Aerodynamically rough surfaces of forests provide for efficient air/ canopy exchange of mass, heat and momentum. In that context, the effects of forest edges come into focus, and therefore, coastal-zone forests constitute aparticular concern. Aerosol-sink modelling is of importance to the global-scalecontext, because sink strengths influence the concentration of aerosol particles in the atmosphere, and that concentration, in turn, influences climate. Dry deposition models are insufficient due to a lack of semi-empirical data and because of difficulties in parameterization of the efficiency (E) with which leaves capture aerosols. Quantifications of such parameters promote possibilities for modelling aerosol-sink processes within various canopy layers. This thesis focuses on studies of sea-salt aerosol dry deposition within models of oak canopies exposed to artificially generated aerosols in a wind tunnel. The overall goal is to advance the understanding of deposition processes in forest ecosystems. Aims are to determine capture efficiencies and deposition velocities (Vd) for oak (Quercus robur L.), to investigate E and Vd dependence on aerosol particle size, wind velocity and vegetation structural elements such as Leaf Area Index (LAI), to explore edge effects on deposition, to relate my results to natural situations in the field, and to address modelling applications. This thesis is a result of five studies. The first study is based on developing awind tunnel approach with a main focus on establishing reference conditions.The next step is to quantify E and provide estimates of how E, with respect toa well defined mass-vs-particle-size distribution, varies with wind speed. To that end, a special wash-off technique is developed. Finally, edge effects ondeposition processes are investigated. Results demonstrate that forest ecosystems would experience substantially increased deposition at edges. The findings suggest that field measurements of deposition in the interior of a forest “island” in an otherwise open landscape would underestimate the deposition to the entire forest. Results clearly indicate needs for further research on the effects of LAI on capture efficiency and deposition velocity. The obtained capture efficiencies can be translated into deposition velocities for trees with a specific leaf area. An increase of Vd with increasing wind speed is found, and is consistent with other studies. Results confirm advantages of the wind tunnel approach, including its ability to enable experiments under controlled conditions. However, several problems require that explicit sub-models be developed of wind-speed dependent effects on leaf posture in the aerosol flow field and that gradients in relative humidity close to leaf surfaces need further attention. The results also propose needs for a range of further experimental investigations regarding aerosol deposition across the complete sea-to-land aerodynamic transition.

Thesis (Ph.D.)--University of Wollongong, School of Biological Sciences. / Typescript. Includes bibliographical references: leaf 161-203.

Univ., Diss.--Bremen, 2005. / Literaturverz. S. 152 - 174.

Thesis (M.M.S.-Res.)--University of Wollongong, 2007. / Typescript. Includes bibliographical references: leaf 135-149.

Thesis (Ph. D.)--Delft University of Technology, 2004. / Includes bibliographical references and abstracts in English and Dutch.

Thesis (Ph. D.)--Institute of Social Studies, The Hague, 2004. / Errata slips (3 p.) inserted. Includes bibliographical references (p. [242]-260).

Thesis (Ph. D.)--University of Washington, 2007. / Includes bibliographical references (leaves 162-176).

Η έννοια του περιβάλλοντος στις μέρες μας αποτελεί ίσως ένα από τα πλέον καυτά θέματα συζήτησης όχι μόνο στους κόλπους της επιστημονικής κοινότητας αλλά και στην καθημερινότητα των σύγχρονων ανθρώπων. Η παρουσία του ανθρώπου σε ένα οικοσύστημα, το οποίο έχει προσαρμοστεί στις ανάγκες του και τροποποιηθεί ανάλογα, με στόχο να καλύπτει τις απαιτήσεις του έχει ως αποτέλεσμα να δέχεται εισροές από το εξωτερικό περιβάλλον και να παράγει εισροές με την σειρά του για άλλα συστήματα. Σήµερα η απειλή από ένα πλήθος περιβαλλοντικών πιέσεων καθιστά αναγκαία τη γνώση εκείνων των παραγόντων που οδηγούν στην υποβάθµιση των υδάτινων οικοσυστηµάτων. Μια από τις πλέον επιβαρυντικές δραστηριότητες του ανθρώπου όσο αναφορά την ποιότητα των υδάτων είναι η γεωργία. Η ευρεία και τις περισσότερες φορές ανεξέλεγκτη χρήση αγροχημικών σκευασμάτων, τα οποία χρησιμοποιούνται ευρέως από τους καλλιεργητές με κύριο στόχο την αύξηση της απόδοσης της αγροτικής παραγωγής τους, αλλά και την προστασία των προϊόντων αυτής από τη δράση επιβλαβών οργανισμών, έχει ως αποτέλεσμα την επιβάρυνση των υδάτων με υψηλές συγκεντρώσεις ρυπογόνων ή και τοξικών χημικών ουσιών. Αντικείµενο της παρούσας µελέτης είναι η έρευνα και καταγραφή των θρεπτικών στοιχείων καθώς και άλλων παραμέτρων στο νερό των ποταμών, των ρεμάτων και της θαλάσσιας ακτογραμμής, των αγροτικών κατά κύριο λόγο περιοχών που επιλέχθηκαν για μελέτη. Επιχειρείται η διερεύνηση της επιρροής των γεωργικών απορροών στο υδάτινο παράκτιο περιβάλλον μέσω της διακίνησης και κατανομής μακροστοιχείων που αποτελούν και τα κύρια συστατικά των εφαρμοζόμενων λιπασμάτων. / -

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Made available in DSpace on 2015-05-07T14:49:25Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 7985320 bytes, checksum: b62fc406031b14e7970624818fe47957 (MD5) Previous issue date: 2013-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Sustainability indicators are powerful tools that merge qualitative and quantitative aspects of multiple dimensions, thus guiding actions, giving support and assessing the progress toward the development sustainable. It is essential to apply these indicators in areas where there are large anthropogenic pressure as the coastal zone, where 40% of the world population lives. The research aim is to assess the degree of sustainability of the coastal zone of João Pessoa / PB through sustainability indicators. Therefore, we set the following specific goals: selecting indicators that are relevant to depict the degree of sustainability of the area; calculate the sustainability index of the region through the Dashboard of Sustainability Method and propose recommendations that can improve the indicators performance. The studies were conducted at the coastal zone of the João Pessoa / PB. Featuring stretch of 24 km the region is bordered to the north by the Bessa neighborhood and to the south by the Barra Gramame neighborhood. Were selected 17 indicators for that region and they can be divided into four dimensions: environmental, social, economic and institutional. The results demonstrate the sustainability index of the region was found at the intermediate level. However, when a comparison is made between the north area and south area we can observe some differences. On the southern coast of the region this index was found between the bad and the intermediate zone, while on the northern coast the sustainability index was found between the intermediate and reasonable zone. From these results we could produce an evaluation on the coastal area of João Pessoa that includes the social, economic, environmental and institutional dimensions and allow us to develop interventions aimed at improvements towards sustainability, as well as promoting a better insight into the complexity factors involved negatively on the stability of natural ecosystems present in the coastal zone of João Pessoa. / Indicadores de sustentabilidade são instrumentos essenciais para guiar a ação e subsidiar o acompanhamento e a avaliação do progresso alcançado rumo ao desenvolvimento sustentável, pois aglutinam aspectos qualitativos e quantitativos de múltiplas dimensões. Esses indicadores são de grande valia principalmente em regiões onde há grande pressão antrópica como a zona costeira, onde vive 40% da população mundial. O objetivo geral do trabalho é avaliar o grau de sustentabilidade do litoral de João Pessoa/PB através da utilização de indicadores de sustentabilidade. Para tanto foram estabelecidos os seguintes objetivos específicos: selecionar indicadores que sejam relevantes para retratar o grau de sustentabilidade da região; calcular o índice de sustentabilidade da região pelo Método do Painel da Sustentabilidade; propor recomendações que possam melhorar o desempenho dos indicadores obtidos para a área. A área de estudo compreende a faixa litorânea do município de João Pessoa/PB. Apresentando extensão de 24 km é limitada ao norte pelo bairro do Bessa e ao sul pelo bairro da Barra de Gramame. Foram selecionados 17 indicadores para região que podem ser divididos em quatro dimensões, ambiental, social, econômica e institucional. Os resultados encontrados demonstram que o índice de sustentabilidade da região se encontra num patamar intermediário. No entanto, quando é feita uma comparação entre as regiões norte e sul da área estudada pode-se observar diferenças. No litoral sul da região este índice se encontra entra a zona ruim e intermediária, enquanto que no litoral norte o índice de sustentabilidade ficou entre a zona intermediária e razoável. A partir desses resultados produziu-se um diagnóstico sobre a zona costeira de João Pessoa que tratou das dimensões social, econômica, ambiental e institucional, possibilitando a realização de intervenções que visem melhorias no sentido da sustentabilidade; bem como promovendo um melhor esclarecimento sobre a complexidade de fatores que intervêm negativamente sobre a estabilidade natural dos ecossistemas presentes na zona costeira de João Pessoa.