borne Disease And Parasitic Nematodes?, Erika Whitney Jan 2020

Can Arbuscular Mycorrhizal Fungi Protect Rubus Idaeus From The Effects Of Soil-Borne Disease And Parasitic Nematodes?, Erika Whitney

WWU Graduate School Collection

Chemical controls for agricultural pests and diseases can have detrimental effects on human health and the environment. One alternative is to introduce soil microbes, such as arbuscular mycorrhizal fungi (AMF), that can improve crop resilience to pests and pathogens. While many plants form symbioses with AMF, not all crops benefit from inoculation. We conducted three studies that questioned the effect of AMF from various sources on R. idaeus growth and resilience to pests/pathogens. First, in a small observational study, we investigated whether AMF colonization of raspberry roots covaried with stand vigor. In two subsequent greenhouse experiments, we asked (1) if …


Clam Garden Bivalve Dietary Responses And Trophic Shifts In Relation To Environment, Octavio Cruz Jan 2020

Clam Garden Bivalve Dietary Responses And Trophic Shifts In Relation To Environment, Octavio Cruz

WWU Graduate School Collection

Clam gardens are a method of Indigenous aquaculture, involving altering of beach gradients, to increase clam habitat that have been used since pre-contact. Ecological examinations of clam gardens have been increasingly led by First Nations groups, as restoration projects begin on clam gardens aiming to re-establish pre-contact conditions.

The purpose of this study was to measure condition indices of traditionally-harvested littleneck clams (Leukoma staminea), dietary parameters and beach-level oceanographic conditions were used to investigate differences between clam gardens from non-walled beaches in Kanish Bay, Quadra Island, British Columbia. I utilized non-metric multidimensional scaling, distance-based redundancy analysis, and Bayesian 3-source isotopic …


Slip Rates And Kinematics Of Active Crustal Faults In The Central Oregon Cascades, Katherine Alexander Jan 2020

Slip Rates And Kinematics Of Active Crustal Faults In The Central Oregon Cascades, Katherine Alexander

WWU Graduate School Collection

New cosmogenic 3He chronologies and surficial geologic mapping constrain the age of glacial deposits and slip rates of predominantly normal faults in the White Branch and Dilman Meadows fault zones in central Oregon, USA, over the last ca. ~80 kyr. Our mapping of glacial landforms and deposits distinguishes three primary episodes of glacial deposition in the White Branch fault zone. Twenty-two new cosmogenic 3He surface exposure dates indicate that the youngest glacial unit represents a last glacial maximum deposit (ca. 19.4 +10.1/-6.2 kyr). Mapping of outwash terrace surfaces and deposits in the Dilman Meadows fault zone, constrained by …


Timing And Conditions Of Metamorphism In The Cascades Crystalline Core From Garnet Lu-Hf And Sm-Nd Geochronology, Peter Baker Jan 2020

Timing And Conditions Of Metamorphism In The Cascades Crystalline Core From Garnet Lu-Hf And Sm-Nd Geochronology, Peter Baker

WWU Graduate School Collection

The Chiwaukum Schist and Tonga Formation of Cascades Crystalline Core experienced three distinct metamorphic events: (M1) an early metamorphism that predates regional pluton emplacement, (M2) low-pressure contact metamorphism in the aureoles of the Mount Stuart batholith and Beckler Peak pluton, and (M3) regional Barrovian metamorphism. The timing of these distinct metamorphic events is critical to testing models for the tectonic evolution of the region and mechanisms that lead to burial of rocks within the orogen. I present new garnet Lu-Hf and Sm-Nd isochrons, average pressure and temperature calculations, and pseudosection modeling from the Chiwaukum Schist and Tonga Formation in order …


Polybenzoxazine-Grafted Composites: Accelerated Polymerization Of Benzoxazine Resins From Bulk- To Microscale Mesylated Materials, Cassidy L. Crickmore Jan 2020

Polybenzoxazine-Grafted Composites: Accelerated Polymerization Of Benzoxazine Resins From Bulk- To Microscale Mesylated Materials, Cassidy L. Crickmore

WWU Graduate School Collection

Benzoxazine-based resins often afford high modulus and high glass transition polymers that are desirable for creating safe and reliable thermoset parts and composites. However, benzoxazine resins have had limited widespread deployment into industry due to their high cure temperature. By blending functionalized glass substrates with the benzoxazine monomer, we hypothesize that the cure temperature of thermosetting resin can be lowered. The structure and purity of the particles, determined by NMR and FTIR, will be presented. DSC studies on the stability and cure accelerating properties of blends composed of functionalized glass substrates and benzoxazine monomer will be determined and compared against …


Integrating Synthetic Biology Derived Variables Into Ecological Risk Assessment Using The Bayesian Network – Relative Risk Model: Gene Drives To Control Nonindigenous M. Musculus On Southeast Farallon Island, Ethan A. Brown Jan 2020

Integrating Synthetic Biology Derived Variables Into Ecological Risk Assessment Using The Bayesian Network – Relative Risk Model: Gene Drives To Control Nonindigenous M. Musculus On Southeast Farallon Island, Ethan A. Brown

WWU Graduate School Collection

Ecological risk assessment has not been conducted for the proposed environmental applications of synthetic biology. To develop a quantitative framework for risk assessment of synthetic biology, I selected Southeast Farallon Island as a case study for modeling the deployment of gene drive modified house mice to reduce impacts to threatened species. Southeast Farallon Island is part of the Farallon Islands National Wildlife Refuge. The island is populated by invasive house mice that impact indigenous species. Gene drive technology has been proposed as a method to suppress invasive rodent populations through CRISPR-mediated genome editing. I applied the Bayesian Network – Relative …


Forest Restoration Of The Exposed Lake Mills Bed: Assessing Vegetation, Ectomycorrhizae, And Nitrogen Relative To Riverbank Lupine (Lupinus Rivularis), James Kardouni Jan 2020

Forest Restoration Of The Exposed Lake Mills Bed: Assessing Vegetation, Ectomycorrhizae, And Nitrogen Relative To Riverbank Lupine (Lupinus Rivularis), James Kardouni

WWU Graduate School Collection

This thesis investigated the managed revegetation outcomes of the exposed Lake Mills reservoir bed was investigated following the Glines Canyon dam removal on the Elwha River located in the Pacific Northwest, United States. During the following four years of restoration, one seeded species, riverbank lupine (Lupinus rivularis), quickly established on the coarse textured terraces that also had low organic matter (OM) and low soil nitrogen (N) levels. Nitrogen-fixing lupines may facilitate plant recruitment and conifer establishment, while demonstrating a relationship with ectomycorrhizal (ECM) communities which perform essential forest ecosystem functions. The purpose of this study was to investigate lupine’s influence …


The Planet, 2019, Fall, Emily Dietzel, Huxley College Of The Environment, Western Washington University Oct 2019

The Planet, 2019, Fall, Emily Dietzel, Huxley College Of The Environment, Western Washington University

The Planet

No abstract provided.


Before College Math, Roxane Elena Ronca Sep 2019

Before College Math, Roxane Elena Ronca

A Collection of Open Access Books and Monographs

Most math books for college students start out reviewing “rules” in an introductory chapter. The review usually goes like this: here are the “rules”, here are some examples of using those “rules” and here are 10 to 100 exercises where you will practice using those “rules” and then you’ll be tested on them.

The problem with that approach, even if it seems familiar and comfortable to you, is that people learn, in part, by connecting new ideas and perspectives to what they already understand, and correcting any previous misunderstandings. This process takes time and effort. Memorizing rules to quickly retrieve …


Floodplains Provide Important Amphibian Habitat Despite Facing Multiple Ecological Threats, Meredith A. Holgerson, Adam Duarte, Marc P. Hayes, Michael J. Adams, Julie A. Tyson, Keith A. Douville, Angela Strecker Sep 2019

Floodplains Provide Important Amphibian Habitat Despite Facing Multiple Ecological Threats, Meredith A. Holgerson, Adam Duarte, Marc P. Hayes, Michael J. Adams, Julie A. Tyson, Keith A. Douville, Angela Strecker

Environmental Sciences Faculty and Staff Publications

Floodplain ponds and wetlands are productive and biodiverse ecosystems, yet they face multiple threats including altered hydrology, land use change, and non-native species. Protecting and restoring important floodplain ecosystems requires understanding how organisms use these habitats and respond to altered environmental conditions. We developed Bayesian models to evaluate occupancy of six amphibian species across 103 off-channel aquatic habitats in the Chehalis River floodplain, Washington State, USA. The basin has been altered by changes in land use, reduced river–wetland connections, and the establishment of non-native American bullfrogs (Rana catesbeiana = Lithobates catesbeianus) and centrarchid fishes, all of which we …


Dataset For The Environmental Risk Assessment Of Chlorpyrifos To Chinook Salmon In Four Rivers Of Washington State, United States, Wayne G. Landis, Valerie R. Chu, Scarlett Graham, Meagan J. Harris, April J. Markiewicz, Chelsea J. Mitchell, Katherine E. Stackelberg, John Stark Aug 2019

Dataset For The Environmental Risk Assessment Of Chlorpyrifos To Chinook Salmon In Four Rivers Of Washington State, United States, Wayne G. Landis, Valerie R. Chu, Scarlett Graham, Meagan J. Harris, April J. Markiewicz, Chelsea J. Mitchell, Katherine E. Stackelberg, John Stark

Environmental Sciences Faculty and Staff Publications

Data files available below.

This data set is in support of Landis et al (in press) The integration of chlorpyrifos acetylcholinesterase inhibition, water temperature and dissolved oxygen concentration into a regional scale multiple stressor risk assessment estimating risk to Chinook salmon in four rivers in Washington State, USA. DOI: 10.1002/ieam.4199. In this research We estimated the risk to populations of Chinook salmon (Oncorhynchus tshawytscha) due to chlorpyrifos (CH), water temperature (WT) and dissolved oxygen concentrations (DO) in four watersheds in Washington State, USA. The watersheds included the Nooksack and Skagit Rivers in the Northern Puget Sound, the Cedar …


Integration Of Chlorpyrifos Acetylcholinesterase Inhibition, Water Temperature, And Dissolved Oxygen Concentration Into A Regional Scale Multiple Stressor Risk Assessment Estimating Risk To Chinook Salmon, Wayne G. Landis, Valerie R. Chu, Scarlett E. Graham, Meagan J. Harris, April J. Markiewicz, Chelsea J. Mitchell, Katherine E. Von Stackelberg, John D. Stark Aug 2019

Integration Of Chlorpyrifos Acetylcholinesterase Inhibition, Water Temperature, And Dissolved Oxygen Concentration Into A Regional Scale Multiple Stressor Risk Assessment Estimating Risk To Chinook Salmon, Wayne G. Landis, Valerie R. Chu, Scarlett E. Graham, Meagan J. Harris, April J. Markiewicz, Chelsea J. Mitchell, Katherine E. Von Stackelberg, John D. Stark

IETC Publications

We estimated the risk to populations of Chinook salmon (Oncorhynchus tshawytscha) due to chlorpyrifos (CH), water temperature (WT), and dissolved oxygen concentration (DO) in 4 watersheds in Washington State, USA. The watersheds included the Nooksack and Skagit Rivers in the Northern Puget Sound, the Cedar River in the Seattle–Tacoma corridor, and the Yakima River, a tributary of the Columbia River. The Bayesian network relative risk model (BN‐RRM) was used to conduct this ecological risk assessment and was modified to contain an acetylcholinesterase (AChE) inhibition pathway parameterized using data from CH toxicity data sets. The completed BN‐RRM estimated risk at a …


Building Arc Crust: Plutonic To Volcanic Connections In An Extensional Oceanic Arc, The Southern Alisitos Arc, Baja California, Rebecca A. Morris, Susan M. Debari, Cathy Busby, Sarah Medynski, Brian R. Jicha May 2019

Building Arc Crust: Plutonic To Volcanic Connections In An Extensional Oceanic Arc, The Southern Alisitos Arc, Baja California, Rebecca A. Morris, Susan M. Debari, Cathy Busby, Sarah Medynski, Brian R. Jicha

Geology Faculty Publications

The ~50 km long Rosario segment of the Cretaceous Alisitos oceanic arc terrane provides undeformed three-dimensional exposures of the upper 7 km of an oceanic extensional arc, where crustal generation processes are recorded in both the volcanic and underlying plutonic rocks. These exceptional exposures allow for the study of the physical and chemical links between the rock units and help constrain the differentiation processes active during the growth and evolution of arc crust. This study focuses on the southern third of the Rosario segment, previously referred to as the southern volcano-bounded basin, and its plutonic underpinnings. Upper crustal rocks in …


Modeling Distances Between Various Attractions And Nearest City Parks Using Exponential Distribution, Ashley Hall May 2019

Modeling Distances Between Various Attractions And Nearest City Parks Using Exponential Distribution, Ashley Hall

Scholars Week

We examine the park data in Twin Cities Metropolitan Area (TCMA) to understand the distances between various attractions (water features, transit stops, bike paths, sport fields, etc.) and nearest city parks. We verify our research hypothesis that these distance variables are exponentially distributed using histograms and chi-squared goodness-of-fit test. Our findings suggest that most of the distance variables are indeed exponentially distributed except the one that measures the distance between the metropolitan area and the nearest city parks. Based on that, we further hypothesize that the locations of the various attractions relative to the nearest city parks follow the spatial …


Polycarbodiimides And Polyguanidines : Their Reactivity And Applications In Covalent Adaptable Networks, Alberto Melchor Bañales May 2019

Polycarbodiimides And Polyguanidines : Their Reactivity And Applications In Covalent Adaptable Networks, Alberto Melchor Bañales

Scholars Week

We have recently discovered a new chemical transformation in which N,N’,N’’ tri-substituted guanidines undergo a thermal exchange reaction. Kinetic investigations indicate that the transformation is first order with respect to the guanidine, indicating a dissociative mechanism in which a carbodiimide and amine are formed as intermediates. This new reaction has been applied to polymer systems. Polycarbodiimides were shown to undergo postpolymerization modification with amines to form polyguanidines at room temperature under an hour. Polyguanidines undergo the newly found chemical transformation to form different substituted polyguanidines. This exchange reaction will be applied to the preparation of a covalent adaptable network by …


Vibrations On Networks, Zachary Pontrantolfi May 2019

Vibrations On Networks, Zachary Pontrantolfi

Scholars Week

Studying vibrations on networks helps inform our understanding of random processes on other networks with similar geometry. We discuss two physical models to build up intuition about their eigenvectors. We conclude with a hidden connection between the rate of convergence of random walks, and the ground state energies of molecules.


Performance Annotation Framework, Quentin Jensen, Chloe Dawson May 2019

Performance Annotation Framework, Quentin Jensen, Chloe Dawson

Scholars Week

Large scale applications developers have many tools at their disposal to optimize and verify their software. One of which is Caliper, an annotation-based performance measurement tool. Caliper is very powerful and versatile, however, can be cumbersome to apply to complex applications. To solve this problem, we have created a framework to automatically prepare an application for performance measurement. This framework provides a layer of abstraction between the user and the source-code annotations and library linking. As a result, the process of measuring the performance of an application can be fully automated away – a huge step towards automatic software optimization.


Resources For Interdisciplinary Understanding Of Energy, Alessandra Hughes, Jessica Trottier May 2019

Resources For Interdisciplinary Understanding Of Energy, Alessandra Hughes, Jessica Trottier

Scholars Week

In most undergraduate curricula, students are expected to have the ability to apply, or transfer, a learned concept to new coursework. In the sciences, students are often introduced to energy ideas with discipline-specific vocabulary and tasks which encourage compartmentalized, surface-level understandings of energy concepts. Our research investigates student transfer of energy ideas within a coherent science course series, where physics is the foundational course. Similar modeling tools and vocabulary are used in the classes to help students see energy as a unifying framework. We seek to identify and describe what transfer “looks like” in this idealized context by interviewing students …


Spectral Analysis Of Stratigraphy At Eberswalde Crater, Mars, Cory Hughes May 2019

Spectral Analysis Of Stratigraphy At Eberswalde Crater, Mars, Cory Hughes

Scholars Week

We will analyze spectral characteristics of stratigraphy in the catchment and deposit at Eberswalde Crater, Mars. This crater is a frequent contender for the preferred destination of future Mars rover and human science missions in the search for evidence of life on the Red Planet.


Strategy Flexibility: Choosing Different Systems To Apply The Work Energy Principle, Grace Baker, Thanh Le May 2019

Strategy Flexibility: Choosing Different Systems To Apply The Work Energy Principle, Grace Baker, Thanh Le

Scholars Week

An important goal of physics instruction is to help students become adaptive problem solvers so that they can approach a wide range of situations. One aspect of adaptive problem solving is strategy flexibility — knowing multiple ways to approach a problem and choosing the most appropriate approach. In this study, we examine the role of meta strategic judgements in students’ application of strategy flexibility. Specifically, we study students’ meta-strategic judgements when choosing a system with which to apply the work-energy principle to various scenarios. College students enrolled in an introductory mechanics course were interviewed about their rationales for their system …


Engineering Sortase; Activity And Selectivity Of New Hybrid And Ancestral Variants Of Sortase A, Sarah Struyvenberg May 2019

Engineering Sortase; Activity And Selectivity Of New Hybrid And Ancestral Variants Of Sortase A, Sarah Struyvenberg

Scholars Week

Bacterial sortase enzymes are a beneficial tool in innovative mechanisms of protein engineering. However, important limitations to utilization of sortases for engineered purposes exist; namely, that sortase A (SrtA) is a relatively poor enzyme and very specific for the substrate containing LPATXG motif. Exciting previous work from our collaborators reveals that sortases from different species recognize different sequences and that activity can vary. Therefore, we wanted to create and investigate hybrid sortase enzymes between SrtA from S. aureus and Streptococcus pneumoniae, wherein we swapped a substrate-interacting loop between the beta-E and beta-F strands. Our hypothesis is that these residues are …


A Quantitative Assessment Of The Diabetes Self-Management Education Program, Grace Mcfarlane May 2019

A Quantitative Assessment Of The Diabetes Self-Management Education Program, Grace Mcfarlane

Scholars Week

A Diabetes Self-Management Education (DSME) program offered in an inner-city health center run by the Cincinnati Health Department, which started in 2014, was created to help those in an underserved population learn how to manage their diabetes. Two key measurements, A1C (glycated hemoglobin) and BMI (body mass index), were taken over time to monitor their progress. In this study, we analyzed quantitatively whether or not there was a significant improvement in their BMI and A1C values over the course of two years since they joined DSME program as any improvement would imply a potentially healthier lifestyle in regards to their …


A Simulation Platform For Generation Of Synthetic Videos For Human Activity Recognition, Gary Plunkett May 2019

A Simulation Platform For Generation Of Synthetic Videos For Human Activity Recognition, Gary Plunkett

Scholars Week

The field of human activity recognition from video data has recently made great strides. However, the large amount of labelled data needed to train activity recognition models remains a common bottleneck. We introduce a simulation platform to procedurally generate synthetic videos of household activities, which randomizes portions of the virtual scene like camera position, human model, and interaction motion to introduce video variation.


An Automated Spectrogoniometer System With Planetary Science Applications, Kathleen Hoza May 2019

An Automated Spectrogoniometer System With Planetary Science Applications, Kathleen Hoza

Scholars Week

Reflectance spectroscopy is a major technique for characterizing the composition of planetary surfaces, and has led to key findings such as the characterization of alteration minerals indicative of an aqueous, neutral-pH environment in Mars’ past. When a reflectance spectrometer collects data, it does so at some viewing geometry, which is defined by the angular relationships between the light source illuminating the surface, the target material, and the detector. In the lab, this is usually at a standard viewing geometry (e.g. incidence=0, emission=30). In situ measurements taken by spacecraft, however, may be taken at a wide range of viewing geometries. This …