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Articles 1531 - 1560 of 2458

Full-Text Articles in Atmospheric Sciences

Extremely Sensitive Rayleigh-Scatter Lidar At Usu, Vincent B. Wickwar, Leda Sox, David Barton, Matthew T. Emerick Jun 2014

Extremely Sensitive Rayleigh-Scatter Lidar At Usu, Vincent B. Wickwar, Leda Sox, David Barton, Matthew T. Emerick

Posters

Rayleigh lidar opened a portion of the atmosphere, from 30 to 90 km, to ground-based observations. Rayleigh-scatter observations were made at the Atmospheric Lidar Observatory (ALO) at Utah State University (USU) from 1993–2004 between 45 and 90 km, creating a very dense data set consisting of ~5000 hours of observations carried out over ~900 nights. The lidar had a mirror of area 0.15 m2 and a frequency-doubled Nd:YAG laser operating at 532 nm at 30 Hz at ~21 W, giving a power-aperture product (PAP) of ~3.1 Wm2.


Seasonal Variations Of Relative Neutral Densities Between 45 And 90 Km Determined From Usu Rayleigh Lidar Observations, David Barton, Vincent B. Wickwar, Leda Sox, Joshua P. Herron Jun 2014

Seasonal Variations Of Relative Neutral Densities Between 45 And 90 Km Determined From Usu Rayleigh Lidar Observations, David Barton, Vincent B. Wickwar, Leda Sox, Joshua P. Herron

Posters

A Rayleigh-scatter lidar operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W), part of Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), collected extensive data between 1993 and 2004. From the Rayleigh lidar photon-count profiles, relative densities were determined throughout the mesosphere, from 45 to 90 km. Using these relative densities three climatologies were derived, each using a different density normalization at 45 km. The first normalized the relative densities to a constant; the second to the NRL-MSISe00 empirical model which has a strong annual component; and the third to the CPC analyses …


Interpretation (Or Is It Calibration?) Of Rayleigh-Scatter Lidar Signals, Vincent B. Wickwar, Leda Sox Jun 2014

Interpretation (Or Is It Calibration?) Of Rayleigh-Scatter Lidar Signals, Vincent B. Wickwar, Leda Sox

Presentations

No abstract provided.


Progress On Understanding Atmospheric Mercury Hampered By Uncertain Measurements, Daniel A. Jaffe, Seth N. Lyman, Helen M. Amosl, Mae Sexauer Gustin, Jiaoyan Huang, Noelle E. Selin, Leonard Levin, Arnout Ter Schure, Robert P. Mason, Robert Talbot, Andrew Rutter, Brandon Finley, Lyatt Jaeglé, Viral Shah, Crystal Mcclure, Jesse Ambrose, Lynne Gratz, Steven Lindberg, Peter Weiss-Penzias, Guey-Rong Sheu, Dara Feddersen, Milena Horvat, Ashu Dastoor, Anthony J. Hynes, Huiting Mao, Jeroen E. Sonke, Franz Slemr, Jenny A. Fisher, Ralf Ebinghaus, Yanxu Zhang, Grant Edwards Jun 2014

Progress On Understanding Atmospheric Mercury Hampered By Uncertain Measurements, Daniel A. Jaffe, Seth N. Lyman, Helen M. Amosl, Mae Sexauer Gustin, Jiaoyan Huang, Noelle E. Selin, Leonard Levin, Arnout Ter Schure, Robert P. Mason, Robert Talbot, Andrew Rutter, Brandon Finley, Lyatt Jaeglé, Viral Shah, Crystal Mcclure, Jesse Ambrose, Lynne Gratz, Steven Lindberg, Peter Weiss-Penzias, Guey-Rong Sheu, Dara Feddersen, Milena Horvat, Ashu Dastoor, Anthony J. Hynes, Huiting Mao, Jeroen E. Sonke, Franz Slemr, Jenny A. Fisher, Ralf Ebinghaus, Yanxu Zhang, Grant Edwards

USU Uintah Basin Faculty Publications

Mercury (Hg) is a potent neurotoxin and globally reducing environmental levels is seen as paramount for protecting human and wildlife health. In 2013, many countries finalized the negotiations on, and have now signed, the Minamata Convention on Mercury, which commits participating countries to reduce emissions and use of mercury. Successful implementation of the treaty will require adequate verification through global monitoring.


Atmospheric Oxidation Chemistry And Ozone Production: Results From Sharp 2009 In Houston, Texas, Katherine A. Duderstadt, Jack E. Dibb, Charles H. Jackman, Cora E. Randall, Stanley C. Solomon, Michael J. Mills, Nathan A. Schwadron, Harlan E. Spence Jun 2014

Atmospheric Oxidation Chemistry And Ozone Production: Results From Sharp 2009 In Houston, Texas, Katherine A. Duderstadt, Jack E. Dibb, Charles H. Jackman, Cora E. Randall, Stanley C. Solomon, Michael J. Mills, Nathan A. Schwadron, Harlan E. Spence

Earth Sciences

This study considers whether spikes in nitrate in snow sampled at Summit, Greenland, from August 2000 to August 2002 are related to solar proton events. After identifying tropospheric sources of nitrate on the basis of correlations with sulfate, ammonium, sodium, and calcium, we use the three-dimensional global Whole Atmosphere Community Climate Model (WACCM) to examine unaccounted for nitrate spikes. Model calculations confirm that solar proton events significantly impact HOx, NOx, and O3 levels in the mesosphere and stratosphere during the weeks and months following the major 9 November 2000 solar proton event. However, solar proton event (SPE)-enhanced NOy calculated within …


Umphlett Qci June 2014, Natalie Umphlett Jun 2014

Umphlett Qci June 2014, Natalie Umphlett

High Plains Regional Climate Center: Staff Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

􏰞􏰥􏰬􏰨􏰤􏰮􏱨Streamflow

Drought Impacts to Livestock

Continued Cold Hampers Producers in North

3-Month Precipitation and Temperature Outlooks

U.S. Seasonal Drought Outlook


Thermospheric Dissipation Of Upward Propagating Gravity Wave Packets, C. J. Heale, J. B. Snively, M. P. Hickey, C. J. Ali May 2014

Thermospheric Dissipation Of Upward Propagating Gravity Wave Packets, C. J. Heale, J. B. Snively, M. P. Hickey, C. J. Ali

Publications

We use a nonlinear, fully compressible, two-dimensional numerical model to study the effects of dissipation on gravity wave packet spectra in the thermosphere. Numerical simulations are performed to excite gravity wave packets using either a time-dependent vertical body forcing at the bottom boundary or a specified initial wave perturbation. Three simulation case studies are performed to excite (1) a steady state monochromatic wave, (2) a spectrally broad wave packet, and (3) a quasi-monochromatic wave packet. In addition, we analyze (4) an initial condition simulation with an isothermal background. We find that, in cases where the wave is not continually forced, …


Probable Causes Of The Abnormal Ridge Accompanying The 2013-14 California Drought: Enso Precursor And Anthropogenic Warming Footprint, Shih-Yu (Simon) Wang May 2014

Probable Causes Of The Abnormal Ridge Accompanying The 2013-14 California Drought: Enso Precursor And Anthropogenic Warming Footprint, Shih-Yu (Simon) Wang

Plants, Soils, and Climate Faculty Publications

The 2013–2014 California drought was initiated by an anomalous high-amplitude ridge system. The anomalous ridge was investigated using reanalysis data and the Community Earth System Model (CESM). It was found that the ridge emerged from continual sources of Rossby wave energy in the western North Pacific starting in late summer and subsequently intensified into winter. The ridge generated a surge of wave energy downwind and deepened further the trough over the northeast U.S., forming a dipole. The dipole and associated circulation pattern is not linked directly with either El Niño–Southern Oscillation (ENSO) or Pacific Decadal Oscillation; instead, it is correlated …


Very Low Frequency Subionospheric Remote Sensing Of Thunderstorm-Driven Acoustic Waves In The Lower Ionosphere, R. A. Marshall, J. B. Snively May 2014

Very Low Frequency Subionospheric Remote Sensing Of Thunderstorm-Driven Acoustic Waves In The Lower Ionosphere, R. A. Marshall, J. B. Snively

Publications

"We present observations of narrowband subionospheric VLF transmitter signals on 20 March 2001, exhibiting coherent fluctuations of over 1 dB peak to peak. Spectral analysis shows that the fluctuations have periods of 1–4 min and are largely coherent. The subionospheric propagation path of the signal from Puerto Rico to Colorado passes over two regions of convective and lightning activity, as observed by GOES satellite imagery and National Lightning Detection Network lightning data. We suggest that these fluctuations are evidence of acoustic waves launched by the convective activity below, observed in the 80–90 km altitude range to which nighttime VLF subionospheric …


Intercomparison Of Field Measurements Of Nitrous Acid (Hono) During The Sharp Campaign, J R. Pinto, Jack E. Dibb, B H. Lee, B Rappengluck, E C. Wood, M Levy, R Y. Zhang, Barry Lefer, Xinrong Ren, J Stutz, C Tsai, L Ackermann, J Golovko, S C. Herndon, M Oakes, Q Y. Meng, J W. Munger, M Zahniser, J Zheng May 2014

Intercomparison Of Field Measurements Of Nitrous Acid (Hono) During The Sharp Campaign, J R. Pinto, Jack E. Dibb, B H. Lee, B Rappengluck, E C. Wood, M Levy, R Y. Zhang, Barry Lefer, Xinrong Ren, J Stutz, C Tsai, L Ackermann, J Golovko, S C. Herndon, M Oakes, Q Y. Meng, J W. Munger, M Zahniser, J Zheng

Earth Sciences

Because of the importance of HONO as a radical reservoir, consistent and accurate measurements of its concentration are needed. As part of SHARP (Study of Houston Atmospheric Radical Precursors), time series of HONO were obtained by six different measurement techniques on the roof of the Moody Tower at the University of Houston. Techniques used were long path differential optical absorption spectroscopy (DOAS), stripping coil-visible absorption photometry (SC-AP), long path absorption photometry (LOPAP® ), mist chamber/ion chromatography (MC-IC), quantum cascade-tunable infrared laser differential absorption spectroscopy (QC-TILDAS), and ion drift-chemical ionization mass spectrometry (ID-CIMS). Various combinations of techniques were in operation from …


Impact Of Soil Moisture–Atmosphere Interactions On Surface Temperature Distribution, Alexis Berg, Benjamin R. Lintner, Kirsten L. Findell, Sergey Malyshev, Paul C. Loikith, Pierre Gentine May 2014

Impact Of Soil Moisture–Atmosphere Interactions On Surface Temperature Distribution, Alexis Berg, Benjamin R. Lintner, Kirsten L. Findell, Sergey Malyshev, Paul C. Loikith, Pierre Gentine

Geography Faculty Publications and Presentations

Understanding how different physical processes can shape the probability distribution function (PDF) of surface temperature, in particular the tails of the distribution, is essential for the attribution and projection of future extreme temperature events. In this study, the contribution of soil moisture–atmosphere interactions to surface temperature PDFs is investigated. Soil moisture represents a key variable in the coupling of the land and atmosphere, since it controls the partitioning of available energy between sensible and latent heat flux at the surface. Consequently, soil moisture variability driven by the atmosphere may feed back onto the near-surface climate—in particular, temperature. In this study, …


The Effects Of Downsloping On Storm Precipitation Distributions In The Capital District Of New York State, Kyle James Pallozzi May 2014

The Effects Of Downsloping On Storm Precipitation Distributions In The Capital District Of New York State, Kyle James Pallozzi

Atmospheric & Environmental Sciences

Downsloping is a process which has an impact on many precipitation events in the Capital District of New York State. This study examines the effect of 850 hPa and 925 hPa mean vector wind direction, as well as the individual 850 hPa and 925 hPa wind directions observed through soundings, during precipitation events on precipitation distributions in the Capital District of New York State. Results from this study suggests that 850 hPa and 925 hPa mean vector wind as well as the 850 hPa and 925 hPa wind favor downsloping off of the Greens and Taconics, and therefore lower precipitation …


Spatiotemporal Analysis Of The January Northern Hemisphere Circumpolar Vortex Over The Contiguous United States, Thomas J. Ballinger, Michael J. Allen, Robert V. Rohli May 2014

Spatiotemporal Analysis Of The January Northern Hemisphere Circumpolar Vortex Over The Contiguous United States, Thomas J. Ballinger, Michael J. Allen, Robert V. Rohli

Political Science & Geography Faculty Publications

January 2014 will be remembered for the sensationalized media usage of the term "polar vortex" which coincided with several polar air outbreaks. A United States polar vortex (USPV) perspective is presented to better understand the January spatial and temporal variability of this regional component of the Northern Hemisphere circumpolar vortex. Use of the monthly mean 5460 m isohypse to represent the location of the USPV extent and area revealed that the spatial features of the January 2014 USPV were not extreme relative to certain 1948–2013 Januaries. Furthermore, the Arctic Oscillation (AO), Pacific-North American (PNA) Pattern, and Pacific Decadal Oscillation (PDO) …


Hail Formation In Florida, Matthew Stanley May 2014

Hail Formation In Florida, Matthew Stanley

USF Tampa Graduate Theses and Dissertations

ABSTRACT

Hail poses a substantial threat to life and property in the state of Florida. These losses could be minimized through better understanding of the relationships between atmospheric variables that impact hail formation in Florida. Improving hail forecasting in Florida requires analyzing a number of meteorological parameters and synoptic data related to hail formation.

NOAA archive data was retrieved to create a database that was used to categorize text files of hail days. The text files were entered into the National Oceanic and Atmospheric Administration Earth System Research Laboratory website to create National Centers for Environmental Prediction/National Center for Atmospheric …


Probability Distributions And Threshold Selection For Monte Carlo–Type Tropical Cyclone Wind Speed Forecasts, Steven M. Lazarus, Michael E. Splitt, Sarah Collins, Denis N. Botambekov, William P. Roeder Apr 2014

Probability Distributions And Threshold Selection For Monte Carlo–Type Tropical Cyclone Wind Speed Forecasts, Steven M. Lazarus, Michael E. Splitt, Sarah Collins, Denis N. Botambekov, William P. Roeder

Aeronautics Faculty Publications

Probabilistic wind speed forecasts for tropical cyclones from Monte Carlo–type simulations are assessed within a theoretical framework for a simple unbiased Gaussian system that is based on feature size and location error that mimic tropical cyclone wind fields. Aspects of the wind speed probability data distribution, including maximumexpected probability and forecast skill, are assessed. Wind speed probability distributions are shown to be well approximated by a bounded power-law distribution when the feature size is smaller than the location error and tends toward a U-shaped distribution as the location error becomes small. Forecast skill (i.e., true and Heidke skill scores) is …


Effects Of Stratospheric Ozone Recovery On Photochemistry And Ozone Air Quality In The Troposphere, H. Zhang, Shiliang Wu, Y. Huang, Y. Wang Apr 2014

Effects Of Stratospheric Ozone Recovery On Photochemistry And Ozone Air Quality In The Troposphere, H. Zhang, Shiliang Wu, Y. Huang, Y. Wang

Michigan Tech Publications, Part 1

There has been significant stratospheric ozone depletion since the late 1970s due to ozone-depleting substances (ODSs). With the implementation of the Montreal Protocol and its amendments and adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. In this study, we examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). With a full recovery of the stratospheric ozone, the projected increases in ozone column range from 1% over the low latitudes to more than 10% over the polar regions. The sensitivity factor …


Seasonal Variability As A Source Of Uncertainty In The West Siberian Regional Ch4 Flux Upscaling, A. F. Sabrekov, Benjamin R. K. Runkle, M. V. Glagolev, I E. Kleptsova, S. S. Maksyutov Apr 2014

Seasonal Variability As A Source Of Uncertainty In The West Siberian Regional Ch4 Flux Upscaling, A. F. Sabrekov, Benjamin R. K. Runkle, M. V. Glagolev, I E. Kleptsova, S. S. Maksyutov

Biological and Agricultural Engineering Faculty Publications and Presentations

This study compares seasonal and spatial variations in methane fluxes as sources of uncertainty in regional CH4 flux upscaling from the wetlands of West Siberia. The study examined variability in summertime CH4 emissions from boreal peatlands, with a focus on two subtaiga fen sites in the southern part of West Siberia (Novosibirskaya oblast). We measured CH4 flux, water table depth, air and peat temperature, pH and electric conductivity of peat water during three field campaigns in summer 2011 (9–12 July, 26–28 July and 20–21 August). Fluxes were measured with static chambers at sites chosen to represent two of the most …


Auroral Ionospheric F Region Density Cavity Formation And Evolution: Mica Campaign Results, M. Zettergren, K. A. Lynch, D. L. Hampton, M. Nicolls, B. Wright, Et Al. Apr 2014

Auroral Ionospheric F Region Density Cavity Formation And Evolution: Mica Campaign Results, M. Zettergren, K. A. Lynch, D. L. Hampton, M. Nicolls, B. Wright, Et Al.

Publications

Auroral ionospheric F region density depletions observed by PFISR (Poker Flat Incoherent Scatter Radar) during the MICA (Magnetosphere‐Ionosphere Coupling in the Alfvén Resonator) sounding rocket campaign are critically examined alongside complementary numerical simulations. Particular processes of interest include cavity formation due to intense frictional heating and Pedersen drifts, evolution in the presence of structured precipitation, and refilling due to impact ionization and downflows. Our analysis uses an ionospheric fluid model which solves conservation of mass, momentum, and energy equations for all major ionospheric species. These fluid equations are coupled to an electrostatic current continuity equation to self‐consistently describe auroral electric …


The Surface Energy Balance And Its Drivers In A Boreal Peatland Fen Of Northwestern Russia, Benjamin R. K. Runkle, Christian Wille, Michal Gazovic, M. Wilmking, L. Kutzbach Apr 2014

The Surface Energy Balance And Its Drivers In A Boreal Peatland Fen Of Northwestern Russia, Benjamin R. K. Runkle, Christian Wille, Michal Gazovic, M. Wilmking, L. Kutzbach

Biological and Agricultural Engineering Faculty Publications and Presentations

Boreal peatland energy balances using the eddy covariance technique have previously been made in Alaska, Canada, Scandinavia, and Western Siberia, but not in the European portion of the Russian Federation. European Russia contains approximately 200,000 km2 of peatlands and has a boreal (subarctic), continental climate influencing the region’s energy balance. To help fill this research gap, the surface energy balance was determined for a boreal peatland fen in the Komi Republic of Russia for an 11-month period in 2008–2009 using the eddy covariance method. The total measurement period’s cumulative energy balance closure rate was 86%, with higher closure during the …


Brown Carbon In The Continental Troposphere, Jiumeng Liu, Eric Scheuer, Jack E. Dibb, Luke D. Ziemba, Kenn L. Thornhill, Bruce Anderson, Armin Wisthaler, Tomas Mikoviny, J J. Devi, Mike Bergin, Rodney J. Weber Apr 2014

Brown Carbon In The Continental Troposphere, Jiumeng Liu, Eric Scheuer, Jack E. Dibb, Luke D. Ziemba, Kenn L. Thornhill, Bruce Anderson, Armin Wisthaler, Tomas Mikoviny, J J. Devi, Mike Bergin, Rodney J. Weber

Earth Sciences

No abstract provided.


Climate Change In Northern New Hampshire: Past, Present And Future, Cameron P. Wake, C. Keeley, Elizabeth A. Burakowski, Peter Wilkinson, Katharine Hayhoe, Anne Stoner, Julie Labrance Apr 2014

Climate Change In Northern New Hampshire: Past, Present And Future, Cameron P. Wake, C. Keeley, Elizabeth A. Burakowski, Peter Wilkinson, Katharine Hayhoe, Anne Stoner, Julie Labrance

The Sustainability Institute Publications

EARTH’S CLIMATE CHANGES. It always has and always will. However, an extensive and growing body of scientific evidence indicates that human activities—including the burning of fossil fuel (coal, oil, and natural gas) for energy, clearing of forested lands for agriculture, and raising livestock—are now the primary force driving change in the Earth’s climate system. This report describes how the climate of northern New Hampshire has changed over the past century and how the future climate of the region will be affected by a warmer planet due to human activities.


Climate Change In Southern New Hampshire: Past, Present And Future, Cameron P. Wake, Elizabeth A. Burakowski, Peter Wilkinson, Katharine Hayhoe, Anne Stoner, C. Keeley, Julie Labranche Apr 2014

Climate Change In Southern New Hampshire: Past, Present And Future, Cameron P. Wake, Elizabeth A. Burakowski, Peter Wilkinson, Katharine Hayhoe, Anne Stoner, C. Keeley, Julie Labranche

The Sustainability Institute Publications

EARTH’S CLIMATE CHANGES. It always has and always will. However, an extensive and growing body of scientific evidence indicates that human activities—including the burning of fossil fuel (coal, oil, and natural gas) for energy, clearing of forested lands for agriculture, and raising livestock—are now the primary force driving change in the Earth’s climate system. This report describes how the climate of southern New Hampshire has changed over the past century and how the future climate of the region will be affected by a warmer planet due to human activities.


Wind Pattern Effects On The Southern Shetland Islands, Helen Pottle Apr 2014

Wind Pattern Effects On The Southern Shetland Islands, Helen Pottle

Thinking Matters Symposium Archive

The Shetland Islands, northeast of Scotland, experienced an unusually extreme storm that caused unique sand shifting patterns and sand dune formations that resulted in the destruction of the Village of Broo. There is little existing information about the weather and terrain of the Shetland Islands during the extreme storm that was estimated to have occurred between 1650 and 1670. WindNinja, a wind model originally developed for wildland fire application, was used to understand the wind patterns that may have caused the unique sand patterns and resulting destruction. It incorporates existing terrain elevations and vegetation as well as average wind speed …


Mercury Speciation At A Coastal Site In The Northern Gulf Of Mexico: Results From The Grand Bay Intensive Studies In Summer 2010 And Spring 2011, Xinrong Ren, Winston T. Luke, Paul Kelley, Mark Cohen, Fong Ngan, Richard Artz, Jake Walker, Steve Brooks, Christopher Moore, Phil Swartzendruber, Dieter Bauer, James Remeika, Anthony Hynes, Jack E. Dibb, John Rolison, Nishanth Krishnamurthy, William M. Landing, Arsineh Hecobian, Jeffery Shook, L Gregory Huey Apr 2014

Mercury Speciation At A Coastal Site In The Northern Gulf Of Mexico: Results From The Grand Bay Intensive Studies In Summer 2010 And Spring 2011, Xinrong Ren, Winston T. Luke, Paul Kelley, Mark Cohen, Fong Ngan, Richard Artz, Jake Walker, Steve Brooks, Christopher Moore, Phil Swartzendruber, Dieter Bauer, James Remeika, Anthony Hynes, Jack E. Dibb, John Rolison, Nishanth Krishnamurthy, William M. Landing, Arsineh Hecobian, Jeffery Shook, L Gregory Huey

Earth Sciences

During two intensive studies in summer 2010 and spring 2011, measurements of mercury species including gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM), trace chemical species including O3, SO2, CO, NO, NOY, and black carbon, and meteorological parameters were made at an Atmospheric Mercury Network (AMNet) site at the Grand Bay National Estuarine Research Reserve (NERR) in Moss Point, Mississippi. Surface measurements indicate that the mean mercury concentrations were 1.42 ± 0.12 ng∙m−3 for GEM, 5.4 ± 10.2 pg∙m−3 for GOM, and 3.1 ± 1.9 pg∙m−3 for …


Droughtscape, Spring 2014, Kelly Smith Apr 2014

Droughtscape, Spring 2014, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

Director’s report

Outlook . 2

Drought climate recap 3

Drought impacts .

DroughtAtlas

Missouri River Basin pilot 9

NASA Horn of Africa project 10

U2U tools and social science . 12

Consulting for Turkey 14

Czech drought monitoring 14


Investigation Of Isotope Effects Of Ozone As A Function Of Temperature, Daniel J. Mcmahon Apr 2014

Investigation Of Isotope Effects Of Ozone As A Function Of Temperature, Daniel J. Mcmahon

Open Access Theses

Ozone is an important oxidizer in the atmosphere and plays a crucial role as a cleanser, removing various compounds such NOx and SOx. It also is intriguing to those that study stable isotopes as it has a unique signature found in no other oxygen containing molecule. Ozone is observed to fractionate mass independently, which means it does not follow the typical δ 17 O /δ18 O = 0.52 ratio expected for molecules enriched with 17 O and 18 O. The magnitude of ozone's mass independent enrichment has been studied in laboratory experiments and atmospheric observations but its explanation is still …


Evaluation And Economic Value Of Winter Weather Forecasts, Derrick William Snyder Apr 2014

Evaluation And Economic Value Of Winter Weather Forecasts, Derrick William Snyder

Open Access Theses

State and local highway agencies spend millions of dollars each year to deploy winter operation teams to plow snow and de-ice roadways. Accurate and timely weather forecast information is critical for effective decision making. Students from Purdue University partnered with the Indiana Department of Transportation to create an experimental winter weather forecast service for the 2012-2013 winter season in Indiana to assist in achieving these goals. One forecast product, an hourly timeline of winter weather hazards produced daily, was evaluated for quality and economic value.

Verification of the forecasts was performed with data from the Rapid Refresh numerical weather model. …


Cosmogenic Beryllium Cycling In A Natural Forest Setting, Grace Conyers Apr 2014

Cosmogenic Beryllium Cycling In A Natural Forest Setting, Grace Conyers

Open Access Theses

10 Bemet , or cosmogenic beryllium, has a long half-life of 1.4 million years and quick adsorption on soil particles, which may make it ideal for dating soil erosion in historical context. However, there are questions on about the fundamental assumptions of the retentivity of 10 Bemet . This manuscript explores these assumptions and the context of nutrient cycling in a natural forest setting.

To see if 10 Bemet was being cycled through the trees, and at what rate, we looked at the[10 Bemet ] in the soil, 4 species of trees, and their leaves. The isotopic ratio 10 Be/9 …


Uncertainties In Life Cycle Greenhouse Gas Emissions From U.S. Beef Cattle, Quentin M. Dudley, Adam Liska, Andrea K. Watson, Galen E. Erickson Apr 2014

Uncertainties In Life Cycle Greenhouse Gas Emissions From U.S. Beef Cattle, Quentin M. Dudley, Adam Liska, Andrea K. Watson, Galen E. Erickson

Adam Liska Papers

Beef cattle feedlots are estimated to contribute 26% of U.S. agricultural greenhouse gas (GHG) emissions, and future climate change policy could target reducing these emissions. Life cycle assessment (LCA) of GHG emissions from U.S. grain-fed beef cattle was conducted based on industry statistics and previous studies to identify the main sources of uncertainty in these estimations. Uncertainty associated with GHG emissions from indirect land use change, pasture soil emissions (e.g. soil carbon sequestration), enteric fermentation from cattle on pasture, and methane emissions from feedlot manure, respectively, contributed the most variability to life cycle GHG emissions from beef production. Feeding of …


Modeling The Thermosphere As A Driven-Dissipative Thermodynamic System, William R. Frey, C. S. Lin, Matthew B. Garvin, Ariel O. Acebal Apr 2014

Modeling The Thermosphere As A Driven-Dissipative Thermodynamic System, William R. Frey, C. S. Lin, Matthew B. Garvin, Ariel O. Acebal

Faculty Publications

Thermospheric density impacts satellite position and lifetime through atmospheric drag. More accurate specification of thermospheric temperature, a key input to current models such as the High Accuracy Satellite Drag Model, can decrease model density errors. This paper improves the model of Burke et al. (2009) to model thermospheric temperatures using the magnetospheric convective electric field as a driver. In better alignment with Air Force satellite tracking operations, we model the arithmetic mean temperature, T 1/2, defined by the Jacchia (1977) model as the mean of the daytime maximum and nighttime minimum exospheric temperatures occurring in opposite hemispheres at a …