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Articles 1 - 19 of 19
Full-Text Articles in Atmospheric Sciences
The Impact Of Sea-Level Rise In Numerically Modeled Landfalling Hurricanes: Katrina And The Gulf Coast., Serenity Nadirah Mercuri
The Impact Of Sea-Level Rise In Numerically Modeled Landfalling Hurricanes: Katrina And The Gulf Coast., Serenity Nadirah Mercuri
Electronic Theses and Dissertations
With climate change, landfalling hurricanes become an increasing threat to coastal regions. However, the interactions between the coastal landscape and landfalling hurricanes are often overlooked when addressing sea-level rise outside of inundation and independent of sea surface temperature. This study analyzed the potential impacts regarding structure and intensity as a result of sea-level rise in the Gulf of Mexico using the WRF-ARW numerical model coupled with a 1D ocean model. Analysis showed that 10 m windspeed from landfall forward was higher in modified coastlines, and minimum sea-level pressure post-landfall was consistently lower for modified runs where storms maintain a higher …
Predictability Issues Associated With Near-Freezing Precipitation Type In Complex Terrain, Matthew Seymour
Predictability Issues Associated With Near-Freezing Precipitation Type In Complex Terrain, Matthew Seymour
Legacy Theses & Dissertations (2009 - 2024)
Predictability challenges are heightened in winter weather forecasting when the environment for high-impact weather is marginal or varies over short distances. High-resolution numerical weather prediction (NWP), such as the High-Resolution Rapid Refresh (HRRR), and ensemble forecast systems, such as the Global Ensemble Forecast System (GEFS), are useful for constraining forecasts. However, their use can be challenging in marginal, near-freezing, situations when precipitation type is uncertain. Uncertainties in planetary boundary layer (PBL) and microphysics (MP) parameterizations and subtle synoptic-scale model errors brought on by differences in initial and lateral boundary conditions (IC/BCs) complicate the p-type forecast. Further, complex terrain, such as …
On The Improvements Of Boundary-Layer Representation For High Resolution Weather Forecasting In Costal-Urban Environments, David Melecio-Vazquez
On The Improvements Of Boundary-Layer Representation For High Resolution Weather Forecasting In Costal-Urban Environments, David Melecio-Vazquez
Dissertations and Theses
As large urban centers around the world become more densely populated, the global conversion from natural to man-made land surfaces will only increase. These land-use changes affect the urban surface energy budget which in turn changes the structure of the planetary boundary layer (PBL) above. With current high-performance computing systems, meteorological and built environment information can be better utilized to quantify the anthropogenic effects of these modifications. Although these systems have improved forecasting near-surface weather conditions, a comprehensive approach to represent urban impacts on the PBL is still limited. Improved PBL representation can lead to better weather and climate forecasts, …
Land-Atmosphere-Cloud Interaction : Sensitivity Of Weather Forecast Models To Complex Land Surface Conditions In New York State, Lanxi Min
Legacy Theses & Dissertations (2009 - 2024)
The land-atmosphere coupling system is important for the simulation of key quantities like surface temperature, precipitation, and radiative energy. Over the complex terrain of New York State, the land-atmosphere coupling process is quite complex and misrepresenting the coupling processes could lead to strong biases. Evaluating the weather forecasting models is vital for enhancing understanding of physical and processes and further improving the model forecasting. A comprehensive observation network, the New York State Mesonet (NYSM) provides a great opportunity to investigate how the land atmosphere coupling process are simulated over complex terrain region. This research includes three components. In first part, …
Dynamical Downscaling Of Near-Term Climate Variability And Change For The Main Hawaiian Islands Using Wrf, Katrina Marie Fandrich
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 …
Forecasting Lightning Initiation Utilizing Dual-Polarization Radar Parameters Over Washington, D.C., Sarah A. Olsen
Forecasting Lightning Initiation Utilizing Dual-Polarization Radar Parameters Over Washington, D.C., Sarah A. Olsen
Theses and Dissertations
Accurate forecasts of thunderstorms are vital to space launch, aviation, and public safety. Prior studies by Woodard (2011), Thurmond (2014), and Travis (2015) show that dual-polarization radar can be utilized to identify the presence of hydrometeors necessary for cloud charging. These studies emphasized that a combination of radar reflectivity (Z) and differential reflectivity (ZDR) predictors have the potential to improve forecast skill of lightning initiation over methods that rely on Z alone (Roeder and Pinder, 1998; Yang and King, 2010). Travis (2015) discovered two parameters, when used together, produced the best results: Z ≥ 36.5 dBZ and ZDR …
Aerosol Direct Radiative And Cloud Adjustment Effects On Surface Climate Over The Eastern China : Analyses Of Wrf Model Simulations, Yangyang Song
Aerosol Direct Radiative And Cloud Adjustment Effects On Surface Climate Over The Eastern China : Analyses Of Wrf Model Simulations, Yangyang Song
Legacy Theses & Dissertations (2009 - 2024)
Aerosol climate effects consist of the initial forcing of atmospheric radiation perturbation through both the direct radiative effect and the modulation of radiatively-important cloud microphysics, and the subsequent changes in meteorology that also affect cloud macro- and micro-physics. The aerosol-induced cloud adjustment therefore involves many couplings and interactions, and its quantitative evaluation requires the use of model simulations. This study uses WRF model simulated changes in clouds and meteorology due to anthropogenic aerosol increases (versus 1970s) for 2002−2008 summers over the eastern China to address two relevant issues: direct radiative vs. cloud adjustment effects, and their roles in affecting surface …
Evaluation Of Lightning Jumps As A Predictor Of Severe Weather In The Northeastern United States, Pamela Eck
Evaluation Of Lightning Jumps As A Predictor Of Severe Weather In The Northeastern United States, Pamela Eck
Legacy Theses & Dissertations (2009 - 2024)
Severe weather events in the northeastern United States can be challenging to forecast, given how the evolution of deep convection can be influenced by complex terrain and the lack of quality observations in complex terrain. To supplement existing observations, this study explores using lightning to forecast severe convection in areas of complex terrain in the northeastern United States. A sudden increase in lightning flash rate by two standard deviations (2σ), also known as a lightning jump, may be indicative of a strengthening updraft and an increased probability of severe weather.
Understanding Predictive Skill Of Arctic Sea Ice And Its Linkage With Mid-Latitude Weather And Climate In The Ncep Climate Forecast System, Colleen Mchugh
Understanding Predictive Skill Of Arctic Sea Ice And Its Linkage With Mid-Latitude Weather And Climate In The Ncep Climate Forecast System, Colleen Mchugh
Legacy Theses & Dissertations (2009 - 2024)
Arctic climate is undergoing significant change, particularly rapid decline of sea ice. Arctic sea ice plays an important role in local, regional, and global climate through a variety of physical processes as seen in observational analysis as well as modeling studies. Recent research suggested that decreasing autumn and winter Arctic sea ice extent (SIE) has been shown to have an effect on mid-latitude weather patterns during the winter months. Therefore, accurate forecasts of Arctic sea ice extent and the associated teleconnections with the mid-latitudes are important for accurate seasonal climate prediction. The NCEP Climate Forecast System version 2 (CFSv2) is …
Evaluating Hourly Rainfall Characteristics Over The U.S. Great Plains In Dynamically Downscaled Climate Model Simulations Using Nasa-Unified Wrf, Huikyo Lee, Duane E. Waliser, Robert Ferraro, Takamichi Iguchi, Christa D. Peters-Lidard, Baijun Tian, Paul C. Loikith, Daniel B. Wright
Evaluating Hourly Rainfall Characteristics Over The U.S. Great Plains In Dynamically Downscaled Climate Model Simulations Using Nasa-Unified Wrf, Huikyo Lee, Duane E. Waliser, Robert Ferraro, Takamichi Iguchi, Christa D. Peters-Lidard, Baijun Tian, Paul C. Loikith, Daniel B. Wright
Geography Faculty Publications and Presentations
Accurate simulation of extreme precipitation events remains a challenge in climate models. This study utilizes hourly precipitation data from ground stations and satellite instruments to evaluate rainfall characteristics simulated by the NASA-Unified Weather Research and Forecasting (NU-WRF) regional climate model at horizontal resolutions of 4, 12, and 24 km over the Great Plains of the United States. We also examined the sensitivity of the simulated precipitation to different spectral nudging approaches and the cumulus parameterizations. The rainfall characteristics in the observations and simulations were defined as an hourly diurnal cycle of precipitation and a joint probability distribution function (JPDF) between …
Utilizing Four Dimensional Lightning And Dual-Polarization Radar To Develop Lightning Initiation Forecast Guidance, Andrew J. Travis
Utilizing Four Dimensional Lightning And Dual-Polarization Radar To Develop Lightning Initiation Forecast Guidance, Andrew J. Travis
Theses and Dissertations
Lightning initiation is a major forecast challenge faced by Air Force's 45th Weather Squadron (45 WS), which provides weather support to Cape Canaveral Air Force Station and Kennedy Space Center (KSC). Prior studies by Thurmond (2014) and Woodard (2011) have shown that dual-polarization (DP) radar can be used to identify the presence of hydrometeors indicative of cloud charging, leading to improved lightning initiation forecasts. The 45 WS currently employs empirical lightning initiation forecast rules which state that in-cloud lightning is likely when radar reflectivity meets or exceeds 37.0 dBZ above the -10°C height. This study examined 249 convective cells from …
The Impacts Of Varability In Temperature And Humidity On Electricity Consumption In New York State, Eric Adamchick
The Impacts Of Varability In Temperature And Humidity On Electricity Consumption In New York State, Eric Adamchick
Legacy Theses & Dissertations (2009 - 2024)
A seasonal harmonic linear regression approach is presented to model the seasonal and diurnal relationships between surface weather observations and electricity load data in New York State. The relationships between dry-bulb, dew point, and wet-bulb temperatures with electricity load were evaluated using the correlation coefficient to test the strength of the relationships, while the regression slope coefficient provided an interpretable scale for those relationships. We found that the strongest seasonal and diurnal relationships occur during boreal summer from the afternoon through the overnight hours, while similar but negative relationships are observed during the winter. Using the same seasonal harmonic linear …
An Analysis Of High-Impact, Low-Predictive Skill Severe Weather Events In The Northeast U.S, Matthew Thomas Vaughan
An Analysis Of High-Impact, Low-Predictive Skill Severe Weather Events In The Northeast U.S, Matthew Thomas Vaughan
Legacy Theses & Dissertations (2009 - 2024)
An objective evaluation of Storm Prediction Center slight risk convective outlooks, as well as a method to identify high-impact severe weather events with poor-predictive skill are presented in this study. The objectives are to assess severe weather forecast skill over the northeast U.S. relative to the continental U.S., build a climatology of high-impact, low-predictive skill events between 1980–2013, and investigate the dynamic and thermodynamic differences between severe weather events with low-predictive skill and high-predictive skill over the northeast U.S. Severe storm reports of hail, wind, and tornadoes are used to calculate skill scores including probability of detection (POD), false alarm …
Upper-Tropospheric Precursors Associated With Subtropical Cyclone Formation In The North Atlantic Basin, Alicia Marie Bentley
Upper-Tropospheric Precursors Associated With Subtropical Cyclone Formation In The North Atlantic Basin, Alicia Marie Bentley
Legacy Theses & Dissertations (2009 - 2024)
Oceanic cyclones exhibiting properties of both tropical and extratropical systems have been categorized as subtropical cyclones (STCs) since the early 1950s. The opportunity to investigate the roles of baroclinic and diabatic processes during the evolution of STCs from a potential vorticity (PV) perspective motivates this study. This study investigates the roles of baroclinic and diabatic processes during the evolution of STCs by calculating three PV metrics from the National Centers for Environmental Prediction Climate Forecast System Reanalysis 0.5° gridded dataset. The three PV metrics quantify the relative contributions of lower-tropospheric baroclinic processes, midtropospheric diabatic heating, and upper-tropospheric dynamical processes during …
The Integrated Wrf/Urban Modeling System: Development, Evaluation, And Applications To Urban Environmental Problems, Fei Chen, Hiroyuki Kusaka, Robert Bornstein, Jason Ching, C.S.B. Grimmond, Susanne Grossman-Clarke, Thomas Loridan, Kevin W. Manning, Alberto Martilli, Shiguang Miao, David J. Sailor, Francisco P. Salamanca, Haider Taha, Mukul Tewari, Xuemei Wang, Andrzej A. Wyszogrodzki, Chaolin Zhang
The Integrated Wrf/Urban Modeling System: Development, Evaluation, And Applications To Urban Environmental Problems, Fei Chen, Hiroyuki Kusaka, Robert Bornstein, Jason Ching, C.S.B. Grimmond, Susanne Grossman-Clarke, Thomas Loridan, Kevin W. Manning, Alberto Martilli, Shiguang Miao, David J. Sailor, Francisco P. Salamanca, Haider Taha, Mukul Tewari, Xuemei Wang, Andrzej A. Wyszogrodzki, Chaolin Zhang
Mechanical and Materials Engineering Faculty Publications and Presentations
To bridge the gaps between traditional mesoscale modeling and microscale modeling, the National Center for Atmospheric Research (NCAR), in collaboration with other agencies and research groups, has developed an integrated urban modeling system coupled to the Weather Research and Forecasting (WRF) model as a community tool to address urban environmental issues. The core of this WRF/urban modeling system consists of: 1) three methods with different degrees of freedom to parameterize urban surface processes, ranging from a simple bulk parameterization to a sophisticated multi-layer urban canopy model with an indoor outdoor exchange sub-model that directly interacts with the atmospheric boundary layer, …
The Downstream Extratropical Flow Response To Recurving Western North Pacific Tropical Cyclones, Heather M. Archambault
The Downstream Extratropical Flow Response To Recurving Western North Pacific Tropical Cyclones, Heather M. Archambault
Legacy Theses & Dissertations (2009 - 2024)
The factors that govern the downstream flow response to recurving western North Pacific (WNP) tropical cyclones (TCs) are investigated from climatological, composite analysis, case study, and predictability perspectives. A 1979–2009 climatology of WNP TC recurvature indicates that TC recurvature is followed by a four-day period of above-normal North Pacific meridional flow. The relationship between TC recurvature and above-normal North Pacific meridional flow is found to be stronger in late summer through mid-fall than in early summer and early winter, and stronger for TCs that interact strongly with the jet stream than for TCs that interact weakly with the jet stream. …
Local Adjustment Of The Background Error Correlation For Surface Analyses Over Complex Terrain, David T. Myrick, John D. Horel, Steven M. Lazarus
Local Adjustment Of The Background Error Correlation For Surface Analyses Over Complex Terrain, David T. Myrick, John D. Horel, Steven M. Lazarus
Aeronautics Faculty Publications
The terrain between grid points is used to modify locally the background error correlation matrix in an objective analysis system. This modification helps to reduce the influence across mountain barriers of corrections to the background field that are derived from surface observations. This change to the background error correlation matrix is tested using an analytic case of surface temperature that encapsulates the significant features of nocturnal radiation inversions in mountain basins, which can be difficult to analyze because of locally sharp gradients in temperature. Bratseth successive corrections, optimal interpolation, and three-dimensional variational approaches are shown to yield exactly the same …
In-Line Particulate Transport And Dispersion Modeling Using The Regional Atmospheric Modeling System (Rams), John W. Englert
In-Line Particulate Transport And Dispersion Modeling Using The Regional Atmospheric Modeling System (Rams), John W. Englert
Theses and Dissertations
There are a number of analytical and semi-empirical models that describe the behavior of particulate matter in the atmosphere. Many of these require modification for all types of weather, dry versus wet deposition, and overall effects can be quite non-linear. Rainfall (rate, drop size, etc.), snowfall (rate, flake size, etc.), humidity, pressure, temperature, and combination of these greatly affect particle settling and washout rates. To that end, a method for tracking released constituents using the Regional Atmospheric Modeling System (RAMS) microphysics package is developed by modifying one of the hydrometeor categories (hail) in the microphysics package. The RAMS microphysics package …
Experimental Goes Sounder Products For The Assessment Of Downburst Potential, Gary P. Ellrod, James P. Nelson Iii, Michael R. Witiw, Lynda Bottos, William P. Roeder
Experimental Goes Sounder Products For The Assessment Of Downburst Potential, Gary P. Ellrod, James P. Nelson Iii, Michael R. Witiw, Lynda Bottos, William P. Roeder
Aeronautics Faculty Publications
Several experimental products derived from Geostationary Operational Environmental Satellite (GOES) Sounder retrievals (vertical profiles of temperature and moisture) have been developed to assist weather forecasters in assessing the potential for convective downbursts. The product suite currently includes the wind index (WINDEX), a dry microburst index, and the maximum difference in equivalent potential temperature (θe) from the surface to 300 hPa. The products are displayed as color-coded boxes or numerical values, superimposed on GOES visible, infrared, or water vapor imagery, and are available hourly, day and night, via the Internet. After two full summers of evaluation, the products have been shown …