The Auroral Large Imaging System (ALIS) was proposed in 1989 by Åke Steen as a joint Scandinavian ground-based nework of automated auroral imaging stations. The primary scientic objective was in the field of auroral physics, but it was soon realised that ALIS could be used in other fields, for example, studies of Polar Stratospheric Clouds (PSC), meteors, as well as other atmospheric phenomena. This report describes the design, operation and scientic results from a Swedish prototype of ALIS consisting of six unmanned remote-controlled stations located in a grid of about 50 km in northern Sweden. Each station is equipped with a sensitive high-resolution (1024 x 1024 pixels) unintensified monochromatic CCDimager. A six-position filter-wheel for narrow-band interference filters facilitates absolute spectroscopic measurements of, for example, auroral and airglow emissions. Overlapping fields-of-view resulting from the station baseline of about 50 km combined with the station field-of-view of 50° to 60°, enable triangulation as well as tomographic methods to be employed for obtaining altitude information of the observed phenomena. ALIS was probably one of the first instruments to take advantage of unintensi- fied (i.e. no image-intensifier) scientific-grade CCDs as detectors for spectroscopic imaging studies with multiple stations of faint phenomena such as aurora, airglow, etc. This makes absolute calibration a task that is as important as it is dificult. Although ALIS was primarily designed for auroral studies, the majority of the scientific results so far have, quite unexpectedly, been obtained from observations of HF pump-enhanced airglow (recently renamed Radio-Induced Aurora). ALIS made the first unambiguous observation of this phenomena at high-latitudes and the first tomography-like inversion of height profiles of the airglow regions. The scientific results so far include tomographic estimates of the auroral electron spectra, coordinated observations with satellite and radar, as well as studies of polar stratospheric clouds. An ALIS imager also participated in a joint project that produced the first ground-based daytime auroral images. Recently ALIS made spectroscopic observations of a Leonid meteor-trail and preliminary analysis indicates the possible detection of water in the Leonid.

The horizontal and vertical distributions of ozone and its precursors over North America during spring and summer are frequently determined by several factors: cloud convection, lightning NOx production, mixing depth, and long-range transport. The critical factors that contribute to the spatial distribution of air pollutants are studied using the Regional chEmical trAnsport Model (REAM) with diverse satellite measurements as well as in-situ surface and aircraft measurements. Surface and aircraft measurements show a large amount of reactive nitrogen tracers over the Antarctic plateau during summer. These enhanced measurements are investigated, and their photochemical impact is accessed by 1-D CTM and REAM.

Several studies suggest that deep convection that penetrates the tropical tropopause layer may influence the long-term trends in lower stratospheric water vapor. This thesis investigates the relationship between penetrating deep convection and lower stratospheric water vapor variability using historical infrared (IR) observations. However, since infrared observations do not directly resolve cloud vertical structure and cloud top height, and there has been some debate on their usefulness to characterize penetrating deep convective clouds, CloudSat/Calipso and Aqua MODIS observations are first combined to understand how to best interpret IR observations of penetrating tops. The major findings of the combined CloudSat/Calipso and Aqua MODIS analysis show that penetrating deep convection predominantly occur in the western tropical Pacific Ocean. This finding is consistent with IR studies but is in contrast to previous radar studies where penetrating deep convective clouds predominantly occur over land regions such as equatorial Africa. Estimates on the areal extent of penetrating deep convection show that when using IR observations with a horizontal resolution of 10 km, about two thirds of the events are large enough to be detected. Evaluation of two different IR detection schemes, which includes cold cloud features/pixels and positive brightness temperature differences (+BTD), show that neither schemes completely separate between penetrating deep convection and other types of high clouds. However, the predominant fraction of +BTD distributions and cold cloud features/pixels ≤ 210 K is due to the coldest and highest penetrating tops as inferred from collocated IR and radar/lidar observations. This result is in contrast to previous studies that suggest the majority of cold cloud features/pixels ≤ 210 K are cirrus/anvil cloud fractions that coexist with deep convective clouds. Observations also show that a sufficient fraction of penetrating deep convective cloud tops occur in the extratropics. This provides evidence that penetrating deep convection should be documented as a pathway of stratospheric-tropospheric exchange within the extratropical region. Since the cold cloud feature/pixel ≤ 210 K approach was found to be a sufficient method to detect penetrating deep convection it was used to develop a climatology of the coldest penetrating deep convective clouds from GridSat observations covering years 1998-2008. The highest frequencies of the coldest penetrating deep convective clouds consistently occur in the western-central Pacific and Indian Ocean. Monthly frequency anomalies in penetrating deep convection were evaluated against monthly anomalies in lower stratospheric water vapor at 82 mb and show higher correlations for the western-central Pacific regions in comparison to the tropics. At a lag of 3 months, the combined western-central Pacific had a small but significant anticorrelation, where the largest amount of variance explained by the combined western-central Pacific region was 8.25%. In conjunction with anomalies in the 82 mb water vapor mixing ratios, decreasing trends for the 1998-2008 period were also observed for tropics, the western Pacific and Indian Ocean. Although none of these trends were significant at the 95% confidence level, decreases in the frequency of penetrating deep convection over the 1998-2008 shows evidence that could explain in part some of the 82 mb lower stratospheric water vapor variability.

Arctic geoengineering wherein sunlight absorption is reduced only in the Arctic has been suggested as a remedial measure to counteract the on-going rapid climate change in the Arctic. Several modelling studies have shown that Arctic geoengineering can minimize Arctic warming but will shift the Inter-tropical Convergence Zone (ITCZ) southward, unless offset by comparable geoengineering in the Southern Hemisphere. In this study, we investigate and quantify the implications of this ITCZ shift due to Arctic geoengineering for the global monsoon regions using the Community Atmosphere Model version 4 coupled to a slab ocean model. A doubling of CO2 from pre-industrial levels leads to a warming of ~ 6 K in the Arctic region and precipitation in the monsoon regions increases by up to ~15 %. In our Arctic geoengineering simulation which illustrates a plausible latitudinal distribution of the reduction in sunlight, an addition of sulfate aerosols (11 Mt) in the Arctic stratosphere nearly offsets the Arctic warming due to CO2 doubling but this shifts the ITCZ southward by ~1.5⁰ relative to the pre-industrial climate. The combined effect from this shift and the residual CO2-induced climate change in the tropics is a decrease/increase in annual mean precipitation in the Northern Hemisphere /Southern Hemisphere monsoon regions by up to -12/+17%. Polar geoengineering where sulfate aerosols are prescribed in both the Arctic (10 Mt) and Antarctic (8 Mt) nearly offsets the ITCZ shift due to Arctic geoengineering, but there is still a residual precipitation increase (up to 7 %) in most monsoon regions associated with the residual CO2 induced warming in the tropics. The ITCZ shift due to our Global geoengineering simulation, where aerosols (20 Mt) are prescribed uniformly around the globe, is much smaller and the precipitation changes in most monsoon regions are within ±2 % as the residual CO2-induced warming in the tropics is also much less than in Arctic and Polar geoengineering. Further, global geoengineering nearly offsets the Arctic warming. Based on our results we infer that Arctic geoengineering leads to ITCZ shift and leaves residual CO2 induced warming in the tropics resulting in substantial precipitation changes in the monsoon regions.

Bromine compounds play an important role as catalyst of the ozone destruction in both the stratosphere and troposphere. While the impact of bromine species on the chemistry of the stratosphere is known to a large extend, a number of uncertainties remain regarding the sources and sinks of atmospheric bromine as well as the chemistry and impact of bromine species on the troposphere. <p>This work describes remote-sensing observations of bromine monoxide (BrO) derived from scattered sunlight spectra in the ultraviolet region measured by ground-based multi-axis and satellite nadir viewing instruments (GOME and GOME-2). The method of differential optical absorption spectroscopy is used to retrieve the columnar concentration of BrO along the effective light path through the atmosphere. New algorithms to derive vertical columns of BrO resolved into their stratospheric and tropospheric contributions are developed and described. For the ground-based geometry a way was found to determine independently the stratospheric and tropospheric BrO columns from the diurnal variation of the BrO measurements. For the satellite observations, the contribution of the stratospheric BrO to the measured column is estimated using an innovative stratospheric BrO climatology. This climatology is based on a state-of-the-art stratospheric chemical transport model, and explicitly accounts for the impact of atmospheric dynamics and photochemistry on the stratospheric BrO distribution. As for the tropospheric fraction of the measured total BrO column, it is derived using a residual technique accounting for the effects of clouds and surface reflectivity. <p>Supported by an extensive set of correlative data, the results presented here allow to study properly the spatial and temporal evolution of atmospheric BrO at the global scale and enable to better assess the significance of BrO in the polar planetary boundary layer and free-troposphere as well as the contribution from very short-lived brominated sources gases to the stratospheric bromine budget. We also report on the first satellite detection of BrO in a volcanic plume, using GOME-2 measurements.<p><p><p><p>Les composés bromés jouent un rôle important dans la stratosphère et la troposphère en tant que catalyseurs de la destruction d’ozone. Bien que l’impact des espèces bromées sur la chimie de la stratosphère soit largement compris, il reste de nombreuses incertitudes en ce qui concerne les sources et les pertes de brome dans l’atmosphère ainsi qu’à propos de la chimie et de l’impact des espèces bromées sur la troposphère.<p>Le travail présenté dans ce manuscrit porte sur la télédétection du monoxyde de brome (BrO) à partir de spectres du rayonnement solaire diffusé, mesurés dans l’ultraviolet à partir d’instruments au sol de type multi-axis et satellitaires à visée nadir (GOME et GOME-2). La méthode de spectroscopie d’absorption optique différentielle est utilisée pour inverser la colonne intégrée de BrO le long du chemin optique effectif dans l’atmosphère. Nous avons développé de nouveaux algorithmes afin de dériver les colonnes verticales de BrO résolues en leurs contributions stratosphérique et troposphérique. Pour la géométrie d’observation au sol, un moyen a été trouvé pour déterminer indépendamment les colonnes de BrO stratosphérique et troposphérique, et cela à partir de la variation diurne des mesures de BrO. Pour les observations satellitaires, la contribution de la stratosphère à la colonne mesurée de BrO est estimée à partir d’une climatologie innovante de BrO stratosphérique. Cette climatologie est basée sur un modèle de pointe de la chimie et du transport de la stratosphère; par ailleurs, elle tient compte explicitement de l’impact de la dynamique atmosphérique et de la photochimie sur la distribution du BrO dans la stratosphère. La fraction troposphérique de la colonne totale mesurée de BrO est quant à elle dérivée à partir d’une technique résiduelle tenant compte des effets des nuages et de la réflectivité de la surface. <p>Soutenus par un vaste jeu de données corrélatives, les résultats présentés dans ce travail permettent d’étudier de manière appropriée l’évolution spatiale et temporelle du BrO atmosphérique à l’échelle globale. Ces résultats permettent également de mieux estimer l’importance du BrO dans la couche limite planétaire polaire et dans la troposphère libre ainsi que la contribution des précurseurs bromés à temps de vie court sur le budget de brome dans la stratosphère. Nous présentons également la première détection satellitaire de BrO dans un panache volcanique, à l’aide de mesures effectuées avec l’instrument GOME-2. <p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Les rayons cosmiques ont été découverts il y a un siècle par Victor Hess à bord d'un vol scientifique en ballon. La physique des rayons cosmiques et les ballons stratosphériques ont partagé depuis lors une histoire commune, que ce soit pour d'authentiques découvertes ou en utilisant les ballons comme plateformes de test technologique pour de nouvelles missions satellites. Cette thèse, développée au sein de la collaboration JEM-EUSO, traite d'un démonstrateur en ballon stratosphérique. Notre but scientifique final est l'étude des Rayons Cosmiques de Ultra-Haute Energie (RCUHE), les particules les plus énergétiques connues dans l'Univers. Les RCUHES ont des énergies macroscopiques de plus de 10^20eV mais étant extrêmement rares, leurs origines sont encore inconnues. Ces derniers pénètrent notre atmosphère à une fréquence de un par km2 par siècle, produisant une gerbe atmosphérique géante, détectable notamment par la lumière de fluorescence ultraviolette qu'elle émet. Le principe de détection proposé par notre collaboration consiste dans l'utilisation d'un observatoire spatial, JEM-EUSO. Son objectif est d'observer un très grand volume d'atmosphère afin d'enregistrer un nombre significatif des événements ultra-violet de fluorescence initiés par les RCUHEs. Le démonstrateur EUSO-Ballon a été développé par la collaboration JEM-EUSO dans le but de démontrer les technologies et méthodes utilisées par le futur instrument spatial. Le 25 août 2014, EUSO-Ballon a été lâché depuis la base de ballons stratosphériques de Timmins (Ontario, Canada) par la division ballon du CNES. L'instrument a fonctionné pendant toute une nuit astronomique, observant depuis 38km d'altitude la lumière UV provenant de divers types de sols et de centaines de gerbes atmosphériques simulées. Ces dernières ont été produites par des flashers et un laser embarqués dans un hélicoptère volant sous EUSO-Ballon pendant deux heures. Ces résultats ont été rendus possibles par la restitution de l'attitude de l'instrument effectuée à l'IRAP, c'est-à-dire une analyse exhaustive des données du vol des différents appareils de mesure d'attitude de la nacelle du ballon. Une caractérisation précise de chaque sous-système était aussi indispensable à l'exploitation des données du vol. Le système optique innovant, composé de deux grandes lentilles de Fresnel, a été intégré et entièrement testé à l'IRAP. Face au large système réfractif de l'instrument, une nouvelle méthodologie de test a été développée. Les performances de l'optique, efficacité et spot focal, ont ainsi été mesurées et se sont révélées étonnamment différentes des prédictions des modèles numériques. Ces mesures sont utilisées pour l'analyse des données du premier vol et pour mieux comprendre le comportement de ces toutes nouvelles optiques, éléments clés dans la conception de l'instrument JEM-EUSO. / A century ago Cosmic Rays were discovered by Victor Hess during one of the very first scientific balloon flights. Ever since, Cosmic Ray physics and stratospheric balloons have shared a common history - either through genuine discoveries or by using balloon platforms as technology test beds for new satellite missions. This thesis, carried out within the JEM-EUSO collaboration, is about such a pathfinder balloon mission. Our ultimate science goal is the study of Ultra-High Energy Cosmic Rays (UHECR), the most energetic particles known in the Universe. Having macroscopic energies of over 10^20 eV, UHECRs are of yet unknown cosmic origin and are extremely rare. They penetrate our atmosphere at a rate of about one event per km2 and century, producing energetic atmospheric air showers, detectable through the ultraviolet fluorescence light they emit. The technique that our collaboration proposes for their detection consists of a spaceborne observatory, JEM-EUSO. Its objective is to monitor a very large volume of the Earth's nighttime atmosphere from above, recording a significant sample of ultraviolet light tracks initiated by UHECRs. In order to demonstrate the technologies and methods featured in the future space instrument, the EUSO-Balloon pathfinder has been developed by the JEM-EUSO collaboration. On August 25, 2014, EUSO-Balloon was launched from Timmins Stratospheric Balloon Base (Ontario, Canada) by the balloon division of the French Space Agency CNES. From a float altitude of 38 km, the instrument operated during the entire astronomical night, observing UV-light from a variety of groundcovers and from hundreds of simulated air showers, produced by flashers and a laser during a two-hour helicopter under-flight. These results have been made possible by the restitution of the instruments attitude carried out at IRAP, i.e. an exhaustive analysis of the flight data from various attitude sensors on board of the balloon gondola. Also, a precise understanding of the Fresnel optics was required to analyze the data of the first EUSO-balloon flight. The all new optical system, integrated and tested at IRAP, has been characterized during two measurement campaigns. To test this large refractive system, a new test method has been developed. The optics performance, i.e. the efficiency and point spread function, came as something of a surprise, since none of the numerical models had predicted the observed behavior. These measurements are used in the analysis of the flight data and for the deep understanding of these brand-new Fresnel optics, key element in the design of the JEM-EUSO instrument.

L'ozone joue un rôle primordial sur l'équilibre photochimique de l'atmosphère et participe au processus d'équilibrage radiatif entre les deux hémisphères (Mecke, 1931). Dans la troposphère, l'ozone détermine la capacité oxydante de la majorité des gaz et absorbe continuellement dans la stratosphère les radiations ultraviolettes nocives (McMicheal et al., 2003). D'où l'intérêt de surveiller la variation de la couche d'ozone de façon régulière. Il a été constaté au début des années 80, une diminution inquiétante et progressive de la colonne totale de l'ozone dûe aux émissions anthropiques des substances riches en chlore, brome et fluor. Ce constat a conduit au Protocole de Montréal en 1987 dont l'objectif est de mettre en place une politique internationale visant à réduire les émissions des substances appauvrissant l'ozone. Dix ans après la signature du dit Protocole, la concentration de ces substances commence à diminuer dans l'atmosphère et la prospection d'un recouvrement progressif de la couche d'ozone demeure aujourd'hui un sujet d'actualité (UNEP/PNUE, 2009 ; OMM, 2010 et 2014). Les besoins d'aujourd'hui sont de réaliser des mesures continues et fiables de l'ozone dont leurs exploitation dans des méthodes et/ ou des modèles bien adaptés à la problématique aideront la communauté à suivre l'évolution de l'ozone et d'estimer les tendances à long terme. Dans ce travail, une variété de produits d'ozone issue de différents instruments a été combinée pour construire des bases des données fiables et homogènes afin d'étudier sa variabilité et d'estimer la tendance de l'ozone dans les régions tropicale et subtropicale sud. L'application de ces bases de données sur les ondelettes a permis d'identifier les principaux forçages qui contrôlent la variabilité de l'ozone et la période de retour associée à chaque forçage. Il s'agit des variations saisonnières du climat, les oscillations quasi-biennales, les oscillations australes El-Niño et l'activité solaire dont le cycle moyen est évalué à 11ans. Le comportement et l'influence de chacun de ces paramètres sur la viabilité de l'ozone sont étudiés. Cette étude est faite en s'appuyant sur des méthodes statistiques et sur le modèle Trend-Run. Avec ce modèle, la part de contribution et la réponse de chaque paramètre sur la variabilité de l'ozone sont quantifiées. Les résultats sur les tendances montrent une augmentation de la couche d'ozone avec un taux variant entre 0 et 2.78% par décade (selon la région et le site) sur la période 1998-2012. Cette amélioration est bien observée au-dessus de 22km, surtout aux subtropiques par rapport à la région équatoriale. / Ozone plays an important role on photochemical equilibrium of atmosphere and participate on radiative balance process between hemispheres (Mecke, 1931). In the troposphere, ozone determines the oxidizing capacity of major species and absorbs continuously in the stratosphere the harmful ultraviolet radiation (McMichael et al, 2003). Based on the above facts, it is important to monitor ozone continuously with consistency and accuracy. Global total column ozone (TCO) has depleted gradually since 1980 with an increase of chlorofluorocarbon concentrations in the stratosphere due to anthropogenic activities. In 1987, the Montreal protocol was formulated in order to regulate the emissions of substances that deplete ozone. Concentrations of these substances are observed to decrease ten years after the Montreal protocol. Thus we have been expecting an increase in ozone by now (UNEP/PNUE, 2009; WMO, 2010 and 2014). The current needs are to achieve consistent and reliable measurements in which their exploitation on adapted methods/models can help scientists to follow the ozone evolution and to estimate long term ozone trend. In this work, a variety of ozone products from different instruments was combined in order to create reliable and homogenous dataset to study the ozone variability and trend over the southern tropics and subtropics. The dataset application on wavelets method allowed to identify the dynamic parameters that control ozone variability and their periodicities. These include seasonal variations of climate, the quasi-biennial oscillations, the El-Niño Southern Oscillation and the 11-years solar cycle. The behavior of each parameter and its influence on ozone variability were analysed based on statistical method and the Trend-Run model. The contribution and response of each variable on ozone variability were quantified from the model. The obtained trends results exhibit an increase of total ozone from 1998 to 2012 with a rate varying between 0 and 2.78% par decade (depending of the site and region). The ozone increase was observed mainly above 22 km and it is more important over the subtropical region with respect to equatorial zone.

This thesis conducts research into different rechargeable battery technologies and their applicability to the high altitude balloon flights conducted at Esrange space center. The research focuses on the possible use of lithium ion batteries’, sodium ion batteries, nickel metal hydrate, and Metal hydridelithiumion batteries. Resulting in lithium ion batteries in 18650 cells being recommended. The thesis continues with a modular power distribution system architecture design. The system architecture is established with solarcharging capabilities, up to 1500W peak output power, over 600W continuous output power, multiple output voltages, more than six output channels, remote output power switching, and monitoring of power consumption. A prototype is built from this architecture on which limited testing is performed.The testing shines light on future improvements and displays proof of concept for some parts.

The Auroral Large Imaging System (ALIS) was proposed in 1989 by Åke Steen as a joint Scandinavian ground-based nework of automated auroral imaging stations. The primary scientic objective was in the field of auroral physics, but it was soon realised that ALIS could be used in other fields, for example, studies of Polar Stratospheric Clouds (PSC), meteors, as well as other atmospheric phenomena. This report describes the design, operation and scientic results from a Swedish prototype of ALIS consisting of six unmanned remote-controlled stations located in a grid of about 50 km in northern Sweden. Each station is equipped with a sensitive high-resolution (1024 x 1024 pixels) unintensified monochromatic CCDimager. A six-position filter-wheel for narrow-band interference filters facilitates absolute spectroscopic measurements of, for example, auroral and airglow emissions. Overlapping fields-of-view resulting from the station baseline of about 50 km combined with the station field-of-view of 50° to 60°, enable triangulation as well as tomographic methods to be employed for obtaining altitude information of the observed phenomena. ALIS was probably one of the first instruments to take advantage of unintensi- fied (i.e. no image-intensifier) scientific-grade CCDs as detectors for spectroscopic imaging studies with multiple stations of faint phenomena such as aurora, airglow, etc. This makes absolute calibration a task that is as important as it is dificult. Although ALIS was primarily designed for auroral studies, the majority of the scientific results so far have, quite unexpectedly, been obtained from observations of HF pump-enhanced airglow (recently renamed Radio-Induced Aurora). ALIS made the first unambiguous observation of this phenomena at high-latitudes and the first tomography-like inversion of height profiles of the airglow regions. The scientific results so far include tomographic estimates of the auroral electron spectra, coordinated observations with satellite and radar, as well as studies of polar stratospheric clouds. An ALIS imager also participated in a joint project that produced the first ground-based daytime auroral images. Recently ALIS made spectroscopic observations of a Leonid meteor-trail and preliminary analysis indicates the possible detection of water in the Leonid.

Global civilisation, and therefore population health, is threatened by excessive inequality, weapons of mass destruction, inadequate economic and political theory and adverse global environmental change. The unequal distribution of global foreign exchange adjusted income is both a cause and a reflection of global social characteristics responsible for many aspects of these inter-related crises. ¶ The global distribution of foreign exchange adjusted income for the period 1964-1999 is examined. Using data for more than 99% of the global population, a substantial divergence in its distribution is found. The global Gini co-efficient, adjusted for national income inequality, increased from an already high value of 71% in 1964 to peak at more than 80% in 1995, before falling, very slightly, to 79% in 1999. The global distribution of purchasing parity power income is also examined, for a similar period. Though also found to be extremely unequal, its trend has not been to increased inequality. Implications of the differences between these two trends are discussed. ¶ A weighted time series index of global environmental change (IGEC) for the period 1960-1997 was also calculated. This uses nine categories of global time series environmental data, each scaled so that 100% represents the level of each category in nature prior to anthropogenic change; zero represents decline to a critical point. This index fell from 82% in 1960 to 55% in 1997, and will further decline during this century. ¶ Using evidence from several disciplines, it is argued that the decline in the IGEC correlates with major macro-environmental changes, which, combined with flawed social responses to scarcity and its perception, place at risk the ability of civilisation to function. This could occur because of the interaction of conflict, economically disastrous extreme climatic events, deterioration of other ecosystem services, regional food and water insecurity, and currently unforeseen events. Uncertainty regarding both a safe rate of decline and the tolerable nadir of the IGEC is substantial. ¶ Substantial reduction in the inequality of foreign exchange adjusted income is vital to enhance the development of policies able to reverse the decline in the environmental goods which underpin civilisation, and to promote the co-operation needed to maximise the chance that civilisation will survive.