Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-07-27T11:59:51Z No. of bitstreams: 1 PDF - Chayenne Edna da Silva Rodrigues.pdf: 17429390 bytes, checksum: 0bdef27d89dbb3d103280bf8a69a7fd2 (MD5) / Made available in DSpace on 2017-07-27T11:59:51Z (GMT). No. of bitstreams: 1 PDF - Chayenne Edna da Silva Rodrigues.pdf: 17429390 bytes, checksum: 0bdef27d89dbb3d103280bf8a69a7fd2 (MD5) Previous issue date: 2017-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this study, the winds obtained by meteor radar at São João do Cariri (7.4 S, 35 W) during 2005, 2006, 2007 and 2008 years, and at Cachoeira Paulista (22.7 S, 45.0 W) during 2002, 2003, 2004, 2005, 2006 and 2008, have been used to characterize the dynamics of the mesosphere region over the two sites during the sudden stratospheric warming events on polar stratosphere in the Northern Hemisphere. The wind measurements were subjected to a wavelet spectrum analysis to identify a presence of periodic oscillations. Wave amplitudes were obtained through harmonic analysis by least squares fitting and the 2-day wave momentum fluxes have been estimated from the wind perturbations. The values of the 2-day wave amplitudes and the respective zonal momentum fluxes observed over C. Paulista were higher in the 2003, 2004 and 2006 summers, and over S. J. do Cariri in 2006 summer, when events of SSW Major have occurred. The mean wind behavior it is indicative that the MLT region, during the summer, have been affected by 2-day wave, however, it was not possible to identify pattern associated with the effects of the SSW events on dynamic behavior of the MLT region over two sites. From analyzes, the 2-day wave intensification and their momentum fluxes during years in which SSWs were major, provide additional evidence to stratospheric jet instabilities, which is the main 2-day wave source mechanism in the summer hemisphere. / Nesta pesquisa, estimativas do campo de velocidade dos ventos obtidas por radar meteórico em São João do Cariri (7,4 S, 35 O), durante os anos de 2005, 2006, 2007 e 2008, e em Cachoeira Paulista (22,7 S, 45,0 O), durante os anos de 2002, 2003, 2004, 2005, 2006 e 2008, foram usadas para caracterizar a dinâmica da região da mesosfera sobre ambas as localidades durante eventos de aquecimento abrupto da estratosfera polar do hemisfério norte. As medidas de vento foram submetidas a análise de espectro de ondaletas para identificar a presença de oscilações periódicas. As amplitudes da s ondas foram obtidas através análise harmônica por ajuste de mínimos quadrados e os fluxos de momentum da onda de 2 dias foram estimados a partir das perturbações. Os valores das amplitudes da onda de 2 dias e dos respectivos fluxos de momentum zonais observados em C. Paulista foram maiores nos verões de 2003, 2004 e 2006, e em S. J. do Cariri em 2006, quando ocorreram eventos de SSW fortes. O comportamento do vento médio demostra que a dinâmica da região MLT durante o verão é impactada pela onda de 2 dias, contudo, não foi possível identificar padrão associado a efeitos dos eventos de SSW com o comportamento dinâmico da região MLT sobre as duas localidades, a partir dessas análises. A intensificação da onda de 2 dias e dos fluxos de momentum durante os anos em que ocorreram SSW fortes fornecem indícios de forçamento adicional para instabilidade do jato estratosférico, que é o principal mecanismo de excitação da onda no hemisfério de verão.

Nous avons développé un détecteur intégré à base d'une diode pour être embarqué dans un ballon stratosphérique afin de caractériser l'environnement radiatif atmosphérique. Le détecteur a été calibré avec une source Californium, et il a été pleinement caractérisé lors de tests sous faisceaux de neutrons qui produisent diverses particules ionisantes secondaires. Les sections efficaces différentielles de détection pour différentes énergies de faisceaux de neutrons sont avérées être en bon accord avec les simulations effectuées avec le code MC-Oracle. Nous avons effectué un certain nombre de vols en ballon stratosphériques (avec l'ESA et le CNES) et confirmé la corrélation entre le taux de comptage et de l'altitude. En outre, nous avons observé que l'environnement radiatif n'est pas isotrope et démontré le potentiel de notre outil pour étudier l'environnement radiatif atmosphérique. Ces résultats sont utiles pour estimer le flux de particules qui affecte appareils et systèmes électroniques à bord des appareils. / We developed an integrated silicon detector to be embedded in a stratospheric balloon in order to investigate the radiative atmospheric environment. The detector was calibrated with a Californium source, and it was fully characterized under neutron beams which produced various secondary ionizing particles. Differential detection cross sections for different neutron beam energies were shown to be in good agreement with simulations performed with the MC-Oracle code. We performed four stratospheric balloon flights (with ESA and CNES) and confirmed the correlation between the count rate and the altitude. Moreover, we observed that the radiative environment is not isotropic and demonstrated the potential of our tool for investigating the radiative atmospheric environment. These results are useful for estimating the particle flux that affects electronic devices and onboard aircraft systems.

Several phenomena in the middle latitude stratosphere are studied in the thesis. The reanalyses are utilized as a source of data for our study. Different reanalyses are compared each other and with observations and problems of reanalyses are shown. We are interested in connection between ozone, dynamics and other phenomena (Sudden Stratospheric Warmings, solar cycle, NAO etc.) in the stratosphere, mainly from 1979 to present using ERA-Interim, NCEP/NCAR reanalyses or satellite observations. The linear connection between total ozone difference and 100 hPa eddy heat flux is found in winter middle latitudes. Ozone trends in Europe and China are analysed. The meridional and zonal wind is also studied using MERRA reanalysis and model output (CCM SOCOL v3.0). The comparison of geographical distribution of geopotential height and meridional wind is done. Differences between MERRA and CCM SOCOL v3.0 has been observed for geopotential hight and meridional wind for winter season.

Thesis: Ph. D., Joint Program in Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 105-114). / The circulation of air in the stratosphere is important for the distribution of radiatively-important trace gases, such as ozone and water vapor, and other chemical species, including ozone-depleting chlorofluorocarbons. Age of air in the stratosphere is an idealized tracer with unique mathematical properties, which we exploit to derive a theory for the relationship of tracer observations to the stratospheric circulation. We show that the meridional age gradient is a measure of the global diabatic circulation, the total overturning strength through an isentropic surface, and test this time-dependent theory in a simple atmospheric general circulation model. We apply the theory to satellite data of sulfur hexafluoride (SF6 and nitrous oxide to derive the first observationally-based estimates of the global meridional overturning circulation strength at all levels in the stratosphere. These two independent global satellite data products agree to within 5% on the strength of the diabatic circulation in the lower stratosphere. We compare to re-analyses and find broad agreement in the lower stratosphere and disagreement (~ 100%) in the upper stratosphere. To understand the relationship between the diabatic circulation and other metrics of the circulation, we calculate it in a state-of-the-science atmospheric model and in three different reanalysis data products. The variability of the global diabatic circulation is very similar to one typical circulation metric, and it is correlated with total column ozone in the tropics and in Southern hemisphere mid latitudes in both a model and in reanalysis-data comparisons. Furthermore, we develop a metric for the mean adiabatic mixing, showing that it is related to the meridional age difference and the vertical gradient of age. We calculate this metric for a range of simple model runs to determine its utility as a measure of mixing. We find very little mixing of air into the tropics in the mid-stratosphere, and the vertical structure of mixing in the lower stratosphere and upper stratosphere varies among model runs and between hemispheres. A picture of global average stratospheric circulation could thus be obtained using age of air data, given reliable long-term records. / by Marianna Katherine Linz. / Ph. D.

This paper aims to study how varying crossflow burning temperatures from 1100 C to 1800 C affect the liquid droplet breakup, size distribution, and atomization of a liquid water jet injected into a vitiated crossflow. The LJIC injection mechanism was implemented using the high-pressure axially staged combustion facility at the University of Central Florida. The measurement devices used to gather particle data from the exhaust plume were the TSI Aerodynamic Particle Sizer (APS), which measures particles between 0.523 µm and 20 µm, and the Sensirion SPS30 (SPS30), which measures particles between 0.3 µm and 10 µm. Both measurement devices were placed 3 ft away from the choked exit. Table 3 shows that the 1800 C crossflow temperature behaved as predicted by having the largest particle distribution of 67.97% and the largest particle count of 19,301 at 0.523 µm. The 1100 C crossflow produced the second-largest normalized particle count of 66.69% and raw particle count of 20,209 at 0.523 µm. This result is contrary to the original hypothesis because it shows that the relationship between temperature and particle count is non-linear and that many other factors must be at play in the atomization process, such as the droplet distribution at the nano level. The SPS30 was used to compare the particle size distributions between a 1500 C and 1800 C crossflow. Acquiring number concentration data for particles up to 10 µm in size, the 1800 C crossflow had a distribution peak at 802.76416 N/cm3, and the 1500 C crossflow had a peak of 867.28272 N/cm3. For the 0.5 µm peak, The 1800 C had a 10 µm particle size distribution peak at 674.27.76416 N/cm3, and the 1500C crossflow had a peak of 730.501 N/cm3. The decreased number concentration from 1500 C to 1800 C case grants the water particles in the 1800 C crossflow increased surface area, which allows for increased heat exposure from the vitiated crossflow [7]. Despite some nonlinear particle count results, the highest crossflow temperature of 1800 C produces the best atomization results by reducing the total particle count and having the largest collection of particles at the lowest detectable particle size of 0.523 µm.

Gravity wave (GW) breaking and associated GW drag is not uniformly distributed among latitudes and longitudes. In particular, regions of enhanced GW breaking, so-called GW hotspots, have been identified, major Northern Hemisphere examples being located above the Rocky Mountains, the Himalayas and the East Asian region. These hotspots influence the middle atmosphere circulation both individually and in combination. Their interference is here examined by performing simulations including (i) the respective single GW hotspots, (ii) two GW hotspots, and (iii) all three GW hotspots with a simplified global circulation model. The combined GW hotspots lead to a modification of the polar vortex in connection with a zonal mean flow decrease and an increase of the temperature at higher latitudes. The different combinations of GW hotspots mainly prevent the stationary planetary wave (SPW) 1 from propagating upward at midlatitudes leading to a decrease in energy and momentum transfer in the middle atmosphere caused by breaking SPW 1, and in turn to an acceleration of the zonal mean flow at lower latitudes. In contrast, the GW hotspot above the Rocky Mountains alone causes an increase in SPW 1 amplitude and Eliassen–Palm flux (EP flux), inducing enhanced negative EP divergence, decelerating the zonal mean flow at higher latitudes. Consequently, none of the combinations of different GW hotspots is comparable to the impact of the Rocky Mountains GW hotspot alone. The reason is that the GW hotspots mostly interfere nonlinearly. Depending on the longitudinal distance between two GW hotspots, the interference between the combined Rocky Mountains and East Asian GW hotspots is more additive than the interference between the combined Rocky Mountains and Himalaya GW hotspots. While the Rocky Mountains and the East Asian GW hotspots are longitudinally displaced by 105°, the Rocky Mountains are shifted by 170° to the Himalayas. Moreover, while the East Asian and the Himalayas are located side by side, the interference between these GW hotspots is the most nonlinear because they are latitudinally displaced by 20°. In general, the SPW activity, e.g., represented in SPW amplitudes, EP flux or Plumb flux, is strongly reduced, when the GW hotspots are interacting with each other. Thus, the interfering GW hotspots mostly have a destructive effect on SPW propagation and generation.

This dissertation comprises multiple studies surrounding the middle atmosphere's chemistry, composition, and dynamics. The middle atmosphere refers to the region from ~ 10 km to ~ 100 km and consists of the Stratosphere, Mesosphere, and Lower Thermosphere. The Stratosphere, Mesosphere, and Thermosphere are bounded by pauses where the strongest changes in chemical composition, movement, density, and thermal behavior take place. While several studies in the past have investigated the chemical composition of the middle atmosphere and quantified the distribution of various species from the stratosphere to the lower thermosphere, seasonal variations and redistribution of species resulting from transport events make it important to continuously monitor the middle atmosphere. Dynamic events such as Sudden Stratospheric Warmings (SSW) impact the temperature gradient and the zonal mean wind pattern in the stratopause. Descent events triggered by SSWs result in enhanced transport of species from the lower thermosphere to the stratosphere. Temperature increments during SSWs have an important impact on Polar Stratospheric Clouds (PSCs), resulting in Antarctic ozone enhancement and a smaller ozone hole. The middle atmosphere is, thus, home to a diverse range of dynamics and chemistry, making it a critical subject that warrants attention from the science community. The continuous monitoring of the middle atmosphere is important to this end. Several satellite missions in the past have been dedicated to monitoring the middle atmosphere and collecting data for decades. However, continual revisions and revaluations of measurement approaches and the introduction of novel space instruments are necessary to compensate for the limitations associated with existing missions, expand the extant specimen database, and improve phenomenon-centric observations. The Solar Occultation for Ice Experiment (SOFIE) is one of the two instruments on the Aeronomy of Ice in the Mesosphere (AIM) spacecraft. The studies presented in this dissertation primarily focus on the use of SOFIE observations combined with results from other science missions, an atmospheric model, and other datasets. Chapter I is an overview of the research goals and the motivations that propelled this research. In Chapter II, a validation study of the Version 1.3 SOFIE ozone data against the Atmospheric Chemistry Experiment (ACE) and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) ozone data is presented. The SOFIE-ACE and SOFIE-MIPAS data pairs demonstrate similar variability in the ozone vertical profile. SOFIE vertical ozone profiles agree best with ACE from 30 - 70 km and MIPAS from 30-64 km. The mean difference values averaged over all seasons and both hemispheres are typically < 24% with ACE and < 20 % with MIPAS. Atomic oxygen is an important species in the mesopause region (~ 80 – 100 km) that impacts the region's ozone photochemistry and radiative balance. In Chapter III, SOFIE ozone measurements used to derive daytime atomic oxygen are compared to coincident retrievals from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument and the Naval Research Laboratory Mass Spectrometer Incoherent Scatter radar (NRLMSIS 2.0) model. The datasets agree qualitatively. Results indicate a strong seasonal variation of atomic oxygen with summer and wintertime maxima at ~ 84 km and 94 km, respectively. The middle atmospheric composition is redistributed by the transport of species during SSWs. In Chapter IV, the 2019 SSW in the northern hemisphere that triggered a large transport event from the lower thermosphere to the stratosphere is evaluated using SOFIE, ACE, and the Modern-Era Retrospective analysis for Research and Applications (MERRA-2) observations. The event was similar to the major SSW-triggered descent events in the northern hemisphere since 2004 and led to the enhancement of nitric oxide produced by Energetic Particle Precipitation, attributed to unusual meteorology. The transport peak descended by ~ 5-6 km every 10 days. An SSW event occurred in the southern hemisphere in 2019 and led to enhanced ozone in the stratosphere. In Chapter V, satellite instruments, ground station data, and measurements from NASA Ozone Watch are used to conclude that large temperature increments evaporated PSCs, resulting in the lower conversion of halogen reservoir species into ozone-destroying forms. Thus, a large ozone enhancement was recorded in 2019. Chapter VI concludes all findings and Chapter VII summarizes future work. / Doctor of Philosophy / The middle atmosphere is the region between ~ 10 and 100 km in the atmosphere and is comprised of the Stratosphere, Mesosphere, and Lower Thermosphere. The middle atmosphere is a dynamic region, and the chemistry of this region is subject to variations occurring naturally or those triggered by anomalous events such as Sudden Stratospheric Warmings (SSW). Several species in the middle atmosphere need to be measured continuously or reevaluated for improved understanding. Dynamical events in the middle atmosphere are responsible for transporting and redistributing species in the middle atmosphere. Thus, the continuous monitoring of the middle atmosphere is necessary. Novel approaches with improved techniques and approaches are thus important to explore the middle atmosphere and quantify the chemistry of the region. The Solar Occultation for Ice Experiment (SOFIE) instrument is an instrument onboard the Aeronomy of Ice in the Mesosphere (AIM) spacecraft. SOFIE typically measures at high latitudes and looks at a wide range of wavelengths. This dissertation uses SOFIE and other datasets to evaluate the varying chemistry and dynamics of the middle atmosphere. The dissertation addresses four research problems and assimilates them to evaluate the middle atmosphere. Ozone is an important species in the middle atmosphere, which is present in the highest quantity in the stratosphere, followed by the lower thermosphere (~ 85 – 100 km). Ozone is important as it absorbs ultraviolet radiations and impacts the stratospheric radiative balance. Missions in the past have monitored ozone in the middle atmosphere. Novel approaches and improved observation techniques to compensate for the limitations of past missions and the continuous measurement of ozone are necessary. Thus, ozone retrievals from SOFIE are validated against independent and established datasets to demonstrate the robustness and usability of the SOFIE ozone data product within the atmospheric science community. Atomic oxygen is an important species in the mesopause region (~ 80 – 100 km) because of its role in ozone photochemistry and impact on the radiative balance of the region. It is technologically challenging to make direct measurements of atomic oxygen; thus, most conventionally, derived measurements and model results are used. To this date, atomic oxygen has been understood in a limited capacity with several inaccuracies. To improve the understanding of atomic oxygen and fill the current knowledge gaps, atomic oxygen is derived from SOFIE ozone measurements during the daytime using the Chapman equations for ozone photochemistry. Further, the derived atomic oxygen is compared to other established datasets from satellite instrument-derived measurements and model predictions. The seasonal variability of atomic oxygen is evaluated with a focus on the difference in its behavior during summer and winter. Lastly, inter-hemispheric differences in atomic oxygen distribution are evaluated. Apart from the natural atmospheric variation in species, SSW-triggered transport events redistribute species in the atmosphere. The 2019 SSW event in the northern hemisphere was similar to those in 2004, 2006, 2009, and 2013. Large quantities of nitric oxide were transported from the lower thermosphere to the stratosphere. Air poor in water vapor and methane was also transported. Atomic oxygen was transported from the lower thermosphere to several kilometers below in amounts higher than usual. The increased nitric oxide concentration in the stratosphere due to the transport catalytically destroyed the ozone in the region. The vertical transport rates were calculated to understand the speed of the descent. The low geomagnetic index in 2019, like in all years besides 2004, indicates that these events are attributed to unusual meteorology. An SSW event took place in the southern hemisphere in 2019 during the Antarctic winter. This led to a large increase in temperature, which evaporated the Polar Stratospheric Clouds (PSCs). PSCs provide their surface for converting halogen reservoir species into ozone-destroying reactive forms. The absence of PSCs during and immediately after the SSW event led to a lower conversion of halogen reservoir species into reactive forms. Satellite instrument measurements agree with theoretical expectations. The 2002 SSW in the SH led to similar outcomes and are compared to the 2019 event. Large enhancements in ozone in 2019 led to the smallest ozone hole since ~ 1982.

Scientific stratospheric balloons offer a valuable service to scientists wishing to test or demonstrate developing technological instruments, or to run fully operational instruments with short preparation times and for a cheap price compared to other similar services. The ballooning industry is therefore a vital part of the scientific community as it enables less funded and experienced scientific organisations to actively engage in the development of their technologies. In the context of scientific stratospheric balloons, the speed of permeation affects among other things the flight time and the flight planning, as these are determined by the rate of loss of the buoyancy force keeping the balloon afloat. Most balloons today use helium as lifting gas, but the ballooning industry is today facing increased pressure to switch to hydrogen gas. Before making this switch, understanding how hydrogen gas behaves differently, in terms of permeation or otherwise, is important to prevent unexpected flight paths among other things. In this thesis, two experiments were conducted in order to attempt to determine the ratio of permeation speed between hydrogen gas and helium through balloon membranes. One experiment used a manometric method, where the pressure of permeant in a diffusion chamber was measured over time. The other experiment measured the buoyancy force of permeant-filled balloons over time. The resulting ratio of permeation speed may give more confidence in predicting how much faster or slower a stratospheric balloon filled with hydrogen will lose buoyancy force.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / After briefly presenting the TRANSMED mission, the configuration of the Telemetry and Telecommand links is illustrated and the their dimensioning is analyzed. Both links operate at S-band with satellite grade standards. The system composition, the main equipment and the system growth potential are thereafter presented.

The Lagrangian dynamics of two-dimensional incompressible fluid flows is considered, with emphasis on transport processes in atmospheric and oceanic flows. The dynamical-systems-based approach is adopted; the Lagrangian motion in such systems is studied with the aid of Kolmogorov-Arnold-Moser (KAM) theory, and results relating to stable and unstable manifolds and lobe dynamics. Some nontrivial extensions of well-known results are discussed, and some extensions of the theory are developed. In problems for which the flow field consists of a steady background on which a time-dependent perturbation is superimposed, it is shown that transport barriers arise naturally and play a critical role in transport processes. Theoretical results are applied to the study of transport in measured and simulated oceanographic and atmospheric flows. Two particular problems are considered. First, we study the Lagrangian dynamics of the zonal jet at the perimeter of the Antarctic Stratospheric Polar Vortex during late winter/early spring within which lies the "ozone hole". In this system, a robust transport barrier is found near the core of a zonal jet under typical conditions, which is responsible for trapping of the ozone-depleted air within the ozone hole. The existence of such a barrier is predicted theoretically and tested numerically with use of a dynamically-motivated analytically-prescribed model. The second, oceanographic, application considered is the study of the surface transport in the Adriatic Sea. The surface flow in the Adriatic is characterized by a robust threegyre background circulation pattern. Motivated by this observation, the Lagrangian dynamics of a perturbed three-gyre system is studied, with emphasis on intergyre transport and the role of transport barriers. It is shown that a qualitative change in transport properties, accompanied by a qualitative change in the structure of stable and unstable manifolds occurs in the perturbed three-gyre system when the perturbation strength exceeds a certain threshold. This behavior is predicted theoretically, simulated numerically with use of an analytically prescribed model, and shown to be consistent with a fully observationally-based model.