Les orages tropicaux jouent un rôle incertain dans le transport de l'air troposphérique dans la stratosphère limitant notre capacité à prévoir le climat futur. Le transport par les orages pourrait en effet être sous-estimé dans les modèles de climat aux résolutions trop grossières. L'efficacité de ce transport est analysée à partir de simulations numériques de l'orage Hector the Convector jusqu'à une résolution de 100 m, la plus fine jamais utilisée pour un cas de convection très profonde. Les percées nuageuses, qui avaient été observées à son sommet à 18 km d'altitude, sont reproduites et l'hydratation nette de la stratosphère est quantifiée. La contribution des orages tropicaux au flux d'eau de la troposphère à la stratosphère est ainsi estimée à près de 20 %. La quasi-convergence aux résolutions de 200 m et 100 m suggère que de telles résolutions sont nécessaires pour représenter correctement les ascendances. L'analyse individuelle des ascendances indique que les deux plus grandes contribuent à plus de 90 % du flux de masse vers la basse stratosphère. Elles sont plus larges, plus puissantes et contiennent plus d'eau que les plus grandes ascendances une heure avant et une heure après, et leur cœur convectif apparaît très peu dilué. L'alimentation en surface par des lignes de convergence intensifiées par des poches froides et la faible dilution des deux plus grandes ascendances sont déterminantes dans l'apparition de la convection très profonde. L'analyse isentropique de la circulation générale dans Hector confirme le flux de masse calculé par l'analyse des ascendances. Elle le corrige dans les basses couches en prenant en compte les flux turbulents, et en haute troposphère en filtrant les ondes de gravité. Elle met en évidence l'importance du dégagement de chaleur latente dû à la congélation dans les plus grandes ascendances pendant la phase de percée en stratosphère. / The tropical thunderstorms play an uncertain role in the transport of tropospheric air into the stratosphere, limiting our capability to predict the future climate. The transport by the thunderstorms may be underestimated by the climate models, due to their coarse resolutions. The efficiency of this transport is analysed using numerical simulations of the thunderstorm Hector the Convector with resolutions down to 100 m, the finest ever used for a case of very deep convection. The overshoots, that were observed at its top at 18 km altitude, are captured and the net hydration of the stratosphere is quantified. The contribution of the tropical thunderstorms to the water flux from the troposphere to the stratosphere is then estimated to about 20 %. The almost convergence at 200 m and 100 m suggests that such resolutions are necessary to correctly represent the updafts. The individual analysis of the updrafts indicates that the two tallest contribute beyond 90 % of the mass flux into the stratosphere. They are larger, more vigorous and contain more water than the tallest updrafts one hour before and one hour after, and their convective core was weakly diluted. The supply from the surface by the convergence lines, intensified by the cold pools, and the weak dilution of the two tallest updrafts are determinant for the development of very deep convection. The isentropic analysis of the overturning inside Hector confirms the mass flux computed with the updrafts analysis. It corrects the estimate in the lower troposphere by taking into account the turbulent flux, and in the upper troposphere by filtering out the gravity waves. It highlights the importance of the latent heating due to freezing in the two tallest updrafts during the phase of overshoot in the stratosphere.

137 f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-04-05T12:52:18Z No. of bitstreams: 1 TESE_Doutorado_Neuza Neves.pdf: 14182671 bytes, checksum: 1dc20a7a01160b563c11a087932580c1 (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-06-07T14:39:03Z (GMT) No. of bitstreams: 1 TESE_Doutorado_Neuza Neves.pdf: 14182671 bytes, checksum: 1dc20a7a01160b563c11a087932580c1 (MD5) / Made available in DSpace on 2013-06-07T14:39:03Z (GMT). No. of bitstreams: 1 TESE_Doutorado_Neuza Neves.pdf: 14182671 bytes, checksum: 1dc20a7a01160b563c11a087932580c1 (MD5) Previous issue date: 2009 / Ozônio pode afetar a saúde humana sendo a ele atribuída a responsabilidade por centenas de milhares de mortes prematuras a cada ano e por centenas de internações hospitalares adicionais, além da perda de milhões de dias de trabalho. Estes impactos na saúde são causados tanto por exposições a longo prazo (crônica) quanto a curto prazo (aguda). De forma semelhante a que ocorre atualmente próximo às grandes cidades do mundo e aos centros industriais, as concentrações ambientais de ozônio estavam ultrapassando o padrão de qualidade do ar estabelecido no Brasil, nas vizinhanças do Pólo Petroquímico de Camaçari, especialmente durante os anos de 2000 a 2003. Com o objetivo de avaliar a formação e dispersão de ozônio na região do Recôncavo Baiano, foi desenvolvido um estudo, usando modelagem matemática, para melhor compreender as principais fontes dos precursores de ozônio, bem como sua formação e dispersão na referida região. A metodologia adotada no estudo foi a elaboração de um inventário de emissões atmosféricas para as regiões urbanas e industriais e utilização do modelo matemático fotoquímico denominado STEM III – Sulfur Transport and Deposition Model, da Universidade de Iowa (USA), para simular a formação e dispersão deste poluente fotoquímico secundário na atmosfera na região do Recôncavo Baiano. Os resultados do modelo foram comparados com as concentrações medidas por uma rede de monitoramento contínuo da qualidade do ar do Pólo Petroquímico, referente a um período em abril de 2003. Concluiu-se que os resultados calculados para ozônio na região do Recôncavo Baiano, através do modelo matemático STEM são adequados, uma vez que há concordância satisfatória com os dados medidos. Os desvios encontrados ocorreram especificamente durante os episódios com baixas velocidades do vento, quando foram registrados picos de concentrações deste poluente próximo ao Pólo Petroquímico de Camaçari. Os modelos matemáticos meteorológicos não descrevem adequadamente a situação real quando a velocidade do vento é inferior a 1 m/s. ix Os resultados das simulações demonstram que a formação de ozônio ocorre em regiões situadas muito além dos locais onde estão situadas as estações de monitoramento do ar do Pólo, e atinge áreas distantes de Salvador e da região industrial, como Feira de Santana e Santo Estevão, situadas a jusante dos ventos que sopram do quadrante Este, predominantes na região. Todas as concentrações calculadas para ozônio foram inferiores ao limite de 160 µg/m3 estabelecidas pela Resolução CONAMA 003/90, para períodos horários e portanto, não deverão causar impactos na saúde humana. No entanto as concentrações encontradas até cerca de 100 a 150 Km das fontes consideradas podem afetar os ecossistemas pois as concentrações máximas simuladas estão próximas do limite de 40 ppb.h (do inglês:Accumulated Dose Over Threshold of 40 ppb.h - AOT40), na região Oeste e Noroeste do domínio estudado. O regime de formação de ozônio na região de Camaçari e de Candeias é limitado pelo NOx, e as reduções das emissões de NO2 efetuadas pelo Pólo Petroquímico à partir de 2004 resultaram na eliminação das violações dos limites de ozônio na sua região de influência. Considerando-se o atual cenário de desenvolvimento do Brasil, em dez anos as concentrações de ozônio nas áreas costeiras do Recôncavo poderão representar uma ameaça para a produtividade agrícola desenvolvida na região situada no interior da Bahia, e eventualmente poderão representar também uma ameaça para a saúde humana, a depender do aumento das emissões, particularmente veiculares. / Salvador

Le PPP (Precise Point Positioning) est une méthode GNSS (Global Navigation Satellite Systems), basée sur le concept SSR (State Space Representation). Grâce aux améliorations récentes des modèles atmosphériques, le PPP en temps réel (RT-PPP) peut être également amélioré. L'objectif principal de ce travail est d'étudier le RT-PPP et l'infrastructure optimisée en termes de coûts et d'avantages pour réaliser la méthode en utilisant des corrections atmosphériques. Pour cela, différentes configurations d'un réseau GNSS dense et régulier existant en France, le réseau Orphéon, sont utilisées. Ce réseau compte environ 160 sites, propriété de Geodata-Diffusion (Hexagon Geosystems). Dans un premier temps, le mode «PPP-RTK flottant» a été évalué, il correspond au RT-PPP avec des améliorations issues des corrections de réseau, mais avec les ambiguïtés flottantes. Ensuite, des corrections de réseau sont appliquées pour améliorer le mode « PPP-RTK » où les ambiguïtés sont fixées à leurs valeurs entières. Pour le PPP-RTK flottant, une version modifiée du package RTKLib 2.4.3 (beta) est utilisée pour prendre en compte les corrections réseau. Les effets ionosphériques de premier ordre ont été éliminés par la combinaison iono-free et le retard troposphérique zénithal est estimé. Les corrections ont été appliquées en introduisant des paramètres troposphériques a priori contraints. Une modélisation adaptative basée sur les OFCs (Optimal Fitting Coefficients) a été mise en place pour décrire le comportement de la troposphère, en utilisant des estimations des retards troposphériques pour les stations Orphéon. Cette solution permet une communication monodirectionnelle entre le serveur et l'utilisateur. Les gains réalisés sur le temps de convergence pour obtenir un positionnement de 10 centimètres de précision ont été quantifiés statistiquement. La topologie du réseau a été évaluée, en réduisant le nombre de stations de référence (jusqu'à 75%), via une configuration de réseau lâche. Dans la deuxième étape, le PPP-RTK est réalisé grâce au logiciel PPP-Wizard 1.3 et avec les produits temps réel CNES (Centre Nacional de Estudes Spatiales) pour les orbites, les horloges et les biais de phase des satellites. Le RT-IPPP (RT-Integer PPP) est réalisé avec estimation des délais troposphériques et ionosphériques. Les corrections ionosphériques et troposphériques sont introduites en tant que paramètres a priori contraints au PPP-RTK. Pour générer des corrections ionosphériques, il a été mis en place un algorithme d'interpolation à distance inversée (IDW–Inverse Distance Weighting). Les améliorations apportées au positionnement horizontal dues aux corrections atmosphériques SSR externes provenant d’un réseau (dense ou lâche) sont prometteuses et peuvent être utiles pour les applications qui dépendent principalement du positionnement horizontal. / PPP (Precise Point Positioning) is a GNSS (Global Navigation Satellite Systems) method, based on SSR (State Space Representation) concept. Thanks to recent improvements in atmospheric models, Real-time PPP (RT-PPP) can also be improved. The main objective of this work is to study the RT-PPP and the optimized infrastructure in terms of costs and benefits to realize the method using atmospheric corrections. Therefore, different configurations of a dense and regular GNSS network existing in France, the Orpheon network, are used. This network has about 160 sites and is owned by Geodata-Diffusion (Hexagon Geosystems). Initially, ‘float PPP-RTK’ was evaluated, it corresponds to RT-PPP with improvements resulting from network corrections, although with ambiguities kept float. Further on, network corrections are applied to improve “PPP-RTK” where ambiguities are fixed to their integer values. For the float PPP-RTK, a modified version of the RTKLib 2.4.3 (beta) package is used to apply network corrections. First-order ionospheric effects were eliminated by the iono-free combination and zenith tropospheric delay estimated. The corrections were applied by introducing a priori constrained tropospheric parameters. Adaptive modeling based on OFCs (Optimal Fitting Coefficients) has been developed to describe the behavior of the troposphere, using estimates of tropospheric delays for Orpheon stations. This solution allows one-way communication between the server and the user. The gains achieved in convergence time to 10 centimeters accuracy were statistically quantified. Network topology was assessed by reducing the number of reference stations (up to 75%) using a sparse network configuration. In the second step, PPP-RTK is realized using the PPP-Wizard 1.3 software and CNES (Centre National d'Etudes Spatiales) real-time products for orbits, clocks and phase biases of satellites. The RT-IPPP (RT-Integer PPP) is performed with estimation of tropospheric and ionospheric delays. Ionospheric and tropospheric corrections are introduced as a priori parameters constrained in PPP-RTK. To generate ionospheric corrections, it was implemented an Inverse Distance Weighting (IDW) algorithm. Improvements achieved in horizontal positioning due to external SSR corrections from a (dense or sparse) network are promising and may be useful for applications that depend primarily on horizontal positioning. / O PPP (Precise Point Positioning) é um método GNSS (Global Navigation Satellite Systems) baseado no conceito SSR (State Space Representation). Graças às melhorias recentes nos modelos atmosféricos, o PPP em tempo real (RT-PPP) também pode ser aprimorado. O objetivo principal deste trabalho é estudar o RT-PPP e a infraestrutura otimizada em termos de custos e benefícios para realizar o método usando correções atmosféricas. Portanto, são utilizadas diferentes configurações de uma rede GNSS densa e regular existente na França, a rede Orphéon. Esta rede tem cerca de 160 estações, sendo propriedade da Geodata-Diffusion (Hexagon Geosystems). Inicialmente, foi avaliado o "float PPP-RTK", que corresponde ao RT-PPP com melhorias resultantes de correções de rede, embora mantendo as ambiguidades como float. Em um segundo momento, as correções de rede são aplicadas para aprimorar o "PPP-RTK", onde ambiguidades são fixadas para seus valores inteiros. Para o float PPP-RTK, uma versão modificada do software RTKLib 2.4.3 (beta) é empregada de modo a levar em consideração as correções de rede. Os efeitos ionosféricos de primeira ordem foram eliminados pela combinação iono-free e o atraso troposférico é estimado. As correções são aplicadas introduzindo parâmetros troposféricos a priori injuncionados. Uma modelagem adaptativa baseada em OFCs (Optimal Fitting Coefficients) foi implementada para descrever o comportamento da troposfera, utilizando estimativas de atraso troposférico para estações da rede Orpheon. Tal solução permite a comunicação unidirecional entre o servidor e o usuário. Os ganhos alcançados no tempo de convergência para acurácia de 10 centímetros foram quantificados estatisticamente. A topologia de rede foi avaliada reduzindo o número de estações de referência (até 75%) usando uma configuração de rede esparsa. Na segunda etapa, o PPP-RTK é realizado usando o software PPP-Wizard 1.3, bem como os produtos para tempo real do CNES (Centre National d’Etudes Spatiales) de órbitas, relógios e biases de fase de satélites. O RT-IPPP (RT-Integer PPP) é realizado com estimativa de atrasos troposféricos e ionosféricos. As correções ionosféricas e troposféricas são introduzidas como parâmetros a priori injuncionados no PPP-RTK. Para gerar correções ionosféricas, foi implementado um algoritmo baseado na ponderação pelo inverso da distância (IDW–Inverse Distance Weighting). As melhorias alcançadas no posicionamento horizontal com o uso das correções SSR externas de uma rede (densa ou esparsa) são promissoras e podem ser úteis para aplicações que dependem principalmente do posicionamento horizontal.

Le phénomène de destruction de l’ozone est un sujet vaste mettant en scène de nombreux processus. Il a pour origine l’émission de composés dits gaz sources (SGs) dans la troposphère. Récemment, les espèces à très courte durée de vie (VSLS) ont été identifiées comme SGs possibles. Cependant, elles ne possèdent pas un temps de vie suffisamment long pour atteindre directement la stratosphère. Les VSLS se dégradent au cours de leur transport, conduisant à des composés intermédiaires, les gaz produits (PGs). Les SGs et les PGs des VSLS vont entrer dans la stratosphère au niveau des régions équatoriales où règne un transport vertical rapide, la convection. Les SGs à temps de vie plus long peuvent accéder à la stratosphère par tous les types de transport possibles. Une fois dans la stratosphère, les SGs et PGs vont être convertis en espèces réactives capables de détruire l’ozone. Cette thèse présente l’étude des différentes étapes se produisant avant la destruction de l’ozone : l’émission et le transport des SGs dans l’atmosphère, leur chimie de dégradation au cours de leur transport et enfin leur contribution à la destruction de l’ozone. Les traceurs chimiques tels que CO sont tout d’abord utilisés pour mettre en évidence le transport des SGs et PGs de la troposphère à la stratosphère. Puis, deux études décrivant 2 types d’espèces différentes, entrant dans le processus de destruction de l’ozone, sont présentées : pour OCS (sulfure de carbonyle) et les VSLS bromés (CHBr3 et CH2Br2). OCS est l’un des principaux précurseurs d’aérosols sulfatés présents dans la stratosphère catalysant la destruction de l’ozone par chimie hétérogène. Cependant, sa contribution à cette couche comporte de nombreuses incertitudes. Ses sources d’émissions, sa répartition avec la latitude et sa contribution à la couche d’aérosols sulfatés sont présentées. La contribution des VSLS bromées au brome de la stratosphère est une question en cours de résolution. Leur chimie au cours de leur transport dans l’atmosphère est décrite de manière détaillée. / Ozone depletion is a complex subject involving several processes starting by the emission of the sources gases (SGs) in the lower troposphere. Recently the VSLS (very short lived substances) have been identified as potential SGs. However they do not have a lifetime long enough to reach directly the stratosphere. During the transport, the VSLS undergo degradation leading to products gases (PGs). The SGs and PGs of the VSLS reach the stratosphere in the Tropical region where a rapid vertical transport occurs, the convection. The SGs with longer lifetime can reach the stratosphere by any transport pathway from the location of their emissions. Once in stratosphere the SGs and PGs will be converted into reactive species able to deplete ozone. This thesis presents the study of the several steps occurring before the ozone depletion: SGs emission, SGs and PGs transport into the atmosphere, the chemical degradation occurring during their transport and finally their contribution to the ozone depletion. First, chemical tracers, as CO, are used to highlight the main pathways from the troposphere to the stratosphere. Then two studies of two different types of species entering in the process of ozone destruction are presented: for OCS (carbonyl sulfide) and the brominated VSLS (CHBr3 et CH2Br2). OCS is one of the sulfate aerosols precursors catalyzing the ozone depletion. However, OCS contribution to this layer has some uncertainties. OCS emission sources, the latitude repartition and the contribution to the sulfate aerosols are presented. The contribution of the brominated VSLS to the stratospheric bromine is a key issue that being almost resolved. The brominated VSLS chemical degradation during the atmospheric transport will be described in detail.

[pt] O crescimento da demanda por serviços de telecomunicações em terra firme também pode ser encontrado em ambientes marítimos por usuários a bordo de embarcações, sejam elas civis ou militares. Nestes ambientes, um fenômeno conhecido como duto de evaporação influencia a propagação eletromagnética na troposfera, proporcionando a comunicação ponto-a-ponto em distâncias além do horizonte rádio. Este trabalho utiliza a técnica de traçado de raios para analisar o comportamento da onda eletromagnética nestes meios. Foi elaborado um algoritmo capaz de traçar raios e determinar amplitudes e fases do campo elétrico em meios inomogêneos bidimensionais dado um mapa de refratividade modificada M. A partir destes mapas, o algoritmo calcula os gradientes verticais de M, que podem variar ao longo do percurso, e traça os raios, a partir da antena transmissora. Como aplicação, além de cenários com dutos de evaporação, foram utilizados mapas de M estimados com base em dados meteorológicos fornecidos por radiossondas lançadas no litoral brasileiro. Os resultados obtidos foram comparados aos fornecidos pelo software Advanced Refractive Effects Prediction System (AREPS), baseado na solução numérica de equação parabólica. Este trabalho também apresenta resultados estatísticos de dutos de evaporação no litoral brasileiro, a partir de dados meteorológicos fornecidos por boias oceanográficas do Programa Nacional de Boias (PNBOIA). Para tal, é utilizado, com pequenas alterações, o algoritmo de Paulus-Jeske, que estima a altura de dutos de evaporação. / [en] The demand growth for land-based telecommunications services can also be found in maritime environments by users on board ships, whether civilian or military. In these environments, a phenomenon known as the evaporation duct influences electromagnetic propagation in the troposphere, providing point-to-point communication at distances beyond the radio horizon. This work uses the raytracing technique to analyze the behavior of electromagnetic waves in these media. An algorithm capable of tracing rays and determining electric field amplitudes and phases in two-dimensional inhomogeneous media was developed, given a map of modified refractivity M. From these maps, the algorithm calculates the vertical gradients of M, which can vary along the path, and traces rays from the transmitting antenna. As an application, in addition to scenarios with evaporation ducts, M maps were estimated based on meteorological data provided by radiosondes launched in the Brazilian coast. The results obtained were compared with those provided by the Advanced Refractive Effects Prediction System (AREPS) software, based on the numerical solution of parabolic equation. This work also presents statistical results of evaporation ducts in the Brazilian coast, based on meteorological data provided by oceanographic buoys of Programa Nacional de Boias (PNBOIA). For this, the Paulus-Jeske algorithm, which estimates the height of the evaporation ducts, is used with small changes.

Atmospheric formaldehyde (H2CO) is an intermediate product common to the degradation of many volatile organic compounds and therefore it is a central component of the tropospheric chemistry. While the global formaldehyde background is due to methane oxidation, emissions of non-methane volatile organic compounds (NMVOCs) from biogenic, biomass burning and anthropogenic continental sources result in important and localised enhancements of the H2CO concentration. Recent spaceborne nadir sensors provide an opportunity to quantify the abundance of tropospheric formaldehyde at the global scale, and thereby to improve our knowledge of NMVOC emissions. This is essential for a better understanding of the processes that control the production and the evolution of tropospheric ozone, a key actor in air quality and climate change, but also of the hydroxyl radical OH, the main cleansing agent of our troposphere. For this reason, H2CO satellite observations are increasingly used in combination with tropospheric chemistry transport models to constrain NMVOC emission inventories in so-called top-down inversion approaches. Such inverse modelling applications require well characterised satellite data products consistently retrieved over long time periods.<p>This work reports on global observations of formaldehyde columns retrieved from the successive solar backscatter nadir sensors GOME, SCIAMACHY and GOME-2, respectively launched in 1995, 2002 and 2006. The retrieval procedure is based on the differential optical absorption spectroscopy technique (DOAS). Formaldehyde concentrations integrated along the mean atmospheric optical path are derived from the recorded spectra in the UV region, and further converted to vertical columns by means of calculated air mass factors. These are obtained from radiative transfer simulations, accounting for cloud coverage, surface properties and best-guess H2CO profiles, the latter being derived from the IMAGES chemistry transport model. A key task of the thesis has consisted in the optimisation of the H2CO retrieval settings from multiple sensors, taking into account the instrumental specificities of each sounder. As a result of these efforts, a homogeneous dataset of formaldehyde columns covering the period from 1996 to 2010 has been created. This comes with a comprehensive error budget that treats errors related to the spectral fit of the columns as well as those associated to the air mass factor evaluation. The time series of the GOME, SCIAMACHY and GOME-2 H2CO observations is shown to be consistent and stable over time. In addition, GOME-2 brings a significant reduction of the noise on spatiotemporally averaged observations, leading to a better identification of the emission sources. Our dataset is used to study the regional formaldehyde distribution, as well as its seasonal and interannual variations, principally related to temperature changes and fire events, but also to anthropogenic activities. Moreover, building on the quality of our 15-year time series, we present the first analysis of long-term changes in the H2CO columns. Positive trends, in the range of 1.5 to 4% yr-1, are found in Asia, more particularly in Eastern China and India, and are related to the known increase of anthropogenic NMVOC emissions in these regions. Finally, our dataset has been extensively used in several studies, in particular by the BIRA-IASB modelling team to constrain NMVOC emission fluxes. The results demonstrate the high potential of satellite data as top-down constraint for biogenic and biomass burning NMVOC emission inventories, especially in Tropical ecosystems, in Southeastern Asia, and in Southeastern US. <p><p>Le formaldéhyde (H2CO) joue un rôle central dans la chimie de la troposphère en tant que produit intermédiaire commun à la dégradation chimique de la plupart des composés organiques volatils dans l’atmosphère. L’oxydation du méthane est responsable de plus de la moitié de la concentration moyenne globale du formaldéhyde. Sur les continents en revanche, les hydrocarbures non-méthaniques (NMVOCs) émis par la végétation, les feux de biomasse et les activités humaines, augmentent de façon significative et localisée la concentration de H2CO. Les récents senseurs satellitaires à visée nadir offrent la possibilité de quantifier à l’échelle globale l’abondance du formaldéhyde dans la troposphère et de ce fait, d’améliorer notre connaissance des émissions de NMVOCs. Ceci est essentiel à la compréhension des mécanismes contrôlant la production et l’évolution de l’ozone troposphérique, élément clé pour la qualité de l’air et les changements climatiques, mais aussi du composé hydroxyle OH, le principal agent nettoyant de notre troposphère. C’est pourquoi, une méthode de plus en plus répandue pour améliorer les inventaires d’émissions des NMVOCs consiste en l’utilisation d’observations satellitaires de H2CO en combinaison avec un modèle de chimie et de transport troposphérique, dans une approche appelée modélisation inverse. Ce genre d’application demande des produits satellitaires bien caractérisés et dérivés de façon cohérente sur de longues périodes de temps.<p>Le travail présenté dans ce manuscrit porte sur l’inversion des colonnes de formaldéhyde à partir de spectres de la radiation solaire rétrodiffusée par l’atmosphère terrestre, mesurés par les senseurs GOME, SCIAMACHY et GOME-2, lancés successivement en 1995, 2002 et 2006. La méthode d’inversion est basée sur la spectroscopie d’absorption optique différentielle (DOAS). Les concentrations de formaldéhyde intégrées le long du chemin optique moyen dans l’atmosphère sont dérivées à partir des spectres mesurés, et ensuite transformées en colonnes verticales par le biais de facteurs de conversion appelés facteurs de masse d’air. Ces derniers sont calculés à l’aide d’un modèle de transfert radiatif, en tenant compte de la présence de nuages, des propriétés de la surface terrestre et la distribution verticale supposée du formaldéhyde, fournie par le modèle IMAGES. Un des objectifs principaux de la thèse a été d’optimiser les paramètres d’inversion pour H2CO, et ceci pour les trois senseurs, tout en tenant compte des spécificités de chaque instrument. Ces efforts ont conduit à la création d’un jeu de données homogène, couvrant la période de 1996 à 2010. Les colonnes sont fournies avec un bilan d’erreur complet, incluant les erreurs liées à l’inversion des concentrations dans les spectres, ainsi que celles provenant de l’évaluation des facteurs de masse d’air. La série temporelle des observations de GOME, SCIAMACHY et GOME-2 présente une bonne cohérence et stabilité sur toute la période. Nous montrons aussi que la meilleure couverture terrestre de GOME-2 entraîne une réduction significative du bruit sur les observations moyennées, permettant une meilleure identification des sources d’émission. Notre jeu de données est exploité pour étudier la distribution régionale du formaldéhyde, ainsi que ses variations saisonnières et interannuelles, principalement liées aux variations de température et aux feux de végétation, mais aussi aux activités anthropiques. De plus, en s’appuyant sur la qualité de la série temporelle de 15 ans, nous présentons la première analyse des variations à long terme des concentrations de H2CO. Des tendances positives, de l’ordre de 1.5 à 4% par an, sont observées en Asie, en particulier dans l’est de la Chine et en Inde, liées à l’augmentation des émissions anthropiques d’hydrocarbures dans ces régions. Finalement, nos données ont été largement exploitées par le groupe de modélisation de l’IASB pour faire des études de modélisation inverse des émissions de NMVOCs. Les résultats démontrent le haut potentiel des données satellitaires pour contraindre les inventaires d’émissions dues à la végétation et aux feux de biomasse, particulièrement dans les écosystèmes tropicaux, en Asie du sud-est, et dans le sud-est des Etats-Unis. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this Dissertation were identified events of influence of the Antarctic ozone hole over the South of Brazil that occurred in the period between 1979 and 2011. For this, we analyzed the daily average data of total ozone column obtained through the Brewer Spectrophotometers MKIV #081 model during the period 1992-2000, MKII model #056 of 2000-2002 and MKIII #167 model from 2002 to the present day, installed in the Southern Space Observatory- OES/CRS/INPE MCTI (29,4 °S; 53,8°O; 488,7m) and by satellite instruments Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) to the same latitude of the southern Space Observatory in the absence of surface equipment data, searching for days of falls in ozone content. For these days, isentrópicas analyses were conducted of potential vorticity using Reanalysis data provided by the National Centers for Environmental PredictionAtmospheric Research (NCEPNCAR), in order to verify the origin of ozone-poor air mass. Confirmation of the origin of polar air masses took place through the analysis of the trajectories retroactive made through the Hysplit model of NOAA. In addition, it was also conducted a complementary analysis through the pictures of the ozone content of TOMS and OMI, the ozone hole in the Antarctic region and its connection to the South of Brazil. The methodology used was effective in the identification of 66 events of the Influence of Antarctic Ozone Hole over south of Brazil, which showed an average drop of 8.66 ± 3.13 in the ozone content. The identification of the stratospheric circulation pattern through the medium of the vorticity field potential for the occurrence of the phenomenon was performed. In addition, were shown an analysis of synoptic weather troposphere during the occurrence of two events, noting that in both cases, the events occurred in a situation front post on the South of Brazil, coupled with the passage of the input region polar polar or subtropical jet stream, characterized by the occurrence of the event of the tropopause folding where stratospheric air intrusion occurs in the troposphere, and advancement of a high-pressure front post system that prevents the formation of significant cloud cover. Leveraging the operating environment of the Atmospheric Modeling Group (GRUMA) at the Federal University of Santa Maria (UFSM), using data from the output of numerical weather forecasting model Global Forecast System (GFS) in making maps of potential vorticity, can carry out effectively the clue of the forecast arrival of stratospheric air masses of polar origin on the southern Brazil during the spring of the year of 2012 with at least four days in advance, coinciding with the events of transport these side effects of the Antarctic ozone hole over the South of Brazil identified in the current year. / Na presente Dissertação foram identificados os eventos de Efeito Secundário do Buraco de Ozônio Antártico ocorridos sobre o Sul do Brasil no período entre 1979 e 2011. Para isso, foram analisados os dados médios diários da coluna total de ozônio obtidos através dos Espectrofotômetros Brewer modelo MKIV #081 durante o período de 1992 2000, modelo MKII #056 de 2000 2002 e modelo MKIII #167 de 2002 até os dias atuais, instalados no Observatório Espacial do Sul OES/CRS/INPE MCTI (29,4 °S; 53,8°O; 488,7m) e pelos instrumentos de satélite Total Ozone Mapping Spectrometer (TOMS) e Ozone Monitoring Instrument (OMI) para a mesma latitude do Observatório Espacial do Sul na falta de dados do equipamento de superfície, buscando dias de quedas no conteúdo de ozônio. Para estes dias, foram realizadas análises isentrópicas de vorticidade potencial utilizando dados de reanálise fornecidos pelo National Centers for Environmental Prediction/Atmospheric Research (NCEP/NCAR), a fim de verificar a origem da massa de ar pobre em ozônio. A confirmação da origem polar das massas de ar deu-se através da análise das trajetórias retroativas confeccionadas através do modelo Hysplit da NOAA. Além disso, foi também realizada uma análise complementar através das imagens do conteúdo de ozônio dos satélites TOMS e OMI, verificando-se a atuação do Buraco de Ozônio na região Antártica e sua conexão com o Sul do Brasil. A metodologia empregada mostrou-se eficaz na identificação de 66 eventos de Efeito Secundário do Buraco de Ozônio Antártico sobre o Sul do Brasil, os quais apresentaram uma queda média de 8,66 ± 3,13 % no conteúdo de ozônio. Foi realizada a identificação do padrão de circulação estratosférica através da confecção do campo médio da vorticidade potencial para os dias de ocorrência do fenômeno. Além disso, foram mostradas as analises das condições sinótica troposférica durante a ocorrência de dois eventos, observando-se que em ambos os casos, os eventos ocorreram em uma situação pós frontal sobre o Sul do Brasil, associada à passagem da região de entrada polar da corrente de jato subtropical ou polar, caracterizada pela ocorrência de evento de quebra da tropopausa onde ocorre intrusão de ar estratosférico para dentro da troposfera, e avanço de um sistema de alta pressão pós frontal que impede a formação de nebulosidade significativa. Aproveitando o ambiente operacional do Grupo de Modelagem Atmosférica (GRUMA) da Universidade Federal de Santa Maria (UFSM), utilizando dados da saída do modelo de previsão numérica de tempo Global Forecast System (GFS) na confecção de mapas de vorticidade potencial, pode-se realizar eficazmente a previsão do indício da chegada de massas de ar estratosféricas de origem polar sobre o Sul do Brasil durante o período da primavera do ano de 2012, com pelo menos quatro dias de antecedência, coincidindo estes transportes com os eventos de Efeito Secundário do Buraco de Ozônio Antártico sobre o Sul do Brasil identificados no corrente ano.

Dans un contexte de changement climatique, il est important d'étudier les processus de distribution et les tendances des gaz à l'état de traces dans l'atmosphère tels que l'ozone et la vapeur d'eau. L'observatoire atmosphérique du Maïdo, situé à 2160 m, héberge un ensemble d'instruments de mesures atmosphériques in-situ et par télédétection, dont le Lidar1200, pour la mesure de profils verticaux de vapeur d'eau. La validation, l'évaluation et une première exploitation des données du Lidar1200 font l'objet de cette thèse. Des comparaisons avec des radiosondages ont permis de valider les profils de vapeur d'eau du lidar depuis la basse troposphère jusqu'à 22 km d'altitude dès lors qu'un nombre suffisant de données est intégré. À courte échelle de temps, le Lidar1200 est capable de suivre temporellement des structures de l'ordre de la centaine de mètres d'épaisseur jusqu'à une dizaine de kilomètres d'altitude. L'analyse des données montre le potentiel du Lidar1200 de surveillance de la vapeur d'eau à long-terme dans la basse stratosphère avec un ou deux points de mesure par mois. La base de données 2013-2015 apporte des informations sur la variabilité saisonnière de la vapeur d'eau au-dessus de La Réunion. Les données de vapeur d'eau permettent de documenter divers processus atmosphériques dont les échanges stratosphère-troposphère. Des signatures d'intrusion stratosphérique ont été observées sur des observations lidar quasi simultanées et co-localisées d'ozone et de vapeur d'eau pendant la campagne de mesure MALICCA (MAïdo LIdar Calibration Campaign, La Réunion), le 4 avril 2013, suggérant un processus d'intrusion stratosphérique avec plusieurs origines. / In a context of climate change, it is important to study distribution processes and the trends of trace atmospheric gases such as ozone and water vapor. The Maïdo atmospheric observatory, located at 2160 m in height, hosts a set of atmospheric in-situ and remote sensing instruments, including the Lidar1200 providing vertical water vapor profiles. This thesis aims to provide a thorough work of validation, evaluation and analysis of the Lidar1200 data. Comparisons with radiosoundings allowed to validate the water vapor profiles of the lidar from the lower troposphere up to an altitude of 22 km if a sufficient number of data is integrated. At a smaller temporal scale, the Lidar1200 is able to follow temporally structures in the range of a hundred of meters thick up to a dozen of kilometers in altitude. The data analysis show the potential of the lidar in monitoring the water vapor in the lower stratosphere on a long term with one to two points of measurements by month. The database 2013-2015 brings information on the seasonal variability of the water vapor over Reunion Island. The water vapor data allow to study various atmospheric processes including stratosphere-troposphere exchanges. Signatures of stratospheric intrusions were observed on quasi-simultaneous and co-localized ozone and water vapor observations realized by two lidars of the Maïdo Observatory during the measurement campaign MALICCA-1 (MAïdo LIdar Calibration CAmpaign, Reunion Island), on April 4, 2013, suggesting stratospheric intrusions with multiple origins.

Doppler radar wind profilers are already widely used to measure atmospheric winds throughout the free troposphere and stratosphere. Several methods have been developed to quantify atmospheric turbulence with such radars, but to date they have remained largely un-tested; this thesis presents the first comprehensive validation of one such method. Conventional in-situ measurements of turbulence have been concentrated in the surface layer, with some aircraft and balloon platforms measuring at higher altitudes on a case study basis. Radars offer the opportunity to measure turbulence near continuously, and at a range of altitudes, to provide the first long term observations of atmospheric turbulence above the surface layer. Two radars were used in this study, a Mesosphere-Stratosphere-Troposphere (MST) radar, at Capel Dewi, West Wales, and the Facility for Ground Based Atmospheric Measurements (FGAM) mobile boundary layer profiler. In-situ measurements were made using aircraft and tethered-balloon borne turbulence probes. The spectral width method was chosen for detailed testing, which uses the width of a radar's Doppler spectrum as a measure of atmospheric velocity variance. Broader Doppler spectra indicate stronger turbulence. To obtain Gaussian Doppler spectra (a requirement of the spectral width method), combination of between five and seven consecutive spectra was required. Individual MST spectra were particularly non-Gaussian, because of the sparse nature of turbulence at its observation altitudes. The width of Gaussian fits to the Doppler spectrum were compared to those from the `raw' spectrum, to ensure that non-atmospheric signals were not measured. Corrections for non-turbulent broadening, such as beam broadening, and signal processing, were investigated. Shear broadening was found to be small, and the errors in its calculation large, so no corrections for wind shear were applied. Beam broadening was found to be the dominant broadening contribution, and also contributed the largest uncertainty to spectral widths. Corrected spectral widths were found to correlate with aircraft measurements for both radars. Observing spectral widths over time periods of 40 and 60 minutes for the boundary layer profiler and MST radar respectively, gave the best measure of turbulence intensity and variability. Median spectral widths gave the best average over that period, with two-sigma limits (where sigma is the standard deviation of spectral widths) giving the best representation of the variability in turbulence. Turbulent kinetic energies were derived from spectral widths; typical boundary layer values were 0.13 m 2.s (-2) with a two-sigma range of 0.04-0.25 m 2.s (-2), and peaked at 0.21 m 2.s (-2) with a two-sigma range of 0.08-0.61 m 2.s (-2). Turbulent kinetic energy dissipation rates were also calculated from spectral widths, requiring radiosonde measurements of atmospheric stability. Dissipation rates compared well width aircraft measurements, reaching peaks of 1x10 (-3) m 2.s (-3) within 200 m of the ground, and decreasing to 1-2x10 (-5) m 2.s (-3) near the boundary layer capping inversion. Typical boundary layer values were between 1-3x10 (-4) m 2.s (-3). Those values are in close agreement with dissipation rates from previous studies.

To understand the contribution of aerosol particles to radiative forcing and heterogeneous chemical processes in the upper troposphere and lowermost stratosphere (UT/LMS), the knowledge of the particle size distribution is mandatory. Unfortunately, measurements in the UT/LMS are costly. Research aircrafts are expensive and thus their application is limited in time and space. Satellite remote sensing measurements provide a good temporal and spatial (horizontal) coverage, but only a limited vertical resolution and currently cannot resolve the particle size distribution. Therefore, within this thesis an optical particle counter (OPC) unit was modified for the application onboard a passenger long-haul aircraft within the CARIBIC project (www.caribic-atmospheric.com). The CARIBIC OPC unit provides regular and cost-efficient particle size distribution measurements of accumulation mode particles in the UT/LMS. In April 2010, the new OPC unit was installed for the first time onboard the Lufthansa Airbus A340 600 (D-AIHE) for the measurement of the volcanic ash cloud from the Eyjafjallajökull eruption (April to May 2010). Since June 2010 the OPC unit measures on usually four intercontinental flights per month the UT/LMS particle size distribution in the particle size range 125 to 1300 nm particle diameter. As the data acquisition stores the scattering raw signal and all housekeeping data as well, during the post flight data analysis the temporal- and size channel resolution can be flexible set. Within this work the data were analyzed with 32 size channels and 300 seconds. As aircraft-borne measurements are always time-consuming, the development of the OPC unit and the analysis routine, as well as its characterization and certification took more than two thirds of the total working time of this thesis. Therefore, the analysis of the data is limited to the first year of regular measurements until May 2011. Nevertheless, this dataset is sufficient to demonstrate the scientific relevance of these measurements. To validate the OPC data, a comparison to particle size distributions measured from board research aircraft was carried out. The analysis of the volcanic ash flights in April and May 2010 showed strongly enhanced particle mass concentrations inside the plumes and agreed in some regions very well to the particle mass concentration predicted by a dispersion model. A further case study shows the occurrence of a surprising large (1000 km) and high concentrated pollution plume over eastern Asia close to Osaka (Japan). Inside the plume the highest particle number- and mass concentrations measured with the OPC unit in the analysis period were observed (except volcanic ash flights). A detailed analysis of the in parallel measured trace gasses as well as meteorological- and LIDAR data showed, the observed plume originate from biomass burning and industrial emissions in eastern China. A third case study gives a first attempt of a mass closure/validation between the particle masses derived by the CARIBIC OPC unit and the CARIBIC impactor particle samples. First statistical analyses to the vertical, meridional, and seasonal variation of the accumulation mode particle size distribution and therefrom derived parameter indicate a stratospheric vertical increasing gradient for the particle number- and mass concentration. In general in the mid-latitude LMS the concentration of accumulation mode particles was found to be on average 120% higher than in the mid-latitude UT. The mid-latitude LMS particle size distribution shows a seasonal variation with on average 120% higher concentrations during spring compared to fall. This results can be explained with general dynamics in the stratosphere (Brewer-Dobson Circulation) and in the tropopause region (stratosphere-troposphere-exchange, STE). An anti-correlation of gaseous mercury to the stratospheric particle surface area concentration (R²=0.97) indicates that most likely stratospheric aerosol particles do act as a sink for gaseous mercury. Finally, two comparisons of the OPC data to data from satellite remote sensing and a global aerosol model underline the OPC potential and the benefits of creating an in situ measured reference dataset. / Um die Rolle von Aerosolpartikeln beim Strahlungsantrieb und der heterogenen chemischen Prozessen in der oberen Troposphäre und untersten Stratosphäre (OT/US) verstehen zu können, ist es unabdingbar die Partikelgrößenverteilung zu kennen. Messungen der Partikelgrößenverteilung in dieser Region sind allerdings aufwendig. Der Einsatz von Forschungsflugzeugen ist teuer und deshalb zeitlich und räumlich nur begrenzt. Satellitenmessungen bieten zwar eine gute zeitliche und räumliche (horizontal) Abdeckung, aber nur eine begrenzte vertikale Auflösung. Weiterhin können bisherige Satellitenmessungen die Partikelgrößenverteilung nicht auflösen. Im Rahmen dieser Arbeit wurde deshalb ein optischer Partikelzähler (OPC) Messeinschub für den Einsatz an Bord eines Langstrecken-Passagierflugzeugs aufgebaut (CARIBIC Projekt, www.caribic-atmospheric.com). Mit diesem Messeinschub kann regelmäßig und kosteneffizient die Partikelgrößenverteilung des Akkumulationsmodes in der OT/US gemessen werden. Im April 2010 wurde der neue OPC Einschub erstmals an Bord des Lufthansa Airbus A340-600 (D-AIHE) installiert um die Vulkanasche der Eyjafjallajökull Eruption (April bis Mai 2010) zu messen. Seit Juni 2010 misst der OPC Einschub auf durchschnittlich vier Interkontinentalflügen pro Monat die Partikelgrößenverteilung der OT/US im Größenbereich zwischen 125 und 1300 nm Partikeldurchmesser. Während des Fluges speichert die Datenerfassung alle Rohsignale ab und ermöglicht dadurch eine nutzerspezifische Datenauswertung nach dem Flug (z. B. Anzahl der Größenkanäle oder Zeitauflösung). Im Rahmen dieser Arbeit wurden die Daten mit 32 Größenkanälen und 300 Sekunden analysiert. Da fluggetragene Messungen immer sehr aufwendig sind, beanspruchte die Entwicklung des OPC Einschubs und des Analysealgorithmus, sowie die Charakterisierung und Zertifizierung mehr als zwei Drittel der Gesamtarbeitszeit dieser Arbeit. Daher ist die Analyse der Messdaten auf das erste Jahr der regulären Messungen bis Mai 2011 beschränkt. Dennoch ist dieser Datensatz geeignet um die wissenschaftliche Relevanz dieser Messungen zu demonstrieren. Um die OPC-Daten zu validieren, wurde ein Vergleich mit bisherigen OPC Messungen von Bord Forschungsflugzeugen durchgeführt. Die Analyse der Vulkanascheflüge im April und Mai 2010 zeigte in der Abluftfahne stark erhöhte Partikelmassekonzentrationen, welche in einigen Vergleichsregionen sehr gut mit der Vorhersage eines Disperionsmodells übereinstimmten. Eine weitere Fallstudie zeigt das Auftreten einer überraschend großen (1000 km) und hoch konzentrierten Abluftfahne über Ostasien nahe Osaka (Japan). In der Abluftfahne wurde die im Analysezeitraum höchste mit dem CARIBIC OPC gemessene Partikelanzahl- und Massenkonzentration beobachtet (ausgenommen Vulkanascheflüge). Eine detaillierte Analyse der parallel gemessenen Spurengase, sowie meteorologischer Daten und LIDAR Profile zeigte, dass die beobachtete Abluftfahne eine Mischung aus Biomasseverbrennungs- und Industrieabgasen aus Ost-China war. Eine dritte Fallstudie stellt einen ersten Versuch einer Massenschließung/Validierung zwischen der aus den CARIBIC OPC-Daten abgeleiteten Partikelmasse und der Partikelmasse aus CARIBIC Impaktorproben dar. Erste statistische Analysen zur vertikalen, meridionalen und saisonalen Variabilität der Partikelgrößenverteilung im Akkumulationsmode und daraus abgeleiteten Parametern zeigen einen vertikal ansteigenden Gradienten für die Partikelanzahl- und Massenkonzentration. Generell war in der US der mittleren Breiten die Konzentration von Akkumulationsmode Partikeln im Mittel um 120% höher als in der OT der mittleren Breiten. Weiterhin wurde in der US der mittleren Breiten eine jahreszeitliche Schwankung gefunden. Im Frühling war die mit dem OPC gemessene Partikelkonzentrationen im Mittel um 120% höher als im Herbst. Diese Befunde lassen sich mit der atmosphärischen Dynamik in der Stratosphäre (Brewer-Dobson Zirkulation) und in der Tropopausenregion (Stratosphäre-Troposphäre-Austauschprozesse) erklären. Eine gefundene negative Korrelation von gasförmigen Quecksilber mit der stratosphärischen Partikeloberflächenkonzentration (R²=0.97) ist ein starker Indikator dafür, dass in der US Aerosolpartikel eine Senke für gasförmiges Quecksilber darstellen. Zum Abschluss unterstreichen zwei Vergleiche der OPC-Daten mit Satellitenmessungen und Ergebnissen eines globalen Aerosolmodels das Potential und den Nutzen der CARIBIC OPC Daten als in-situ gemessenen Referenzdatensatz.