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Theses/Dissertations

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Articles 241 - 270 of 311

Full-Text Articles in Meteorology

Estimation Of Atmospheric Precipitable Water Using The Global Positioning System, David A. Garay Mar 2002

Estimation Of Atmospheric Precipitable Water Using The Global Positioning System, David A. Garay

Theses and Dissertations

This research focuses on using the Global Positioning System (GPS) for atmospheric precipitable water (PW) estimation. Water vapor, measured in terms of PW, plays a crucial role in atmospheric processes and short-term weather forecasting. Traditional methodologies for measuring atmospheric water vapor distributions have known inadequacies, resulting in the motivation to gain good water vapor characterization via GPS. The ability to accurately forecast cloud formation and other weather phenomenon is critical, especially in the case of military operations. Using a network of GPS receivers, it is possible to estimate precipitable water throughout the network region with better accuracy than traditional methods …

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Designing An Algorithm To Predict The Intensity Of The Severe Weather Season, Hugh J. Freestrom Mar 2002

Designing An Algorithm To Predict The Intensity Of The Severe Weather Season, Hugh J. Freestrom

Theses and Dissertations

The Mesoscale Model 5th Generation (MM5) is used for operational support to Air Force missions in the Alaskan Theater. The 11th Operational Weather squadron has identified problems with the MM5 producing excessively warm surface temperatures. The Polar MM5 (PMM5), developed by the Byrd Polar Research Center for high latitude ice sheets, is tested over the Alaskan domains used by the Air Force Weather Agency to determine the utility in replacing the MM5 with the PMM5. The verification of surface temperature, pressure and wind as well as upper-air temperature, geopotential height, and relative humidity of 27-hour PMM5 forecasts are compared to …

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Application Of The Wind Gust Estimate And Comparison To The Afwa Mm5 Wind Gust Algorithm, Kevin W. Lacroix Mar 2002

Application Of The Wind Gust Estimate And Comparison To The Afwa Mm5 Wind Gust Algorithm, Kevin W. Lacroix

Theses and Dissertations

The Air Force Weather Agency (AFWA) runs the Penn State/NCAR Mesoscale Model 5 (MM5) as their main mesoscale weather forecast model. One of the post-processing procedures is a diagnostic algorithm, which is used to help identify convective and non-convective wind gusts. O. Brassuer has identified a new Wind Gust Estimate (WGE), as a physically based method of computing non-convective wind gusts. The WGE surmises that Turbulent Kinetic Energy (TKE) transfers the momentum of faster upper-air winds to the surface, overcoming the buoyant energy of the surface layer. This work converts Brassuer's WGE to FORTRAN code and utilizing post-processed CONUS AFWA …

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Synthesis Of 3-Dimensional Lightning Data And Weather Radar Data To Determine The Distance That Naturally Occurring Lightning Travels From Thunderstorms, Lee A. Nelson Mar 2002

Synthesis Of 3-Dimensional Lightning Data And Weather Radar Data To Determine The Distance That Naturally Occurring Lightning Travels From Thunderstorms, Lee A. Nelson

Theses and Dissertations

Military base weather stations are required to issue lightning warnings to protect military equipment and personnel. The issuance of warnings is based on a 5 nautical mile (n mi) distance criterion. This criterion appears to have evolved over time as a balance between safety and mission impact. The goal of this thesis is to challenge the 5 n mi lightning warning criteria by quantifying the distance that CG lightning travels. A secondary goal is to examine the characteristics of the peak current of CG lightning strokes to determine if a relationship exists between peak current, the distance a stroke travels, …

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Exploration Of Teleconnection Indices For Long-Range Seasonal Temperature Forecasts, Robb M. Randall Mar 2002

Exploration Of Teleconnection Indices For Long-Range Seasonal Temperature Forecasts, Robb M. Randall

Theses and Dissertations

The goal of this research was to examine the possibility of establishing guidance for lightning avoidance and lightning warning criteria based upon lightning radar reflectivity signatures. Determining how far naturally occurring lightning normally travels from thunderstorms can provide insight to decision makers concerning in-flight and ground safety measures. 3D lightning data are merged with archived weather radar data. To analyze the radar characteristics of the lightning data, radar data are interpolated to a 3D grid of reflectivity. Lightning flashes were analyzed to resolve the reflectivity of the flash origin and to determine the distance of the flash origin from the …

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The Horizontal Extent Of Cloud-To-Ground Lightning Over The Kennedy Space Center, Todd M. Mcnamara Jan 2002

The Horizontal Extent Of Cloud-To-Ground Lightning Over The Kennedy Space Center, Todd M. Mcnamara

Theses and Dissertations

The Air Force Weather Agency (AFWA) runs the Penn State/NCAR Mesoscale Model 5 (MM5) as their main mesoscale weather forecast model. One of the post-processing procedures is a diagnostic algorithm, which is used to help identify convective and non-convective wind gusts. O. Brassuer has identified a new Wind Gust Estimate (WGE), as a physically based method of computing non-convective wind gusts. The WGE surmises that Turbulent Kinetic Energy (TKE) transfers the momentum of faster upper-air winds to the surface, overcoming the buoyant energy of the surface layer. This work converts Brassuer's WGE to FORTRAN code and utilizing post-processed CONUS AFWA …

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Evolution Of Cloud-To-Ground Lightning Discharges In Tornadic Thunderstorms, Wendy L. Seaman Mar 2001

Evolution Of Cloud-To-Ground Lightning Discharges In Tornadic Thunderstorms, Wendy L. Seaman

Theses and Dissertations

Air Force operations are directly impacted by weather on a daily basis. Erroneous forecasts negatively impact mission readiness and consequently cost the government time, in terms of wasted man-hours, and money. Advanced forecast lead-time could make a difference to minimize loss to both USAF personnel and assets. This study examined lightning data from 64 storm events from 1995-2000 in search of unique lightning signatures indicative of tornadic activity. Overall flash rates, percentage of positive flashes, positive and negative peak currents and multiplicity for each case were separated into two categories based on tornado intensity and season of occurrence. Based on …

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Analyzing The Effects Of Meteorology On Radar Measured Index Of Refraction Structure Parameter, Jeffrey W. Budai Mar 2001

Analyzing The Effects Of Meteorology On Radar Measured Index Of Refraction Structure Parameter, Jeffrey W. Budai

Theses and Dissertations

Forecasting optical turbulence is essential for the Air Force's Airborne Laser program to optimize placement of aircraft. To find bow meteorology affects Cn2, the intensity of turbulence in the index of refraction, case studies of synoptically interesting times are first chosen. Correlation coefficients are then computed between radar measured Cn2 and meteorological quantities. The potential for mechanically turbulent activity is looked at. In the analysis of this work, six meteorological features were found likely to affect Cn2. Two features associated with affecting potential refractivity, and thus Cn2, are jets …

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Validation And Assessment Of Dmsp Electron Temperatures In The Topside Ionosphere, Bradford S. Green Mar 2001

Validation And Assessment Of Dmsp Electron Temperatures In The Topside Ionosphere, Bradford S. Green

Theses and Dissertations

Geomagnetic disturbances in the near earth space environment can adversely affect numerous military and Department of Defense (DoD) systems and operations. To improve the prediction accuracy of such disturbances, the next generation of space environment forecast models aims to automatically ingest real-time ionospheric measurements. This research validates and assesses one such measurement - the Defense Military Satellite Program (DMSP) measured electron temperature (Te). DMSP Te data were validated against near simultaneous incoherent scatter radar (ISR) Te measurements from Millstone Hill, MA and Sondrestrom, Greenland between Winter 1996 and Summer 2000. Of the 37 Millstone and six …

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Analysis Of Cloud-To-Ground Lightning Clusters With Radar Composite Imagery, Rhonda B. Scott Mar 2001

Analysis Of Cloud-To-Ground Lightning Clusters With Radar Composite Imagery, Rhonda B. Scott

Theses and Dissertations

The most recent research conducted at the Air Force Institute of Technology involved studying a large volume of lightning data without coupling radar imagery (Parsons 2000). Parsons finding could not be acted on because no individual storms were studied. The primary goal of this research is to determine whether the techniques used by Parsons can be applied to storms by examining the radar imagery and lightning data. This research used the methodology applied to lightning data by Parsons and radar imagery to determine whether the location of lightning clusters were located near storms. A composite reflectivity radar image was generated …

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Development Of Predictors For Cloud-To-Ground Lightning Activity Using Atmospheric Stability Indices, Kenneth C. Venzke Mar 2001

Development Of Predictors For Cloud-To-Ground Lightning Activity Using Atmospheric Stability Indices, Kenneth C. Venzke

Theses and Dissertations

A detailed examination was performed on several commonly applied atmospheric stability indices and lightning activity from 1993 to 2000 to determine the indices usefulness as predictive tools for determining cloud-to-ground lightning activity. Predetermined radii of 50 nautical miles around upper-air stations in the Midwest U.S. were used for the lightning summaries. Also explored is an improvement upon the commonly accepted thresholds of the stability indices as general thunderstorm indicators. An improvement was found and new threshold ranges were developed for relating stability index values to lightning occurrence. Traditional statistical regression methods failed to find a significant predictive relationship. By examining …

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Use Of Climatology To Predict Maximum Wind Speeds At The Kennedy Space Center And Cape Canaveral Air Station, Lisa K. Coleman Mar 2000

Use Of Climatology To Predict Maximum Wind Speeds At The Kennedy Space Center And Cape Canaveral Air Station, Lisa K. Coleman

Theses and Dissertations

This thesis uses statistical analysis to forecast the probability of meeting or exceeding the maximum allowable wind speeds for each of the launch pads at the Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). Wind data were collected from the Weather Information Network Display System (WINDS), a collection of 47 meteorological towers located throughout KSC and CCAS, over a period of five winters. A Fortran program was written to calculate conditional probabilities of meeting or exceeding a given threshold speed during eight consecutive one-hour periods, using the current wind direction and peak wind speed as inputs. Forecast probabilities …

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A 3d Display System For Lightning Detection And Ranging (Ldar) Data, Michael W. Darwin Mar 2000

A 3d Display System For Lightning Detection And Ranging (Ldar) Data, Michael W. Darwin

Theses and Dissertations

Lightning detection is an essential part of safety and resource protection at Cape Canaveral. In order to meet the unique needs of launching space vehicles in the thunderstorm prone Florida environment, Cape Canaveral has the only operational three- dimensional (3D) lightning detection network in the world, the Lightning Detection and Ranging (LDAR) system. Although lightning activity is detected in three dimensions, the current LDAR display, developed 20 years ago, is two-dimensional. This thesis uses modern three-dimensional graphics, object-oriented software design, and innovative visualization techniques to develop a 3D visualization application for LDAR data.

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An Evaluation Of Microburst Prediction Indices For The Kennedy Space Center And Cape Canaveral Air Station (Ksc/Ccas), Steven N. Dickerson Mar 2000

An Evaluation Of Microburst Prediction Indices For The Kennedy Space Center And Cape Canaveral Air Station (Ksc/Ccas), Steven N. Dickerson

Theses and Dissertations

A wet-microburst event on 16 August 1994 at the Kennedy Space Center's Shuttle Landing Facility alerted forecasters from the 45th Weather Squadron (45WS), the provider of weather support to the Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS), to the challenges of wet-microburst prediction. Although there was no operational impact, this event caused the 45WS to revise their severe thunderstorm forecasting procedures to specifically address microbursts, resulting in the locally developed Microburst-Day Potential Index (MDPI). MDPI provides a several-hour outlook of microburst potential based on the results of the Microburst and Severe Thunderstorm (MIST) project. The 45WS also …

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Techniques For Forecasting The Cessation Of Lightning At Cape Canaveral Air Station And The Kennedy Space Center, Michael W. Holmes Mar 2000

Techniques For Forecasting The Cessation Of Lightning At Cape Canaveral Air Station And The Kennedy Space Center, Michael W. Holmes

Theses and Dissertations

The focus of this research effort is directed toward identifying new methods of forecasting the cessation of lightning along the Central Atlantic Coast of Florida. Cloud-to-ground lightning flashes place Air Force (AF) personnel and assets at risk almost daily at this location. Providing a more accurate method of forecasting the cessation of lightning would allow for safer and more efficient execution of AF operations. A data set consisting of 40 thunderstorm cases was identified within a 90 nautical miles (nmi) region surrounding the Melbourne, Florida WSR-88D (KMLB) site. Each case falls between the months of May and September and the …

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Data Warehouse Techniques To Support Global On-Demand Weather Forecast Metrics, Meriellen C. Joga Mar 2000

Data Warehouse Techniques To Support Global On-Demand Weather Forecast Metrics, Meriellen C. Joga

Theses and Dissertations

Air Force pilots and other operators make crucial mission planning decisions based on weather forecasts; therefore, the ability to forecast the weather accurately is a critical issue to Air Force Weather (AFW) and its customers. The goal of this research is to provide Air Force Weather with a methodology to automate statistical data analysis for the purpose of providing on-demand metrics. A data warehousing methodology is developed and applied to the weather metrics problem in order to present an option that will facilitate on-demand metrics. On-line analytical processing (OLAP) and data mining solutions are also discussed.

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An Intelligent User Interface To Support Air Force Weather Product Generation And Automated Metrics, Darryl N. Leon Mar 2000

An Intelligent User Interface To Support Air Force Weather Product Generation And Automated Metrics, Darryl N. Leon

Theses and Dissertations

Air Force pilots require dependable weather reports so they may avoid unsafe flying conditions. In order to better gauge the accuracy of its weather products, Air Force Weather has established the requirement for an Air Force-wide automated weather metrics program. Under the guidelines for this program, forecasts will automatically be compared to observed weather to determine their accuracy. Statistics will be collected in the hopes of determining forecast error trends that can be corrected through education and training. In order for the statistical data produced by such a program to draw reliable conclusions about forecast accuracy, however, the correct format …

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Determining The Horizontal Distance Distribution Of Cloud-To-Ground Lightning, Tamara L. Parsons Mar 2000

Determining The Horizontal Distance Distribution Of Cloud-To-Ground Lightning, Tamara L. Parsons

Theses and Dissertations

This research effort attempted to quantify what constitutes a safe distance when lightning is present. The method used in this research project groups lightning flashes into clusters using spatial and temporal constraints. However, not all flashes meet the time and distance criteria for clustering and remained outside of tile grouped flashes and as such are identified as isolated flashes. These isolated flashes are outliers in the data set, but are precisely the flashes that prove most dangerous. For this reason not only were the distances between each flash and cluster center studied, but also the distances between each isolated flash …

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Timing Of Thunderstorm Occurrence For Cape Canaveral, Florida, Thomas G. Renwick Mar 2000

Timing Of Thunderstorm Occurrence For Cape Canaveral, Florida, Thomas G. Renwick

Theses and Dissertations

This research is concerned with improving an existing algorithm to accurately forecast thunderstorm starting times for Cape Canaveral, Florida. This was accomplished by investigating different linear regression techniques than those used in the existing algorithm. The result is three new thunderstorm start time algorithms. The forecast start times of these new algorithms were then compared to actual thunderstorm start times to determine which method produced the most accurate results. The average thunderstorm starting time was also calculated from the data. This time was also compared to actual thunderstorm starting time. Upon examination of the various start times produced, it was …

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Mixed Layer Height Estimates – A Statistical Analysis Of Algorithm Performance, Lisa C. Shoemaker Mar 2000

Mixed Layer Height Estimates – A Statistical Analysis Of Algorithm Performance, Lisa C. Shoemaker

Theses and Dissertations

The Air Force Technical Applications Center (AFTAC) conducts dispersion transport modeling as part of their mission support for the United States Atomic Energy Detection System. Part of that modeling effort requires knowledge of the height of the mixed layer in the lower atmosphere to determine the vertical extent through which particulates can be distributed. The mixed layer can be estimated by analyzing atmospheric profiles of parameters obtained from observations (e.g., upper air soundings) or atmospheric models. Six mixed layer algorithms were evaluated: Gradient Richardson Number (RICH), Potential Temperature (POTEMP), Potential Instability Mixing Depth (PIMIX), and three variations of the PIMIX …

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Sensitivity Studies On A Limited Area Mesoscale Model: An Examination Of Lateral Boundary Placement, Grid Resolution And Nesting Type, Robert A. Stenger Mar 2000

Sensitivity Studies On A Limited Area Mesoscale Model: An Examination Of Lateral Boundary Placement, Grid Resolution And Nesting Type, Robert A. Stenger

Theses and Dissertations

With the advances of computer technology in recent years, limited area mesoscale models are being used to produce operational forecasts on a broader scale worldwide than ever before. The past limitations of computational resources have caused previous research efforts to focus more on model physics, thus creating a gap in the number of sensitivity studies conducted on these models. This research is intended to bridge a gap in the apparent paucity of sensitivity studies on the limited area model (LAM). The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model 5 was utilized to conduct sensitivity studies on lateral boundary …

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A Study Of Morning Radiation Fog Formation, Jimmie L. Trigg Jr. Mar 2000

A Study Of Morning Radiation Fog Formation, Jimmie L. Trigg Jr.

Theses and Dissertations

This research focuses on developing a linear regression formula that forecasters in the Midwest can use to accurately anticipate the formation of radiation fog. This was accomplished in three stages. First a study of the surface and upper air parameters and processes required to develop radiation fog were identified and explored. Next, a linear regression technique was applied to the 23 parameters identified. The top four indicators were then reprocessed and a new linear regression equation was developed. Finally, the new regression equation was compared to an existing fog forecasting technique. The existing forecast technique selected was the 2nd Weather …

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An Analysis In Cloud-To-Ground Lightning Over Land Versus Water, Elizabeth A. Boll Mar 2000

An Analysis In Cloud-To-Ground Lightning Over Land Versus Water, Elizabeth A. Boll

Theses and Dissertations

Understanding lightning characteristics over land and water is vital to achieving optimal safety and success in Air Force missions. Lightning safety rules are often based on experience rather than a scientific understanding of lightning. Examining lightning characteristics over water and land will assist in a better understanding of lightning and provide answers that can protect human lives and property. Water and land have different compositions and surface conductivity values. A lightning stroke is detected through a change in the electro-magnetic field at the surface. The change in surface conductivity values from land to water can affect the detection of a …

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Extensible Markup Language As A Weather Tool, Michael J. Calidonna Mar 2000

Extensible Markup Language As A Weather Tool, Michael J. Calidonna

Theses and Dissertations

This thesis is a proof of concept work that will extend the Core Mapping Application Program Interface (CMAPI) components to include weather data. The CMAPI project is headed by Air Force Research Lab (AFRL)/Information Directorate Information Handling Branch (IFEB) at Rome labs in Rome, New York. This work extends the CMAPI project in two distinct areas. The first goal is to figure out how to overlay and display weather data on a dynamically linked Internet platform. This was accomplished by incorporating existing data from the Air Force Weather Agency (AFWA) into the CMAPI program in a static environment. The other …

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A Neural Network Solution To Predicting Wind Speed At Cape Canaveral’S Atlas Launch Pad, Kenneth P. Cloys Mar 2000

A Neural Network Solution To Predicting Wind Speed At Cape Canaveral’S Atlas Launch Pad, Kenneth P. Cloys

Theses and Dissertations

This thesis demonstrates the potential for using time-delay neural networks to provide Launch Weather Officers (LWOs) at 45th Weather Squadron (45 WS) with advance warning of wintertime (November-March) peak wind speeds at the Atlas launch pad. The 45 WS provides weather support to the United States space program at Cape Canaveral Air Station, NASA's Kennedy Space Center, and Patrick Air Force Base. Due to the complex wintertime environment produced by the effects of friction and instability, 45 WS LWOs consider wintertime launch pad winds their toughest forecast challenge. Neural networks were developed, trained, and tested using observations of wintertime peak …

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A Refinement And Cross-Validation Of The Special Sensor Microwave Imager (Ssm/I) Calibration-Validation (Cv) Brightness Temperature Algorithm, Mark R. Adair Mar 1999

A Refinement And Cross-Validation Of The Special Sensor Microwave Imager (Ssm/I) Calibration-Validation (Cv) Brightness Temperature Algorithm, Mark R. Adair

Theses and Dissertations

The Air Force Weather Agency (AFWA) currently uses an algorithm to calculate surface temperatures from microwave observations taken by the Special Sensor Microwave Imager (SSM/I) aboard the orbiting platforms of the Defense Meteorological Satellite Program (DMSP). This algorithm, called the Calibration-Validation (CV) algorithm, used multiple linear regression to calculate coefficients relating microwave brightness temperatures and land surface temperatures. Because the coefficients in this algorithm do not take into account the identity of the individual satellite, the question arose whether this assumption was valid. This thesis used multiple linear regression, stepwise linear regression, and qualitative regression on 3700 data sets from …

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A Comparison Of Horizontal Cloud-To-Ground Lightning Flash Distance Using Weather Surveillance Radar And The Distance Between Successive Flashes Method, Christopher C. Cox Mar 1999

A Comparison Of Horizontal Cloud-To-Ground Lightning Flash Distance Using Weather Surveillance Radar And The Distance Between Successive Flashes Method, Christopher C. Cox

Theses and Dissertations

On April 29th, 1996 an airman servicing a C-130 aircraft on Huriburt AFB Florida was struck and killed by a lightning flash that traveled an estimated 7 to 10 miles from storms south of the airfield. Ten other workers were injured in the incident. The fatal flash occurred just 8 minutes after the base weather station allowed a lightning advisory to expire. The incident brought to question the adequacy of lightning advisory criteria. Very little research has been done on the horizontal distance that cloud-to-ground lightning flashes occurs from the center of a thunderstorm. This thesis used the WSR-88D method, …

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Improving Cape Canaveral's Next-Day Thunderstorm Forecasting Using A Meso-Eta Model-Based Index, John C. Crane Mar 1999

Improving Cape Canaveral's Next-Day Thunderstorm Forecasting Using A Meso-Eta Model-Based Index, John C. Crane

Theses and Dissertations

Reliable thunderstorm forecasts are essential to safety and resource protection at Cape Canaveral. Current methods of forecasting day-2 thunderstorms provide little improvement over forecasting by persistence alone and are therefore in need of replacement. This research focused on using the mesoscale eta model to develop an index for improved forecasting of day-2 thunderstorms. Logistic regression techniques were used to regress the occurrence of a thunderstorm at Cape Canaveral against day-2 forecast variables output, or derived, from the mesoscale eta model. Accuracy and bias scores were calculated for the forecasts made by the regression equations, and the forecast results were compared …

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Evaluation Of Barnes' Method And Kriging For Estimating The Low Level Wind Field, Michael W. Engel Mar 1999

Evaluation Of Barnes' Method And Kriging For Estimating The Low Level Wind Field, Michael W. Engel

Theses and Dissertations

This thesis evaluates two different methods of estimating a three dimensional wind field based upon a limited number of irregularly-spaced observations. This work was performed for the 45th Weather Squadron to determine how well the two methods worked and their potential for use in a visualization program. The two methods evaluated were Barnes' method and a method called Kriging, which is commonly used in geostatistics. Both of these estimation techniques were implemented and then evaluated to determine how accurate the estimates were that they created. The methods' accuracies were determined by withholding an observation from the observed wind field data …

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An Improved Thunderstorm Forecast Index For Cape Canaveral, Florida, James A. Everitt Mar 1999

An Improved Thunderstorm Forecast Index For Cape Canaveral, Florida, James A. Everitt

Theses and Dissertations

This thesis creates a new algorithm to replace the Neumann-Pfeffer Thunderstorm Index (NPTI). The 45th Weather Squadron at Patrick AFB, Florida, uses the NPTI as an objective means of determining the probability of thunderstorm occurrence at Cape Canaveral. The probability is used for mission planning and resource protection, and increasing the accuracy of NPTI can potentially save billions of dollars for the United States space program. Stratified logistical regressions are performed and probability equations are derived for May through September using upper air data and surface observations for Cape Canaveral. A logistical regression of NPTI was also performed. Variables include …

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