Depuis 2007, une nouvelle génération de capteurs RSO (RADAR à Synthèse d'Ouverture) a été mise en orbite. Ces capteurs (TerraSAR-X, Cosmo-SkyMed, RADARSAT-2, Sentinel) sont caractérisés par des résolutions spatiales métriques à la différence des capteurs précédents (ERS, JERS, ALOS, ASAR) de résolution spatiale d'une vingtaine de mètres. La résolution spatiale métrique met en évidence une information texturale intéressante qui était inaccessible avec les RSO satellitaires existants précédemment. Les travaux de cette thèse ont pour but d'évaluer le potentiel de l'analyse texturale des images RADAR à haute résolution spatiale, pour la classification des forêts tropicales. Trois différents sites d'étude avec différentes problématiques ont été choisis pour évaluer l'apport de l'analyse texturale au Cambodge, Cameroun et Brésil. La méthode d'analyse texturale des images est réalisé moyennant les paramètres de texture de Haralick, paramètres statistique de second ordre. Une classification supervisée, en utilisant la méthode SVM (Support Vector Machine) a été adopté pour évaluer l'apport des paramètres de texture utilisés / Since 2007, a new generation of SAR sensors (Synthetic Aperture RADAR) was launched. These sensors (TerraSAR-X, Cosmo-SkyMed, RADARSAT-2, and Sentinel) are characterized by metric spatial resolutions unlike previous sensors (ERS, JERS, ALOS, ASAR) with a spatial resolution of about twenty meters. Metric spatial resolution highlights interesting textural information that was inaccessible with the previously existing SAR sensors. This thesis aims at evaluating the contribution of textural analysis from high spatial resolution images for tropical forests mapping. Three different study sites with different problematic have been chosen to evaluate the textural analysis in Cambodia, Cameroun and Brazil. Indeed, the contribution of the analysis of textural information for classification has been emphasized. The latter is understood through the analysis of Haralick textural parameters, second order statistic parameters. The retained algorithm of classification is the SVM (Support Vector Machine), as it allows taking into account numerous parameters, which can be heterogeneous with respect to their physical dimension

Os seringueiros localizados dentro de reservas e assentamentos extrativistas no Estado do Acre, Amazônia Ocidental, Brasil, possuem como meio econômico o extrativismo da borracha e da castanha e pretendem diversificar a produção com outros recursos florestais que complementem a renda a curto prazo, respeitando ao mesmo tempo os seus modos tradicionais de vida e a diversidade biológica. O conceito do manejo dos frutos de Euterpe precatoria (Açaí) engloba aspectos sociais, econômicos e ecológicos concernentes a floresta. Este estudo fez uma análise do potencial ecológico e sócio econômico da extração de frutos do Açaí em áreas da Reserva Extrativista Chico Mendes e do Seringal Caquetá, Acre, para responder: (1) E. precatoria possui características populacionais como grande produção de frutos, alta densidade e regeneração natural, estrutura e estabilidade populacional que podem favorecer o seu manejo sustentável? (2) Qual é a estimativa da colheita sustentável para áreas de florestas no Caquetá? (3) Qual a forma de organização comunitária para a produção de Açaí? (4) Qual é a rentabilidade do manejo dos frutos no Seringal Caquetá? (5) Quais as práticas necessárias para o bom manejo do recurso? No levantamento do potencial ecológico foram avaliados a densidade, estrutura populacional, potencial produtivo, dinâmica e estabilidade populacional em florestas inundadas e de Terra Firme. Através de um modelo de matriz foi feita a simulação da quantidade de frutos que podem ser retirados da floresta sem alterar a densidade atual da população. No levantamento sócio-econômico foram avaliados a forma de organização comunitária e a rentabilidade obtida com o manejo do Açaí, da castanha e da borracha e com a diária local de trabalho. E. precatoria apresentou um alto potencial de manejo devido a sua alta densidade, estrutura populacional em forma de J invertido, alta freqüência, alta produção de frutos e estabilidade populacional de crescente a estável. A simulação da colheita de frutos na floresta de Baixio mostrou que a manutenção de 50% do recrutamento inicial é necessária para manter a estabilidade da população, isto é, a cada duas palmeiras, coleta-se frutos em apenas uma. Na Terra Firme é necessário a manutenção de 25% do recrutamento inicial, ou a cada quatro palmeiras coleta-se frutos em três. A organização comunitária em mutirão ou estrutura familiar deve se adequar de acordo com a disponibilidade de recursos para a atividade produtiva das diferentes famílias, tais como, mão de obra, animais de carga e mercados. A remuneração que a comunidade do Caquetá pode conseguir com a comercialização do Açaí foi maior que a conseguida com a borracha ou com diária local. Com a castanha a renda do Açaí foi similar, mas poderia ser maior, caso tivesse o mesmo subsídio para o transporte. / Rubber tappers in extractive reserves and settlements in Acre State, Western Amazonia, Brazil, live from rubber and brazil nuts extraction and recently started to be interested in diversification of their production with other forest resources that could complement their annual income in the short term, while at the same time preserving their traditional way of life and also biodiversity. The concept of fruit management of Euterpe precatoria (Açaí) encompasses social, economic and ecological aspects related to the forest. This study analyzes the social, economic and ecological potential of fruit extraction of Açaí in areas of the Extractive Reserve Chico Mendes and the Seringal Caquetá, Acre State to answer some questions: (1) Does E. precatoria have populational characteristics such as great production of fruits, high natural density and regeneration, population structure and stability that allow its sustainable management? (2) What is the estimate for sustainable harvest in forested areas in Caquetá? (3) What is the community organization for Açaí production? (4) What is the fruit management profitability in Seringal Caquetá?(5) What are the right practice for a good resource management? For the inventory of ecological potential, we evaluated density, population structure, production potential, population dynamics and stability in seasonal flooded and upland forests. A matrix model was applied to simulate the amount of fruits that could be harvested from the forest without altering the current population density. In the social and economic inventory we evaluated the way the community is organized to work and the profitability achieved with the Açaí, rubber and Brazil nut management, and each product profit per year. E. precatoria showed a very high management potential due to its high density, population structure in a inverted J shaped, high frequency, high fruit production and a increasing to stable population stability. The simulation of fruit harvest in the seasonal flooded forest showed that the maintenance of 50% of the initial recruitment is necessary for the stability of the population, therefore from each two palms only one should be harvested for a sound sustainable management. In upland forest the initial recruitment must be 25%, or from each four palms, three could be harvested. The community organization in a structural family must adapt to the productive system of each family, such as labor, animals for transportation and market availability. The profit that the Caquetás community can achieve with the commercialization of Açaí was greater than the achieved with rubber and other economic activities. The Açai profit is similar to Brazil nuts extraction, but could be higher if it had the same transportation subsidies that the nut receives.

Les eaux continentales sont des sources de méthane (CH4), de dioxyde de carbone (CO2)et de protoxyde d’azote (N2O). Dans le but de préciser leur importance dans le bilan global des émissions de gaz à effet de serre (GES), de nombreuses études ont été réalisées afin de quantifier les différents flux de carbone et d’azote les parcourant. Ces flux sont perturbés par la mise en place de barrages sur le lit des fleuves. Peu d’études présentent des bilans de carbone et d’azote complets (apports, exports, flux vers l’atmosphère et enfouissement) pour les lacs de barrages, et elles concernent uniquement des écosystèmes boréaux et tempérés. Suite à la création d’un barrage, de la matière organique (MO) est mise en eau (sols et forêts), elle se dégrade rapidement les premières années suivant la mise en eau puis plus lentement par la suite. L’état de dégradation de la MO et la principale source de GES dans un lac de barrage près de 20 ans après la mise en eau sont souvent méconnus. L’étude réalisée 18 ans après la mise en eau du lac de Petit Saut (Guyane Française) est la première étude où les principaux éléments des cycles du carbone et de l’azote d’un lac de barrage hydroélectrique, et de son fleuve en aval, situé en climat équatorial et dont la création a entraîné la mise en eau de forêt primaire, sont étudiés près de 20 ans après la mise en eau. Cette étude se base sur (i) la mesure mensuelle de la qualité des eaux et des concentrations en carbone et azote en amont, dans, et en aval du lac de barrage, (ii) la mesure et/ou le calcul des différents flux de GES vers l’atmosphère, (iii) des données de la signature isotopique et de l’état de dégradation de la MO en amont, dans, et en aval du lac, (iv) des prélèvements de sédiments et de troncs d’arbres ennoyés en 1994 et (v) des incubations d’eau du fleuve, de sédiments et de troncs d’arbres du lac. L’ensemble des données collectées au cours des 12 mois de campagnes réalisées en 2012 - 2013 nous a permis de déterminer que (i) les sols inondés sont toujours des sources significatives de GES contrairement aux troncs d’arbres ennoyés, (ii) dans le lac 84 % des émissions de CH4 et 51 % des émissions de CO2 ont lieu dans la zone littorale (< 10 m de profondeur), (iii) 54 % du CO2 produit dans le fleuve en aval provient de la dégradation de la MO apportée par le lac. Cette étude nous a aussi permis de réaliser des bilans de carbone et d’azote à Petit Saut et un bilan des émissions de chacun des GES émis (CH4, CO2, N2O) près de 20 ans après la mise en eau. / Inland waters are sources of methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O). In order to define their importance in the global balance of greenhouse gases (GHG) emissions, numerous studies have been conducted to quantify the different fluxes of the carbon and nitrogen browsing them. These fluxes are modified by the creation of dams on river beds. Few studies present full carbon and nitrogen balances (inputs, outputs, fluxes to the atmosphere and sequestration) for reservoirs, and they concern only boreal and temperate ecosystems. The creation of a dam floods organic matter (OM) (soils and forests), which is rapidly degraded the first years following the impoundment and thereafter more slowly. The state of degradation of the OM and the main source of GHG in a reservoir nearly 20 years after impoundment are often unknown. The study conducted 18 years after the impoundment of the Petit Saut Reservoir (French Guiana) is the first study where the main elements of carbon and nitrogen cycles of an hydroelectric reservoir, and its river downstream, located in equatorial climate and which creation resulted in the flooding of primary forest, are studied nearly 20 years after impoundment. This study is based on (i) a monthly measurement of water quality and carbon and nitrogen concentrations upstream, in, and downstream of the reservoir, (ii) measurements and/or calculations of the different fluxes of GHG through the atmosphere, (iii) data of the isotopic signature and of the state of degradation of OM upstream, in, and downstream of the reservoir, (iv) sediments and 1994’s flooded tree trunks sampling and (v) incubations of downstream river water, sediments and tree trunks from the reservoir. All the data collected during the 12 months of campaigns carried out in 2012 - 2013 allowed us to determine that (i) flooded soils are still significant sources of GHG unlike flooded tree trunks, (ii) in the reservoir 84 % of CH4 emissions and 51 % of CO2 emissions occur in the littoral zone (< 10 m depth), (iii) 54 % of the CO2 produced in the river downstream of the dam come from the degradation of the OM provided by the reservoir. This study also allowed us to achieve carbon and nitrogen balances in Petit Saut and emission balance of each GHG emitted (CH4, CO2, N2O) nearly 20 years after impoundment.

No description available.

Ce travail de thèse est une contribution à la description des signaux océaniques de fines échelles dans les tropiques, fines échelles objet de la futur mission altimétrique SWOT. Ces fines échelles spatiales concernent à la fois des phénomènes dits de méso et sous mésoéchelle, produits par la dynamique océanique (tourbillons, filaments) mais aussi des ondes internes (dont la marée barocline ou marée interne). Les fines échelles sont une source importante de mélange pour l'océan. La méso et sous mésoéchelle océanique traduisent une dynamique turbulente associée à des cascades d'énergie donnant lieu à des pentes spectrales sur des spectres en nombre d'onde de niveau de la mer ou d'énergie cinétique tourbillonnaire. Les pentes spectrales des spectres du niveau de la mer altimétrique sont calculées dans la bande 250-70 km, ces pentes sont très plates dans les tropiques. Par conséquence, elles sont en désaccord aussi bien avec les théories de la turbulence qu'avec les pentes des spectres du niveau de la mer des modèles numériques. Cette thèse vise à élucider ces désaccords dans le Pacifique tropical (20°S-20°N), en quantifiant les niveaux d'énergie et les longueurs d'onde relatives à la dynamique méso-échelle et aux ondes internes. L'importance de la marée interne dans les tropiques est illustrée dans le contexte régional de la mer des Salomon, où cette marée contribue à un fort mélange dans une zone de connexion entre la région subtropicale et la région équatoriale. La première partie de la thèse est une analyse spectrale 3D (fréquence, longueurs d'ondes zonales et méridiennes) de la dynamique tropicale à partir d'un modèle au 1/12°. La région équatoriale (10°N-10°S) se caractérise par une dynamique grande échelle zonale associée aux ondes équatoriales et une dynamique fine échelle (< 600 km) marquée par des mouvements préférentiellement méridiens en lien avec les ondes tropicales d'instabilité. Dans les régions non équatoriales (entre 10° et 20° de latitude) la fine échelle est davantage isotropique, concentrée dans la bande 300-70 km, et connectée à la grande échelle zonale par un continuum d'énergie traduisant l'importance de la cascade inverse. Les pentes des spectres en nombre d'onde de niveau de la mer relatives à la méso/sous-méso échelle des différentes régions sont curieusement proches des pentes théoriques typiques des moyennes latitudes,mais restent en désaccord avec celles issues des observations altimétriques. [...] / This thesis work contributes to our understanding of the fine scale oceanic signals in the tropics, that are the focus of attention for the future altimeter mission SWOT. These fine scales concern meso and submesoscale due to ocean dynamics (eddies, filaments) and internal waves such as the barocline or internal tide. Fines scales are important source of ocean mixing. Meso and submesoscale reflect turbulent dynamic associated with energy cascades giving rise to sea surface height or eddie kinetic wavenumber spectrum slope. The observed altimetric sea surface height spectral slope evaluated in the band 250-70 km are very flat in the tropics. They disagree with turbulence theories and with sea surface height spectral slope of the numerical model. This thesis aims to remove the ambiguity of this spectra flattening in the tropical Pacific (20°S-20°N) by quantifying energy levels and wavelengths related to mesoscale dynamics and internal waves. The importance of the internal tide in the tropics is then illustrated in a regional context in the Solomon Sea, where water mass mixing plays an important role in the connections between the subtropical region and the equatorial region. The first part of the thesis is based on a 3D spectral analysis (frequency, zonal and meridional wavelengths) of tropical dynamics from a 1/12° model. The equatorial region (10°N-10°S) is characterized by large zonal dynamics associated with equatorial waves and finer scale dynamics ( < 600 km) marked by preferentially meridional movements associated with tropical instabilities waves. In the non-equatorial regions (10°-20°NS) the finer scales are more isotropic and concentrated in the band 300-70 km, and are connected to the large zonal scales by an energy continuum reflecting the importance of the indirect cascade. The slopes of the modelled sea surface height wavenumber spectra over the meso/submesoscale band in the different tropical regions are curiously close to the QG/SQG theoretical spectra typical of mid latitudes, but the slopes disagree with those from altimetry observations. Including the high frequency internal waves in a 1/36° model forced by the barotropic tide shows that coherent (predictable) internal tide is the main contributor causing the flattening of the spectra in the tropics, and particularly the M2 first baroclinic mode. However, the contribution of the incoherent (non-predictable) tide dominates at scales below 70 km and still affects scales up to 200 km. [...]

No description available.

[pt] A matéria orgânica particulada (MOP) em suspensão presente entre a Baía de Guanabara e o oceano costeiro foi caracterizada através de composição elementar (C e N), razões isotópicas (delta 13C e delta 15N) e marcadores moleculares (esteróis, n-álcoois e ácidos graxos) em dois períodos (verão e outono) ao longo de um transecto e de um fundeio de 25h. As assinaturas elementares (C/N = 5 a 23) e isotópicas (delta 13C = -27,7 a -16,2 por mil e delta 15N = 2,4 a 11,2 por mil) foram típicas de predomínio de matéria orgânica planctônica. Ácidos graxos (totais de 12,08 ± 7,78 Micrograma L–1 no verão e 22,06 ± 1,75 Micrograma L–1 no outono para o transecto; e de 13,47 ± 5,15 Micrograma L–1 no verão e 15,84 ± 3,61 Micrograma L–1 no outono para o fundeio de 25h) ocorreram como compostos de cadeia curta, mono- e poli-insaturados. Concentrações totais de esteróis variaram de 0,04 a 7,32 Micrograma L-1, com predominância de colesterol e fitoesteróis. n-álcoois foram um componente menos importante (0,01 a 5,67 Micrograma L-1). A abordagem multiparâmetros revelou a contribuição predominante de fontes autóctonas de MOP, o que reflete a influência da Baía de Guanabara sobre processos ecológicos na zona de transição aqui considerada. A contribuição fecal sobre a MOP também foi identificada, mas sendo um componente menos significativo, possivelmente pela diluição causada pelas fontes autóctonas ou pela degradação dos marcadores fecais. Além disso, a MOP de origem terrestre não é exportada da baía e, portanto, deve sofrer um processo de acúmulo nos sedimentos internos da baía. Isso suporta a necessidade de quantificar essa contribuição continental para melhor estabelecer o balanço de carbono na baía. / [en] Suspended particulate organic matter (POM) present between Guanabara Bay and the coastal ocean was characterized by elemental composition (C and N), isotopic ratios (delta13C and delta15N) and molecular markers (sterols, n-alcohols and fatty acids) in two periods (summer and fall) along a transect and a fixed station. Elemental (C/N of 5 to 23) and isotopic (delta13C= -27.7 to -16.2 per thousand and delta15N = 2.4 to 11.2 per thousand) signatures were typical for the predominance of planktonic organic matter. Fatty acids (totals of 12.08 ± 7.78 microgram L–1 in summer and 22.06 ± 1.75 microgram L–1 in the fall for the transect, and 13.47 ± 5.15 microgram L–1 in summer and 15.84 ± 3.61 microgram L–1 in the fall for the fixed station) were presente as short-chain, monoand poly-unsaturated compounds. Total sterol concentrations ranged from 0.04 to 7.32 microgram L–1, with the predominance of cholesterol and phytosterols. n-alcohols were a minor component (0.01 to 5.67 microgram L–1 ). The multi-proxy approach revealed an overwhelming contribution of autochthonous POM sources, reflecting the influence of the Guanabara Bay outflow on ecological processes in the transition zone considered herein. Fecal contribution to POM was also identified, albeit as a less significant component, possibly due to dilution caused by autochthonus sources or degradation of fecal markers. Moreover, the terrestriallyderived POM was not exported from the bay and, therefore, must experience an accumulation process in the inner bay sediments. This supports the need to quantify such continental contribution to better establish the carbon balance in the bay.

Master of Landscape Architecture / Department of Landscape Architecture/Regional and Community Planning / Timothy D. Keane / The International Ecotourism Society (TIES), the world’s first ecotourism organization, coined what has become the most succinct definition of ecotourism: “Responsible travel to natural areas that conserves the environment and improves the wellbeing of local people (Honey 2008, p. 6).” Ecolodges are accommodation facilities within ecotourism destinations which must satisfy specific principles, while reflecting the definition of ecotourism. Ecolodge principles include water conservation, preservation of flora and fauna, design to create a small footprint, and interpretive programs to educate both employees and tourists about the surrounding natural and cultural environments, to name just a few. (Mehta 2002, p. 5) Tropical locations, where ecolodges are often found, are comprised of unique ecosystems. With tropical locales, there are specific considerations that could determine the success of a proposed ecolodge development. As a designer, one must understand the biophysical characteristics on site, to inform design decisions of the ecolodge development. In addition, a designer must understand how the indigenous populations utilize the site culturally, physically and spiritually to fully understand the importance of the ecolodge development. (Mehta 2002, p. 12) When proper analysis of cultural and biophysical factors is completed, an ecolodge development is able to conform to the ecotourism definition and satisfy ecolodge principles. Within this manual, a hierarchical list of design principles, guidelines and criteria are communicated to achieve an overall design goal called fitness design. A “fit” design is intended to achieve sustainability and quality of life for the environment and the communities that have daily interaction with the development. As readers navigate through the document, they will be exposed to various considerations of a tropical ecolodge development. The intent of the manual is to provide a structural framework to guide an ecolodge design process.

Tuberculosis, caused by infection with Mycobacterium tuberculosis (M.tb), remains a global health problem. Drug resistance and high rates of HIV infection have fuelled the pandemic and, although a vaccine exists, its ability to protect from pulmonary tuberculosis varies between 0 and 80%. Bacille Calmette Guerin (BCG) has been administered to billions worldwide yet its protective mechanisms remain unknown, as do the reasons for its failure to protect in many parts of the world. Modified Vaccinia virus Ankara expressing antigen 85A (MVA85A) is a novel candidate vaccine designed to boost immune responses to BCG and improve protection. An aim of this thesis has been to characterise the innate immune response to an MVA85A boosting vaccination in both UK adults and South African infants. In the former, volunteers develop a strong innate response following vaccination however this does not always translate into a robust adaptive response to antigen 85A (Ag85A), which is determined in part by Treg expansion and the nuclear protein HMGB1 signaling through the TLR1-2-6 axis. By contrast, not all South Africa infants mount a strong innate immune response to MVA85A yet this response is correlated with the magnitude of the adaptive response. The immune response to BCG in both populations is also characterised and an association found between increased production of IL-17, IL-22 and IFN-γ in response to BCG stimulation and control of mycobacterial growth. The results presented here further the knowledge on the links between innate and adaptive responses to vaccination with BCG and MVA85A and the variation in mechanisms involved in different populations.

Thesis (MEng (Civil Engineering))--University of Stellenbosch, 1999. / 100 leaves single printed pages, preliminary pages and numberd pages 1.1-9.1.Includes bibliography. List of figures, tables, symbols and acronyms. Scanned with a HP Scanjet 8250 Scanner to pdf format (OCR). / ENGLISH ABSTRACT: A tropical cyclone is a non-frontal, synoptic scale, low-pressure system over tropical or subtropical waters with organised convection and a definite cyclonic surface wind circulation. The system varies in size between a hundred and a few thousand kilometres in diameter with high winds circulating around a central low pressure. The process of bringing the lower atmospheric layers into thermodynamic equilibrium with the warm tropical waters add the energy to the atmosphere and lower the surface pressure. If favourable climatic conditions exist this leads to the formation of a warm core vortex, which can develop into a tropical cyclone. The occurrence of tropical cyclones follows seasonal variations, the tropical cyclone season for the Southwest Indian Ocean being between November and March. The occurrences peak along the Southern African East Coast between Mid-January and Mid-February. The data on the location and intensity of tropical cyclones along the Southeast Africa coastline were obtained from the Joint Typhoon Warning Centre and span the period between 1848 and 1999. The available data before 1945 consist of tropical cyclone tracks that influenced populated areas or were encountered by ships. It was assumed that a number of tropical cyclones before 1945 were not recorded and therefore data collected before 1945 were disregarded in the analysis. The development of radar in 1945 significantly improved the detection of tropical cyclones. Some of the tropical cyclone tracks recorded between 1945 and 1956 contain information about the intensity of the tropical cyclone. Since the dawn of the satellite age in the mid 1980's, the detection of tropical cyclones and intensity measurements have improved vastly. Monte Carlo simulation techniques were used to create long term data series based on the available measured data. Statistical distributions were fitted for each characteristic describing the tropical cyclone at its nearest position to the site under investigation. Tropical cyclones frequently occur along the Southern African East Coast. The region where more than one tropical cyclone per 100 years can be expected is bordered by latitudes 2.5°S to 32.5°S. The design parameters for structures in these regions should provide for the influence that a tropical cyclone will have on the site. The occurrence rate and expected maximum intensity of tropical cyclones with a 1DO-year return period vary with latitude along the Southern African East Coast. The maximum number of tropical cyclones in a 1DO-year period occurs at latitude 15°S with an expected number of tropical cyclones of 157.2 per 100 years. The maximum expected tropical cyclone intensity in a 100-year period is 143.5 knots at latitude 17.5°S. / AFRIKAANSE OPSOMMING: Tropiese siklone is nie-frontale laagdrukstelsels wat hulle ontstaan het oor tropiese en subtropiese oseane. 'n Stelsel bestaan uit 'n sentrale laagdrukstelsel met sirkulerende winde daar om. 'n Sikloon se deursnee kan wissel van 'n honderd tot 'n paar duisend kilometer. 'n Laagdrukstelsel ontstaan as gevolg van 'n termodinamiese wanbalans tussen die atmosfeer en die warm oseaanwater in die trope. Indien die benodigde atmosferiese toestande heers kan die laagdrukstelsel in 'n tropiese sikloon ontwikkel. In die Suidwestelike Indiese Oseaan vorm tropiese siklone tussen November en Maart. Die meeste siklone kom hier voor vanaf middel Januarie tot middel Februarie. Data is verkry vanaf die "Joint Typhoon Warning Centre" vir die Suidwestelike Indiese Oseaan en strek vanaf 1848 tot 1999. Die data voor 1945 verteenwoordig slegs die tropiese siklone wat bewoonde areas of skeepsvaart beinvloed het. Daar is aangeneem dat 'n betekenisvolle getal van die tropiese siklone voor 1945 nie gedokumenteer is nie en derhalwe is slegs data van sikloon voorkomste na 1945 gebruik in die studie. Vanaf 1945 het die ontwikkeling van radar die opsporing van siklone in onbewoonde areas moontlik gemaak. Die gebruik van weersatelliete vanaf die middel 1980's het die kwaliteit van die data nog verder verbeter. Monte Carlo simulasie tegnieke is gebruik om langtermyn data vir spesifieke posisies langs die kus te genereer. Statistiese verdelings is gepas op die eienskappe wat die sikloon beskryf wanneer dit die naaste posisie aan die terrein bereik. Die passing van die verdelings is gedoen op die beskikbare historiese data. Die verdelings is dan gebruik om langtermyn data stelle te skep vir die terrein. Tropiese siklone kom gereeld in die Suidwestelike Indiese Oseaan voor en beinvloed die Suid-Afrikaanse Ooskus. Meer as een tropiese sikloon kan elke 100 jaar verwag word in kusgebiede tussen breedtegrade 2.5° S en 32.5° S. Die ontwerpe vir strukture in die gebied moet dus voorsiening maak vir die invloed van tropiese siklone. Die voorkoms en intensiteit van tropiese siklone varieer met breedtegraad langs die Suid-Afrikaanse Ooskus. Die meeste siklone word verwag by breedtegraad 15°S met 'n gemiddelde van 157.2 siklone per 100 jaar. Die mees intensiewe siklone kom voor by breedtegraad 17.5°S met 'n verwagte 1:100 jaar intensiteit van 143.5 knope.