Atmospheric Sciences Commons^™

Classifying Reanalysis Surface Temperature Probability Density Functions (Pdfs) Over North America With Cluster Analysis, Paul C. Loikith, Benjamin R. Lintner, Jinwon Kim, Huikyo Lee

Geography Faculty Publications and Presentations

An important step in projecting future climate change impacts on extremes involves quantifying the underlying probability distribution functions (PDFs) of climate variables. However, doing so can prove challenging when multiple models and large domains are considered. Here an approach to PDF quantification using k-means clustering is considered. A standard clustering algorithm (with k = 5 clusters) is applied to 33 years of daily January surface temperature from two state-of-the-art reanalysis products, the North American Regional Reanalysis and the Modern Era Retrospective Analysis for Research and Applications. The resulting cluster assignments yield spatially coherent patterns that can be broadly related to …

The Optical Manifestation Of Dispersive Field‐Aligned Bursts In Auroral Breakup Arcs, H. Dahlgren, J. L. Semeter, R. A. Marshall, M. Zettergren

Publications

High‐resolution optical observations of a substorm expansion show dynamic auroral rays with surges of luminosity traveling up the magnetic field lines. Observed in ground‐based imagers, this phenomenon has been termed auroral flames, whereas the rocket signatures of the corresponding energy dispersions are more commonly known as field‐aligned bursts. In this paper, observations of auroral flames obtained at 50 frames/s with a scientific‐grade Complementary Metal Oxide Semiconductor (CMOS) sensor (30° × 30° field of view, 30 m resolution at 120 km) are used to provide insight into the nature of the precipitating electrons similar to high‐resolution particle detectors. Thanks to the …

Mesoscale Modeling And Satellite Observation Of Transport And Mixing Of Smoke And Dust Particles Over Northern Sub-Saharan African Region, Zhifeng Yang

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The transport and vertical distribution of smoke and mineral dust aerosols over the Northern Sub-Saharan African (NSSA) region have important implications for regional and global air quality and climate. This study employs ground-based and satellite observations, and numerical simulations conducted with a fully-coupled meteorology-chemistry-aerosol model, Weather Research and Forecasting model with Chemistry (WRF-Chem). The WRF-Chem simulation is for February 2008 and uses hourly dynamic smoke emissions from the Fire Locating and Modeling of Burning Emissions (FLAMBE) database derived from Moderate Resolution Imaging Spectroradiometer (MODIS) fire products. Model performance of smoke and dust simulation is evaluated using numerous satellite and ground-based …

Droughtscape, Summer 2013, National Drought Mitigation Center

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

Contents

Director’s report

July 25 webinar: Drought management database, NIDIS update

Republican River Basin workshops July 31, August 1

Summer climate outlook, spring summary

Spring impacts: wildfire, water, agriculture and business

Data help managers assess Nebraska groundwater declines after drought of 2012

Tadesse helps Mexico with Veg-DRI concept

Visiting scholar explores remote sensing of drought in forests

U.S. Drought Monitor Forum photo recap, details online

Workshop helps New Mexico ranchers cope with drought

Alabama’s new drought plan

National Drought Forum report

Drought Impacts Community of Practice report

The Preservation Of Atmospheric Nitrate In Snow At Summit, Greenland, Dorothy L. Fibiger, Meredith G. Hastings, Jack E. Dibb, L Gregory Huey

Earth Sciences

There is great interest in using nitrate NO3 isotopic composition in ice cores to track the history of precursor nitrogen oxides (NOx = NO + NO2) in the atmosphere. Nitrate NO3 however can be lost from the snow by surface processes, such as photolysis back to NOx upon exposure to sunlight, making it difficult to interpret records of NO3 as a tracer of atmospheric NOx loading. In a campaign consisting of two field seasons (May–June) at Summit, Greenland, high temporal frequency surface snow samples were collected and analyzed for the oxygen isotopic composition of NO3. The strong, linear relationship observed …

Snow Spectral Albedo At Summit, Greenland: Measurements And Numerical Simulations Based On Physical And Chemical Properties Of The Snowpack, Carlo Carmagnola, Florent Domine, Marie Dumont, Patrick Wright, B Strellis, M Bergin, Jack E. Dibb, G Picard, Q Libois, L Arnaud, S Morin

Earth Sciences

The broadband albedo of surface snow is determined both by the near-surface profile of the physical and chemical properties of the snowpack and by the spectral and angular characteristics of the incident solar radiation. Simultaneous measurements of the physical and chemical properties of snow were carried out at Summit Camp, Greenland (72°36´ N, 38°25´ W, 3210 m a.s.l.) in May and June 2011, along with spectral albedo measurements. One of the main objectives of the field campaign was to test our ability to predict snow spectral albedo by comparing the measured albedo to the albedo calculated with a radiative transfer …

Interspecific Variation In Leaf-Level Biogenic Emissions Of The Bambuseae, Andrea Natalie Melnychenko

Dissertations and Theses

Plants emit a diverse range of biogenic volatile organic compounds (BVOCs) into the atmosphere, of which isoprene is the most abundantly emitted. Isoprene significantly affects biological and atmospheric processes, but the range of isoprene and BVOCs present in bamboos has not been well characterized. In this thesis I explore the range of isoprene emission found in bamboos and relate it to plant morphological and physiological characteristics. In addition, I measure and relate the entire suite of BVOCs present in the bamboos to their fundamental isoprene emission rate.

Interspecific variation in isoprene emission documented in a comprehensive survey of bamboos. Two …

The Upgraded Rayleigh Lidar At Usu’S Atmospheric Lidar Observatory, Vincent B. Wickwar, Leda Sox, Joshua P. Herron

All Physics Faculty Presentations

No abstract provided.

Rayleigh Lidar Temperature Studies In The Upper Mesosphere And Lower Thermosphere, Leda Sox, Vincent B. Wickwar, Joshua P. Herron, Matthew T. Emerick

Posters

Rayleigh lidar technology opened the middle atmosphere (from 30–90 km) to ground-based observations. The upgraded system at the Atmospheric Lidar Observatory (ALO) on the campus of Utah State University (41.74, 111.81) has shown that these ground-based observations can be extended to 109 km, with the goal of reaching 120 km. The resultant study of short and long-term temperature trends, using Rayleigh lidar, contributes immensely to the overall understanding of the properties and dominant physical processes in the middle atmosphere and Mesosphere-Lower Thermosphere (MLT) region. Temperature variations on short time scales, from minutes to days, give insight into the effects of …

Observations Of Mesospheric Temperature Variability Over The Andes, Jonathan Pugmire, Michael J. Taylor, Yucheng Zhao, P. D. Paudet, James M. Russell

Graduate Student Posters

Observations of mesospheric OH(6,2) rotational temperatures by the Utah State University Mesospheric Temperature Mapper (MTM) located at the Andes Lidar Observatory, Cerro Pachon, Chile (30.3°S, 70.7°S) reveal a large range of nightly variations induced by atmospheric gravity waves and tides, as well as strong seasonal oscillations. This study investigates MTM temperature variability over the past 3.5 years comprising over 800 nights of high-quality data and compares the results with ground-based spectrometric measurements from nearby El Leoncito Observatory, Argentina, Maui-MALT, Hawaii MTM measurements (2001-2005) and coincident mesospheric temperature measurement by SABER on the NASA TIMED satellite.

Improving Multiple Surface Range Estimation Of A 3-Dimensional Flash Ladar In The Presence Of Atmospheric Turbulence, Brian J. Neff

Theses and Dissertations

Laser Radar sensors can be designed to provide two-dimensional and three-dimensional (3-D) images of a scene from a single laser pulse. Currently, there are various data recording and presentation techniques being developed for 3-D sensors. While the technology is still being proven, many applications are being explored and suggested. As technological advancements are coupled with enhanced signal processing algorithms, it is possible that this technology will present exciting new military capabilities for sensor users. The goal of this work is to develop an algorithm to enhance the utility of 3-D Laser Radar sensors through accurate ranging to multiple surfaces per …

Winter Climatology Of Short-Period Mesospheric Gravity Waves Over Alaska, Michael Negale, Kim Nielsen, Michael J. Taylor, Dominique Pautet

Physics Student Research

Momentum deposition by short-period (<1 h) gravity waves is known to play a major role in the global circulation in the mesosphere and lower thermosphere (MLT) region ~80-100 km (e.g. Fritts and Alexander, 2003). Observations of these waves over the Arctic region are few and their impact on the Arctic MLT region is of high interest, but has yet to be determined. The Mesospheric Airglow Imaging and Dynamics (MAID) project was initiated in January 2011 to investigate short-period gravity wave dynamics over central Alaska.

In this poster, we focus on quantifying the climatology of short-period gravity waves during two winter seasons (2011-2012) over central Alaska

Discontinuities And Alfvenic Fluctuations In The Solar Wind, G. Paschmann, S. Haaland, B. Sonnerup, T. Knetter

Dartmouth Scholarship

We examine the Alfvenicity of a set of 188 solar wind directional discontinuities (DDs) identified in the Cluster data from 2003 by Knetter (2005), with the objective of separating rotational discontinuities (RDs) from tangential ones (TDs). The DDs occurred over the full range of solar wind velocities and magnetic shear angles. By performing the Walen test in the de Hoffmann–Teller (HT) frame, we show that 77 of the 127 crossings for which a good HT frame was found had plasma flow speeds exceeding 80 % of the Alfven speed at an average angular deviation of 7.7◦; 33 cases had speeds …

Climate Change Tipping Points: A Point Of No Return?, Elise Lequire

Joint Fire Science Program Digests

Summer 2012 saw records fall for intensity of drought and number, size, and cost of wildfires in the Central and Western United States, and the climate forecast calls for more of the same in the near and distant future. When wildfire breaks out, emergency responders decide their immediate strategy based on past experience and quick judgment calls. But in the long term, land managers need to plan for a warmer climate on a time scale of decades, or even a century or more, to better reflect the life span of trees and forests. Studies supported by the Joint Fire Science …

Middle Atmosphere Temperature Results From A New, High-Powered, Large-Aperture Rayleigh Lidar, Leda Sox, Vincent B. Wickwar, Joshua P. Herron

Conference publications

In June–July 2012, observations were carried out using the recently upgraded, large-aperture, Rayleigh-scatter lidar system located at the Atmospheric Lidar Observatory (ALO) on the campus of Utah State University, in Logan, UT (41.7 N, 111.8 W). This time period was significant because it enabled us to observe the annual temperature minimum in the upper mesosphere-lower thermosphere region. The data collected during the campaign were analyzed for temperatures between ~70–109 km. The results above ~95 km are the first obtained with a Rayleigh-scatter lidar, extending the technique well into the lower thermosphere. A great deal of variability from night-to-night is evident …

On The Export Of Reactive Nitrogen From Asia: NoX Partitioning And Effects On Ozone, T H. Bertram, Paul J. Wooldridge, Jack E. Dibb, Robert C. Cohen, A E. Perring

Earth Sciences

The partitioning of reactive nitrogen (NO_y was measured over the remote North Pacific during spring 2006. Aircraft observations of NO, NO₂, total peroxy nitrates (ΣPNs), total alkyl and multi-functional nitrates (ΣANs) and nitric acid (HNO₃, made between 25° and 55° N, confirm a controlling role for peroxyacyl nitrates in NO_x production in aged Asian outflow. ΣPNs account for more than 60% of NO_y above 5 km, while thermal dissociation limits their contribution to less than 10% in the lower troposphere. Using simultaneous observations of NO_x, ΣPNs, ΣANs, HNO₃ and average …

Acting To Address The Ocean-Related Impacts Of Climate Change On Human And National Security, With Recommendations For Priority Actions Drawn From The Discussions Of The Global Conference On Oceans, Climate And Security At The University Of Massachusetts Boston, Robbin Peach, Felix Dodds, Michael Strauss, Collaborative Institute For Oceans, Climate And Security, University Of Massachusetts Boston

Collaborative Institute for Oceans, Climate and Security Publications

In the course of the past calendar year the United States has been struck by a series of droughts, tornadoes, hurricanes, blizzards, wildfires, and floods whose size and path of resulting damage defy previously established patterns. The U.S. thus joins nations on every continent that have increasingly experienced extreme and extremely damaging weather events over the past two decades.

At the same time, the world’s oceans have been exhibiting a less-visible but equally dangerous sequence of temperature rise, acidification increase, fish kills, coastal erosion, salinity shifts, algae blooms, and steady decreases in commercially available fish and shellfish species.

Those impacts …

An Examination Of The Mechanisms And Environments Supportive Of Bow Echo Mesovortex Genesis, George Limpert

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Low-level mesovortices are associated with enhanced surface wind gusts and high-end wind damage in quasi-linear thunderstorms. Although damage associated with mesovortices can approach that of moderately strong tornadoes, skill in forecasting mesovortices is low. The overarching goal of this work is to understand mesovortices and how they develop, to improve the skill in forecasting them. This was done by developing a climatology of mesovortices, which required a tracking algorithm, and numerical simulations were conducted to answer questions that could not be answered through the observational data. A climatology of mesovortices was constructed from 44 events during 2009 and 2010 to …

Lunar Tidal Effects In The Electrodynamics Of The Low-Latitude Ionosphere, Brian David Tracy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In order to model and perform better forecasts of the upper atmosphere, we have studied variations in the equatorial ionosphere due to lunar tidal forcing. We used extensive measurements made by the Jicamarca Unattended Long-Term Investigations of the Ionosphere and Atmosphere (JULIA) and Incoherent Scatter Radar (ISR) systems at Jicamarca, Peru during geomagnetic quiet conditions to determine the season, local time, and lunar age-dependent lunar tidal effects on equatorial vertical plasma drifts. The amplitudes and phases of the semimonthly and monthly lunar tidal perturbations were derived using a least squares method. Our results indicate that, as expected, lunar tidal effects …

The Effects Of Climate Science Literacy And Cultural Polarization Around Climate Change Risk Perception, Gabriel R. Young, Helen R. Neill

Graduate Research Symposium (2010 - 2017)

Science communicators have struggled to provide meaningful information about climate change due to the complex nature of the problem and the polarized political and media landscapes, and yet, a well informed public is a crucial element to both public acceptance and policy initiatives aimed at climate change mitigation. Current literature suggests that scientific literacy actually increases cultural polarization around the issue of climate change (Kahan, 2012). This study adds to the literature by testing the hypothesis that climate change risk perception is more heavily tied to climate science literacy than general science literacy when controlling for cultural worldviews. We use …