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Assessing Student Performance And Interest From The Start Of The Covid-19 Pandemic To Present Using Engagement, Attendance, And Grades As Indicators, Nazrul I. Khandaker Oct 2022

Assessing Student Performance And Interest From The Start Of The Covid-19 Pandemic To Present Using Engagement, Attendance, And Grades As Indicators, Nazrul I. Khandaker

Publications and Research

ASSESSING STUDENT PERFORMANCE AND INTEREST FROM THE START OF THE COVID-19 PANDEMIC TO PRESENT USING ENGAGEMENT, ATTENDANCE, AND GRADES AS INDICATORS

SINGH, Andrew, KHANDAKER, Nazrul, ZARINE, Ali, ROBBINS, Kathy H., JACKSON, Shirley and AHMED, Masud,

Geological Society of America Abstracts with Programs. Vol 54, No. 5, https://doi.org/10.1130/abs/2022AM-379409

SINGH, Andrew1, KHANDAKER, Nazrul2, ZARINE, Ali3, ROBBINS, Kathy H.4, JACKSON, Shirley3 and AHMED, Masud5, (1)Earth and Physical Sciences, York College of CUNY, 9420 Guy R Brewer Blvd, AC-2F09, Jamaica, NY 11451-0001, (2)Geology Discipline, York College of CUNY, 9420 Guy R Brewer …


Deciphering Regional Geology Using The New Usgs-Ewu Mineral Separation Lab, Zachary Shimp, Katlin Gamache, Travis Morton, Chad Pritchard Jan 2022

Deciphering Regional Geology Using The New Usgs-Ewu Mineral Separation Lab, Zachary Shimp, Katlin Gamache, Travis Morton, Chad Pritchard

2022 Symposium

U/Pb radiometric dating of zircon is one of the most widely used methods to determine the crystallization ages of igneous and metamorphic rocks and the provenance of sedimentary rocks. Eastern Washington University (EWU) has collaborated with the U.S. Geological Survey (USGS) to build a mineral separation lab for isolating zircon (and other) minerals for analysis. This lab was completed in Fall 2022 and is currently being transferred to the new ISC for future use. Graphically illustrated below are the methods used for sampling and pulverizing the rock, as well as grain mount preparation techniques. One of the EWU projects that …


Cuny York College–Hosted Nasa Stem Outreach Program Graduates Over 30,000 Students – The Legacy Continues Amidst The Covid-19 Pandemic, Nazrul I. Khandaker Dec 2021

Cuny York College–Hosted Nasa Stem Outreach Program Graduates Over 30,000 Students – The Legacy Continues Amidst The Covid-19 Pandemic, Nazrul I. Khandaker

Publications and Research

The NASA MUREP (Minority University Research and Education Project) and SEMAA (Science, Engineering, Mathematics and Aerospace Academy) at York College CUNY (City University of New York), borough of Queens, New York City, recently earned a distinction by graduating over 30,000 underrepresented minority students since 1999 with the culmination of the fall 2021 session! African American students are leading the graduates, followed by Hispanic and Asian students being almost equal in proportion. The primary objective of both MAA (MUREP Aerospace Academy) and SEMAA is getting underrepresented minority students exposure to innovative STEM content and prepare many of them to enter higher …


Multi-Faceted Geoscience Research Using Open Access Resources: The Successful Participation Of K9-16 Students, Nazrul I. Khandaker, Noshin Sharmili, Omadevi Singh, Gurwinder Sahota, Sol De Leon, Matthew Khargie, Ali Zarine, Krishna Mahabir, Adacia Teemal, Mildred M. Selby Oct 2021

Multi-Faceted Geoscience Research Using Open Access Resources: The Successful Participation Of K9-16 Students, Nazrul I. Khandaker, Noshin Sharmili, Omadevi Singh, Gurwinder Sahota, Sol De Leon, Matthew Khargie, Ali Zarine, Krishna Mahabir, Adacia Teemal, Mildred M. Selby

Publications and Research

Students interested in geosciences, for the most part, missed out their traditional field- based research activities due to strict social distancing, travel restrictions and/or lacking financial support. An absence of physical laboratory opportunities forced students to choose topics deemed doable through online research. Available data from online sources on extreme weather related case studies, flooding, droughts, groundwater depletion in urban and suburban areas, coastal erosion rate, sealevel rise, landslides, earthquakes, volcanic eruptions, and atmospheric pollution became quite handy and lucrative. Readily available pertinent data sources enabled K9-16 students to conduct summer research at “stay home” situations. Selective peer mentoring was …


Addressing The Learning Loss During The Covid-19 Pandemic Through The Adaptation Of Virtual Platforms, Nazrul I. Khandaker, Anika Nawar Mayeesha, Violeta Escandon Correa, Toralv Munro, Andrew Singh, Matthew Khargie, Ality Aghedo, Jasmin Budhan, Krishna Mahabir, Belal A. Sayeed Oct 2021

Addressing The Learning Loss During The Covid-19 Pandemic Through The Adaptation Of Virtual Platforms, Nazrul I. Khandaker, Anika Nawar Mayeesha, Violeta Escandon Correa, Toralv Munro, Andrew Singh, Matthew Khargie, Ality Aghedo, Jasmin Budhan, Krishna Mahabir, Belal A. Sayeed

Publications and Research

The York College-hosted NASA MAA (MUREP AEROSPACE ACADEMY) has always played a pivotal role in minimizing the learning loss during the summer months, which was heightened during the pandemic. Support from AT&T, Con Edison and NASA enabled the MAA program at York College to offer a virtual STEM education with an earth science concentration to 1000 plus underserved K1-12 students from the community last summer, including 160 high school students. Two factors made this endeavor fruitful: allowing additional time to engage in STEM lessons and increasing self-motivation to successfully accomplish assigned tasks. Students built partnerships and resolved technical issues with …


Microgravity And Its Bearing With Space Flight-Related Research, Farhan Tanvir, Nazrul I. Khandaker, Rajendra Persaud, Jeff Guan Oct 2020

Microgravity And Its Bearing With Space Flight-Related Research, Farhan Tanvir, Nazrul I. Khandaker, Rajendra Persaud, Jeff Guan

Publications and Research

This study investigates the unique properties and applications of microgravity in the context of spaceflight research. Understanding and harnessing the behaviors of a microgravity environment opens up the doors to long-term space travel and consequently, future missions to other planets within our solar system. More specifically, simulating and conducting experiments in microgravity environments helps us explore its effects on the various necessary tasks and behaviors that are carried out during spaceflight. The most immediate and pronounced effects of microgravity are on human physiology. In particular, studies have shown that prolonged exposure to microgravity can result in a 20% decrease in …


The Nasa Murep Aerospace Academy Program (Maa): Playing A Pivotal Role In Bridging The Knowledge-Gap During The Covid-19 Pandemic, Nazrul I. Khandaker, Omadevi Singh, Sol De Leon, Violeta Escandon, Tajriyan Chowdhury, Anthony Ramnarain, Sahaj Khan, Najina Tojiboeva, Raj Datta, Brian Sukhnandan, Farshad Hosseinie, Fiorella Guevara Oct 2020

The Nasa Murep Aerospace Academy Program (Maa): Playing A Pivotal Role In Bridging The Knowledge-Gap During The Covid-19 Pandemic, Nazrul I. Khandaker, Omadevi Singh, Sol De Leon, Violeta Escandon, Tajriyan Chowdhury, Anthony Ramnarain, Sahaj Khan, Najina Tojiboeva, Raj Datta, Brian Sukhnandan, Farshad Hosseinie, Fiorella Guevara

Publications and Research

The COVID-19 pandemic forced all City University of New York CUNY campuses, including York College, to offer virtual learning opportunities to students. NASA MAA, being an outreach STEM program, also fell under the same category and swiftly came-up with a plan to move into DLM. Initial surveys indicated the basic household technology needed to attend virtual sessions and showed complicated situations where parents had multiple children attending the summer 2020 session. To ensure greater participation, computers, iPads, Chromebooks, and cell phones were used. Common platforms. like WebEx and Zoom, were routinely used by our MAA teachers to disseminate online content …


Integrating Digital Tools In Remote Learning To Enhance The Delivery Methods Of Technical Content In Undergraduate Geosciences, Ruslana Baker, Malek Shami, Nazrul I. Khandaker, Stanley Schleifer Oct 2020

Integrating Digital Tools In Remote Learning To Enhance The Delivery Methods Of Technical Content In Undergraduate Geosciences, Ruslana Baker, Malek Shami, Nazrul I. Khandaker, Stanley Schleifer

Publications and Research

The global transition to remote learning due to the COVID-19 pandemic was an extremely difficult task for both students and faculty in geological sciences. Technical courses, such as Structural Geology, Mineralogy, Petrology, and Invertebrate Paleontology, that require in-person lectures and laboratory sessions involving various rocks and mineral samples, fossils, maps, and models, were a major concern at the start. The challenge of delivering the technical content via Microsoft Teams, Skype, Webex, Blackboard Collaborate Ultra, Zoom, and other internet based platforms was not only a burden for the faculty to carry, as students were struggling to conceptualize outcrop-and-type-section-based information and link …


Hydraulic Tomography: 3d Hydraulic Conductivity, Fracture Network, And Connectivity In Mudstone, Claire R. Tiedeman, Warren Barrash Mar 2020

Hydraulic Tomography: 3d Hydraulic Conductivity, Fracture Network, And Connectivity In Mudstone, Claire R. Tiedeman, Warren Barrash

CGISS Publications and Presentations

We present the first demonstration of hydraulic tomography (HT) to estimate the three‐dimensional (3D) hydraulic conductivity (K) distribution of a fractured aquifer at high‐resolution field scale (HRFS), including the fracture network and connectivity through it. We invert drawdown data collected from packer‐isolated borehole intervals during 42 pumping tests in a wellfield at the former Naval Air Warfare Center, West Trenton, New Jersey, in the Newark Basin. Five additional tests were reserved for a quality check of HT results. We used an equivalent porous medium forward model and geostatistical inversion to estimate 3D K at high resolution (K …


Positive Outcomes Of Involving Undergraduate And High School Students In Broader Aspect Of Earth System Science Through Peer Mentoring And Research Activities, Nazrul I. Khandaker, Shuayb Siddique, Matthew Khargie, Juanpablo Rodriguez, Adacia Teemal, Krishna Mahabir, Michael Robinson, Ality Aghedo, Zachary A. Sanichar, Sol De Leon, Tamzid Mubin, Elton Selby Sep 2019

Positive Outcomes Of Involving Undergraduate And High School Students In Broader Aspect Of Earth System Science Through Peer Mentoring And Research Activities, Nazrul I. Khandaker, Shuayb Siddique, Matthew Khargie, Juanpablo Rodriguez, Adacia Teemal, Krishna Mahabir, Michael Robinson, Ality Aghedo, Zachary A. Sanichar, Sol De Leon, Tamzid Mubin, Elton Selby

Publications and Research

The importance of involving undergraduates and high school students in field-and-laboratory research investigations at an early stage through peer mentoring has been clearly demonstrated as a critical tool for essential training to fully comprehend academic content and a deeper understanding of the various STEM, geoscience-and- environmental science related topics. As far as we are concerned, student presenters/participants (over 1000) in our topical sessions since 2004 have always found face-to-face presentation through poster sessions to be an ideal scientific venue where exchange of knowledge and discussion are fruitful, constructive and encouraging. It is quite revealing to note that among the student …


Ionoseis: A Package To Model Coseismic Ionospheric Disturbances, Thomas Dylan Mikesell, Lucie Rolland, Rebekah F. Lee, Florian Zedek, Pierdavide Coïsson, Jean-Xavier Dessa Aug 2019

Ionoseis: A Package To Model Coseismic Ionospheric Disturbances, Thomas Dylan Mikesell, Lucie Rolland, Rebekah F. Lee, Florian Zedek, Pierdavide Coïsson, Jean-Xavier Dessa

CGISS Publications and Presentations

We present the framework of the modeling package IonoSeis. This software models Global Navigation Satellite System (GNSS) derived slant total electron content (sTEC) perturbations in the ionosphere due to the interaction of the neutral atmosphere and charged particles in the ionosphere. We use a simplified model to couple the neutral particle momentum into the ionosphere and reconstruct time series of sTEC perturbations that match observed data in both arrival time and perturbation shape. We propagate neutral atmosphere disturbances to ionospheric heights using a three-dimensional ray-tracing code in spherical coordinates called Windy Atmospheric Sonic Propagation (WASP3D), which works for a …


Tsunamigenic Splay Faults Imply A Long‐Term Asperity In Southern Prince William Sound, Alaska, L. M. Liberty, D. S. Brothers, P. J. Haeussler Apr 2019

Tsunamigenic Splay Faults Imply A Long‐Term Asperity In Southern Prince William Sound, Alaska, L. M. Liberty, D. S. Brothers, P. J. Haeussler

CGISS Publications and Presentations

Coseismic slip partitioning and uplift over multiple earthquake cycles is critical to understanding upper‐plate fault development. Bathymetric and seismic reflection data from the 1964 Mw9.2 Great Alaska earthquake rupture area reveal sea floor scarps along the tsunamigenic Patton Bay/Cape Cleare/Middleton Island fault system. The faults splay from a megathrust where duplexing and underplating produced rapid exhumation. Trenchward of the duplex region, the faults produce a complex deformation pattern from oblique, south‐directed shortening at the Yakutat‐Pacific plate boundary. Spatial and temporal fault patterns suggest that Holocene megathrust earthquakes had similar relative motions and thus similar tsunami sources as in …


Interannual Snow Accumulation Variability On Glaciers Derived From Repeat, Spatially Extensive Ground-Penetrating Radar Surveys, Daniel Mcgrath, Louis Sass, Shad O'Neel, Chris Mcneil, Salvatore G. Candela, Emily H. Baker, Hans-Peter Marshall Nov 2018

Interannual Snow Accumulation Variability On Glaciers Derived From Repeat, Spatially Extensive Ground-Penetrating Radar Surveys, Daniel Mcgrath, Louis Sass, Shad O'Neel, Chris Mcneil, Salvatore G. Candela, Emily H. Baker, Hans-Peter Marshall

CGISS Publications and Presentations

There is significant uncertainty regarding the spatiotemporal distribution of seasonal snow on glaciers, despite being a fundamental component of glacier mass balance. To address this knowledge gap, we collected repeat, spatially extensive high-frequency ground-penetrating radar (GPR) observations on two glaciers in Alaska during the spring of 5 consecutive years. GPR measurements showed steep snow water equivalent (SWE) elevation gradients at both sites; continental Gulkana Glacier's SWE gradient averaged 115 mm 100 m−1 and maritime Wolverine Glacier's gradient averaged 440 mm 100 m−1 (over > 1000 m). We extrapolated GPR point observations across the glacier surface using terrain parameters derived …


Direct Insertion Of Nasa Airborne Snow Observatory-Derived Snow Depth Time Series Into The Isnobal Energy Balance Snow Model, Andrew R. Hedrick, Hans-Peter Marshall Oct 2018

Direct Insertion Of Nasa Airborne Snow Observatory-Derived Snow Depth Time Series Into The Isnobal Energy Balance Snow Model, Andrew R. Hedrick, Hans-Peter Marshall

CGISS Publications and Presentations

Accurately simulating the spatiotemporal distribution of mountain snow water equivalent improves estimates of available meltwater and benefits the water resource management community. In this paper we present the first integration of lidar-derived distributed snow depth data into a physics-based snow model using direct insertion. Over four winter seasons (2013–2016) the National Aeronautics and Space Administration/Jet Propulsion Laboratory (NASA/JPL) Airborne Snow Observatory (ASO) performed near-weekly lidar surveys throughout the snowmelt season to measure snow depth at high resolution over the Tuolumne River Basin above Hetch Hetchy Reservoir in the Sierra Nevada Mountains of California. The modeling component of the ASO program …


Revelation Of Early Detection Of Coseismic Ionospheric Perturbations In Gps-Tec From Realistic Modelling Approach: Case Study, Dhanya Thomas, Mala S. Bagiya, Poikayil Sukumaran Sunil, Lucie Rolland, Anakuzhikkal Sudarsanan Sunil, T. Dylan Mikesell, Srinivas Nayak, Subrahmanyam Mangalampalli, Durbha Sai Ramesh Aug 2018

Revelation Of Early Detection Of Coseismic Ionospheric Perturbations In Gps-Tec From Realistic Modelling Approach: Case Study, Dhanya Thomas, Mala S. Bagiya, Poikayil Sukumaran Sunil, Lucie Rolland, Anakuzhikkal Sudarsanan Sunil, T. Dylan Mikesell, Srinivas Nayak, Subrahmanyam Mangalampalli, Durbha Sai Ramesh

CGISS Publications and Presentations

GPS-derived Total Electron Content (TEC) is an integrated quantity; hence it is difficult to relate the detection of ionospheric perturbations in TEC to a precise altitude. As TEC is weighted by the maximum ionospheric density, the corresponding altitude (hmF2) is, generally, assumed as the perturbation detection altitude. To investigate the validity of this assumption in detail, we conduct an accurate analysis of the GPS-TEC measured early ionospheric signatures related to the vertical surface displacement of the Mw 7.4 Sanriku-Oki earthquake (Sanriku-Oki Tohoku foreshock). Using 3D acoustic ray tracing model to describe the evolution of the propagating seismo-acoustic wave in space …


Seismic Imaging Of The Main Frontal Thrust In Nepal Reveals A Shallow Décollement And Blind Thrusting, Rafael V. Almeida, Judith Hubbard, Lee Liberty, Anna Foster, Soma Nath Sapkota Jun 2018

Seismic Imaging Of The Main Frontal Thrust In Nepal Reveals A Shallow Décollement And Blind Thrusting, Rafael V. Almeida, Judith Hubbard, Lee Liberty, Anna Foster, Soma Nath Sapkota

CGISS Publications and Presentations

Because great earthquakes in the Himalaya have an average recurrence interval exceeding 500 yr, most of what we know about past earthquakes comes from paleoseismology and tectonic geomorphology studies of the youngest fault system there, the Main Frontal Thrust (MFT). However, these data are sparse relative to fault segmentation and length, and interpretations are often hard to validate in the absence of information about fault geometry. Here, we image the upper two km of strata in the vicinity of the fault tip of the MFT in central Nepal (around the town of Bardibas) applying a pre-stack migration approach to two …


Local, Regional, And Remote Seismo‐Acoustic Observations Of The April 2015 Vei 4 Eruption Of Calbuco Volcano, Chile, Robin S. Matoza, David Fee, David N. Green, Alexis Le Pichon, Julien Vergoz, Matthew M. Haney, T. Dylan Mikesell, Luis Franco, O. Alberto Valderrama, Megan R. Kelley, Kathleen Mckee, Lars Ceranna May 2018

Local, Regional, And Remote Seismo‐Acoustic Observations Of The April 2015 Vei 4 Eruption Of Calbuco Volcano, Chile, Robin S. Matoza, David Fee, David N. Green, Alexis Le Pichon, Julien Vergoz, Matthew M. Haney, T. Dylan Mikesell, Luis Franco, O. Alberto Valderrama, Megan R. Kelley, Kathleen Mckee, Lars Ceranna

CGISS Publications and Presentations

The two major explosive phases of the 22–23 April 2015 eruption of Calbuco volcano, Chile, produced powerful seismicity and infrasound. The eruption was recorded on seismo-acoustic stations out to 1,540 km and on five stations (IS02, IS08, IS09, IS27, and IS49) of the International Monitoring System (IMS) infrasound network at distances from 1,525 to 5,122 km. The remote IMS infrasound stations provide an accurate explosion chronology consistent with the regional and local seismo-acoustic data and with previous studies of lightning and plume observations. We use the IMS network to detect and locate the eruption signals using a brute-force, grid-search, cross-bearings …


Diverse Eruptive Activity Revealed By Acoustic And Electromagnetic Observations Of The 14 July 2013 Intense Vulcanian Eruption Of Tungurahua Volcano, Ecuador, J. F. Anderson, J. B. Johnson, A. L. Steele, M. C. Ruiz, B. D. Brand Apr 2018

Diverse Eruptive Activity Revealed By Acoustic And Electromagnetic Observations Of The 14 July 2013 Intense Vulcanian Eruption Of Tungurahua Volcano, Ecuador, J. F. Anderson, J. B. Johnson, A. L. Steele, M. C. Ruiz, B. D. Brand

CGISS Publications and Presentations

During the powerful July 2013 eruption of Tungurahua volcano, Ecuador, we recorded exceptionally high amplitude, long‐period infrasound (1,600‐Pa peak‐to‐peak amplitude, 5.5‐s period) on sensors within 2km of the vent alongside electromagnetic signals from volcanic lightning serendipitously captured as interference. This explosion was one of Tungurahua's most powerful vulcanian eruptions since recent activity began in 1999, and its acoustic wave is among the most powerful volcanic infrasound ever recorded anywhere. We use these data to quantify erupted volume from the main explosion and to classify postexplosive degassing into distinct emission styles. Additionally, we demonstrate a highly effective method of recording lightning‐related …


Ice Core Records Of West Greenland Melt And Climate Forcing, H.P. Marshall, T. Meehan Apr 2018

Ice Core Records Of West Greenland Melt And Climate Forcing, H.P. Marshall, T. Meehan

CGISS Publications and Presentations

Remote sensing observations and climate models indicate that the Greenland Ice Sheet (GrIS) has been losing mass since the late 1990s, mostly due to enhanced surface melting from rising summer temperatures. However, in situ observational records of GrIS melt rates over recent decades are rare. Here we develop a record of frozen meltwater in the west GrIS percolation zone preserved in seven firn cores. Quantifying ice layer distribution as a melt feature percentage (MFP), we find significant increases in MFP in the southernmost five cores over the past 50 years to unprecedented modern levels (since 1550 CE). Annual to decadal …


Forecasting The Eruption Of An Open‐Vent Volcano Using Resonant Infrasound Tones, Jeffrey B. Johnson, Leighton M. Watson, Jose L. Palma, Eric M. Dunham, Jacob F. Anderson Mar 2018

Forecasting The Eruption Of An Open‐Vent Volcano Using Resonant Infrasound Tones, Jeffrey B. Johnson, Leighton M. Watson, Jose L. Palma, Eric M. Dunham, Jacob F. Anderson

CGISS Publications and Presentations

Open‐vent volcanic systems with active degassing are particularly effective at producing infrasound that exhibits resonant tones controlled by the geometry of the volcano's crater. Changes in the infrasound character can thus provide constraints on a crater's lava level, which may vary dynamically in the lead‐up to an eruption. Here we show that the increasing frequency content and damping characteristics of the resonant infrasound at Volcán Villarrica (Chile) relate to lava lake position in its crater/conduit preceding its 2015 eruption. We model the acoustic response of Villarrica's crater to determine that the lake began to rise on 27 February and reached …


Geothermal Play Fairway Analysis, Phase 3: A Provisional Conceptual Model Of The Camas Prairie, Snake River Plain, Idaho, Lee M. Liberty Jan 2018

Geothermal Play Fairway Analysis, Phase 3: A Provisional Conceptual Model Of The Camas Prairie, Snake River Plain, Idaho, Lee M. Liberty

CGISS Publications and Presentations

The Snake River Plain (SRP) Geothermal Play Fairway Analysis team identified two regions of interest during Phase 2 studies: the western SRP near Mountain Home, Idaho and Camas Prairie, Idaho. New geological, geochemical, and geophysical (gravity, magnetic, MT, seismic) studies of both areas led to a focus on Camas Prairie for validation during Phase 3. Camas Prairie is an EW-trending half-graben bounded on the north by the Idaho Batholith and on the south by the Mount Bennett Hills. Camas Prairie is bisected by a major NW-trending fault system (The Pothole fault) that separates NW-trending faults to east from ENE-trending faults …


A Geophysical Characterization Of The Structural Framework Of The Camas Prairie Geothermal System, Southcentral Idaho, Lee Liberty Jan 2018

A Geophysical Characterization Of The Structural Framework Of The Camas Prairie Geothermal System, Southcentral Idaho, Lee Liberty

CGISS Publications and Presentations

Play Fairway Analysis methods, utilizing existing geologic, thermal, geochemical, and geophysical data were employed in an initial assessment of geothermal resources in the Snake River Plain. These efforts identified the Camas Prairie in southcentral Idaho as a region with elevated resource potential. Subsequent efforts included structural and geophysical data collection to identify the most favorable structural settings for exploiting resources in the valley. The present work involved high-resolution gravity, magnetic, magnetotellurics (MT), field mapping, and seismic surveys to further characterize the system and target sites for exploration drilling around Barron’s Hot Springs (BHS) in the southwest part of the valley. …


A Functional Trait Approach To Examine Plant Community Dynamics In South Florida Hardwood Hammock Forests, Suresh Chandra Subedi Jun 2017

A Functional Trait Approach To Examine Plant Community Dynamics In South Florida Hardwood Hammock Forests, Suresh Chandra Subedi

FIU Electronic Theses and Dissertations

The tropical hardwood forests of south Florida persist as well-drained patches of broadleaf forest separated by brackish water swamp, marsh, or pineland. In this dissertation, a functional trait approach was used to understand the structure and dynamics of these communities and their responses to abiotic and biotic variation. Twenty-seven permanent plots (20 x 20 m2) were established across the south Florida landscape, representing four sub-regions: Everglades marsh, Long Pine Key, Upper Keys, and Lower Keys. Community weighted mean trait values for four of six selected traits showed significant inter-sub-regional variation. Out of them, three traits (specific leaf area, …


Regional Greenland Accumulation Variability From Operation Icebridge Airborne Accumulation Radar, Gabriel Lewis, Erich Osterberg, Robert Hawley, Brian Whitmore, Hans Peter Marshall, Jason Box Mar 2017

Regional Greenland Accumulation Variability From Operation Icebridge Airborne Accumulation Radar, Gabriel Lewis, Erich Osterberg, Robert Hawley, Brian Whitmore, Hans Peter Marshall, Jason Box

CGISS Publications and Presentations

The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest to scientists and the general public in the context of future sea-level rise. An improved understanding of temporal and spatial variability of snow accumulation will reduce uncertainties in GrIS mass balance models and improve projections of Greenland's contribution to sea-level rise, currently estimated at 0.089 ± 0.03 m by 2100. Here we analyze 25 NASA Operation IceBridge accumulation radar flights totaling > 17 700 km from 2013 to 2014 to determine snow accumulation in the GrIS dry snow and percolation zones over the past …


Probabilistic Inversion With Graph Cuts: Application To The Boise Hydrogeophysical Research Site, Guillaume Pirot, Niklas Linde, Grégoire Mariethoz, John H. Bradford Feb 2017

Probabilistic Inversion With Graph Cuts: Application To The Boise Hydrogeophysical Research Site, Guillaume Pirot, Niklas Linde, Grégoire Mariethoz, John H. Bradford

CGISS Publications and Presentations

Inversion methods that build on multiple-point statistics tools offer the possibility to obtain model realizations that are not only in agreement with field data, but also with conceptual geological models that are represented by training images. A recent inversion approach based on patch-based geostatistical resimulation using graph cuts outperforms state-of-the-art multiple-point statistics methods when applied to synthetic inversion examples featuring continuous and discontinuous property fields. Applications of multiple-point statistics tools to field data are challenging due to inevitable discrepancies between actual subsurface structure and the assumptions made in deriving the training image. We introduce several amendments to the original graph …


Geothermal Play Fairway Analysis Of The Snake River Plain: Phase 2, Lee M. Liberty Jan 2017

Geothermal Play Fairway Analysis Of The Snake River Plain: Phase 2, Lee M. Liberty

CGISS Publications and Presentations

Play Fairway Analysis (PFA) is a methodology adapted from the petroleum industry that integrates data at the regional or basin scale to define favorable plays for exploration in a systematic fashion. Phase 2 of our Play Fairway Analysis of the Western Snake River Plain (WSRP) province in southern Idaho had three primary goals: first, to fill data gaps in critical areas in order to better define potential prospects, second, to integrate these data into new thermal and structural models, and finally, to infer the location of potential resources and drilling targets that could be validated during Phase 3. Prospects in …


Impact Of Spatial Averaging On Radar Reflectivity At Internal Snowpack Layer Boundaries, N. Rutter, H.P. Marshall, K. Tape, R. Essery, J. King Dec 2016

Impact Of Spatial Averaging On Radar Reflectivity At Internal Snowpack Layer Boundaries, N. Rutter, H.P. Marshall, K. Tape, R. Essery, J. King

CGISS Publications and Presentations

Microwave radar amplitude within a snowpack can be strongly influenced by spatial variability of internal layer boundaries. We quantify the impact of spatial averaging of snow stratigraphy and physical snowpack properties on surface scattering from near-nadir frequency-modulated continuous- wave radar at 12–18 GHz. Relative permittivity, density, grain size and stratigraphic boundaries were measured in-situ at high resolution along the length of a 9 m snow trench. An optimal range of horizontal averaging (4–6 m) was identified to attribute variations in surface scattering at layer boundaries to dielectric contrasts estimated from centimetre-scale measurements of snowpack stratigraphy and bulk layer properties. Single …


Monitoring Southwest Greenland’S Ice Sheet Melt With Ambient Seismic Noise, Aurélien Mordret, T. Dylan Mikesell, Christopher Harig, Bradley P. Lipovsky, Germán A. Prieto May 2016

Monitoring Southwest Greenland’S Ice Sheet Melt With Ambient Seismic Noise, Aurélien Mordret, T. Dylan Mikesell, Christopher Harig, Bradley P. Lipovsky, Germán A. Prieto

CGISS Publications and Presentations

The Greenland ice sheet presently accounts for ~70% of global ice sheet mass loss. Because this mass loss is associated with sea-level rise at a rate of 0.7 mm/year, the development of improved monitoring techniques to observe ongoing changes in ice sheet mass balance is of paramount concern. Spaceborne mass balance techniques are commonly used; however, they are inadequate for many purposes because of their low spatial and/or temporal resolution. We demonstrate that small variations in seismic wave speed in Earth’s crust, as measured with the correlation of seismic noise, may be used to infer seasonal ice sheet mass balance. …


Advancements In The Measurement Of The Cryosphere Using Geophysics — Introduction, Andrew D. Parsekian, John Bradford, Georgios Tsoflias, Steven Arcone, Bernd Kulessa Jan 2016

Advancements In The Measurement Of The Cryosphere Using Geophysics — Introduction, Andrew D. Parsekian, John Bradford, Georgios Tsoflias, Steven Arcone, Bernd Kulessa

CGISS Publications and Presentations

Frozen regions of the earth are known as the cryosphere. The arctic, Antarctica, permafrost, ice sheets, and glaciers are some of the most challenging places to measure subsurface parameters, but they can also be some of the most important places to science and engineering research due to their susceptibility to environmental change. Ground-based, airborne, and space-borne geophysical methods are deployed to observe targets below the ground or in ice that may be difficult or impossible to measure using conventional direct observations and measurements. The papers in this special section address recent advances in instrumentation development and deployment and computational capabilities …


A Synthetic Study To Assess The Applicability Of Full-Waveform Inversion To Infer Snow Stratigraphy From Upward-Looking Ground-Penetrating Radar Data, Lino Schmid, Jürg Schweizer, John Bradford, Hansruedi Maurer Jan 2016

A Synthetic Study To Assess The Applicability Of Full-Waveform Inversion To Infer Snow Stratigraphy From Upward-Looking Ground-Penetrating Radar Data, Lino Schmid, Jürg Schweizer, John Bradford, Hansruedi Maurer

CGISS Publications and Presentations

Snow stratigraphy and liquid water content are key contributing factors to avalanche formation. Upward-looking ground penetrating radar (upGPR) systems allow nondestructive monitoring of the snowpack, but deriving density and liquid water content profiles is not yet possible based on the direct analysis of the reflection response. We have investigated the feasibility of deducing these quantities using full-waveform inversion (FWI) techniques applied to upGPR data. For that purpose, we have developed a frequency-domain FWI algorithm in which we additionally took advantage of time-domain features such as the arrival times of reflected waves. Our results indicated that FWI applied to upGPR data …