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Full-Text Articles in Physical Sciences and Mathematics

Plant List Of Accepted Nomenclature, Taxonomy And Symbols, J S. Peterson Aug 2024

Plant List Of Accepted Nomenclature, Taxonomy And Symbols, J S. Peterson

IGC Proceedings (1993-2023)

The Plant List of Accepted Nomenclature, Taxonomy & Symbols (PLANTS) is a dynamic database providing scientific and vernacular names, distributional, growth form, origin, symbols and bibliographic standardised botanical data to US federal agencies. PLANTS encompasses the vascular plant, moss, lichen and liverwort flora of North America, north of the Mexico border, including US states and territories.


Effects Of Plant Species Diversity In Multifunctional Grasslands On Avian Communities, K. K. Bakker, K. F. Higgins Aug 2023

Effects Of Plant Species Diversity In Multifunctional Grasslands On Avian Communities, K. K. Bakker, K. F. Higgins

IGC Proceedings (1993-2023)

Grasslands, planted or native sod, can provide multiple simultaneous functions (e.g., hay-forage production, biomass fuel products, bird nesting cover, soil and water conservation). Bird use of and abundance in grasslands is dependent on vegetation structure, size, and surrounding landscape (Bakker et al., 2002) but little is known about avian relationships to plant species diversity. We evaluated the relationship between plant species diversity and avian community structure in 5 grassland types. The results have application to grazing, haying, burning, and conservation practices applied to native and sown grassland stands and to conservation strategies for declining grassland bird populations.


A Review Of User Perceptions Of Drought Indices And Indicators Used In The Diverse Climates Of North America, R. R. Heim Jr, D. Bathke, B. Bonsal, E. W. Cooper, T. Hadwen, K. Kodama, D. Mcevoy, M. Muth, J. W. Nielsen-Gammon, H. R. Prendeville, R. P. Ramirez Jan 2023

A Review Of User Perceptions Of Drought Indices And Indicators Used In The Diverse Climates Of North America, R. R. Heim Jr, D. Bathke, B. Bonsal, E. W. Cooper, T. Hadwen, K. Kodama, D. Mcevoy, M. Muth, J. W. Nielsen-Gammon, H. R. Prendeville, R. P. Ramirez

School of Natural Resources: Faculty Publications

No abstract provided.


Nabat Ml: Utilizing Deep Learning To Enable Crowdsourced Development Of Automated, Scalable Solutions For Documenting North American Bat Populations, Ali Khalighifar, Benjamin S. Gotthold, Erin Adams, Jenny Barnett, Laura O. Beard, Eric R. Britzke, Paul A. Burger, Kimberly Chase, Zackary Cordes, Paul M. Cryan, Emily Emily, Christopher T. Fill, Scott E. Gibson, G. Scott Haulton, Kathryn M. Irvine, Lara S. Katz, William L. Kendall, Christen A. Long, Oisin Mac Aodha, Tessa Mcburney, Sara Mccarthy, Matthew W. Mckown, Joy O'Keefe, Lucy D. Patterson, Kristopher A. Pitcher, Matthew Rustand, Jordi L. Segers, Kyle Seppanen, Jeremy L. Siemers, Christian Stratton, Bethany R. Straw, Theodore J. Weller, Brian E. Reichert Jul 2022

Nabat Ml: Utilizing Deep Learning To Enable Crowdsourced Development Of Automated, Scalable Solutions For Documenting North American Bat Populations, Ali Khalighifar, Benjamin S. Gotthold, Erin Adams, Jenny Barnett, Laura O. Beard, Eric R. Britzke, Paul A. Burger, Kimberly Chase, Zackary Cordes, Paul M. Cryan, Emily Emily, Christopher T. Fill, Scott E. Gibson, G. Scott Haulton, Kathryn M. Irvine, Lara S. Katz, William L. Kendall, Christen A. Long, Oisin Mac Aodha, Tessa Mcburney, Sara Mccarthy, Matthew W. Mckown, Joy O'Keefe, Lucy D. Patterson, Kristopher A. Pitcher, Matthew Rustand, Jordi L. Segers, Kyle Seppanen, Jeremy L. Siemers, Christian Stratton, Bethany R. Straw, Theodore J. Weller, Brian E. Reichert

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

  1. Bats play crucial ecological roles and provide valuable ecosystem services, yet many populations face serious threats from various ecological disturbances. The North American Bat Monitoring Program (NABat) aims to use its technology infrastructure to assess status and trends of bat populations, while developing innovative and community-driven conservation solutions.

  2. Here, we present NABat ML, an automated machine-learning algorithm that improves the scalability and scientific transparency of NABat acoustic monitoring. This model combines signal processing techniques and convolutional neural networks (CNNs) to detect and classify recorded bat echolocation calls. We developed our CNN model with internet-based computing resources (‘cloud environment’), and …


Into The Depths: Climate Change Part 4, Felicia Bedford May 2022

Into The Depths: Climate Change Part 4, Felicia Bedford

D.U.Quark

No abstract provided.


The Role Of Rare Avian Species For Spatial Resilience Of Shifting Biomes In The Great Plains Of North America, D. Angeler, C. Roberts, D. Twidwell Jr., C. Allen Jan 2022

The Role Of Rare Avian Species For Spatial Resilience Of Shifting Biomes In The Great Plains Of North America, D. Angeler, C. Roberts, D. Twidwell Jr., C. Allen

School of Natural Resources: Faculty Publications

No abstract provided.


Spatiotemporal Analysis Of Extreme Precipitation In The Missouri River Basin From 1950 To 2019, Paul Flanagan, Rezaul Mahmood Jun 2021

Spatiotemporal Analysis Of Extreme Precipitation In The Missouri River Basin From 1950 To 2019, Paul Flanagan, Rezaul Mahmood

School of Natural Resources: Faculty Publications

Extreme precipitation events are challenging to local and regional stakeholders across the United States. The Missouri River basin (MoRB), covering an area over 1.29 million km2, is prone to extreme precipitation events. These events are exacerbated by the complex terrain in the west and the numerous weather and climate features that impact the region on a seasonal and annual basis (low-level jets, mesoscale convective systems, extreme cold air intrusions, etc.). Without an in-depth analysis of extreme precipitation in the MoRB, the evolving nature of extreme precipitation is not known. This situation warrants an analysis of extreme precipitation, especially …


Going Native With Legumes In Rangeland Restoration, Cultivated Pasture And Prairies, Jim P. Muir, Twain J. Butler, W. D. Pitman, J. Lloyd‐Reilley, P. D. Maywauld, R. T. Cragar Mar 2021

Going Native With Legumes In Rangeland Restoration, Cultivated Pasture And Prairies, Jim P. Muir, Twain J. Butler, W. D. Pitman, J. Lloyd‐Reilley, P. D. Maywauld, R. T. Cragar

IGC Proceedings (1993-2023)

No abstract provided.


Dynamic Landscapes In Northwestern North America Structured Populations Of Wolverines (Gulo Gulo), D. M. Krejsa, S. L. Talbot, S. Sonsthagen, T. S. Jung, A. J. Majoun, J. A. Cook Jan 2021

Dynamic Landscapes In Northwestern North America Structured Populations Of Wolverines (Gulo Gulo), D. M. Krejsa, S. L. Talbot, S. Sonsthagen, T. S. Jung, A. J. Majoun, J. A. Cook

School of Natural Resources: Faculty Publications

No abstract provided.


Whose Ground Truth Is It? Harvesting Lessons From Missouri’S 2018 Bumper Crop Of Drought Observations, Kelly Helm Smith, Mark E. Burbach, Michael Hayes, Patrick Guinan, Andrew Tyre, Brian Fuchs, Tonya Haigh, Mark Svoboda Jan 2021

Whose Ground Truth Is It? Harvesting Lessons From Missouri’S 2018 Bumper Crop Of Drought Observations, Kelly Helm Smith, Mark E. Burbach, Michael Hayes, Patrick Guinan, Andrew Tyre, Brian Fuchs, Tonya Haigh, Mark Svoboda

Drought Mitigation Center: Faculty Publications

Drought-related decision-making and policy should go beyond numeric hydrometeorological data to incorporate information on how drought affects people, livelihoods, and ecosystems. The effects of drought are nested within environmental and human systems, and relevant data may not exist in readily accessible form. For example, drought may reduce forage growth, compounded by both late-season freezes and management decisions. An effort to gather crowdsourced drought observations in Missouri in 2018 yielded a much higher number of observations than did previous related efforts. Here we examine 1) the interests, circumstances, history, and recruitment messaging that coincided to produce a high number of reports …


Spatial Fingerprint Of Younger Dryas Cooling And Warming In Eastern North America, David Fastovich, James M. Russell, Stephen T. Jackson, Teresa R. Krause, Shaun A. Marcott, John W. Williams Oct 2020

Spatial Fingerprint Of Younger Dryas Cooling And Warming In Eastern North America, David Fastovich, James M. Russell, Stephen T. Jackson, Teresa R. Krause, Shaun A. Marcott, John W. Williams

Faculty Authored Articles

The Younger Dryas (YD, 12.9–11.7 ka) is the most recent, near‐global interval of abrupt climate change with rates similar to modern global warming. Understanding the causes and biodiversity effects of YD climate changes requires determining the spatial fingerprints of past temperature changes. Here we build pollen‐based and branched glycerol dialkyl glycerol tetraether‐based temperature reconstructions in eastern North America (ENA) to better understand deglacial temperature evolution. YD cooling was pronounced in the northeastern United States and muted in the north central United States. Florida sites warmed during the YD, while other southeastern sites maintained a relatively stable climate. This fingerprint is …


Direct P-Wave Anisotropy Measurements At Homestake Mine: Implications For Wave Propagation In Continental Crust, James Atterholt, Sarah J. Brownlee, Gary L. Pavlis Sep 2020

Direct P-Wave Anisotropy Measurements At Homestake Mine: Implications For Wave Propagation In Continental Crust, James Atterholt, Sarah J. Brownlee, Gary L. Pavlis

Environmental Science and Geology Faculty Research Publications

We measured anisotropic seismic properties of schists of the Homestake Formation located at a depth of 1478 m in the Sanford Underground Research Facility (SURF) in the Black Hills of South Dakota, USA. We deployed a 24-element linear array of three-component geophones in an area in the Homestake Mine called 19-ledge. An airless jackhammer source was used to shoot two profiles: (1) a walkaway survey to appraise any distance dependence and (2) a fan shot profile to measure variations with azimuth. Slowness estimates from the fan shot profile show a statistically significant deviation with azimuth with the expected 180° variation …


Detrital Zircon Petrochronology For Sedimentary Provenance Analysis: Source To Sink Of The Mississippi/Missouri River Drainage Basin, Sage Denali Muttel Aug 2020

Detrital Zircon Petrochronology For Sedimentary Provenance Analysis: Source To Sink Of The Mississippi/Missouri River Drainage Basin, Sage Denali Muttel

MSU Graduate Theses

Detrital petrochronology can provide a detailed look into sedimentary provenance through integrated mineral radioisotopic ages with corresponding mineral chemistry. By combining U-Pb ages and Th/U values of detrital zircon from 13 samples collected from Quaternary sand deposits in the Upper Missouri, Yellowstone, Bighorn, Platte, Kansas, Arkansas, Mississippi, Red and Brazos Rivers, an interpretation of detailed signatures that record evidence of the evolution of the Mississippi/Missouri River drainage and the tectonic events that shaped it were observed. Low Th/U values in zircon correlate temporally to convergent magmatism, whereas, higher and more variable Th/U zircon are coeval with known extensional tectonism. Using …


Migratory Flyways May Affect Population Structure In Double‐Crested Cormorants, Steven J.A. Kimble, Brian S. Dorr, Katie C. Hanson-Dorr, Olin E. Rhodes Jr., Travis L. Devault Feb 2020

Migratory Flyways May Affect Population Structure In Double‐Crested Cormorants, Steven J.A. Kimble, Brian S. Dorr, Katie C. Hanson-Dorr, Olin E. Rhodes Jr., Travis L. Devault

United States Department of Agriculture Wildlife Services: Staff Publications

Double‐crested cormorants (Phalacrocorax auritus) recovered from a demographic bottleneck so well that they are now considered a nuisance species at breeding and wintering grounds across the United States and Canada. Management of this species could be improved by refining genetic population boundaries and assigning individuals to their natal population. Further, recent radio‐telemetry data suggest the existence of Interior and Atlantic migratory flyways, which could reduce gene flow and result in substantial genetic isolation. In this study, we used 1,784 individuals collected across the eastern United States, a large panel of microsatellite markers developed for this species, and individuals banded as …


Using Common Gardens And Aflp Analyses To Identify Metapopulations Of Indigenous Plant Materials For Rangeland Revegetation In Western Usa, Douglas A. Johnson, B. Shaun Bushman, Thomas A. Jones, Kishor Bhattarai Dec 2019

Using Common Gardens And Aflp Analyses To Identify Metapopulations Of Indigenous Plant Materials For Rangeland Revegetation In Western Usa, Douglas A. Johnson, B. Shaun Bushman, Thomas A. Jones, Kishor Bhattarai

IGC Proceedings (1993-2023)

Past mismanagement, overgrazing, invasive weedy species, wildfires, marginal crop production, mineral and energy extraction, recreation and global climate change are challenges currently facing rangelands (Pierson et al. 2011). These disturbances may lead to long-term reductions in biodiversity, altered nutrient and water cycling, diminished forage production for livestock and wildlife, increased wildfire frequency and increased soil erosion and stream sedimentation (Sheley et al. 2008). Rangeland revegetation with desirable plant materials may be required to improve degraded conditions, speed recovery, and prevent further erosion and degradation. There is a critical need for plant materials to restore and revegetate rangeland ecosystems. …


Predation Of Eastern Cottontail Rabbit (Sylvilagus Floridanus) By Great Blue Heron (Ardea Herodias), Carlos E. Cintra-Buenrostro, J. E. Cifuentes-Lujan Dec 2019

Predation Of Eastern Cottontail Rabbit (Sylvilagus Floridanus) By Great Blue Heron (Ardea Herodias), Carlos E. Cintra-Buenrostro, J. E. Cifuentes-Lujan

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

An opportunistic predation by Great Blue Heron (Ardea herodias) on Eastern cottontail rabbit (Sylvilagus floridanus) was observed in south Texas on 31 Oct 2019. The Great Blue Heron had already captured the Eastern cottontail rabbit at the first observation but the maneuvering process, killing, and ingestion were recorded photographically, which make this observation unique even though this might constitute the second report on Great Blue Heron eating Eastern cottontail rabbits.


Change In The Leading Mode Of North America's Wintertime Stationary Eddies, Yu-Tang Chien Aug 2019

Change In The Leading Mode Of North America's Wintertime Stationary Eddies, Yu-Tang Chien

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Extreme winter weather events in North America have become more frequent and increasingly destructive. This phenomenon was linked to a jet stream pattern that generates abnormally warm conditions in the west and cold conditions in the east, referred to as the North American Winter Dipole. Studies have shown that the Dipole may have amplified and this amplification could be linked to global warming. By analyzing the atmospheric and oceanic data worldwide, the wintertime circulation in the Northern Hemisphere shows signs of a persistent change after the 1980s. In the first part of this study, we examine how the ocean has …


Distributary Channel Networks As Moving Boundaries: Causes And Morphodynamic Effects, Robert C. Mahon, John B. Shaw, Wun-Tao Ke, Christopher A. Cathcart Jul 2019

Distributary Channel Networks As Moving Boundaries: Causes And Morphodynamic Effects, Robert C. Mahon, John B. Shaw, Wun-Tao Ke, Christopher A. Cathcart

Earth and Environmental Sciences Faculty Publications

We propose an exploratory model to describe the morphodynamics of distributary channel network growth on river deltas. The interface between deep channels and the shallow, unchannelized delta front deposits is modeled as a moving boundary. Steady flow over the unchannelized delta front is friction dominated and modeled by Laplace's equation. Shear stress along the network boundary produces nonlinear erosion rates at the interface, causing the boundary to move and network elements (channels and branches) to form. The model was run for boundary conditions resembling the Wax Lake Delta in coastal Louisiana, 20 parameterizations of sediment transport, and 3 …


Giant Beaver Palaeoecology Inferred From Stable Isotopes, Tessa Plint, Fred J. Longstaffe, Grant Zazula May 2019

Giant Beaver Palaeoecology Inferred From Stable Isotopes, Tessa Plint, Fred J. Longstaffe, Grant Zazula

Earth Sciences Publications

This is a multi-individual (n = 11), stable carbon and nitrogen isotope study of bone collagen (δ13Ccol and δ15Ncol) from the giant beaver (genus Castoroides). The now-extinct giant beaver was once one of the most widespread Pleistocene megafauna in North America. We confirm that Castoroides consumed a diet of predominantly submerged aquatic macrophytes. These dietary preferences rendered the giant beaver highly dependent on wetland habitat for survival. Castoroidesδ13Ccol and δ15Ncol do not support the hypothesis that the giant beaver consumed trees or woody …


Speleothem Paleoclimatology For The Caribbean, Central America, And North America, Jessica L. Oster, Sophie F. Warken, Natasha Sekhon, Monica M. Arienzo, Matthew Lachniet Jan 2019

Speleothem Paleoclimatology For The Caribbean, Central America, And North America, Jessica L. Oster, Sophie F. Warken, Natasha Sekhon, Monica M. Arienzo, Matthew Lachniet

Geoscience Faculty Research

Speleothem oxygen isotope records from the Caribbean, Central, and North America reveal climatic controls that include orbital variation, deglacial forcing related to ocean circulation and ice sheet retreat, and the influence of local and remote sea surface temperature variations. Here, we review these records and the global climate teleconnections they suggest following the recent publication of the Speleothem Isotopes Synthesis and Analysis (SISAL) database. We find that low-latitude records generally reflect changes in precipitation, whereas higher latitude records are sensitive to temperature and moisture source variability. Tropical records suggest precipitation variability is forced by orbital precession and North Atlantic Ocean …


Quantifying Climate Sensitivity And Climate-Driven Change In North American Amphibian Communities, David A. W. Miller, Evan H Campbell Grant, Erin Muths, Staci M. Amburgey, Michael J. Adams, Maxwell B. Joseph, J. Hardin Waddle, Pieter T. J. Johnson, Maureen E. Ryan, Benedikt R. Schmidt, Daniel L. Calhoun, Courtney L. Davis, Robert N. Fisher, David M. Green, Blake R. Hossack, Tracy A. G. Rittenhouse, Susan C. Walls, Larissa L. Bailey, Sam S. Cruickshank, Gary M. Fellers, Thomas A. Gorman, Carola A. Haas, Ward Hughson, David S. Pilliod, Steve J. Price, Andrew M. Ray, Walt Sadinski, Daniel Saenz, William J. Barichivich, Adrianne Brand Sep 2018

Quantifying Climate Sensitivity And Climate-Driven Change In North American Amphibian Communities, David A. W. Miller, Evan H Campbell Grant, Erin Muths, Staci M. Amburgey, Michael J. Adams, Maxwell B. Joseph, J. Hardin Waddle, Pieter T. J. Johnson, Maureen E. Ryan, Benedikt R. Schmidt, Daniel L. Calhoun, Courtney L. Davis, Robert N. Fisher, David M. Green, Blake R. Hossack, Tracy A. G. Rittenhouse, Susan C. Walls, Larissa L. Bailey, Sam S. Cruickshank, Gary M. Fellers, Thomas A. Gorman, Carola A. Haas, Ward Hughson, David S. Pilliod, Steve J. Price, Andrew M. Ray, Walt Sadinski, Daniel Saenz, William J. Barichivich, Adrianne Brand

Forestry and Natural Resources Faculty Publications

Changing climate will impact species’ ranges only when environmental variability directly impacts the demography of local populations. However, measurement of demographic responses to climate change has largely been limited to single species and locations. Here we show that amphibian communities are responsive to climatic variability, using > 500,000 time-series observations for 81 species across 86 North American study areas. The effect of climate on local colonization and persistence probabilities varies among eco-regions and depends on local climate, species life-histories, and taxonomic classification. We found that local species richness is most sensitive to changes in water availability during breeding and changes in …


Avian Jurisprudence And The Protection Of Migratory Birds In North America, Marshall A. Bowen Aug 2018

Avian Jurisprudence And The Protection Of Migratory Birds In North America, Marshall A. Bowen

St. Mary's Law Journal

Abstract forthcoming


Global Stratigraphy And The Fossil Record Validate A Flood Origin For The Geologic Column, Timothy L. Clarey, Davis J. Werner Jul 2018

Global Stratigraphy And The Fossil Record Validate A Flood Origin For The Geologic Column, Timothy L. Clarey, Davis J. Werner

Proceedings of the International Conference on Creationism

The geologic column has been under the scrutiny of numerous creationists for many decades. Critics have claimed the column is intimately tied to the evolutionary worldview and deep time, and cannot be trusted or used by creation scientists. Other creation scientists have argued that the geologic column, although incomplete at most locations, can provide useful correlations of rocks and fossils across the globe. This paper examines the sedimentary rocks across three continents in an attempt to test the validity of the global geologic column. We attempted to assess the data primarily from a lithologic viewpoint, and as independent of the …


Synoptic-Scale Environments Conducive To Orographic Impacts On Cold-Season Surface Wind Regimes At Montreal, Quebec, Alissa Razy, Shawn M. Milrad, Eyad H, Atallah, John R. Gyakum Jun 2018

Synoptic-Scale Environments Conducive To Orographic Impacts On Cold-Season Surface Wind Regimes At Montreal, Quebec, Alissa Razy, Shawn M. Milrad, Eyad H, Atallah, John R. Gyakum

Shawn M. Milrad

Orographic wind channeling, defined as dynamically and thermally induced processes that force wind to blow along the axis of a valley, is a common occurrence along the St. Lawrence River Valley (SLRV) in Quebec, Canada, and produces substantial observed weather impacts at stations along the valley, including Montreal (CYUL). Cold-season observed north-northeast (n = 55) and south-southeast (n = 16) surface wind events at CYUL are identified from 1979 to 2002. The authors partition the north-northeast wind events into four groups using manual synoptic typing. Types A and D (“inland cyclone” and “northwestern cyclone”) are associated with strong lower-tropospheric geostrophic …


Synoptic-Scale Characteristics And Precursors Of Cool-Season Precipitation Events At St. John's, Newfoundland, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum Jun 2018

Synoptic-Scale Characteristics And Precursors Of Cool-Season Precipitation Events At St. John's, Newfoundland, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Shawn M. Milrad

The issue of quantitative precipitation forecasting continues to be a significant challenge in operational forecasting, particularly in regions susceptible to frequent and extreme precipitation events. St. John’s, Newfoundland, Canada, is one location affected frequently by such events, particularly in the cool season (October–April). These events can include flooding rains, paralyzing snowfall, and damaging winds.

A precipitation climatology is developed at St. John’s for 1979–2005, based on discrete precipitation events occurring over a time period of up to 48 h. Threshold amounts for three categories of precipitation events (extreme, moderate, and light) are statistically derived and utilized to categorize such events. …


Precipitation Modulation By The Saint Lawrence River Valley In Association With Transitioning Tropical Cyclones, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum Jun 2018

Precipitation Modulation By The Saint Lawrence River Valley In Association With Transitioning Tropical Cyclones, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Shawn M. Milrad

The St. Lawrence River valley (SLRV) is an important orographic feature in eastern Canada that can affect surface wind patterns and contribute to locally higher amounts of precipitation. The impact of the SLRV on precipitation distributions associated with transitioning, or transitioned, tropical cyclones that approached the region is assessed. Such cases can result in heavy precipitation during the warm season, as during the transition of Hurricane Ike (2008). Thirty-eight tropical cyclones tracked within 500 km of the SLRV from 1979 to 2011. Utilizing the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR), 19 of the 38 cases …


A Meteorological Analysis Of Important Contributions To The 1999-2005 Canadian Prairie Drought, Lisa M. Hryciw, Eyad H. Atallah, Shawn M. Milrad, John R. Gyakum Jun 2018

A Meteorological Analysis Of Important Contributions To The 1999-2005 Canadian Prairie Drought, Lisa M. Hryciw, Eyad H. Atallah, Shawn M. Milrad, John R. Gyakum

Shawn M. Milrad

Drought is a complex natural hazard that is endemic to the Canadian prairies. The 1999–2005 Canadian prairie drought, which had great socioeconomic impacts, was meteorologically unique in that it did not conform to the traditional persistent positive Pacific–North American (PNA) pattern and west coast ridging paradigm normally associated with prairie drought. The purpose of this study is to diagnose the unique synoptic-scale mechanisms responsible for modulating subsidence during this drought. Using 30-day running means of the percent of normal precipitation from station data, key severe dry periods during 1999–2005 are identified. Analysis of the mean fields from reanalysis data shows …


A Thermodynamic Analysis Of An Intense North American Arctic Air Mass, Jessica K. Turner, John Gyakum, Shawn M. Milrad Jun 2018

A Thermodynamic Analysis Of An Intense North American Arctic Air Mass, Jessica K. Turner, John Gyakum, Shawn M. Milrad

Shawn M. Milrad

Northwestern Canada is a genesis region of arctic air masses often considered to be formed primarily through radiative processes. However, the details of their life cycle are poorly understood. This paper examines the formation, maintenance, and dissipation of an intense and long-lived arctic air mass, using a thermodynamic budget analysis.

The airmass formation is characterized by a deep-layer, multistage process that begins with snow falling into a nascent air mass. Radiative cooling from cloud tops begins the process. After the snow abates and clear skies are observed, the surface temperature drops rapidly, aided by the high emissivity of fresh snow …


Geochemistry And Mineralogy Of Late Quaternary Loess In The Upper Mississippi River Valley, Usa: Provenance And Correlation With Laurentide Ice Sheet History, Daniel R. Muhs, E. Arthur Bettis Iii, Gary L. Skipp Mar 2018

Geochemistry And Mineralogy Of Late Quaternary Loess In The Upper Mississippi River Valley, Usa: Provenance And Correlation With Laurentide Ice Sheet History, Daniel R. Muhs, E. Arthur Bettis Iii, Gary L. Skipp

United States Geological Survey: Staff Publications

The midcontinent of North America contains some of the thickest and most extensive last-glacial loess deposits in the world, known as Peoria Loess. Peoria Loess of the upper Mississippi River valley region is thought to have had temporally varying glaciogenic sources resulting from inputs of sediment to the Mississippi River from different lobes of the Laurentide Ice Sheet. Here, we explore a new method of determining loess provenance using K/Rb and K/Ba values (in K-feldspars and micas) in loess from a number of different regions in North America. Results indicate that K/Rb and K/Ba values can distinguish loess originating from …


Onshore-Offshore Velocity Models North Of The Mendocino Triple Junction In Northern California, Alan Jacquez Jan 2018

Onshore-Offshore Velocity Models North Of The Mendocino Triple Junction In Northern California, Alan Jacquez

Open Access Theses & Dissertations

The Mendocino Triple Junction (MTJ) marks the boundary where the Gorda plate, North American Plate, and Pacific Plate meet, separating the Cascadia subduction zone to the North from transform tectonics of the San Andreas plate boundary. This actively deforming region experiences high seismic activity and young geological features. Here we examine offshore and onshore seismic wide-angle reflection and refraction data north of the MTJ crossing the Cascadia subduction zone from offshore northern California to the Western edge of the Sierra Nevada. We image subsurface structures in this region by creating P-wave velocity models using datasets collected in 1993 to 1994 …