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2002

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Articles 1 - 21 of 21

Full-Text Articles in Meteorology

Transport Out Of The Antarctic Polar Vortex From A Three-Dimensional Transport Model, Shuhua Li, Eugene Cordero, David J. Karoly Jun 2002

Transport Out Of The Antarctic Polar Vortex From A Three-Dimensional Transport Model, Shuhua Li, Eugene Cordero, David J. Karoly

Eugene C. Cordero

[1] A three-dimensional chemical transport model is utilized to study the transport out of the Antarctic polar vortex during the southern hemisphere spring. On average, over five consecutive years between 1993 and 1997, horizontal transport out of the vortex into the midlatitude stratosphere is smaller than vertical transport into the troposphere. However, there is significant interannual variability in the magnitude of mass exchange, which is related to year-to-year fluctuations in planetary wave activity. In 1994 the net loss of the vortex tracer mass in September is similar to that in October. However, the relative mass flux entering the midlatitude stratosphere …


Transport Out Of The Antarctic Polar Vortex From A Three-Dimensional Transport Model, Shuhua Li, Eugene Cordero, David J. Karoly Jun 2002

Transport Out Of The Antarctic Polar Vortex From A Three-Dimensional Transport Model, Shuhua Li, Eugene Cordero, David J. Karoly

Faculty Publications, Meteorology and Climate Science

[1] A three-dimensional chemical transport model is utilized to study the transport out of the Antarctic polar vortex during the southern hemisphere spring. On average, over five consecutive years between 1993 and 1997, horizontal transport out of the vortex into the midlatitude stratosphere is smaller than vertical transport into the troposphere. However, there is significant interannual variability in the magnitude of mass exchange, which is related to year-to-year fluctuations in planetary wave activity. In 1994 the net loss of the vortex tracer mass in September is similar to that in October. However, the relative mass flux entering the midlatitude stratosphere …


Long Range Forecast Possibilities For X-Band Radar Construction On Shemya, Brian K. Schroeder May 2002

Long Range Forecast Possibilities For X-Band Radar Construction On Shemya, Brian K. Schroeder

Theses and Dissertations

Current moisture initialization sources lack the spatial and temporal resolution required for mesoscale moisture forecast accuracy critical for military operations. The Global Positioning System (GPS) satellite constellation provides an opportunity to extract accurate moisture observations based on the refraction of the GPS signal through the troposphere. GPS-derived precipitable water (PW) from two different research areas was independently compared with the Air Force Weather Agency s (AFWA's) MM5 PW model output. Results were concurrent with similar studies comparing GPS-derived PW with numerical weather models. The mean correlation in CONUS was 92.5%, while in Alaska it was 72.8%. Mean model biases were …


An Examination Of Anomalously Low Column Ozone In The Southern Hemisphere Midlatitudes During 1997, Eugene C. Cordero, Terrence R. Nathan Apr 2002

An Examination Of Anomalously Low Column Ozone In The Southern Hemisphere Midlatitudes During 1997, Eugene C. Cordero, Terrence R. Nathan

Eugene C. Cordero

[1] Observations from both ground-based and satellite instruments show record low column ozone abundance between 20°S and 40°S during 1997. The 1997 monthly averaged column ozone from the Total Ozone Mapping Spectrometer (TOMS) is up to 25 Dobson units (DU) lower than the TOMS climatological mean (1979–1996) and up to 20 DU below the previous record low values. Observations from the Halogen Occultation Experiment show that below average ozone concentrations during 1997 were confined primarily to the lower stratosphere. Residual circulation statistics calculated from the United Kingdom Meteorological Office temperature analyses indicate that circulation anomalies during 1997 can account for …


An Examination Of Anomalously Low Column Ozone In The Southern Hemisphere Midlatitudes During 1997, Eugene C. Cordero, Terrence R. Nathan Apr 2002

An Examination Of Anomalously Low Column Ozone In The Southern Hemisphere Midlatitudes During 1997, Eugene C. Cordero, Terrence R. Nathan

Faculty Publications, Meteorology and Climate Science

[1] Observations from both ground-based and satellite instruments show record low column ozone abundance between 20°S and 40°S during 1997. The 1997 monthly averaged column ozone from the Total Ozone Mapping Spectrometer (TOMS) is up to 25 Dobson units (DU) lower than the TOMS climatological mean (1979–1996) and up to 20 DU below the previous record low values. Observations from the Halogen Occultation Experiment show that below average ozone concentrations during 1997 were confined primarily to the lower stratosphere. Residual circulation statistics calculated from the United Kingdom Meteorological Office temperature analyses indicate that circulation anomalies during 1997 can account for …


Quantification Of The Effects Of Data Denial And Limitation In Mm5 Initialization On Forecast Accuracy, Robert W. Evans Mar 2002

Quantification Of The Effects Of Data Denial And Limitation In Mm5 Initialization On Forecast Accuracy, Robert W. Evans

Theses and Dissertations

The current hub-and-spoke network in the European Theater is made up of locations built and organized around a Cold War threat. The threat of large-scale attrition warfare seems to have passed, and the threat of multiple, smaller scale contingencies has placed greater demands on the US military's ability to transport equipment and personnel to multiple locations simultaneously. This research effort utilizes a Multiple Objective Linear Programming (MOLP) model to analyze optimal hub locations in USEUCOM. The model used to analyze the network was developed in Microsoft Excel and followed MOLP techniques to determine the trade-offs between the two constructs of …


The Horizontal Extent Of Lightning Based On Altitude And Atmospheric Temperature, David R. Vollmer Mar 2002

The Horizontal Extent Of Lightning Based On Altitude And Atmospheric Temperature, David R. Vollmer

Theses and Dissertations

Due to multiple factors, including an increase in military operations tempo and the improved resolution of meteorological models, demand for access to customized aviation weather products has increased exponentially. This has given rise to a need for a multi-purpose interactive aviation weather product generation software solution. This software solution must be platform-independent, multiple data source access configurable, robust, extensible or upgradeable, user-friendly, and an improvement over current visualization applications used in the operational military aviation weather community. This thesis determines whether Unidata MetApps meets these criteria. A software reuse and component-based engineering approach was taken in this thesis. Two experimental …


Gps-Derived Precipitable Water Compared With The Air Force Weather Agency's Mm5 Model Output, Patricia A. Vollmer Mar 2002

Gps-Derived Precipitable Water Compared With The Air Force Weather Agency's Mm5 Model Output, Patricia A. Vollmer

Theses and Dissertations

Lightning poses a threat to aircraft in flight. To mitigate this threat, the U.S. Air Force requested a study of lightning distances. Three-Dimensional lightning data were examined for this study, spanning 1 March 1997 to 31 May 2001 and obtained from the Lightning Detection and Ranging System (LDAR) at the Kennedy Space Center, FL. The LDAR data points were first grouped into lightning flashes and branches using spatial and temporal criteria. Rawinsonde data were vertically interpolated to determine the temperature at the flash source point and each branch end point. The horizontal distance from flash sources to branch end was …


Suitability Of Unidata Metapps For Incorporation In Platform-Independent User-Customized Aviation Weather Products Generation Software, Harmen P. Visser Mar 2002

Suitability Of Unidata Metapps For Incorporation In Platform-Independent User-Customized Aviation Weather Products Generation Software, Harmen P. Visser

Theses and Dissertations

The Air Force Combat Climatology Center (AFCCC) is tasked to provide long-range seasonal forecasts for worldwide locations. Currently, the best long-range temperature forecasts the weather community has are the climatological standard normals. This study creates a stepping-stone into the solution of long-range forecasting by finding a process to predict temperatures better than those using climatological standard normals or simple frequency distributions of occurrences. Northern Hemispheric teleconnection indices and the standardized Southern Oscillation index are statistically compared to three-month summed Heating Degree Days (HDDs) and Cooling Degree Days (CDDs) at 14 U.S. locations. First, linear regression was accomplished. The results showed …


Extratropical Transition Of Southwest Pacific Tropical Cyclones. Part I: Climatology And Mean Structure Changes, Mark R. Sinclair Mar 2002

Extratropical Transition Of Southwest Pacific Tropical Cyclones. Part I: Climatology And Mean Structure Changes, Mark R. Sinclair

Applied Aviation Sciences - Prescott

A database of tropical cyclone best track and intensity information for the southwest Pacific Ocean basin is used to construct a 28-year climatology for tropical cyclones that move into middle latitudes. Of the nine or so tropicalcyclones that form each year, an average of about three can be expected to migrate south of 35°S, with the greatest fraction in March. Storms entering the Tasman Sea west of New Zealand (NZ) move almost due south on average and retain greater intensity than those to the east of NZ, where storms decay quickly while moving rapidly away to the southeast. Storms east …


Verification Of Mm5 Cloud Microphysics Schemes For East Asia, Dean J. Carter Mar 2002

Verification Of Mm5 Cloud Microphysics Schemes For East Asia, Dean J. Carter

Theses and Dissertations

Using the 3-Dimensional Variational Analysis data assimilation scheme and the (MM5), input observations were denied in three different categories: total, upper air, and surface observation denial. Two control groups were run using all available data as received by AFWA. The main control group used a 6 hours old first guess as a baseline. The data denied test cases and the secondary control group used a 30-hour old first guess because it was not possible to deny data from the first guess. The secondary control group was used to estimate errors resulting from the use of different first guess forecasts between …


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, …


Verification And Comparison Of Polar Mm5 And Afwa Mm5 Forecasts Over Alaska, William E. Courtemanche Mar 2002

Verification And Comparison Of Polar Mm5 And Afwa Mm5 Forecasts Over Alaska, William E. Courtemanche

Theses and Dissertations

This research compares biases of the Reisner Mixed-Phase Explicit Moisture Microphysics graupel and non-granpel schemes to determine if including graupel and riming processes within the Fifth Generation Mesoscale Model (MM5) will lead to improved forecasts of winter precipitation for Korea and Japan. MM5 forecasts were generated every 12 hours for a 20 days case period from January 1998. Model derived meteorological fields were interpolated to the station coordinates of four verification sites within the East Asian domain and radiosonde observations were used to compare the differences between the average temperature and water vapor errors of the two cloud microphysics schemes. …


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 …


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 …


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 …


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 …


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 …


Is The Ozone Hole Over Your Classroom?, Eugene Cordero Jan 2002

Is The Ozone Hole Over Your Classroom?, Eugene Cordero

Eugene C. Cordero

First year university science students are surveyed about their understanding of the ozone layer, ozone depletion and the effect of ozone depletion on Australia. Although students seem to understand the basic function of the ozone layer, over 65% of students incorrectly believe that the ozone hole is over Australia, and over 90% of students incorrectly believe that the ozone hole is present during the summer. Together these ideas seem to explain why nearly 75% of students blame the ozone hole for Australia’s high rate of skin cancer. Survey results also indicate that students seem confused about global warming, and the …


Is The Ozone Hole Over Your Classroom?, Eugene Cordero Jan 2002

Is The Ozone Hole Over Your Classroom?, Eugene Cordero

Faculty Publications, Meteorology and Climate Science

First year university science students are surveyed about their understanding of the ozone layer, ozone depletion and the effect of ozone depletion on Australia. Although students seem to understand the basic function of the ozone layer, over 65% of students incorrectly believe that the ozone hole is over Australia, and over 90% of students incorrectly believe that the ozone hole is present during the summer. Together these ideas seem to explain why nearly 75% of students blame the ozone hole for Australia’s high rate of skin cancer. Survey results also indicate that students seem confused about global warming, and the …


Land Use Change And Modification Of Near-Surface Thermal Records In The Northern Great Plains, Rezaul Mahmood, Ken Hubbard, Christy Carlson Jan 2002

Land Use Change And Modification Of Near-Surface Thermal Records In The Northern Great Plains, Rezaul Mahmood, Ken Hubbard, Christy Carlson

HPRCC Personnel Publications

The North American Great Plains have experienced a rapid overturning of natural grasslands to agricultural land use over the last century. Moreover, in some areas more than 80% of the land use has changed from dry land to irrigated agriculture during the second half of the twentieth century. It is speculated that these changes have modified near-surface atmospheric condition and our modeling study seems to support this. To identify changes in land surface- atmospheric modifications we have applied a soil moistureenergy balance model at three locations in Nebraska: Mead, York, and McCook. The model was applied for three land uses …