Teses / dissertações sobre o tema "Atmospheric cycle"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Atmospheric cycle".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
Ruane, Alexander C. "Diurnal to annual variations in the atmospheric water cycle". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3263195.
Texto completo da fonteTitle from first page of PDF file (viewed July 10, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 146-154).
Sturm, Kristof. "Regional atmospheric modelling of the stable water istope cycle". Université Joseph Fourier (Grenoble), 2005. https://tel.archives-ouvertes.fr/tel-00010157.
Texto completo da fonteClimate change has recently become a major concerning among scientists and the general public. A better knowledge of past climates helps forecasting the future evolution of climate. Stable water isotopes stand as an outstanding paleo-climate proxy. Physical properties of heavy stable water isotopes (H182 O; HDO) cause fractionation processes related to temperature and degree of distillation. If the isotopic signal is correctly inverted, past climate change can be inferred from isotopic archives. Andean ice-cores offer a unique records of tropical climate and its variability through time. However, the interpretation of the isotopic signal is difficult because of complex atmospheric dynamic over South America. For this purpose, we developed a module handling the stable water isotope fractionation processes within the regional circulation model REMO and applied it to South America. The manuscript outlines the major milestones of the present PhD. We first introduce the research topic in the wider scope of climate change; the description of the stable water isotope enabled regional circulation model REMOiso; an initial validation of REMOiso over Europe; an investigation of the seasonal variations of precipitation, atmospheric circulation and isotopic signal over South America; and at last the recording of the south American monsoon system (SAMS) by stable water isotope diagnostics
Park, Sewon. "Diurnal cycle of deep tropical convection". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/54985.
Texto completo da fonteTitle as it appears in the M.I.T. Graduate List, Feb. 1992: Diurnal cycle of deep cloud cover in tropics.
Includes bibliographical references (leaf 53).
by Sewon Park.
M.S.
Stephens, Britton Bruce. "Field-based atmospheric oxygen measurements and the ocean carbon cycle /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035435.
Texto completo da fonteIto, Takamitsu 1976. "Feedback mechanism in the oceanic carbon cycle". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/54435.
Texto completo da fonteIncludes bibliographical references (p. [84]-[87]).
In this thesis, I designed and implemented a simple atmosphere-ocean coupled carbon cycle model which can be used as a tool to uncover the mechanisms of the interaction between the dynamics of the atmosphere-ocean system and the oceanic reservoir of CO 2 on the 101 to 103 years time scale. The atmosphere-ocean coupled model is originally developed by Marotzke (20,21), and the biogeochemical model is developed by Follows(personal communication). The atmosphere-ocean-carbon model makes the atmosphere-ocean dynamics and the carbon cycle fully interactive, and results in two stationary states characterized by two distinct patterns of the thermohaline circulation. The temperature driven, high latitudes sinking mode showed significantly lower atmospheric pCO2 than the salinity-driven, low latitudes sinking mode. The atmosphere-ocean dynamics dominates the system behavior of the model. The carbon cycle weakly feedbacks on the atmosphere-ocean system through the radiation balance. The model reveals two feedback mechanisms, the global warming feedback and the thermohaline pCO 2 feedback. The thermohaline pCO2 feedback has three sub-components, which are the biological pump feedback, the outgassing feedback and the DIC exporting feedback. The numerical experiments estimate the relative importance among them. The system becomes less stable when all the feedback mechanism is introduced. The model could be used to understand some basic mechanism of the situations similar to the anthropogenic global warming. The stability analysis is applied to evaluate the model runs. The current rate of 7 GTC yr - 1 can induce the spontaneous shutdown of thermohaline circulation after 550 years of constant emission. The stability of the thermohaline circulation rapidly decreases even before the system stops the thermohaline circulation. The model parameterized surface alkalinity as a simple function of sea surface salinity or as a constant, rather than solving the alkalinity cycle explicitly. The system is sensitive to the parameterization, in which different assumptions on alkalinity lead to different results both analytically and numerically.
by Takamitsu Ito.
S.M.
Wallace, Craig. "Variability in the annual cycle of temperature and the atmospheric circulation". Thesis, University of East Anglia, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399842.
Texto completo da fonteVan, Damme Martin. "Assessment of global atmospheric ammonia using IASI infrared satellite observations". Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209085.
Texto completo da fonteThe natural nitrogen cycle has been and is significantly perturbed by anthropogenic emissions of reactive nitrogen (Nr) compounds into the atmosphere, resulting from our production of energy and food. In the last century global ammonia (NH3) emissions have doubled and represent nowadays more than half of total the Nr emissions. NH3 is also the principal atmospheric base in the atmosphere and rapidly forms aerosols by reaction with acids. It is therefore a species of high relevance for the Earth's environment, climate and human health (Chapter 1). As a short-lived species, NH3 is highly variable in time and space, and while ground based measurements are possible, they are sparse and their spatial coverage is largely heterogeneous. Consequently, global spatial and temporal patterns of NH3 emissions are poorly understood and account for the largest uncertainties in the nitrogen cycle. The aim of this work is to assess distributions and saptiotemporal variability of NH3 using satellite measurements to improve our understanding of its contribution to the global nitrogen cycle and its related effects.
Recently, satellite instruments have demonstrated their abilities to measure NH3 and to supplement the sparse surface measuring network by providing global total columns daily. The Infrared Atmospheric Sounding Interferometer (IASI), on board MetOp platforms, is measuring NH3 at a high spatiotemporal resolution. IASI circles the Earth in a polar Sun-synchronous orbit, covering the globe twice a day with a circular pixel size of 12km diameter at nadir and with overpass times at 9:30 and 21:30 (local solar time when crossing the equator). An improved retrieval scheme based on the calculation of Hyperspectral Range Index (HRI) is detailed in Chapter 2 and compared with previous retrieval methods. This approach fully exploits the hyperspectral nature of IASI by using a broader spectral range (800-1200 cm-1) where NH3 is optically active. It allows retrieving total columns from IASI spectra globally and twice a day without large computational resources and with an improved detection limit. More specifically the retrieval procedure involves two steps: the calculation of a dimensionless spectral index (HRI) and the conversion of this index into NH3 total columns using look-up tables (LUTs) built from forward radiative transfer simulations under various atmospheric conditions. The retrieval also includes an error characterization of the retrieved column, which is of utmost importance for further analysis and comparisons. Global distributions using five years of data (1 November 2007 to 31 October 2012) from IASI/MetOp-A are presented and analyzed separately for the morning and evening overpasses. The advantage of the HRI-based retrieval scheme over other methods, in particular to identify smaller emission sources and transport patterns over the oceans is shown. The benefit of the high spatial sampling and resolution of IASI is highlighted with the regional distribution over China and the first four-year time series are briefly discussed.
We evaluate four years (1 January 2008 to 31 December 2011) of IASI-NH3 columns from the morning observations and of LOTOS-EUROS model simulations over Europe and Western Russia. We describe the methodology applied to account for the variable retrieval sensitivity of IASI measurements in Chapter 3. The four year mean distributions highlight three main agricultural hotspots in Europe: The Po Valley, the continental part of Northwestern Europe, and the Ebro Valley. A general good agreement between IASI and LOTOS-EUROS is shown, not only over source regions but also over remote areas and over seas when transport is observed. The yearly analyses reveal that, on average, the measured NH3 columns are higher than the modeled ones. Large discrepancies are observed over industrial areas in Eastern Europe and Russia pointing to underestimated if not missing emissions in the underlying inventories. For the three hotspots areas, we show that the seasonality between IASI and LOTOS-EUROS matches when the sensitivity of the satellite measurements is taken into account. The best agreement is found in the Netherlands, both in magnitude and timing, most likely as the fixed emission timing pattern was determined from experimental data sets from this country. Moreover, comparisons of the daily time series indicate that although the dynamic of the model is in reasonable agreement with the measurements, the model may suffer from a possible misrepresentation of emission timing and magnitude. Overall, the distinct temporal patterns observed for the three sites underline the need for improved timing of emissions. Finally, the study of the Russian fires event of 2010 shows that NH3 modeled plumes are not enough dispersed, which is confirmed with a comparison using in situ measurements.
Chapter 4 describes the comparisons of IASI-NH3 measurements with several independent ground-based and airborne data sets. Even though the in situ data are sparse, we show that the yearly distributions are broadly consistent. For the monthly analyzes we use ground-based measurements in Europe, China and Africa. Overall, IASI-derived concentrations are in fair agreement but are also characterized by less variability. Statistically significant correlations are found for several sites, but low slopes and high intercepts are calculated in all cases. At least three reasons can explain this: (1) the lack of representativity of the point surface measurement for the large IASI pixel, (2) the use of a single profile shape in the retrieval scheme over land, which does therefore not account for a varying boundary layer height, (3) the impact of the averaging procedure applied to satellite measurements to obtain a consistent quantity to compare with the in situ monthly data. The use of hourly surface measurements and of airborne data sets allows assessing IASI individual observations. Much higher correlation coefficients are found in particular when comparing IASI-derived volume mixing ratio with vertically resolved measurements performed from the NOAA WP-3D airplane during CalNex campaign in 2010. The results demonstrate the need, for validation of the satellite columns, of measurements performed at various altitudes and covering a large part of the satellite footprint.
The six-year of IASI observations available at the end of this thesis are used to analyze regional time series for the first time (Chapter 5). More precisely, we use the IASI measurements over that period (1 January 2008 to 31 December 2013) to identify seasonal patterns and inter-annual variability at subcontinental scale. This is achieved by looking at global composite seasonal means and monthly time series over 12 regions around the world (Europe, Eastern Russia and Northern Asia, Australia, Mexico, South America, 2 sub-regions for Northern America and South Asia, 3 sub-regions for Africa), considering separately but simultaneously measurements from IASI morning and evening overpasses. The seasonal cycle is inferred for the majority of these regions. The relations between the NH3 atmospheric abundance and emission processes is emphasized at smaller regional scale by extracting at high spatial resolution the global climatology of the month of maxima columns. In some region, the predominance of a single source appears clearly (e.g. agriculture in Europe and North America, fires in central South Africa and South America), while in others a composite of source processes on small scale is demonstrated (e.g. Northern Central Africa and Southwestern Asia).
Chapter 6 presents the achievements of this thesis, as well as ongoing activities and future perspectives.
FRANCAIS:
Le cycle naturel de l'azote est fortement perturbé suite aux émissions atmosphériques de composés azotés réactifs (Nr) résultant de nos besoins accrus en énergie et en nourriture. Les émissions d'ammoniac (NH3) ont doublé au cours du siècle dernier, représentant aujourd'hui plus de la moitié des émissions totales de Nr. De plus, le NH3 étant le principal composé basique de notre atmosphère, il réagit rapidement avec les composés acides pour former des aérosols. C'est dès lors un constituant prépondérant pour l'environnement, le climat et la santé publique. Les problématiques environnementales y étant liées sont décrites au Chapitre 1. En tant que gaz en trace le NH3 se caractérise par une importante variabilité spatiale et temporelle. Bien que des mesures in situ soient possibles, elles sont souvent rares et couvrent le globe de façon hétérogène. Il en résulte un manque de connaissance sur l'évolution temporelle et la variabilité spatiale des émissions, ainsi que de leurs amplitudes, qui représentent les plus grandes incertitudes pour le cycle de l'azote (également décrites au Chapitre 1).
Récemment, les sondeurs spatiaux opérant dans l'infrarouge ont démontré leurs capacités à mesurer le NH3 et par là à compléter le réseau d'observations de surface. Particulièrement, l'Interféromètre Atmosphérique de Sondage Infrarouge (IASI), à bord de la plateforme MetOp, mesure le NH3 à une relativement haute résolution spatiotemporelle. Il couvre le globe deux fois par jour, grâce à son orbite polaire et son balayage autour du nadir, avec un temps de passage à 9h30 et à 21h30 (temps solaire local quand il croise l'équateur). Une nouvelle méthode de restitution des concentrations basée sur le calcul d'un index hyperspectral sans dimension (HRI) est détaillée et comparée aux méthodes précédentes au Chapitre 2. Cette méthode permet d'exploiter de manière plus approfondie le caractère hyperspectral de IASI en se basant sur une bande spectrale plus étendue (800-1200 cm-1) au sein de laquelle le NH3 est optiquement actif. Nous décrivons comment restituer ces concentrations deux fois par jour sans nécessiter de grandes ressources informatiques et avec un meilleur seuil de détection. Plus spécifiquement, la procédure de restitution des concentrations consiste en deux étapes: le HRI est calculé dans un premier temps pour chaque spectre puis est ensuite converti en une colonne totale de NH3 à l'aide de tables de conversions. Ces tables ont été construites sur base de simulations de transfert radiatif effectuées pour différentes conditions atmosphériques. Le processus de restitution des concentrations comprend également le calcul d'une erreur sur la colonne mesurée. Des distributions globales moyennées sur cinq ans (du 1 novembre 2007 au 31 Octobre 2012) sont présentées et analysées séparément pour le passage diurne et nocturne de IASI. L'avantage de ce nouvel algorithme par rapport aux autres méthodes, permettant l'identification de sources plus faibles de NH3 ainsi que du transport depuis les sources terrestres au-dessus des océans, est démontré. Le bénéfice de la haute couverture spatiale et temporelle de IASI est mis en exergue par une description régionale au-dessus de la Chine ainsi que par l'analyse de premières séries temporelles hémisphériques sur quatre ans.
Au Chapitre 3, nous évaluons quatre ans (du 1 janvier 2008 au 31 décembre 2011) de mesures matinales de IASI ainsi que de simulations du modèle LOTOS-EUROS, effectuées au-dessus de l'Europe et de l'ouest de la Russie. Nous décrivons une méthodologie pour prendre en compte, dans la comparaison avec le modèle, la sensibilité variable de l'instrument IASI pour le NH3. Les comparaisons montrent alors une bonne concordance générale entre les mesures et les simulations. Les distributions pointent trois régions sources: la vallée du Pô, le nord-ouest de l'Europe continentale et la vallée de l'Ebre. L'analyse des distributions annuelles montre qu'en moyenne, les colonnes de NH3 mesurées sont plus élevées que celles simulées, à part pour quelques cas spécifiques. Des différences importantes ont été identifiées au-dessus de zones industrielles en Europe de l'est et en Russie, ce qui tend à incriminer une sub-estimation voire une absence de ces sources dans les inventaires d'émissions utilisés en entrée du modèle. Nous avons également montré que la saisonnalité est bien reproduite une fois la sensibilité des mesures satellites prise en compte. La meilleure concordance entre le modèle et IASI est observée pour les Pays-Bas, ce qui est certainement dû au fait que le profil temporel des émissions utilisé pour les simulations LOTOS-EUROS est basé sur des études expérimentales réalisées dans ce pays. L'étude des séries temporelles journalières indique que la dynamique du modèle est raisonnablement en accord avec les mesures mais pointe néanmoins une possible mauvaise représentation du profil temporel ainsi que de l'ampleur des émissions. Finalement, l'étude des importants feux ayant eu cours en Russie à l'été 2010 a montré que les panaches modélisés sont moins étendus que ceux observés, ce qui a été confirmé grâce à une comparaison avec des mesures sols.
Le chapitre 4 est dédié à la confrontation des mesures IASI avec différents jeux de données indépendants acquis depuis le sol et par avion. Les distributions globales annuelles sont concordantes, bien que la couverture spatiale des mesures sols soit limitée. Des mesures effectuées à la surface en Europe, en Chine et en Afrique sont utilisées pour les comparaisons mensuelles. Ces dernières révèlent une bonne concordance générale, bien que les mesures satellites montrent une plus faible amplitude de variations de concentrations. Des corrélations statistiquement significatives ont été calculées pour de nombreux sites, mais les régressions linéaires sont caractérisées par des pentes faibles et des ordonnées à l'origine élevées dans tous les cas. Au minimum, trois raisons contribuent à expliquer cela: (1) le manque de représentativité des mesures ponctuelles pour l'étendue des pixels IASI, (2) l'utilisation d'une seule forme de profil vertical pour la restitution des concentrations, qui ne prend dès lors pas en compte la hauteur de la couche limite, (3) l'impact de la procédure utilisée pour moyenner les observations satellites afin d'obtenir des quantités comparables aux mesures sols mensuelles. La prise en compte de mesures en surface effectuées à plus haute résolution temporelle ainsi que de mesures faites depuis un avion permet d'évaluer les observations IASI individuelles. Les coefficients de corrélation calculés sont bien plus élevés, en particulier pour la comparaison avec les mesures effectuées depuis l'avion NOAA WP-3D pendant la campagne CalNex en 2010. Ces résultats démontrent la nécessité de ce type d'observations, effectuées à différentes altitudes et couvrant une plus grande surface du pixel, pour valider les colonnes IASI-NH3.
Les six ans de données IASI disponibles à la fin de cette thèse sont utilisées pour tracer les premières séries temporelles sub-continentales (Chapitre 5). Plus spécifiquement, nous explorons les mesures IASI durant cette période (du 1 janvier 2008 jusqu'au 31 décembre 2013) pour identifier des structures saisonnières ainsi que la variabilité inter-annuelle à l'échelle sous-continentale. Pour arriver à cela, des moyennes saisonnières composites ont été produites ainsi que des séries temporelles mensuelles au-dessus de 12 régions du globe (Europe, est de la Russie et nord de l'Asie, Australie, Mexique, Amérique du Sud, 2 sous-régions en Amérique du nord et en Asie du sud et 3 sous-régions en Afrique), considérant séparément mais simultanément les mesures matinales et nocturnes de IASI. Le cycle saisonnier est raisonnablement bien décrit pour la plupart des régions. La relation entre la quantité de NH3 atmosphérique et ses sources d'émission est mise en exergue à l'échelle plus régionale par l'extraction à haute résolution spatiale d'une climatologie des mois de colonnes maximales. Dans certaines régions, la prédominance d'un processus source apparait clairement (par exemple l'agriculture en Europe et en Amérique du nord, les feux en Afrique du Sud et en Amérique du Sud), alors que, pour d'autres, la diversité des sources d'émissions est démontrée (par exemple pour le nord de l'Afrique centrale et l'Asie du sud-ouest).
Le Chapitre 6 reprend brièvement les principaux aboutissements de cette thèse et présente les différentes recherches en cours et les perspectives associées.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
DeLuca, Cecelia. "Means and variability of some aspects of the hydrological cycle". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10669.
Texto completo da fonteHu, Wenjie. "The semiannual cycle of sea surface and free air temperatures". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/54415.
Texto completo da fonteShannon, Sarah R. "Modelling the atmospheric mineral dust cycle using a dynamic global vegetation model". Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520308.
Texto completo da fonteMooring, Todd A. "Changes in atmospheric eddy length with the seasonal cycle and global warming". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65599.
Texto completo da fonteCataloged from PDF version of thesis.
Includes bibliographical references (p. 59-60).
A recent article by Kidston et al. [8] demonstrates that the length of atmospheric eddies increases in simulations of future global warming. This thesis expands on Kidston et al.'s work with additional studies of eddy length in the NCEP2 reanalysis (a model-data synthesis that reconstructs past atmospheric circulation) and general circulation models (GCMs) from the Coupled Model Intercomparison Project phase 3. Eddy lengths are compared to computed values of the Rossby radius and the Rhines scale, which have been hypothesized to set the eddy length. The GCMs reproduce the seasonal variation in the eddy lengths seen in the reanalysis. To explore the effect of latent heating on the eddies, a modification to the static stability is used to calculate an effective Rossby radius. The effective Rossby radius is an improvement over the traditional dry Rossby radius in predicting the seasonal cycle of northern hemisphere eddy length, if the height scale used for calculation of the Rossby radius is the depth of the free troposphere. There is no improvement if the scale height is used instead of the free troposphere depth. However, both Rossby radii and the Rhines scale fail to explain the weaker seasonal cycle in southern hemisphere eddy length. In agreement with Kidson et al., the GCMs robustly project an increase in eddy length as the climate warms. The Rossby radii and Rhines scale are also generally projected to increase. Although it is not possible to state with confidence what process ultimately controls atmospheric eddy lengths, taken as a whole the results of this study increase confidence in the projection of future increases in eddy length.
by Todd A. Mooring.
S.B.
Morra, Matthew John. "Gaps in the sulfur cycle : biogenic hydrogen sulfide production and atmospheric deposition /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487323583619796.
Texto completo da fonteYeatman, Stuart Gregory. "Major-ion and isotopic studies of aerosol nitrogen species in the marine atmosphere". Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327281.
Texto completo da fonteBorque, Paloma. "Scale analysis of the diurnal cycle of precipitation over Continental United States". Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97238.
Texto completo da fonteCette étude porte sur la variabilité géographique et d'échelle du cycle diurne des précipitations estivales, au-dessus des États-Unis continentaux, par l'analyse de mosaïques radars de 12 ans pour la période de 1996-2007. Les transformées en ondelettes sont utilisées pour saisir l'importance des différentes échelles spatiales de 8 à 512 km dans le cycle diurne. L'objectif de cette mémoire est d'étudier la dépendance de la variabilité du champ de précipitation sur l'endroit géographique et la période du jour, et comment cette variabilité est expliquée par les différentes échelles.Les résultats de cette analyse montre que l'activité maximale de précipitation survient à un temps différent pour différentes échelles spatiales : plus large est l'échelle, plus tard se produit l'importance maximal de l'échelle. L'initiation de précipitation dépend de l'échelle : le début est associé aux petites échelles, qui s'organisent plus tard pour former des chutes de pluie à plus grande échelle. Sur les Grandes Prairies, la moyenne du champ de précipitation montre deux maximums : un en après-midi et relié aux petites échelles (associé au forçage radiative); un second durant la nuit, relié aux grandes échelles (systèmes de chute de pluie se propageant de l'ouest). Au dessus de la région Est, la distribution de précipitation est également dépendante de l'échelle; elle montre un comportement similaire au-dessus du côté Est des Rocheuses. En particulier, un taux maximal de chute de pluie advient en après-midi en association avec des processus de petites échelles. La précipitation mensuelle, et sa décomposition par échelles, est aussi analysée afin d'identifier les différences dans le cycle diurne de précipitation de chaque mois estival.
Panday, Arnico Kumar. "The diurnal cycle of air pollution in the Kathmandu Valley, Nepal". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37361.
Texto completo da fonteThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 213-230).
This dissertation describes the most comprehensive study to date of the diurnal cycle of air pollution in the Kathmandu Valley, Nepal -- a bowl-shaped mountain valley of two million people with a growing air pollution problem but little past research. Field measurements and computer simulations were used to study the interplay of emissions and ventilation. From September 2004 through June 2005, CO (carbon monoxide), ozone, PM10 (particles smaller than 10 micrometers), wind speed and direction, solar radiation, temperature, and humidity were continuously measured east of Kathmandu. Sensors towers and mountains measured the diurnal cycle of the vertical temperature structure and stability. A sodar measured the mixed layer height and upper-level winds. Bag sampling provided the diurnal cycle of CO on mountains, passes and around the valley. Winds were measured on a mountain pass and ozone on a mountaintop. Patterns of air pollution and meteorology in the valley showed remarkable day-to-day similarity, with daily twin peaks of CO and PM10, a noon ozone maximum, afternoon westerly winds, and a stagnant cold pool at night. On mountaintops at night, ozone remained high, while CO dropped to regional background levels.
(cont.) The meso-scale meteorological model MM5 was adapted to the Kathmandu Valley for days in February and May 2005. It was able to capture the essential features of the valley's meteorology and was used to address three specific questions: The break-up of the valley's temperature inversion was found to be dominated in February by up-slope winds on the valley rim, plus subsidence over the valley center; in May surface heating of the valley bottom also played a major role. The pathways of pollutant transport out of the valley were found to be up the valley rim slopes in the morning, but out the eastern and southern passes in the afternoons. At night pollutants remained within the valley except near the river outlet. They were lifted off the ground at night and re-circulated in the morning. The eulerian chemistry transport model CAMx, was used in tracer mode, with MM5 meteorology to simulate the emission, transport and removal of CO from the Kathmandu Valley. The simulations were limited by the accuracy of Kathmandu's emissions inventory, especially the spatial distribution of emissions.
by Arnico K. Panday.
Sc.D.
Weinmann, Julian. "Influence of the Martian regolith on the atmospheric methane and water vapour cycle". Thesis, Luleå tekniska universitet, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75897.
Texto completo da fonteLytle, William. "Coupled Evaluation of Below- and Above-Ground Energy and Water Cycle Variables from Reanalysis Products Over Five Flux Tower Sites in the U.S". Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/595636.
Texto completo da fonteLöfverström, Marcus. "On the interaction between ice sheets and the large-scale atmospheric circulation over the last glacial cycle". Doctoral thesis, Stockholms universitet, Meteorologiska institutionen (MISU), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-107925.
Texto completo da fonteAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 4: Manuscript.
Currey, Pauline M. "Interactions between atmospheric nitrogen deposition and carbon dynamics in peatlands". Thesis, University of Aberdeen, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=165545.
Texto completo da fonteGirard, Éric. "Etude d'un effet indirect des aérosols acides en Arctique : le cycle de déshydratation". Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35887.
Texto completo da fonteSimulations performed with three column models and analysis of observed data at Alert (1991--94) are used to investigate an indirect effect of these aerosols on climate: the dehydration - greenhouse feedback. Each model covers different levels of physical basis and realism of their simulation. Two scenarios have been compared in the simulations: an acid aerosols scenario and a natural aerosols scenario.
Results show that aerosol acidification leads to a depletion of the ice crystal number concentration and an increase of their mean size. As a result, clear sky precipitation (CSP) occurs more frequently than ice fogs during Arctic haze episodes. This result is in agreement with observations that indicate an increase by more than 50% of the weekly mean CSP frequency, when the proportion of sulfuric acid is greater than the mean observed value of 20%. Consequently, the sedimentation flux of ice crystals and the dehydration rate of the lower troposphere are accelerated. The radiative effect is a weaker atmospheric emissivity in the boundary layer, up to the height corresponding approximately to the top of the ice crystal layer. As a result, the infrared flux reaching the surface and the greenhouse effect are decreased. Simulations performed for the period 1991 to 1994 at Alert show a negative radiative forcing of about --3 W/m2 at the surface between November and May. The net result is a strengthening of the surface-based temperature inversion of 1.3°C, with a surface cooling of 0.4°C and a warming of 0.9°C at 800 hpa.
The indirect effect of the dehydration - greenhouse feedback due to anthropogenic acid aerosols can explain in part the observed strengthening of the surface-based temperature inversion in the Arctic (Kahl et al., 1993).
Kambis, Alexis Demitrios. "A numerical model of the global carbon cycle to predict atmospheric carbon dioxide concentrations". W&M ScholarWorks, 1995. https://scholarworks.wm.edu/etd/1539616709.
Texto completo da fonteRahn, Thomas A. "Enrichment of ¹⁵N and ¹⁸O in stratospheric nitrous oxide : observations, experimental results, and implications /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907828.
Texto completo da fonteDavis, Neil Nathaniel. "Dynamic and Stochastic Modeling of Various Components of the Hydrological Cycle for East Africa". NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-05032007-094125/.
Texto completo da fonteWirth, Volkmar. "The seasonal cycle of stationary planetary waves in the southern stratosphere : a numerical study". Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/58229.
Texto completo da fonteXu, Guangzhi. "Diagnosis of the atmospheric hydrological cycle and its variability in the present-day climate". Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/59363/.
Texto completo da fonteMölders, Nicole, Thomas Beckmann e Armin Raabe. "A module to couple an atmospheric and a hydrologic model". Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-212867.
Texto completo da fonteEin Bodenmodul zur Kopplung eines meteorologischen mit einem hydrologischen Modell wird vorgestellt. Er wurde implementiert und getestet in der Leipziger Version von GESIMA. Obgleich der Schwerpunkt des Artikels auf der Beschreibung des Moduls und seiner Auswirkung auf den atmosphärischen Wasserkreislauf liegt, werden auch vorläufige Ergebnisse einer Kopplung mit NASMO präsentiert. Ein positiver Effekt des Moduls ist, daß er ermöglicht, detaillierter die subskalige Evapotranspiration zu beschreiben und den Niederschlag zu heterogenisieren. Dies wirkt sich stark auf die Bodenfeuchte, die Bewölkung und das thermische Regime der atmosphärischen Grenzschicht aus
Barningham, Thomas. "Detection and attribution of carbon cycle processes from atmospheric O2 and CO2 measurements at Halley Research Station, Antarctica and Weybourne Atmospheric Observatory, U.K". Thesis, University of East Anglia, 2018. https://ueaeprints.uea.ac.uk/68343/.
Texto completo da fonteLukac, Martin. "Effects of atmospheric COâ†2 enrichment on root processes and mycorrhizal functioning in short rotation intensive poplar plantation". Thesis, Bangor University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391756.
Texto completo da fonteFerretti, Dominic Francesco. "The development and application of a new high precision GC-IRMS technique for N₂O-free isotopic analysis of astmospheric CO₂". [Wellington, New Zealand] : Victoria University of Wellington, 1999. http://catalog.hathitrust.org/api/volumes/oclc/154329143.html.
Texto completo da fonteSarkodie-Addo, Joseph. "Nitrogen dynamics in a green manure - maize rotation system". Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368885.
Texto completo da fonteBachman, Sarah. "Elevated atmospheric carbon dioxide and precipitation alter ecosystem carbon fluxes over northern mixed-grass prairie at the prairie heating and CO2 enrichment (PHACE) experiment in Cheyenne, Wyoming, USA". Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445355711&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Texto completo da fonteSimmons, Christopher. "An investigation of carbon cycle dynamics since the last glacial maximum using a climate model of intermediate complexity". Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121260.
Texto completo da fonteCette thèse détaille l'application du modèle du système climatique terrestre de l'Université de Victoria (version 2.9) dans le cadre de deux importants champs de recherche en modélisation paléoclimatique : l'augmentation du niveau de dioxyde de carbone (CO2) dans l'atmosphère durant la plus récente transition glaciaire-interglaciaire, ainsi que l'évolution du cycle du carbone durant l'Holocène. Le modèle utilisé dans cette étude est répertorié comme modèle de complexité intermédiaire (Claussen et al. 2002), offrant un traitement à la fois simplifié et exhaustif de la dynamique du système climatique terrestre et du cycle du carbone. Celui-ci comprend un modèle océanique tridimensionnel, un modèle de glace marine dynamique/thermodynamique, un modèle dynamique et global de la végétation, les sédiments océaniques ainsi qu'un traitement interactif du cycle du carbone organique et inorganique.Premièrement, une série de simulations transitoires sont effectuées afin de couvrir la période s'étendant du plus récent maximum glaciaire (LGM) jusqu'à aujourd'hui (2000 apr. J.-C.). Les simulations fondées uniquement sur une prescription des paramètres orbitaux et des calottes glaciaires ne reproduisent pas l'augmentation du CO2 dans l'atmosphère durant la période transitoire tel que mentionné ci-haut, mais exposent toutefois une certaine sensibilité (10-15 ppm) à de faibles (1.9 Tmol/an) variations dans le taux d'érosion. Dans le cas de simulations prenant en compte la gamme complète des effets radiatifs associés au CO2, par contre, la concentration du CO2 dans l'atmosphère s'avère beaucoup plus élevée (une augmentation de 20 ppm par rapport à celles sans effets radiatifs). Cette différence est causée par une plus importante ventilation de carbone inorganique dissous en eaux profondes ainsi qu'une diminution du taux d'absorption de CO2 par l'océan, qui s'explique en partie par une fonte accélérée de la glace marine dans l'hémisphère Sud. Le changement du régime de ventilation en profondeur a également pour effet de diminuer l'alcalinité marine à partir de la fin de la période de déglaciation, augmentant de 10ppm la concentration de CO2 dans l'atmosphère. La présence d'un réservoir de carbone terrestre an hautes latitudes fournit une source additionnelle de carbone, principalement durant les stages initiaux de la période de déglaciation, permettant ainsi aux niveaux de CO2 dans l'atmosphère d'atteindre les 240-250 ppm. En outre, ceci facilite la validation de nos résultats par rapport aux changements dans la concentration de carbonate observées depuis le dernier maximum glaciaire dans les profondeurs marines (Yu et al. 2010). Le faible taux d'érosion terrestre durant le maximum glaciaire et la période de déglaciation qui a suivi est d'autant plus significatif en raison d'un apport accru d'eau douce de fonte en provenance des calottes glaciaires Nord-Américaines. Deuxièmement, nos résultats quant au cycle du carbone durant l'Holocène pointent vers une certaine diminution du niveau de CO2 dans l'atmosphère se manifestant vers 6000 av. J.-C. et qui, en l'absence de forçage externe au modèle, devrait se maintenir jusqu'à aujourd'hui ; celle-ci semble toutefois varier (8-15 ppm) en fonction du mode de circulation océanique. De plus, la concentration atmosphérique de CO2 dans nos simulations démontre une importante sensibilité à l'étendue des barrières de glace en Antarctique, d'où notre conclusion qu'une présence accrue de glace marine durant l'Holocène (par rapport aux autres périodes interglaciaires) pourrait augmenter le niveau de CO2 atmosphérique de près de 5 ppm (effets physiques directs), et de pas moins de 10 ppm en considérant la gamme de modes de circulation océanique ainsi que les changements dans l'alcalinité marine.
Xu, Xiaobin. "Investigations into the tropospheric cycle of COS atmospheric distribution, air-sea and air-vegetation exchanges /". [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=961910690.
Texto completo da fonteDemory, Marie-Estelle. "Sensitivity of the global hydrological cycle to horizontal resolution in an atmospheric general circulation model". Thesis, University of Reading, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654493.
Texto completo da fonteSchwietzke, Stefan. "Atmospheric Impacts of Biofuel and Natural Gas Life Cycle Greenhouse Gas Emissions and Policy Implications". Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/299.
Texto completo da fonteKozlova, Elena A. "Multi-species atmospheric continuous measurements as a tool to study changes in the carbon cycle". Thesis, University of East Anglia, 2010. https://ueaeprints.uea.ac.uk/10570/.
Texto completo da fonteMaltagliati, Luca. "Investigation of the Martian atmospheric water cycle by the OMEGA mapping spectrometer onboard Mars Express". [Katlenburg-Lindau] Copernicus Publ, 2008. http://d-nb.info/990118223/04.
Texto completo da fonteNave, Lucas Emil. "Nitrogen cycling in the northern hardwood forest soil, plant, and atmospheric processes /". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196187071.
Texto completo da fonteSakaguchi, Koichi. "Spatiotemporal Scale Limits and Roles of Biogeochemical Cycles in Climate Predictions". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/268598.
Texto completo da fonteHolian, Gary Louis 1972. "Uncertainty in atmospheric CO₂ concentrations from a parametric uncertainty analysis of a global ocean carbon cycle model". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/59087.
Texto completo da fonteIncludes bibliographical references (leaves 90-95).
Key uncertainties in the global carbon cycle are reviewed and a simple model for the oceanic carbon sink is developed and described. This model for the solubility sink of excess atmospheric CO2 has many enhancements over the more simple 0-D and 1-D box-diffusion models upon which it is based, including latitudinal extension of mixed-layer inorganic carbon chemistry, climate-dependent air-sea exchange rates, and mixing of dissolved inorganic carbon into the deep ocean that is parameterized by 2-D eddy diffusion. By calibrating the key parameters of this ocean carbon sink model to various "best guess" reference values, it produces an average oceanic carbon sink during the 1980s of 1.7 Pg yr-1, consistent with the range estimated by the IPCC of 2.0 Pg yr~1 ± 0.8 Pg (1992; 1994; 1995). The range cited in the IPCC study and widely reported elsewhere is principally the product of the structural uncertainty implied by an amalgamation of the results of several ocean carbon sink models of varying degrees of complexity. This range does not take into account the parametric uncertainty in these models and does not address how this uncertainty will impact on future atmospheric CO 2 concentrations. A sensitivity analysis of the parameter values used as inputs to the 2-D ocean carbon sink model developed for this study, however, shows that the oceanic carbon sink range of 1.2-2.8 Pg/yr for the 1980s is consistent with a broad range of parameter values. By applying the Probabilistic Collocation Method (Tatang, et al. 1997) to this simple ocean carbon sink model, the uncertainty of the magnitude of the oceanic sink for carbon and hence atmospheric CO2 concentrations is quantitatively examined. This uncertainty is found to be larger than that implied by the structural differences examined in the IPCC study alone with an average 1980s oceanic carbon sink estimated at 1.8 ± 1.3 Pg/yr (with 95% Confidence). It is observed that the range of parameter values needed to balance the contemporary carbon cycle yield correspondingly large differences in future atmospheric CO2 concentrations when driven by a prescribed anthropogenic CO2 emissions scenario over the next century. For anthropogenic CO 2 emissions equivalent to the IS92a scenario of the IPCC (1992), the uncertainty is found to be 705 ppm ± 47 ppm (one standard deviation) in 2100. This range is solely due to uncertainty in the "solubility pump" sink mechanism in the ocean and is only one of the many large uncertainties left to explore in the global carbon cycle. Such uncertainties have implications for the predictability of atmospheric CO2 levels, a necessity for gauging the impact of different rates of anthropogenic CO2 emissions on climate for policy-making purposes. Since atmospheric CO 2 levels are one of the primary drivers of changes in radiative forcing this result impacts on the uncertainty in the degree of climate change that might be expected in the next century.
by Gary Louis Holian.
S.M.
Jin, Menglin. "Interpolation of surface radiative temperature measured from polar orbiting satellites to a diurnal cycle". Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/282883.
Texto completo da fonteBarral, Cuesta Abel. "The carbon isotope composition of the fossil conifer Frenelopsis as a proxy for reconstructing Cretaceous atmospheric CO2". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1148.
Texto completo da fonteThe Cretaceous was a period characterized by strongly marked climate change and major carbon cycle instability. Atmospheric CO2 has repeatedly been pointed out as a major agent involved in these changing conditions during the period. However, long-term trends in CO2 described for the Cretaceous are not consistent with those of temperature and the large disturbance events of the carbon cycle described for the period. This raises a double question of whether descriptions of the long-term evolution of atmospheric CO2 made so far are accurate or, if so, atmospheric CO2 was actually a major driver of carbon cycle and climate dynamics as usually stated. In this thesis the close relationship between the carbon isotope composition of plants and atmospheric CO2 is used to address this question. Based on its ecological significance, distribution, morphological features and its excellent preservation, the fossil conifer genus Frenelopsis is proposed as a new plant proxy for climate reconstructions during the Cretaceous. The capacity of carbon isotope compositions of Frenelopsis leaves (d13Cleaf) to reconstruct past atmospheric CO2, with regards to both carbon isotope composition (d13CCO2) and concentration (pCO2), is tested based on materials coming from twelve Cretaceous episodes. To provide a framework to test the capacity of d13Cleaf to reconstruct d13CCO2 and allowing for climate estimates from carbon isotope discrimination by plants (?13Cleaf), a new d13CCO2 curve for the Cretaceous based on carbon isotope compositions of marine carbonates has been constructed. Comparison with d13Cleaf-based d13CCO2 estimates reveals that although d13CCO2 and d13Cleaf values follow consistent trends, models developed so far to estimate d13CCO2 from d13Cleaf tend to exaggerate d13CCO2 trends because of assuming a linear relationship between both values. However, given the hyperbolic relationship between ?13Cleaf and pCO2, by considering an independently-estimated correction factor for pCO2 for a given episode, d13Cleaf values may be a valuable proxy for d13CCO2 reconstructions. ?13Cleaf estimates obtained from d13CCO2 and d13Cleaf values were used to reconstruct the long-term evolution of pCO2. The magnitude of estimated pCO2 values is in accordance with that of the most recent and relevant model- and proxy-based pCO2 reconstructions. However, these new results evidence long-term drawdowns of pCO2 for Cretaceous time intervals in which temperature maxima have been described
zhu, zhenduo. "Mechanisms Governing the Eyewall Replacement Cycle in Numerical Simulations of Tropical Cyclones". FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1389.
Texto completo da fonteRosengard, Sarah Zhou. "Novel analytical strategies for tracing the organic carbon cycle in marine and riverine particles". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/109057.
Texto completo da fonteCataloged from PDF version of thesis.
Includes bibliographical references.
Particulate organic carbon (POC) in the ocean and mobilized by rivers on land transfers -0. 1% of global primary productivity to the deep ocean sediments. This small fraction regulates the long-term carbon cycle by removing carbon dioxide from the atmosphere for centuries to millennia. This thesis investigates mechanisms of POC transfer to the deep ocean by analyzing particles collected in transit through two globally significant carbon reservoirs: the Southern Ocean and the Amazon River Basin. These endeavors test the hypothesis that organic matter composition controls the recycling and transfer efficiency of POC to the deep ocean, and illustrate new applications for ramped pyrolysis/oxidation (RPO), a growing method of POC characterization by thermal stability. By coupling RPO to stable and radiocarbon isotope analyses of riverine POC, I quantify three thermally distinct soil organic carbon pools mobilized by the Amazon River, and evaluate the degradability and fate of these different pools during transport to the coastal Atlantic Ocean. More directly, RPO analyses of marine samples suggest that POC transfer in the water column is in fact selective. Observations of consistent biomolecular changes that accompany transport of phytoplankton-derived organic matter to depth across the Southern Ocean support the argument for preferential degradation of specific POC pools in the water column. Combining discussions of POC recycling and transfer across both marine and terrestrial systems offer new perspectives of thermal stability as a proxy for diagenetic stability and POC degradation state. The challenges of interpreting RPO data in these two environments set the stage for applying the technique to more controlled experiments that trace POC from source to long-term sink.
by Sarah Zhou Rosengard.
Ph. D.
Murphy, Paulette P. "The carbonate system in seawater : laboratory and field studies /". Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/8509.
Texto completo da fonteBednarz, Ewa Monika. "Chemistry-climate modelling studies of decadal and interdecadal variability in stratospheric ozone and climate : the 11-year solar cycle and future ozone recovery". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274359.
Texto completo da fonteLauderdale, Jonathan Maitland. "On the role of the Southern Ocean in the global carbon cycle and atmospheric CO2 change". Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/191935/.
Texto completo da fonteBraziunas, Thomas F. "Nature and origin of variations in late-glacial and Holocene atmospheric 14C as revealed by global carbon cycle modeling /". Thesis, Connect to this title online; UW restricted, 1990. http://hdl.handle.net/1773/6702.
Texto completo da fonteMölders, Nicole, Thomas Beckmann e Armin Raabe. "A module to couple an atmospheric and a hydrologic model". Universität Leipzig, 1996. https://ul.qucosa.de/id/qucosa%3A15045.
Texto completo da fonteEin Bodenmodul zur Kopplung eines meteorologischen mit einem hydrologischen Modell wird vorgestellt. Er wurde implementiert und getestet in der Leipziger Version von GESIMA. Obgleich der Schwerpunkt des Artikels auf der Beschreibung des Moduls und seiner Auswirkung auf den atmosphärischen Wasserkreislauf liegt, werden auch vorläufige Ergebnisse einer Kopplung mit NASMO präsentiert. Ein positiver Effekt des Moduls ist, daß er ermöglicht, detaillierter die subskalige Evapotranspiration zu beschreiben und den Niederschlag zu heterogenisieren. Dies wirkt sich stark auf die Bodenfeuchte, die Bewölkung und das thermische Regime der atmosphärischen Grenzschicht aus.
Roulier, Marine. "Cycle biogéochimique de l'iode en écosystèmes forestiers". Thesis, Pau, 2018. http://www.theses.fr/2018PAUU3026/document.
Texto completo da fonteAs radioisotopes of iodine may concentrate in thyroid gland, 131I (t1/2 = 8.07 days) and 129I (t1/2 = 15.7 106 years) are of health concern. 129I is of major radioecological importance because it can potentially integrate natural biogeochemical cycle of its stable isotope (127I) due to its long half-life. Forests, characterized by their longevity, a high biomass turnover and a strong influence on hydrological and nutrients cycles, can intercept, recycle and accumulate a significant amount of pollutants and radionuclides released into environment. In this context, research developed in this thesis had the purpose of correct long-term prediction of iodine behaviour in forest ecosystems.Rainfall appears to be a significant input flux of iodine in forest soils and vegetation, depending on coastal distance and precipitation amount. Forest canopy modifies quantities and speciation of iodine initially present in rainfall. Humus would act as temporary iodine accumulation layer through its association with organic matter. However, humus layer also behaves as potential iodine mobilisation source by leaching and/or volatilization. This thesis has demonstrated that iodine levels in soils depend both on its atmospheric and litterfall inputs, but also on the soil's ability to fix iodine. Thus, environmental conditions characterized by organic matter accumulation and presence of metal (hydr)oxides in soils promote iodine retention. Thereafter, soil is the main iodine reservoir at the forest plot scale (~99.9%). Given small amounts of iodine in the trees (<0.03% of the total iodine stock), recycling of iodine by vegetation is low, iodine being not an essential element for vegetables.This thesis contributes to fill some gaps in the knowledge of iodine distribution within forests and on the processes of iodine reemission related to organic matter degradation. Data generated by this thesis help to better understand the modeling of iodine cycle in this forest ecosystem