Atmospheric Sciences Commons^™

Southern Hemisphere Summer Mesopause Responses To El Niño–Southern Oscillation, Tao Li, Natalia Calvo, Jia Yue, James Russell Iii, Alan Liu

Publications

In the Southern Hemisphere (SH) polar region, satellite observations reveal a significant uppermesosphere cooling and a lower-thermosphere warming during warm ENSO events in December. An opposite pattern is observed in the tropical mesopause region. The observed upper-mesosphere cooling agrees with a climate model simulation. Analysis of the simulation suggests that enhanced planetary wave (PW) dissipation in the Northern Hemisphere (NH) high-latitude stratosphere during El Niño strengthens the Brewer–Dobson circulation and cools the equatorial stratosphere. This increases the magnitude of the SH stratosphere meridional temperature gradient and thus causes the anomalous stratospheric easterly zonal wind and early breakdown of the SH …

The Use Of Remote Sensing Technologies And Models To Study Pollutants In Pdn Region, Suhail Mahmud

Open Access Theses & Dissertations

Using a suite of modeling techniques and instrumentation we study the atmospheric pollutants in the PdN Region. The first objective of this work was to measure hemi-spherically integrated, spectrally resolved solar photon flux (actinic flux) between the wavelengths 300 and 700 nm, and use the measured actinic flux to improve air quality simulations. Actinic flux was measured in the PdN region in order to calculate photolysis rate coefficients for different pollutants. The improved photolysis rate coefficients were then integrated into a photochemical air quality model (CAMx) in order to improve air quality forecasting. We present the simulations performed for a …

Study Of No2 Photolysis Rate Coefficients For The Paso Del Norte Region, Pema Wangchuk

Open Access Theses & Dissertations

The photolysis of nitrogen dioxide is one of the most influential chemical processes in the formation of photochemical air pollution. In this study, we compared simulated and measured nitrogen dioxide photolysis rate coefficients (J_(NO_2 )) for the Paso Del Norte (PdN) region. The Tropospheric Ultraviolet-Visible (TUV) radiation transfer model was used to calculate J_(NO_2 ) values. The measurements of hemi-spherically integrated, spectrally resolved solar photon flux between the wavelengths 400 and 700 nm were used to obtain the photolysis rate coefficients for ã??NOã??_2. Results are presented for a selected episode on July, 2015. The work investigated the use of measured …

Intermittency Of Gravity Wave Momentum Flux In The Mesopause Region Observed With An All-Sky Airglow Imager, Bing Cao, Alan Z. Liu

Publications

The intermittency of gravity wave momentum flux (MF) near the OH airglow layer (∼87 km) in the mesopause region is investigated for the first time using observation of all-sky airglow imager over Maui, Hawaii (20.7∘N, 156.3∘W), and Cerro Pachón, Chile (30.3∘S, 70.7∘W). At both sites, the probability density function (pdf) of gravity wave MF shows two distinct distributions depending on the magnitude of the MF. For MF smaller (larger) than ∼16 m2 s−2 (0.091 mPa), the pdf follows a lognormal (power law) distribution. The intermittency represented by the Bernoulli proxy and the percentile ratio shows that gravity waves have higher …

First Measurement Of Horizontal Wind And Temperature In The Lower Thermosphere (105–140 Km) With A Na Lidar At Andes Lidar Observatory, Alan Liu, Yafang Guo, Fabia A. Vargas, Gary Swenson,

Publications

We report the first measurement of nighttime atmospheric temperature and horizontal wind profiles in the lower thermosphere up to 140 km with the Na lidar at Andes Lidar Observatory in Cerro Pachón, Chile (30.25°S, 70.74°W), when enhanced thermospheric Na was observed. Temperature and horizontal wind were derived up to 140 km using various resolutions, with the lowest resolution of about 2.7 hr and 15 km above 130 km. Thus, the measurements span 60 km in vertical, more than double the traditional 25 km. On the night of 17 April 2015, the horizontal wind magnitude in the thermosphere exceeds 150 ms−1, …

Turbulence And Overturning Gravity Wave Effects Deduced From Mesospheric Na Density Between 100-105 Km At Andes Lidar Observatory, Chile, Alan Z. Liu, Channing P. Philbrick, Gary R. Swenson, Fabio A. Vargas

Publications

Atmospheric turbulence activity in the mesosphere and lower thermosphere (MLT) region is determined from narrowband Na lidar measurements obtained over 27 nights between 85-105 km altitude at the Andes Lidar Observatory (ALO) in Cerro Pachón, Chile (30.3ºS, 70.7ºW). Photocount perturbations in the applicable spectral subrange are used as a tracer of turbulence activity. Mean altitude profiles reveal a log-scale linear increase in turbulence perturbation amplitude above 95 km. The observed trend is compared against global mean constituent transport profiles derived from SABER and SCIAMACHY satellite borne measurements.

Effects Of Temperature, Irradiance And Pco2 On The Growth And Nitrogen Utilization Of Prorocentrum Donghaiense, Zhangxi Hu, Margaret R. Mulholland, Ning Xu, Shunshan Duan

OES Faculty Publications

Environmental factors such as temp erature, irradiance, and nitrogen (N) supply affect the growth of Prorocentrum donghaiense, but the interactive effects of these physical factors and the effects of atmospheric CO₂ (pCO₂) on growth and N uptake have not been examined. We compared growth kinetics of P. donghaiense grown on 4 different N substrates (nitrate [NO₃ -], ammonium [NH₄ +], urea, and glutamic acid [glu]) with respect to temperature, irradiance, and pCO₂. Temperature (15 to 30°C) had a positive effect on growth (max. growth rates: 0.17 to 0.65 d …

Evidence Of The Excitation Of A Ring-Like Gravity Wave In The Mesosphere Over The Andes Lidar Observatory, Fabio Vargas, Gary Swenson,, Alan Liu, Dominique Pautet

Publications

On 23 March 2012, our all-sky imager recorded a concentric, ring-like gravity wave pattern. The wave arose within the area covered by images of both OH and O(1S) nightglow emissions taken at the Andes Lidar Observatory (ALO), Chile (30.3°S, 70.7°W). We have estimated the observed and intrinsic parameters of the event and located the wave source within the lower mesosphere altitude range using a reverse ray tracing method. By the analysis of GOES and LIS satellite images, we have not found evidence of neither convective nor lightning activity nearby ALO, indicating that the source of the ring-like wave …

Fine Particulate Air Pollution And Hospital Emergency Room Visits For Respiratory Disease In Urban Areas In Beijing, China, In 2013, Qin Xu, Xia Li, Shuo Wang, Chao Wang, Fangfang Huang, Qi Gao, Lijuan Wu, Lixin Tao, Jin Guo, Wei Wang, Xiuhua Guo

Research outputs 2014 to 2021

Background

Heavy fine particulate matter (PM_2.5) air pollution occurs frequently in China. However, epidemiological research on the association between short-term exposure to PM_2.5 pollution and respiratory disease morbidity is still limited. This study aimed to explore the association between PM_2.5 pollution and hospital emergency room visits (ERV) for total and cause-specific respiratory diseases in urban areas in Beijing. Methods Daily counts of respiratory ERV from Jan 1 to Dec 31, 2013, were obtained from ten general hospitals located in urban areas in Beijing. Concurrently, data on PM_2.5 were collected from the Beijing Environmental Protection Bureau, …

Comparison Of Coincident Rayleigh-Scatter And Sodium Resonance Lidar Temperature Measurements From The Mesosphere-Lower-Thermosphere Region, Leda Sox, Vincent B. Wickwar, Neal R. Criddle, Tao Yuan

All Physics Faculty Presentations

There are relatively few instruments that have the capabilities to make near continuous measurements of the mesosphere-lower-thermosphere (MLT) region. Rayleigh scatter and resonance lidars, particularly sodium resonance lidar, have been the two dominant ground-based techniques for acquiring mesosphere and MLT vertical temperature profiles, respectively, for more than two decades. With these measurements, the dynamics (gravity waves, tides) and long-term temperature trends (upper atmosphere cooling) of the MLT region can be studied. The Utah State University (USU; 41.7º N, 111.8º W) campus hosts a unique upper atmospheric observatory which houses both a high-power, large-aperture Rayleigh lidar and a sodium resonance Doppler …

Comparison Of Coincident Rayleigh-Scatter And Sodium Resonance Lidar Temperature Measurements From The Mesosphere-Lower-Thermosphere Region, Leda Sox, Vincent B. Wickwar, Neal R. Criddle, Tao Yuan

All Physics Faculty Publications

There are relatively few instruments that have the capabilities to make near continuous measurements of the mesosphere-lower-thermosphere (MLT) region. Rayleigh scatter and resonance lidars, particularly sodium resonance lidar, have been the two dominant ground-based techniques for acquiring mesosphere and MLT vertical temperature profiles, respectively, for more than two decades. With these measurements, the dynamics (gravity waves, tides) and long-term temperature trends (upper atmosphere cooling) of the MLT region can be studied. The Utah State University (USU; 41.7º N, 111.8º W) campus hosts a unique upper atmospheric observatory which houses both a high-power, large-aperture Rayleigh lidar and a sodium resonance Doppler …

Dynamics Of Density Cavities Generated By Frictional Heating: Formation, Distortion, And Instability, M. D. Zettergren, J. L. Semeter, H. Dahlgren

Publications

A simulation study of the generation and evolution of mesoscale density cavities in the polar ionosphere is conducted using a time-dependent, nonlinear, quasi-electrostatic model. The model demonstrates that density cavities, generated by frictional heating, can form in as little as 90 s due to strong electric fields of ∼120 mV/m, which are sometimes observed near auroral zone and polar cap arcs. Asymmetric density cavity features and strong plasma density gradients perpendicular to the geomagnetic field are naturally generated as a consequence of the strong convection and finite extent of the auroral feature. The walls of the auroral density cavities are …

Three-Dimensional Wind Speed And Flux Measurements Over A Rain-Fed Soybean Field Using Orthogonal And Non-Orthogonal Sonic Anemometer Designs, Taylor Thomas

School of Natural Resources: Dissertations, Theses, and Student Research

The eddy covariance method for estimating fluxes of trace gases, energy and momentum in the constant flux layer above a plant canopy fundamentally relies on accurate measurements of the vertical wind speed. This wind speed is typically measured using a three-dimensional ultrasonic anemometer. Previous studies comparing anemometers with orthogonal transducer sets to those with non-orthogonal transducer sets suggest differences in measured 3D wind speed components, particularly for a vertical component. These differences, attributed to additional flow distortion caused by the non-orthogonal transducer arrangement and support structure, directly affect fluxes of trace gases, energy and momentum. A field experiment was conducted …

Umphlett Qci 2015, Natalie A. Umphlett

High Plains Regional Climate Center: Staff Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Late Hard Freeze

Late Freezes Extended Growing Season

Warm Fall Delays Bird Migrations

Monitoring Water Resources Across the Basin

3-Month Precipitation and Temperature Outlooks

Validation Of The Global Distribution Of Co2 Volume Mixing Ratio In The Mesosphere And Lower Thermosphere From Saber, L. Rezac, Y. Jian, J. Yue, J. M. Russell Iii, A. Kutepov, R. Garcia, K. Walker, P. Bernath

Chemistry & Biochemistry Faculty Publications

The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite has been measuring the limb radiance in 10 broadband infrared channels over the altitude range from ~ 400 km to the Earth's surface since 2002. The kinetic temperatures and CO₂ volume mixing ratios (VMRs) in the mesosphere and lower thermosphere have been simultaneously retrieved using SABER limb radiances at 15 and 4.3 μm under nonlocal thermodynamic equilibrium (non-LTE) conditions. This paper presents results of a validation study of the SABER CO₂ VMRs obtained with a two-channel, self-consistent …

Evaluation Of Large‑Scale Meteorological Patterns Associated With Temperature Extremes In The Narccap Regional Climate Model Simulations, Paul C. Loikith, Duane E. Waliser, Huikyo Lee, J. David Neelin, Benjamin Lintner, Seth Mcginnis, Linda Mears, Jinwon Kim

Geography Faculty Publications and Presentations

Large-scale meteorological patterns (LSMPs) associated with temperature extremes are evaluated in a suite of regional climate model (RCM) simulations contributing to the North American Regional Climate Change Assessment Program. LSMPs are characterized through composites of surface air temperature, sea level pressure, and 500 hPa geopotential height anomalies concurrent with extreme temperature days. Six of the seventeen RCM simulations are driven by boundary conditions from reanalysis while the other eleven are driven by one of four global climate models (GCMs). Four illustrative case studies are analyzed in detail. Model fidelity in LSMP spatial representation is high for cold winter extremes near …

Utilizing Humidity And Temperature Data To Advance Monitoring And Prediction Of Meteorological Drought, Ali Behrangi, Paul C. Loikith, Eric J. Fetzer, Hai M. Nguyen, Stephanie L. Granger

Geography Faculty Publications and Presentations

The fraction of land area over the Continental United States experiencing extreme hot and dry conditions has been increasing over the past several decades, consistent with expectation from anthropogenic climate change. A clear concurrent change in precipitation, however, has not been confirmed. Vapor pressure deficit (VPD), combining temperature and humidity, is utilized here as an indicator of the background atmospheric conditions associated with meteorological drought. Furthermore, atmospheric conditions associated with warm season drought events are assessed by partitioning associated VPD anomalies into the temperature and humidity components. This approach suggests that the concurrence of anomalously high temperature and low humidity …

Spectral Aerosol Extinction (Spex): A New Instrument For In Situ Ambient Aerosol Extinction Measurements Across The Uv/Visible Wavelength Range, C. E. Jordan, B E. Anderson, A J. Beyersdorf, C A. Corr, Jack E. Dibb, Margaret E. Greenslade, R F. Martin, R H. Moore, Eric Scheuer, M A. Shook, Kenn L. Thornhill, D Troop, Luke D. Ziemba, E L. Winstead

Earth Sciences

We introduce a new instrument for the measurement of in situ ambient aerosol extinction over the 300– 700 nm wavelength range, the spectral aerosol extinction (SpEx) instrument. This measurement capability is envisioned to complement existing in situ instrumentation, allowing for simultaneous measurement of the evolution of aerosol optical, chemical, and physical characteristics in the ambient environment. In this work, a detailed description of the instrument is provided along with characterization tests performed in the laboratory. Measured spectra of NO2 and polystyrene latex spheres (PSLs) agreed well with theoretical calculations. Good agreement was also found with simultaneous aerosol extinction measurements at …

Neither Dust Nor Black Carbon Causing Apparent Albedo Decline In Greenland's Dry Snow Zone: Implications For Modis C5 Surface Reflectance, Chris Polashenski, Jack E. Dibb, Mark G. Flanner, Justin Y. Chen, Zoe R. Courville, Alexandra M. Lai, James J. Schauer, Martin M. Shafer, Mike Bergin

Earth Sciences

Remote sensing observations suggest Greenland ice sheet (GrIS) albedo has declined since 2001, even in the dry snow zone. We seek to explain the apparent dry snow albedo decline. We analyze samples representing 2012–2014 snowfall across NW Greenland for black carbon and dust light-absorbing impurities (LAI) and model their impacts on snow albedo. Albedo reductions due to LAI are small, averaging 0.003, with episodic enhancements resulting in reductions of 0.01–0.02. No significant increase in black carbon or dust concentrations relative to recent decades is found. Enhanced deposition of LAI is not, therefore, causing significant dry snow albedo reduction or driving …

Enhancing Quality Assurance Using Virtual Design Engineering: Case Study Of Space Shuttle Challenger, Kouroush Jenab, Scot Paterson

International Journal of Aviation, Aeronautics, and Aerospace

Virtual Design Engineering is an emerging method of increasing quality of systems. Including Virtual Design as a part of the traditional established Failure Mode, Effects, and Criticality Analysis process greatly enhances hazard and risk analysis while reducing overall costs. In this study these enhancements are explored and expanded upon to discover how overall system quality could be increased and all stakeholders could more accurately understand the hazards involved. Stakeholder misunderstanding or misapplication of hazards is of great importance to complex systems. An illustrative example of how these factors could have changed the outcome of a real-world engineering failure is provided.