ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / “Wind Weighting” is the process of assessing the effect of wind on a launch vehicle and determining launcher settings which would counteract that effect. This paper discusses the advantages of using GPS radiosondes to determine wind profiles over the historical method of tracking balloon positions with radar for the purposes of Wind Weighting. The primary advantages are lower costs and greater portability. Also presented is evidence of improved accuracy and reliability. Engineering testing is described and test results are reported.

The views expressed in this thesis are those of the author and do not relfect the offical policy or position of the Department of Defense or the U.S. Government. / Previous modifications were made to the Naval Postgraduate School (NPS) Lidar System to enable comparison of lidar returns with radiosonde vertical profiles. Inaccuracies due to flexing of the lidar mounting structure limited observation of correlation between lidar and balloon data. Reconstruction with anew telescope and integral mounting now provides stable overlap of laser illumination and receiver field-of-view while maintaining eye safety. This revised system permits more measurement of profile correlation. Both day and night lidar measurement series have been compared with concurrent radiosonde launches in the Monterey Bay area. Maximum ranges from clouds greater than 3500 meters by day and greater than 5000 meters by night have been achieved. Within this range comparison can be made with moderate accuracy with the temperature and pressure profile boundary layer ceiling. Recommendations are made for future enhancement of sensitivity of correlation.

Accurate determination of the tropopause is important for applications such as dynamical analysis and forecasting, radiative transfer calculations, and the diagnosis of chemical transport in the atmosphere. In this paper, we examine how well the extratropical tropopause is determined in the National Centers for Environmental Prediction (NCEP) high-resolution Global Forecast System (GFS) model analysis over the continental United States using high-resolution aircraft and radiosonde data. The GFS analyses and sounding data compare well, with r.m.s. differences of approximately 600m, which is comparable to the vertical resolution of the model. The GFS tropopause is a good proxy in areas without in situ observations, but near the subtropical jet the GFS analysis often mistakenly identifies the secondary rather than the primary tropopause. We also explore an alternative method to identify the tropopause by fitting a smoothed step-function to the static stability profile. This new approach provides a measure of the depth of the troposphere-stratosphere transition and facilitates the study of the dynamical behavior of the tropopause region. In particular, using the transition depth, we are able to identify the statistical behavior of temperature in profiles with deep or shallow tropopause transition layers.

<p> A simple model, expressed in terms of cloud amounts and heights, and air temperature (recorded hourly at Ft. St. John, B.C.) and daily radiosonde records (from St. Nelson, B.C.), is used in an attempt to approximate incoming solar and net radiation values at a nearby pasture site, where hourly measurements were recorded. Results from the model indicate that measured values on a daily basis were estimated within 20%, while five and ten day running means were calculated within 10% of the measured means. </p> / Thesis / Bachelor of Arts (BA)

In this paper, a set of local radiosonde meteorological data, from 1990 to 2005, have been used to statistically analyze the refractivity gradient, DeltaN, at the lowest 65 m, 100 m and 1 km of the atmosphere above the surface of the Earth in the Gulf region. These three levels are the reference atmospheric layers in which the refractivity gradients have been evaluated by the ITU-R Recommendations P.453-10 and P.452-12The vertical variations of the refractivity profile aredisplayed through the cumulative distributions of the refractivity gradients at the targeted levels. The obtained results are compared for the three layers and also compared with the estimated values in the ITU maps and tables when available. Index Terms – Atmospheric refraction, Refractivity gradient.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Wallops Flight Facility is NASA’s principal site for management and implementation of suborbital research programs. Recently, WFF resumed its successful satellite-launching history without sacrificing its culture of being low-cost and responsive. Part of what made this possible is the GPS radiosonde. During recent successful Minotaur I launches, this tiny instrument provided upper-air observations that were used in six categories of analysis necessary for such launches: toxics, blast, winds aloft, debris, weather and forecasting, and post-flight. In addition, the GPS radiosonde has reduced costs associated with Wind Weighting at Wallops, and is used in numerous range research projects.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / As renewal interest in building vehicles based on hypersonic technologies begin to emerge again, test ranges anticipating in supporting flight research of these vehicles will face a set of engineering problems. Most fundamentals of these will be to track and gather error free telemetry from the vehicles in flight. The first series of vehicles will likely be reduced-scale models that restrict the locations and geometric shapes of the telemetry antennas. High kinetic heating will further limit antenna design and construction. Consequently, antennas radiation patterns will be sub-optimal, showing lower gains and detrimental nulls. A mobile system designed to address the technical issues above will be described. The use of antenna arrays, spatial diversity and a hybrid tracking system using optical and electronic techniques to obtain error free telemetry in the present of multipath will be presented. System tests results will also be presented.

Vertical mixing is an important process that relates surface fluxes to concentrations of pollutants and other chemical species in the atmosphere. Errors in vertical mixing have been identified as a major source of uncertainties in various atmospheric modeling efforts including tracer transport, weather forecasting, and regional climate simulation. This thesis aims to quantify uncertainties in model-derived mixed layer heights (zi) over North America through direct comparisons between radiosonde observations and four models at different months of the year 2004 through the bulk Richardson number method. Results of this study suggest that considerable errors in zi exist throughout the region with the spatial and temporal variations of the errors differ significantly among the selected models. Over all, errors in zi were larger in global models than in the limited area mesoscale models, and the magnitude of the random error was two times larger than the bias. Notably, spatial regions of with extremely large positive biases correspond to those with especially large random errors. The biases and random errors, however, were not correlated linearly nor can be easily used to predict each other. Uncertainties in model-derived zi were attributed, through errors in the bulk Richardson number, to temperature and horizontal winds. Errors in both horizontal winds and temperatures were found contributing more or less the same to uncertainties in zi, with relative errors in both variables being the greatest in the lowest part of the troposphere. Lastly, independent observations from the cooperative profiler network suggest that data assimilation did not add qualitative advantages for the comparisons presented in this study. The mixed layer height uncertainties demonstrated in this study may provide a guide for selecting a model to simulate regional scale atmospheric transport and for interpreting flux estimation and inversions studies.

Vertical mixing is an important process that relates surface fluxes to concentrations of pollutants and other chemical species in the atmosphere. Errors in vertical mixing have been identified as a major source of uncertainties in various atmospheric modeling efforts including tracer transport, weather forecasting, and regional climate simulation. This thesis aims to quantify uncertainties in model-derived mixed layer heights (zi) over North America through direct comparisons between radiosonde observations and four models at different months of the year 2004 through the bulk Richardson number method. Results of this study suggest that considerable errors in zi exist throughout the region with the spatial and temporal variations of the errors differ significantly among the selected models. Over all, errors in zi were larger in global models than in the limited area mesoscale models, and the magnitude of the random error was two times larger than the bias. Notably, spatial regions of with extremely large positive biases correspond to those with especially large random errors. The biases and random errors, however, were not correlated linearly nor can be easily used to predict each other. Uncertainties in model-derived zi were attributed, through errors in the bulk Richardson number, to temperature and horizontal winds. Errors in both horizontal winds and temperatures were found contributing more or less the same to uncertainties in zi, with relative errors in both variables being the greatest in the lowest part of the troposphere. Lastly, independent observations from the cooperative profiler network suggest that data assimilation did not add qualitative advantages for the comparisons presented in this study. The mixed layer height uncertainties demonstrated in this study may provide a guide for selecting a model to simulate regional scale atmospheric transport and for interpreting flux estimation and inversions studies.

Resumo: A quantificação do vapor d'água integrado na atmosfera (IWV - Integrated Water Vapor), ao contrário de outras variáveis meteorológicas, é algo que ainda se apresenta como um grande desafio para as Ciências Atmosféricas. Diversos mecanismos, envolvendo diferentes técnicas, têm sido empregados e testados para esse fim em diferentes regiões do globo por pesquisa dores das mais variadas áreas da ciência. Essa tese apresenta uma contribuição a esse tema ao empregar receptores GPS (Global Positioning System) em bases terrestres, localizados no Brasil, envolvendo instituições de pesquisa na área de Geodésia e de Meteorologia. Os objetivos principais desse trabalho são validar os valores do IWV obtidos a partir das observações GPS e contribuir com a viabilização da utilização de redes ativas de receptores GPS, existentes atualmente e futuras, no monitoramento do IWV como suporte às atividades da Meteorologia e Climatologia no Brasil. Os resultados obtidos mostram que, com a efetivação desse processo, poderá ser obtida uma fonte adicional de informações da umidade para Previsão Numérica de Tempo (PNT). Além disso, é mostrado também que a alta resolução temporal dos valores do IWV obtidos a partir das observações GPS pode contribuir para a melhoria dos resultados gerados por outras técnicas empregadas na mesma tarefa. Em contrapartida, um modelo de PNT é utilizado para gerar previsões da influência da troposfera nos sinais GPS, visando beneficiar aplicações GPS em tempo real. Os resultados gerados nesse trabalho são frutos da sinergia entre as duas áreas envolvidas e mostram que, atualmente, há boas perspectivas para essa parceria no Brasil. / Abstract: Quantification of Integrated Water Vapor (IWV), unlike other meteorological variables, still represents a significant challenge to the Atmospheric Sciences. In this task several techniques using different mechanisms have been employed and tested in different regions of the planet. Many researchers from several areas of science have been involved in this process. This thesis presents a contribution to this theme, employing ground-based GPS receivers installed on Brazilian territory, involving Geodesy and Meteorology research institutes. The main aim of this work is to contribute in order to make enable the use of the existing networks of continuously operating GPS receivers, and those that will be installed in the future, in IWV monitoring to support meteorological and climatological activities in Brazil. The results generated show that in this process it is possible to obtain an additional source of humidity information for Numerical Weather Prediction (NWP). Furthermore, the prospect of using the ground-based GPS receivers to monitor atmospheric water vapor is promising because thehigh temporal resolution of IWV values from GPS observations can improve the results generated from other techniques employed in the same task. At the same time, a NWP model is applied to generate predictions of the atmosphere's influence over radiofrequency signals, to improve real time GPS applications. The results of this work stem from the synergy between the two areas of science involved. They show that the current outlook for this partnership in Brazil is good, and that both Meteorology and Geodesy will benefit. / Orientador: João Francisco Galera Monico / Coorientador: João Augusto Toledo Machado / Banca: José Antonio Aravequia / Banca: Paul J. de Jonge / Banca: José Tadeu Garcia Tommaselli / Banca: Paulo de Oliveira Camargo / Doutor