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Estimating Mars Surface Wind Stress And Dust Lifting Using Reanalyses Based On Emm And Other Spacecraft Observations, Haneen Abouhaligah
Estimating Mars Surface Wind Stress And Dust Lifting Using Reanalyses Based On Emm And Other Spacecraft Observations, Haneen Abouhaligah
Theses
Studying Mars offers insights into terrestrial planet evolution and informs future human expeditions. This thesis examines dust dynamics in Mars’ lower atmosphere, focusing on understanding its weather and climate. We investigate the role of Near-Surface Wind Stress (NSWS) in dust lifting, using six reanalysis datasets, respectively: MACDA, EMARS, OpenMARS, ACS–TIRVIM (ExoMars observations of the MY34 Global Dust storm), EMM1 and EMM2. Following the parameterization approach by Newman et al. (2002a), areas of agreement and discrepancy among datasets were identified. Time series analysis revealed consistent results where datasets overlap temporally. Some differences were expected and shown due to the different Global …
A New Fire Initialization Method For Operational Coupled Fire-Atmosphere Models: Assimilation Of Infrared Perimeters And Satellite Detections, Kathleen Nicole Clough
A New Fire Initialization Method For Operational Coupled Fire-Atmosphere Models: Assimilation Of Infrared Perimeters And Satellite Detections, Kathleen Nicole Clough
Master's Theses
For coupled fire-atmosphere forecast models, such as WRF-SFIRE, the method used to initialize wildfire within the model can greatly impact meteorological, fire, and smoke extent forecasts. A well-constructed ignition process must be integrated within models to assure the atmospheric component of the model is not destabilized by excessive heat flux released during ignition and realistic fire-induced atmospheric circulation is established. Two ignition methods are tested on the 2020 Creek fire. Analyses indicate a gradual perimeter ignition with selective “masking”, fuel removal, provides the best results in terms of resolving the fire-induced vertical circulation and fire spread, and is thus preferred …
Observational Analysis And Modeling Of The "B" Regional Dust Storm On Mars, Courtney Marylou Batterson
Observational Analysis And Modeling Of The "B" Regional Dust Storm On Mars, Courtney Marylou Batterson
Master's Theses
The annually-recurring, regional B storm on Mars occurs at the highest southernlatitudes in years lacking a global dust storm (GDS), and produces warm temperatures (> 200 K) at 50 Pa over the south pole. Observations of the B storm are limited due to the lack of in-situ data in the polar regions of Mars, and reproducing polar phenomena using traditional latitude-longitude grid models is difficult because of the increasingly small grid spacing at the poles. The development of the new NASA Ames Mars Global Climate Model (MGCM), which has a finite-volume dynamical core, a uniform cubed-sphere grid, and several of …
Image Dehazing From The Perspective Of Environmental Illumination., Sanchayan Santra Dr.
Image Dehazing From The Perspective Of Environmental Illumination., Sanchayan Santra Dr.
Doctoral Theses
Haze and fog are atmospheric phenomena where the particles suspended in the air obscure visibility by scattering the light propagating through the atmosphere. As a result only a part of the reflected light reaches the observer. So, the apparent intensity of the objects get reduced. Apart from that, the in-scatter of the atmospheric light creates a translucent veil, which is a common sight during haze. Image dehazing methods try to recover a haze-free version of a given image by removing the effects of haze.Although attempts have been made to accurately estimate the scene transmittance, the estimation of environmental illumination has …
Fire Weather Associated With The 2019 Northern California Public Safety Power Shutoff Events, Scott Purdy
Fire Weather Associated With The 2019 Northern California Public Safety Power Shutoff Events, Scott Purdy
Master's Theses
Recent high impact wildfire events across California have piloted the implementation of grid de-energization by utilities across the state. The largest utility, Pacific Gas and Electric (PG&E), deployed this tactic on seven separate occasions during 2019, four of which occurred in October. This recent ploy has been established in the wake of many deadly wildfires such as the 2018 Camp Fire as an ignition mitigation tactic. Conditions such as the state of the fuels, meteorological conditions, and the consequent fire danger were evaluated as the primary triggers for the October de-energizations. It was determined that the fuels were critically dry …
Observations And Simulations Of Fire Weather Phenomena Across Scales, Matthew James Brewer
Observations And Simulations Of Fire Weather Phenomena Across Scales, Matthew James Brewer
Master's Theses
The need for a better understanding of wildfires and how the atmosphere affects them provided the motivation for this work. The November 2018 Camp Fire quickly became the deadliest and most destructive wildfire in California history. In chapter 1, we investigate the contribution of meteorological conditions and a downslope windstorm event that occurred during the 2018 Camp Fire. Results show that this event was associated with mid-level and surface synoptic scale processes which created conditions favorable for a North wind event. Sustained surface winds between 3–6 m s-1 were observed with gusts of over 25 m s-1. The meteorological conditions …
Evaluating Tropical Tropospheric Ozone And Water Vapor In Merra-2, Era-Interim, And Cam-Chem Using Aircraft Observations From The Western Pacific, Kathryn Steinmann
Evaluating Tropical Tropospheric Ozone And Water Vapor In Merra-2, Era-Interim, And Cam-Chem Using Aircraft Observations From The Western Pacific, Kathryn Steinmann
Master's Theses
Tropospheric ozone (O3) negatively is a greenhouse gas, affecting global climate. To improve climate predictions, the behavior of O3 and the mechanisms affecting its distribution must be understood and accurately represented in model simulations. This study evaluates O3 and water vapor (H2O) observations from the Convective Transport of Active Species in the Tropics (CONTRAST) campaign with data from the National Center for Atmospheric Research’s (NCAR) Community Atmospheric Model with Chemistry (CAM-Chem), the Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2), and the European Centre for Medium-Range Weather Forecast (ECMWF) Re-Analysis-Interim (ERA-Interim). In the tropical middle troposphere, CAM-Chem shows …
Comparisons Of Upper Tropospheric Ozone At A Coastal And Urban Site And The Impact Of Local Surface Emissions, Chloe Anne Gore
Comparisons Of Upper Tropospheric Ozone At A Coastal And Urban Site And The Impact Of Local Surface Emissions, Chloe Anne Gore
Master's Theses
This study quantified the impact of urban emission sources on the enhancement of ozone (O3) in the troposphere using data from simultaneous ozonesonde launches at Half Moon Bay (HMB), CA and San Jose (SJ), CA on eleven dates in July and August 2018. The urban O3 enhancement in the SJ vertical profile was derived by subtracting out HMB, which represents baseline O3, from the SJ profile. This enhancement was averaged into 1 km layers and statistically analyzed with surface emission concentration data from three locations in SJ, however this did not reveal any discernable trends between the surface and O3 …
Asian Long-Range Transport In Relation To Atmospheric Rivers In Northern California, Catherine Liu
Asian Long-Range Transport In Relation To Atmospheric Rivers In Northern California, Catherine Liu
Master's Theses
The study investigated the effect of aerosol long-range transport on precipitation over northern California during atmospheric river (AR) events in the 2017 cold season (January-April). ARs in 2017 were among the strongest to date and the intense precipitation associated with the ARs resulted in flooding, destruction of property, and contamination of water supplies. The aerosol optical depth (AOD) from Moderate Resolution Imaging Spectroradiometer (MODIS) data showed Asian dust traveling across the northern Pacific Ocean along with AR events. Aerosol measurements in California, provided by the Interagency Monitoring of Protected Visual Environments (IMPROVE), showed that more Asian dust tends to be …
Developing X-Ray Spectromicroscopic Techniques To Quantitatively Determine Population Statistics And Individual Particle Composition Of Complex Mixed Aerosols, Matthew Fraund
University of the Pacific Theses and Dissertations
Aerosols are a major source of uncertainty in estimates of anthropogenic effects on global radiative forcing and can pose serious health concerns. While many instrumental techniques capable of analyzing aerosol samples are available, individual-particle spectromicroscopic techniques like the ones presented here are the only ones to offer morphological and compositional measurements together. Studying the composition and mixing state of aerosol populations allowed for important aspects to be uncovered, such as: aerosol source, formation mechanism, hygroscopicity, optical properties, level of aging, and inhalation dangers. Ambient aerosols from the Amazon, both biogenic and anthropogenic, were apportioned based on their individual composition. Recently …
A New Analysis Of The Gálvez-Davison Index For Convective Forecasts In Northern Africa, Gabriel D. Donndelinger
A New Analysis Of The Gálvez-Davison Index For Convective Forecasts In Northern Africa, Gabriel D. Donndelinger
Theses and Dissertations
Severe wind gusts and thunderstorms have been difficult to forecast in Africa. Traditional convective forecast tools (e.g. Total Totals Index, Lifted Index, K Index (KI) and Convective Available Potential Energy) do not accurately portray potential for thunderstorms in Africa. This research effort used the Gálvez-Davison Index (GDI), a convective index created for the tropics, and assess its applicability to northern Africa. GDI was produced for the Caribbean and Central America, and utilized temperature, moisture, mid-level stability, dry air entrainment and an elevation factor to calculate convective potential. In this research, GDI and KI were calculated using Global Forecast System (GFS) …
The Hydroclimatology Of West Virginia Spatial And Temporal Trends And Their Relationship With The North Atlantic Oscillation, Carson Wright
The Hydroclimatology Of West Virginia Spatial And Temporal Trends And Their Relationship With The North Atlantic Oscillation, Carson Wright
Graduate Theses, Dissertations, and Problem Reports
Global air temperature has risen 0.74°C over the last 100 years, and is one of several factors influencing climate and streamflow variability at global, regional, and local scales. The North Atlantic Oscillation (NAO) is another important factor contributing to climate variability by influencing the intensity of storms entering the eastern US. The Southeastern US is receiving less precipitation and streamflow is decreasing while the northeastern US is receiving greater amounts of precipitation and increasing streamflows. West Virginia is typically overlooked being on the border of both of these regions; therefore the objective of this study is to fill knowledge gaps …
Spatial And Seasonal Variability Of Cloud Condensation Nuclei Number Concentrations Over The Extended North African Continent And The Mediterranean, Hesham Abdel-Monem Afify Hassan
Spatial And Seasonal Variability Of Cloud Condensation Nuclei Number Concentrations Over The Extended North African Continent And The Mediterranean, Hesham Abdel-Monem Afify Hassan
Legacy Theses & Dissertations (2009 - 2024)
The spatiotemporal variability of cloud condensation nuclei (CCN) number concentration is investigated over the extended domain of the North African continent and Mediterranean which is an essential step for better understanding of aerosol-cloud interactions and associated climate impacts over the region. The study is performed by analyzing the output for the period from 2004 to 2011 from the well-validated global chemistry and aerosol transport model GEOS-Chem-APM. The analysis shows that the dominant aerosol type for CCN number concentration is secondary particles all over the domain. Spatial analysis reveals the existence of four characteristic subdomains of variability: over the Mediterranean and …
Development Of Soil Lead And Tree-Ring Methods For Characterizing Atmospheric Deposition Gradients And Subsequent Tree Growth Responses, Bradley P. Breslow
Development Of Soil Lead And Tree-Ring Methods For Characterizing Atmospheric Deposition Gradients And Subsequent Tree Growth Responses, Bradley P. Breslow
Graduate Theses, Dissertations, and Problem Reports
Atmospheric deposition of pollutants and nutrients can have a range of effects on aquatic and terrestrial ecosystems. Despite its ecological importance, it remains a challenge to model patterns of deposition across complex terrain and also to assess how forest ecosystems are reacting to chronic inputs of atmospheric deposition. I measured the lead (Pb) content of forest soils adjacent to atmospheric deposition monitoring stations throughout the central Appalachian Mountains to examine how well patterns of soil Pb relate to regional patterns of inorganic nitrogen (N) deposition. While I found no significant relationship between organic soil Pb content and N deposition, I …
Correlating Simulated Surface Marks With Near-Surface Tornado Structure, Michael I. Zimmerman
Correlating Simulated Surface Marks With Near-Surface Tornado Structure, Michael I. Zimmerman
Graduate Theses, Dissertations, and Problem Reports
Tornadoes often leave behind patterns of debris deposition, or "surface marks", which provide a direct signature of their near surface winds. The intent of this thesis is to investigate what can be learned about near-surface tornado structure and intensity through the properties of surface marks generated by simulated, debris-laden tornadoes. Earlier work showed through numerical simulations that the tornado's structure and intensity is highly sensitive to properties of the near-surface flow and can change rapidly in time for some conditions. The strongest winds often occur within tens of meters of the surface where the threat to human life and property …
The Effect Of Ice Crystal Shape On Aircraft Contrails, Omar E. Meza Castillo
The Effect Of Ice Crystal Shape On Aircraft Contrails, Omar E. Meza Castillo
Graduate Theses, Dissertations, and Problem Reports
Aircraft contrails are a common phenomenon observed in the sky. They are formed mainly of water, from the ambient atmosphere and as a by-product of the combustion process, in the form of ice crystals. They have been identified as a potential contributor to global warming. Some contrails can be long-lived and create man-made cloud cover, thus possibly altering the radiative balance of the earth. There has been a great deal of research on various aspects of contrail development, but to date, little has been done on the influence of ice crystal shapes on the contrail evolution. In-situ studies have reported …