Atmospheric Sciences Commons^™

Determining Atmospheric Boundary Layer Behavior Over Mountainous Terrain Using Aircraft Vertical Profiles From 2009-2018 Nasa Student Airborne Research Program Data, Dallas Mckinney

Mahurin Honors College Capstone Experience/Thesis Projects

The atmospheric boundary layer (ABL) height separates turbulently mixed air and pollutants emitted at the ground from the free troposphere above and is an important parameter in numerical weather prediction and air pollution dispersion models. Discerning the ABL height over mountainous terrain has historically been difficult because of, for example, complex interactions with upper level winds, venting of humidity and aerosols into the free troposphere, and large spatiotemporal variability. ABL over mountainous terrain (MT) can closely follow the terrain, be flat, or be shallower than surrounding valleys depending on the time of day, synoptic conditions, and effects of the surrounding …

Whitepaper: Understanding Land-Atmosphere Interactions Through Tower-Based Flux And Continuous Atmospheric Boundary Layer Measurements, Manuel Helbig, Tobias Gerken, E Beamesderfer, D D. Baldocchi, T Banerjee, S C. Biraud, N A. Brunsell, S P. Butterworth, W S. Chan, A R. Desai, J D. Fuentes, D Y. Hollinger, N Klijun, M Mauder, K A. Novick, J M. Perkins, C Rey-Sanchez, R L. Scott, B Seyednasrollah, P C. Stoy, R C. Sullivan, J Vilà-Guerau De Arellano, S Wharton, C Yi, A D. Richardson

Libraries

Executive summary

● Target audience: AmeriFlux community, AmeriFlux Science Steering Committee & Department of Energy (DOE) program managers [ARM/ASR (atmosphere), TES (surface), and SBR (subsurface)]

● Problem statement: The atmospheric boundary layer mediates the exchange of energy and matter between the land surface and the free troposphere integrating a range of physical, chemical, and biological processes. However, continuous atmospheric boundary layer observations at AmeriFlux sites are still scarce. How can adding measurements of the atmospheric boundary layer enhance the scientific value of the AmeriFlux network?

● Research opportunities: We highlight four key opportunities to integrate tower-based flux measurements with continuous, …

Multi-Doppler Radar Wind Retrieval Data For Deep Convective Cloud Observed On May 11, 2020, Mariko Oue, Kirk North, Andrea Neumann

SoMAS Research Data

The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program’s Southern Great Plains (SGP) site includes a heterogeneous distributed scanning Doppler radar network suitable for collecting coordinated Doppler velocity measurements in deep convective clouds. The surrounding National Weather Service (NWS) Next Generation Weather Surveillance Radar 1988 Doppler (NEXRAD WSR-88D) further supplements this network. The multi-Doppler radar reflectivity and velocity measurements are assimilated in a three-dimensional variational (3DVAR) algorithm to retrieve horizontal and vertical air motions in deep convective clouds. The data includes the 3D wind fields retrieved over a large analysis domain (100 km x 100 km) at storm-scale …

Multi-Doppler Radar Wind Retrieval Data For Deep Convective Clouds Observed In The Southern Great Plains On May 11, 2011, Mariko Oue, Kirk North, Andrea Neumann

SoMAS Research Data

The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program’s Southern Great Plains (SGP) site includes a heterogeneous distributed scanning Doppler radar network suitable for collecting coordinated Doppler velocity measurements in deep convective clouds. The surrounding National Weather Service (NWS) Next Generation Weather Surveillance Radar 1988 Doppler (NEXRAD WSR-88D) further supplements this network. The multi-Doppler radar reflectivity and velocity measurements are assimilated in a three-dimensional variational (3DVAR) algorithm to retrieve horizontal and vertical air motions in deep convective clouds. The data includes the 3D wind fields retrieved over a large analysis domain (100 km x 100 km) at storm-scale …

A Multi-Platform, In-Situ Kinematic And Microphysical Analysis Of A Parallel Stratiform-Mesoscale-Convective System, Andrea Neumann, Michael Poellet, David J. Delene, Mark Askelson, Kirk North, Mariko Oue

Datasets

The North Dakota Citation Research Aircraft obtained measurements of stratiform precipitation clouds within mesoscale convective systems over Oklahoma during the spring of 2011 (MC3E) in conjunction with a multitude of ground- and airborne-based remote sensing instruments. The Citation was used to take measurements of base atmospheric variables as well as cloud and precipitation properties. Cloud droplet properties were measured by the Cloud Imaging Probe (CIP), Two-Dimensional Cloud probe (2D-C), the High-Volume Precipitation Spectrometer Version 3 (HVPS3) probe, with the spectra from these probes combined to create a single drop size distribution. The Atmospheric Radiation Measurement (ARM) program ran three X-Band …

Volcanic Impact On Stratospheric Chlorine Chemistry And Perchlorate Formation: Evidence From Ice Cores, Joshua Andrew Kennedy

Electronic Theses and Dissertations

Perchlorate, suspected to be chemically formed in both the troposphere and stratosphere, has been recently measured in Arctic snow and ice cores. These comprise both discontinuous snow and ice cores from the Canadian Arctic and a continuous record of perchlorate was compiled from an analysis of Greenland ice cores. While the background perchlorate concentration typically is very low, a few spikes in concentration coinciding with deposition of volcanic sulfate were observed in the Greenland record, suggesting that perchlorate levels in the atmosphere may be impacted by volcanic eruptions. As of yet, no work has been done to investigate the connection …

An Annual Time Series Of Weekly Size-Resolved Aerosol Properties In The Megacity Of Metro Manila, Philippines, Connor Stahl, Melliza Templonuevo Cruz, Paola Angela Bañaga, Grace Betito, Rachel A. Braun, Mojtaba Azadi Aghdam, Maria Obiminda L. Cambaliza, Genevieve Rose Lorenzo, Alexander B. Macdonald, Preciosa Corazon Pabroa, John Robin Yee, James Bernard Simpas, Armin Sorooshian

Physics Faculty Publications

Size-resolved aerosol samples were collected in Metro Manila between July 2018 and October 2019. Two Micro-Orifice Uniform Deposit Impactors (MOUDI) were deployed at Manila Observatory in Quezon City, Metro Manila with samples collected on a weekly basis for water-soluble speciation and mass quantification. Additional sets were collected for gravimetric and black carbon analysis, including during special events such as holidays. The unique aspect of the presented data is a year-long record with weekly frequency of size-resolved aerosol composition in a highly populated megacity where there is a lack of measurements. The data are suitable for research to understand the sources, …

Deep Equatorial Pacific Ocean Oxygenation And Atmospheric Co2 Over The Last Ice Age, Franco Marcantonio, Ryan Hostak, Jennifer E. Hertzberg, Matthew W. Schmidt

OES Faculty Publications

Ventilation of carbon stored in the deep ocean is thought to play an important role in atmospheric CO₂ increases associated with Pleistocene deglaciations. The presence of this respired carbon has been recorded by an array of paleoceanographic proxies from various locations across the global ocean. Here we present a new sediment core from the Eastern Equatorial Pacific (EEP) Ocean spanning the last 180,000 years and reconstruct high-resolution 230Th-derived fluxes of 232Th and excess barium, along with redox-sensitive uranium concentrations to examine past variations in dust delivery, export productivity, and bottom-water oxygenation, respectively. Our bottom-water oxygenation record is compared to …

Factors Influencing Rainfall Over The Congo, Ajay Raghavendra

Legacy Theses & Dissertations (2009 - 2024)

The hydrological cycle over tropical rainforests includes some of the most intense thunderstorms and rainfall totals. The energy associated with this convective activity plays an important role in the Earth’s weather and climate system. Therefore, the interannual variability, trends, and future climate projections of the hydrological cycle over tropical rainforests are important topics for research. The Congo rainforest situated over equatorial Africa is the second largest rainforest in the world, and recent studies have documented a >30-year large-scale and long-term drying trend over the Congo since the late-1970s. However, unlike the Amazon rainforest in South America, the Congo rainforest is …

The Impact Of Warm Conveyor Belt Forecast Uncertainty On Downstream Predictability, Jeremy Berman

Legacy Theses & Dissertations (2009 - 2024)

Perturbations to the potential vorticity (PV) waveguide can lead to the downstream radiation of Rossby waves, and in turn high-impact weather events. The PV waveguide is often perturbed in association with cyclogenesis, largely due to the latent heat release within the cyclone’s warm conveyor belt (WCB). Previous studies have hypothesized that forecast uncertainty associated with diabatic heating in WCBs can result in large downstream forecast variability; however these studies have not established a direct connection between the two. This hypothesis is evaluated for six cyclogenesis events characterized by highly amplified flow over the North Atlantic using ensemble model simulations.

Ozone And Reactive Oxidized Nitrogen Chemistry In The Northeast U.S, Matthew Ninneman

Legacy Theses & Dissertations (2009 - 2024)

Ongoing reductions in oxides of nitrogen concentrations ([NOx] = nitric oxide ([NO]) + nitrogen dioxide ([NO2])) throughout the continental United States (U.S.) have important implications for tropospheric ozone (O3) and reactive oxidized nitrogen chemistry (NOy ≈ NOx + nitric acid (HNO3) + particle nitrate (pNO3) + peroxy nitrates (PNs) + alkyl nitrates (ANs)). Specifically, decreasing [NOx] concentrations have likely (1) increased the sensitivity of O3 to the [NOx] level, and (2) affected NOy speciation and partitioning. An understanding of the impacts of continued [NOx] reductions is needed to inform current and future air pollution control strategies, especially since the National …

Global Circulation Variability Associated With Mjo Phase Speed, Alexander Marat Tomoff

Legacy Theses & Dissertations (2009 - 2024)

Differences in the Madden–Julian oscillation (MJO) phase speed help explain some of the variability in the global circulation patterns associated with the MJO. Select mechanisms that identify these distinctive circulation signals are applied to help explain MJO variability associated with different phase speeds. Wavelet filter analysis is first used to compute regression models of the MJO at different phase speeds, isolating the associated patterns in outgoing longwave radiation (OLR), geopotential height, and upper-level wind. Covariance matrices provide a deeper understanding of how the tropical and extratropical patterns compare between two phase speeds at any point in time. Both Fourier and …

An Analysis Of Temperature Trends In The Northeast United States : 1950-2019, Christopher Selca

Legacy Theses & Dissertations (2009 - 2024)

The warming signal associated with anthropogenic climate change shows a significant positive trend globally over the last century. Trends in the magnitude and frequency of annual mean and extreme events do not display a globally uniform signal, as some regions have shown negative trends. This study examines the trends in daily mean and extreme temperatures in the Northeast region of the United States. Station data was selected from the GHCN-D Version 3 data set, using a blend of stations from the weather forecast offices and the cooperative observing network. Station criteria included using a threshold of less than 5% of …

Examining The Impact Of Synoptic-Scale Waves On Stratospheric Polar Vortex Variability From An Ensemble Forecast Perspective, Michael E. Main

Legacy Theses & Dissertations (2009 - 2024)

Major Sudden Stratospheric Warming (SSW) events are characterized by rapid warming of the polar regions at 10 hPa and are accompanied by a reversal of the 10-hPa zonal-mean zonal wind at 60˚N from westerly to easterly. Following an SSW event, stratospheric thermal and momentum anomalies can progress downward and linger near the tropopause for up to 60 days. These anomalies have major impacts on tropospheric sensible weather including increased likelihood of cold air outbreaks and heavy precipitation events. SSW events are largely forced by upward propagation of planetary-scale Rossby waves from the troposphere to the stratosphere. Synoptic-scale waves can contribute …

Dynamical Downscaling Of Near-Term Climate Variability And Change For The Main Hawaiian Islands Using Wrf, Katrina Marie Fandrich

Legacy Theses & Dissertations (2009 - 2024)

As climate models continue to improve, the demand from resource managers and decision-makers for more accurate climate projections is increasing. However, natural climate variability poses a limit to the confidence in regional climate change projections, particularly for the mid-21st century. The unique geographic location of the Hawaiian Islands and its regional climate provide a challenging opportunity for climate modelers. The goal of this project is to examine both the Pacific Decadal Oscillation (PDO) and anthropogenic climate change for their impacts on near-term rainfall and temperature projections for the Hawaiian Islands. Of primary interest are the questions 1) is there a …

Improving Our Understanding Of The Relationship Between Ocean Heat Uptake And Climate Sensitivity, Michael Cameron Rencurrel

Legacy Theses & Dissertations (2009 - 2024)

One of the ultimate goals of the field of climate science is to determine exactly how sensitive the Earth is to anthropogenic forcing, with far reaching implications both from a scientific and policy standpoint. However, despite decades of observational and model analysis, large uncertainties in Earth's climate sensitivity persist. Recent advances have shown that climate feedbacks, the primary mechanism driving the sensitivity spread, are dependent on the spatial patterns of the surface response, intrinsically linked to how the ocean is working to uptake and transport energy across the globe. Given the importance of reducing the range of climate sensitivity from …

Easterly Waves Over The Eastern Pacific, Victor Manuel Torres Puente

Legacy Theses & Dissertations (2009 - 2024)

The research in this thesis explores different processes associated with the life cycle of Easterly Waves over the tropical Eastern Pacific. These include genesis, structural evolution, intensification and a dissipating stage.

Evaluating Large-Scale And Storm-Scale Characteristics Of Rapidly Intensifying And Slowly Intensifying Tropical Cyclones Using An Analog Approach, Jannetta C. Richardson

Legacy Theses & Dissertations (2009 - 2024)

Tropical cyclone (TC) intensity change is modulated by a combination of large-scale and storm-scale processes. On the large-scale, several factors exhibit strong controls on TC rapid intensification (RI): the initial TC intensity, the environmental vertical wind shear (VWS), and the background thermodynamic environment, which determines the TC’s maximum potential intensity (MPI). Previous statistical studies comparing RI and non-RI TCs have shown that TCs undergoing RI tend to be embedded in environments of lower VWS, and have initial intensities that are farther from their MPIs. Although numerous statistical studies have compared the large-scale and storm-scale conditions of RI and non-RI TCs, …

The Significance Of The Nontraditional Coriolis Terms In Tropical Large-Scale Dynamics, Heng Wang

Legacy Theses & Dissertations (2009 - 2024)

The nontraditional Coriolis terms (NCTs) turn eastward motion upward and upward motion westward, and vice versa. NCTs are omitted in most of the current global atmospheric models. However, NCTs are significant in tropical large-scale dynamics in at least three aspects. 1) Using an idealized model that can switch NCTs on or off, omitting NCTs biases large-scale flow response to prescribed diabatic forcing mimicking the intertropical convergence zone (ITCZ). The omission yields a westerly wind bias in the heating region ~ 10% of the westerly jet stream. This bias is due to lack of westward NCT when heating-induced upward motion is …

Droughtscape, Winter 2019, Cory Matteson

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

Contents

From the Director

4th quarter climate summary

2019 year in review summary

4th quarter drought impact summary

2019 drought impact summary

New form helps ‘see more’ drought

Landscape photographers invited to submit photos

Helping Central and South America planning

Database includes more drought planning