Дисертації: "Oceanograpy"

1

McGregor, J. A. "HF radar oceanography." Thesis, University of Canterbury. Physics, 1985. http://hdl.handle.net/10092/7578.

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The development of a 26MHz pulsed Doppler radar system for remote sensing of ocean surface conditions is described. This radar obtains Doppler spectra of echoes from ocean waves within the range 10-40 km from the shore. From these Doppler spectra it is possible to estimate oceanographic parameters such as sea state, wind speed, wind direction, radial components of current velocities and properties of swell. The work concentrates on the radar design principles and includes a detailed study of the effect of ground wave propagation conditions on the performance of radar systems of this type. Results obtained with the radar are discussed from the points of view of both the performance of the system and the oceanographic information contained in the Doppler spectra.

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2

Veilleux, Lorraine. "Physical oceanography of northern estuaries." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59830.

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Within the context of oceanographic research on northern estuaries in James Bay and Hudson Bay, and in relation with hydroelectric developments and their impact on the physical environment, two studies were undertaken. Both concern the importance of bottom topography, tidal motion and fresh water input on the estuarine processes in these areas.
The first one, in Rupert Bay (south-eastern corner of James Bay), describes tidal and local wind effects on circulation and mixing patterns for summer conditions. An estimate of terms in the lateral momentum equation shows that the centrifugal acceleration, the Coriolis force and the baroclinic pressure gradient are the most important forces at a mid-bay cross section transect.
The second study is concerned with the freshwater plume of Great Whale River (south-eastern Hudson Bay). CTD measurements were used to examine the lift-off point of the plume for under-ice and increasing discharge conditions. Comparison with existing models shows them to be inappropriate for under-ice conditions. Finally, the presence of supercooled water masses in the region of the study is reported.

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3

Leathers, Robert A. "Inverse solution methods for optical oceanography /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/7066.

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4

Middleditch, Andrew. "Spectral analysis in high frequency radar oceanography." Thesis, University of Sheffield, 2006. http://etheses.whiterose.ac.uk/3590/.

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High Frequency radar systems provide a unique opportunity to measure evolving littoral oceanic dynamics at high temporal and spatial resolution. Backscattered electromagnetic signals from ocean waves are modulated by Bragg resonant scattering. A perturbation analysis yields an expression for the spectral content of radar signals which can be exploited to provide estimates of oceanographic parameters: the radial component of surface current can be extracted from the frequency locations of the first order peaks; the ocean wave directional spectrum is related to the second order continuum via a non-linear integral equation. The periodogram, based on a Fourier decomposition of radax data, is the standard method used to derive frequency spectra. Limitations in this approach, caused by inhomogeneities in the underlying ocean field, are investigated. An instantaneous frequency technique is proposed in this thesis which mitigates the spectral distortion by demodulating the backscattered radax signals -a filtering procedure is developed which measures the temporally varying Bragg components. Alternative spectral techniques are analysed in order to validate the filter: an autoregressive paxa, metric modelling approach and an eigendecomposition method. The filter is evaluated, using radar and in situ data, which establishes its potential for ocean remote sensing. Significant improvements in the quantity and accuracy of wave measurements are demonstrated. Properties and constraints of the filter are derived using simulated data. Finally, the generic structure of the extracted instantaneous frequency signals is investigated and related to oceanographic processes.

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5

Berry, P. J. "Applications of satellite altimetry to dynamical oceanography." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/46961.

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6

Sheen, Katy Louise. "Seismic oceanography : imaging the antarctic circumpolar current." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609132.

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7

Coleman, Dwight F. "Archaeological oceanography of inundated coastal prehistoric sites /." View online ; access limited to URI, 2003. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3115624.

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8

Zarroug, Moundheur. "Asymptotic methods applied to some oceanography-related problems." Doctoral thesis, Stockholm : Department of Meteorology, Stockholm University, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-37763.

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Diss. (sammanfattning) Stockholm : Stockholms universitet, 2010.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

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9

Nerger, Lars. "Parallel filter algorithms for data assimilation in oceanography." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=975524844.

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10

Koonprasert, Sanoe. "The Sinc-Galerkin Method for Problems in Oceanography." Thesis, Montana State University, 2003. http://etd.lib.Montana.edu/etd/2003/koonprasert/KoonprasertS_03.pdf.

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The model for a wind-driven current with depth-dependent eddy viscosity is developed as a complex velocity formulation and a coupled system formulation. The numerical solutions, calculated by a Sinc-Galerkin method, are compared. A fully Sinc-Galerkin method in both space and time for a partial differential equation with time-dependent boundary conditions is developed. This entirely new technique is applied to the model for a wind-driven current with time-dependent viscosity. Several numerical examples are used to test the performance of the method. This fully Sinc-Galerkin method is then applied to the spin-up and the episodic wind stress oceanography problems.

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11

Thorslund, Josefin. "Hydrological spreading of metal pollution and wetlands as nature-based solutions." Doctoral thesis, Stockholms universitet, Institutionen för naturgeografi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-147613.

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The quality of the Earth’s water resources have deteriorated due to human impacts. A key scientific challenge is to understand, quantify and predict the water-borne spreading of pollutants at relevant scales for freshwater management and water quality restoration programs. However, understanding the natural processes controlling large-scale hydrological transport of pollutants may be masked by river regulation schemes (in the form of dams and reservoirs), which are common in many large rivers. The main objective of this thesis is to increase the current knowledge regarding large-scale spreading of metals in hydrological systems. This objective is addressed through studying net impacts of mining (a main contributor to global metal pollution) on the spreading of metals in water systems and through investigating the mitigation opportunities of wetlands across the landscape. The main study region of this thesis is the Lake Baikal basin of Russia and Mongolia, which includes the large unregulated Selenga River and its delta-wetland areas. In addition, a set of global wetland sites are also studied. A multi-method approach is used in the four studies of this thesis. The methods include field-measurements, data synthesis, metal mass flow and water flow-path quantifications, as well as geochemical modelling. Results show that mining in the upstream part of the Lake Baikal basin is a significant contributor to riverine mass flows of several metals. The mass flows increased by an order of magnitude over the mining site. The observed speciation between dissolved (more bioavailable) and suspended (less bioavailable) phases could be well predicted for some metals (Fe, V, Pb and Zn) using a geochemical equilibrium model. However, the model failed to reproduce the speciation of other metals (Cr, Cu, Mn and Mo). In these cases, non-equilibrium processes may need to be considered, and adsorption databases may need to be developed, in order to make dependable predictions. Results also suggest that the concentration of dissolved organic carbon, which exhibits seasonal variability and long-term increasing trends due to climate change effects in the Arctic, can have a large impact on metal pollution transport. Further, observations showed that individual wetlands of the Selenga River delta locally retained between 77-99 % of incoming metal loads. However, a systematic analysis of current knowledge showed that large-scale net effects can differ considerably from the functions observed at individual wetlands on smaller scales. Along large-scale flow-paths, through which wetlands are connected with each other as well as with the larger landscape, key processes which can considerably contribute to such scale differences in function may occur. A survey of the current wetland research showed that relatively few studies have considered the larger scales at which key pollutant pressures and water quality changes take place. This thesis highlights the need for more research on large-scale wetland systems, which can aid in evaluating net pollution effects at landscape scales. This in turn can facilitate evaluations of how and when wetland systems may function as large-scale nature-based solutions.
Kvaliteten på jordens vattenresurser har försämrats på grund av mänsklig påverkan. En viktig vetenskaplig utmaning är att förstå, kvantifiera och förutsäga den vattenburna spridningen av föroreningar, på skalor som är relevanta för vattenresursförvaltning och åtgärdsprogram. De underliggande, naturliga processer som styr storskalig hydrologisk föroreningstransport kan dock maskeras av att de flesta stora floders flöden är reglerade med hjälp av dammar och reservoarer. Målet med den här avhandlingen är att öka kunskapen kring hydrologisk storskalig spridning av metaller. Detta görs genom att studera nettoeffekter av gruvverksamhet (en viktig källa till globala metallföroreningar) på metallers spridning i vattensystemet, samt att undersöka våtmarkers möjligheter att rena förorenade flöden i landskapet. Avhandlingens huvudstudieområde är Bajkalsjön och dess tillrinningsområde (i Ryssland och Mongoliet), vilket inkluderar den oreglerade Selengafloden och dess delta-våtmarksområden. Även en grupp av globala våtmarksområden har studerats. Flera metoder användes i de fyra studierna som ingår i denna avhandling, inklusive fältmätningar, datasyntes, massflödes- och flödesvägskvantifieringar, och geokemisk modellering. Resultaten visar att gruvdrift i uppströms-delar av Bajkalsjöns tillrinningsområde bidrar betydligt till förhöjda halter av flera metaller i flodsystemen. Massflödenena ökade en storleksordning över gruvområdet. Den observerade metall-specieringen mellan lösta (mer biotillgängliga) och partikulära (mindre biotillgängliga) faser kunde modelleras väl för vissa metaller (Fe, V, Pb och Zn) med en geokemisk jämviktsmodell. Modellen lyckades dock inte reproducera specieringen av andra metaller (Cr, Cu, Mn och Mo). I dessa fall kan icke-jämviktsprocesser behöva beaktas, och adsorptions-databaser kan behöva utvecklas för att förbättra prediktionerna. Resultaten visar också att koncentrationen av upplöst organiskt kol, som uppvisar stora årstidsvariationer samt långsiktigt ökande trender på grund av klimatpåverkan i Arktis, kan ha stor inverkan på metallföroreningars transport. Observationer visade att enskilda våtmarker i Selengafloden lokalt kunde minska inkommande massflöden av metaller med 77 till 99 %. En systematisk genomgång av aktuellt kunskapsläge visade dock att storskaliga nettoeffekter kan skilja sig mycket från de funktioner som observeras vid enskilda våtmarker på mindre skalor. Längs storskaliga flödesvägar, genom vilka flera våtmarker är kopplade till varandra och till det större landskapet, kan viktiga processer ske, vilket avsevärt kan bidra till sådana skal-skillnader i funktion. En genomgång av aktuell våtmarksforskning visade att relativt få studier beaktade dessa större skalor där föroreningsspridning och vattenkvalitetsförändringar sker. Denna avhandling belyser behovet av ökat forskningsfokus på storskaliga våtmarkssystem. Detta kan hjälpa till att förstå föroreningars nettoeffekter på landskapsskalor, vilket underlättar vid bedömning av hur och när våtmarkssystem fungerar som storskaliga, så kallade naturbaserade lösningar.

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12

Amvrosiadi, Nino. "The value of experimental data and modelling for exploration of hydrological functioning: The case of a till hillslope." Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-331856.

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Successfully modeling one system response (e.g. hydrograph or solute transport) sometimes gives the false sense of well-characterizing the modeled system. This is partly because of the well-known equifinality issue; during the calibration process multiple parameter combinations can produce similarly good results. One step forward towards a better-defined system is using measured (at relevant scale) values for the model parameters, as well as using multiple conditions to constrain the model. But when not enough, or relevant, field measurements are available, virtual experiments (VE’s) can be used as a supplementary method to model calibration. The advantage of VE’s over model calibration is that they can also be used to explore assumptions both on the system hydrological processes, and on the model structure. One goal of this study was to utilize both field measurements and models for better characterization of the S-transect hillslope, located in Västrabäcken catchment, Northern Sweden. This included (a) characteristics in space: system vertical boundaries, hydraulic parameters, pore water velocity distribution, spatial correlation of flowpaths, soil water retention properties; (b) characteristic of system’s dynamic behavior: storage – discharge relationship, transit time distribution, turnover time; and (c) outputs’ sensitivity to external forcing, and to small scale structure assumptions. The second goal was to comment on the value of field measurements and virtual experiments for extracting information about the studied system. An intensely monitored study hillslope was chosen for this work. Although the hillslope has already been the subject of multiple field and modelling studies, there are still open questions regarding the characteristics listed above. The models used were the Vertical Equilibrium Model (VEM), and the Multiple Interacting Pathways (MIPs) model. It was found that the hillslope was well connected; from the near-stream areas up to the water divide the storage – discharge relationship could be described as an exponential function. Also, the dynamic storage (which controls the hydrograph dynamics) was much smaller comparing to the total hillslope storage. The unsaturated soil storage was found to be more sensitive to water table positions than vertical flux magnitude. The dynamic condition of external forcing (precipitation and evapotranspiration) affected the transit time distribution (TTD) shape. And, opposite to expectations, TTD was not sensitive to micro-scale structural assumptions tested here.

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13

Hinsley, Westley Richard. "Planktonica : a system for doing biological oceanography by computer." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418316.

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14

Foster, Deborah Anne. "New applications of Â²Â²â¶Ra to oceanography." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409791.

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15

Domingues, Carla Sofia Portela. "Population genetics of C. Maenas : oceanography and larval dispersal." Doctoral thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/973.

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Doutoramento em Biologia
Decifrar a complexa interacção entre os ciclos de vida de espécies marinhas e a oceanografia revela-se fundamental para a compreensão do fluxo genético e da conectividade no meio marinho. Nas espécies marinhas com desenvolvimento indirecto o fluxo de genes entre populações depende da distância que separa as populações, bem como da interacção entre a duração do desenvolvimento larvar, do comportamento das larvas e dos padrões de circulação oceânica. A conectividade larvar influencia uma variedade de processos como a dinâmica de stocks e de populações, a distribuição e limites geográficos das espécies, a estrutura genética das populações e a dispersão de espécies invasivas e reveste-se consequentemente de uma importância fundamental na identificação das unidades populacionais evolucionariamente relevantes e para a gestão e conservação marinhas. Os marcadores genéticos e os Modelos Individuais Acoplados a Modelos Físico-Biológicos (“ICPBMs”) são actualmente ferramentas fundamentais para o estudo dos padrões de dispersão larvar e para avaliar o nível de conectividade populacional. A presente tese respeita à avaliação das escalas espaciais de conectividade de populações de uma espécie costeira, o caranguejo Carcinus maenas, e utiliza conjuntamente informação de marcadores genéticos, análise de séries temporais de fornecimento de larvas e um modelo numérico de circulação oceânica. O primeiro capítulo introduz a temática da conectividade em espécies marinhas e inclui algumas referências aos métodos moleculares, analíticos e de modelação seguidos ao longo da tese. Através da utilização de múltiplas ferramentas – avaliação da estrutura genética geográfica de C. maenas na sua distribuição nativa com recurso a marcadores de DNA (microssatélites) (Capítulo 2), avaliação da estrutura genética temporal das larvas que formam os eventos de fornecimento larvar à Ria de Aveiro, NW Portugal (Capítulo 3), descrição da variabilidade inter-anual do fornecimento larvar à Ria de Aveiro, NW Portugal (Capítulo 4) e validação de um modelo ICPBM que descreve os padrões observados de fornecimento (Capítulo 5) – esta tese espera poder contribuir para uma melhor compreensão dos mecanismos que regulam o fluxo de genes e a conectividade entre populações de organismos marinhos. No Capítulo 6 são apresentadas as principais conclusões da investigação. A análise genética com recurso a microssatélites indicou que as populações de C. maenas são geneticamente homogéneas ao longo de várias centenas de km, dentro da distribuição nativa da espécie. Paralelamente, não foram encontrados indícios da existência de reprodução por “sweepstakes” em C. maenas de populações da costa oeste da Península Ibérica, visto que não se obtiveram diferenças genéticas significativas entre os eventos larvares. Também não se encontrou qualquer estrutura familiar entre as larvas que formam cada episódio de fornecimento, e não houve nenhuma redução significativa da variabilidade genética das larvas quando comparada com a de caranguejos adultos. A análise de séries temporais de suprimento de larvas na Ria de Aveiro em cinco anos estudados indica que este é um fenómeno episódico e variável, sendo os maiores episódios de fornecimento coincidentes com as marés vivas e acentuados por fortes ventos de sul. O modelo ICPBM foi validado com sucesso e parece fornecer uma estimativa realística das escalas espaciais e temporais de dispersão larvar, de acordo com as observações da estrutura genética e da ausência de reprodução por “sweepstake” em C. maenas da costa oeste da Península Ibérica
Unravelling the interactions between life-history strategies and oceanographic processes is central to the understanding of gene flow and connectivity in the marine environment. In particular, for marine species with indirect development gene flow between populations depends on the distance separating the populations and on the interaction between duration of the larval phase, larval behaviour and current patterns. Larval connectivity affects many processes, including stock and population dynamics, species ranges, population genetic structure, and the spread of invasive species and is therefore an important consideration to identify evolutionary relevant population unit and for marine management and conservation efforts. Genetic markers and Individual-based Coupled Physical-Biological Models (ICPBMs) are two of the tools currently available for tracking dispersal pathways of larvae and to assess the degree of population connectivity. The present thesis concerns the spatial and temporal scale assessment of population connectivity of a coastal marine species, the shore crab Carcinus maenas, making use of genetic markers, time series larval supply analysis and an oceanographic numerical model. Chapter 1 introduces the thematic of marine species connectivity, including a brief reference to the molecular, analytical and modelling methods followed during the study. Making use of an interdisciplinary approach – assessment of genetic geographical structure with microsatellite markers within C. maenas native range (Chapter 2), assessment of temporal genetic structure of larvae forming each supply event to the Ria de Aveiro, NW Portugal (Chapter 3), description of interannual variability of larval supply to the Ria de Aveiro, NW Portugal (Chapter 4) and validation of an ICPBM to describe the observed time series of supply (Chapter 5) – the aims of this thesis is to contribute to our understanding of the mechanisms regulating gene flow and connectivity among marine populations. Finally, in Chapter 6 the main results and conclusions achieved are presented. Microsatellites analysis indicated that C. maenas populations were genetically similar across hundreds of km, within the species native range. Additionally, there was no evidence of sweepstakes reproduction in C. maenas from western Iberian coast populations since there were no significant differences amongst larval events. Among larvae in each episode, no genetic relatedness was found, and larvae did not present reduced genetic variability when compared to adult crabs. On a long time scale, larval supply to the Ria de Aveiro was episodic and variable throughout five different studied years, with highest supply numbers generally occurring around spring tides and enhanced by strong southerly winds. The ICPBM was successfully validated and appears to provide a realistic estimate of the observed spatial and temporal scales of the larval dispersal, consistent with the observations on genetic structure and lack of sweepstake reproduction in C. maenas from western Iberian coast.

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16

Mondello, Nicholas. "Physical oceanography off the South Coast of Western Australia." Thesis, Mondello, Nicholas (2017) Physical oceanography off the South Coast of Western Australia. Honours thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/40163/.

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Compared to neighbouring regions of ocean, the south coast of Western Australia (WA) has received relatively little scientific attention despite a range of Australian Commonwealth marine protected areas having been established in the region as of 2012. The ocean off the south coast of WA is characterised by a canyon-dense continental shelf edge including the Bremer Canyon, a shelf edge canyon of approximately 8 km width. There are also two main currents in the region, the eastward flowing Leeuwin Current (LC) situated above the continental shelf edge, and the westward flowing Flinders Current (FC) situated south of the continental shelf. The Blue-link Reanalysis (BRAN) ocean forecasting model simulates the currents, temperature and salinity around Australia at daily intervals from 1994 – 2016 with 1/10th degree resolution. It has been speculated that these currents may interact with the canyons along the shelf edge to induce oceanographic conditions conducive to increased pelagic productivity and ecological diversity. This study was a two-part investigation of the physical oceanography off the south coast of WA with a focus on shelf edge dynamics near Bremer Canyon. It involved the use of the (BRAN) model and in situ data including conductivity, temperature and depth (CTD) profiles during January 2017 and temperature logger measurements from near Bremer Canyon between 2015 and 2017. The BRAN outputs were in close agreement with previous studies of the LC and FC and showed that the mixed layer depth (MLD) was shallowest (<50 m) in summer and deepest in winter (>200 m), in sync with seasonal heat flux. The CTD results were within one SD of the average BRAN profiles and MLD results for January. The volume transport of the LC and strong westerly wind events were dominant drivers of the temperature variation along the shelf edge during autumn and winter of 2015 as the warm LC water was forced downwards. In spring and summer, the volume transport of the LC was lowest (1.6 Sv) and other factors became dominating drivers of the shelf edge temperature variation including eddy kinetics and canyon-related processes. The BRAN outputs effectively simulated the mesoscale features examined in this study including the volume transport of the LC, westerly wind forced response and the influence of mesoscale eddies. These processes have the potential to influence the pelagic ecology through vertical mixing and upwelling.

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17

Djurhuus, Anni. "Microbial oceanography of southern hemisphere seamounts and hydrothermal vents." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:727fb8de-a392-4030-bc86-6390143111fd.

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Microbial biogeography is being increasingly more studied, both in terms of genetic divisions and 'ecotype' variation. This thesis investigates the regional (100-1000s km) and local (10s m) distribution and diversity of microorganisms around hydrothermal vents and seamounts at the East Scotia Ridge and the Southwest Indian Ridge. Microbial communities were characterized using Illumina dye sequencing to de- termine taxon richness and diversity and flow cytometry to obtain cell counts. In addition I investigated the physicochemical environment (nutrients, organic carbon, salinity and temperature) in which the microorganisms persist. Typical deep-sea microorganisms were abundant at vents and below the euphotic zone on the seamounts. The surface layer of the seamounts contained typical open-ocean photoautotrophic organisms. Microbial communities were correlated to or- ganic carbon on both hydrothermal vents and seamounts. With microorganisms possi- bly having a large influence on carbon sequestration into the deep-sea from hydrothermal vents. On a local scale the hydrothermal vents had a relatively higher abundance of chemosynthetic Epsilonproteobacteria and the Gammaproteobacteria family SUP05, which were closely correlated to the redox potential in the vent effluent. This was prominent in both plumes from the East Scotia Ridge and the Southwest Indian Ridge, which also had distinct microbial community structures. Across the Southwest Indian Ocean the microbial communities were firstly segregated by depth. However, on a regional scale their physical environment primarily divided the microbial communities into three biological regimes the sub-tropical, con- vergence zone and the sub-Antarctic. The microbial community structure and biogeography is influenced by steep environmental gradients, displaying a distance-decay relationship between sampling locations. With environmental conditions persisting at different scales, from local (10s m) around the hydrothermal vents to regional (100-1000 km) between the seamounts, driving the microbial community patterns. The same horizontal and vertical patterns for microorganisms and metazoans points to fundamental differences throughout all parts of the ecosystem/food web.

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18

Jarvis, Marley. "Physical Oceanography, Larval Dispersal, and Settlement Across Nearshore Fronts." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/18711.

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The larvae of coastal species interact with nearshore currents that are complex and can alter dispersal. I investigated two sites in southern Oregon with different nearshore hydrodynamics: the first site, Sunset Bay, is a small cove with a topographic front that extends across the mouth during upwelling-favorable winds. Using holey sock drogues at 1.5 m and 5.5 m depths and surface drifters at 10 cm depth, I found that, when the front was present, water at 1.5 m was retained within the bay whereas water was exchanged across the front at a depth of 5.5 m. Surface drifters indicated a surface convergence. Surface plankton tows on either side and within the frontal convergence (a shore-parallel foam line) found significantly higher concentrations of barnacle cyprids, crab megalopae and zoea, polychaete larvae, platyhelminthes juveniles, isopods, amphipods, harpacticoid copepods, and fish eggs. Crustacean nauplii (barnacle, euphausiid, and copepod) and calanoid copepods were not concentrated in the convergence, and when the front and foam line were absent, no taxa were concentrated. Plankton tows taken within the foam line as it dissipated shoreward during a wind-reversal event found that concentrations of cyprids, megalopae, and gastropod veligers remained high as the foam line moved, suggesting that it acts as a moving convergence propagating competent larvae shoreward. I measured settlement of two taxa at Sunset Bay and Shore Acres, an open-coast site <2 km away. Barnacle settlement measured every other day from June-September 2013 was significantly cross-correlated with the maximum daily tidal height at lags of -2 days at Sunset Bay and +2 and +4 days at Shore Acres. Settlement was also significantly negatively cross-correlated with wave height at a lag of -4 days at Sunset Bay. Coralline algae settlement measured during eight 48-hr periods in July-August 2013 was significantly negatively correlated with wave height (n = 8, R2 = 0.76, P = 0.0049) at Shore Acres but not at Sunset Bay. Despite the close proximity of the Sunset Bay and Shore Acres sites, settlement patterns differed between taxa, suggesting that differences in nearshore hydrodynamics might affect the supply of water and larvae to shore. This dissertation includes unpublished co-authored material.

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19

Bâcle, Julie. "The physical oceanography of waters under the North Water Polynya /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ64314.pdf.

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20

Dale, Andrew W. "The oceanography and modelling of the Pontevedra Ria (NW Spain)." Thesis, University of Plymouth, 2003. http://hdl.handle.net/10026.1/1966.

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A multidisciplinary study the oceanography of the Pontevedra Ria (NW Spain), including hydrography, biogeochemistiy and biogeochemical modelling, has been performed. The hydrographical variability of the Pontevedra Ria was dependent on freshwater inputs and upwelling of nutrient-rich East North Atlantic Central Water from the shelf. Intrusions of the Poleward Current were also detected during winter. A stratified box model approach predicted that upwelling water fluxes into the ria of 2-4x10³ m³ s-1, of which >30% rises to the surface waters inside the ria. Freshwater residence time varied from ~4-9 d in the central ria and 1-4 d in the internal ria. Nutrients concentrations showed a strong fluvial and oceanic signal, with a clear zone of near-bed aerobic remineralisation in the internal ria. Nutrient flux experiments showed that high nutrient fluxes, particularly ammonium (3.5 mg N mˉ² hˉ¹), coincided with period of high water influx to the ria. These were related to stirring of quasi-benthic phytodetrital fluff. Denitrification was a major fate for particulate organic nitrogen in the sediment, averaging 2.5 mg N m ˉ² h ˉ¹ for the spring and dry season. A non-steady state nutrient budget revealed that the central and internal zones of the Pontevedra Ria display different biogeochemical characteristics. Net community production (NCP) based on phosphate uptake was spatially and temporally variable, with rates of 9.6 and 20.2 mg C m ˉ² h ˉ¹ in central and internal rias in spring, respectively, and 30.3 and 29.0 mg C m ˉ² h ˉ¹ in the dry season. Previously unquantified benthic nutrient inputs were important, and up to 25% of NCP was due to the sediment nutrient flux in the dry season. Denitrification calculated with the nutrient budget equalled 1.82 and 5.66 mg N m ˉ² h ˉ¹ in the dry season in the central and internal ria, respectively, and was equal to 27 and 42% of dry season NCP. The robustness of the box model was questioned, and found to be an unsuitable modelling approach for the Rias Bajas. This had clear implications for predicting NCP and net nutrient budgets to the coastal zone. Salinity and temperature were simulated with the commercially-available simulation shell, ECoS, to within the analytical error of the observed data. Inorganic nutrient concentrations and benthic effluxes were qualitatively and quantitatively agreeable with observed data. Phytoplankton growth in ECoS was limited by up to 30% by phosphorus rather than nitrogen, as previously believed. The annual evolution of NCP was successfully reproduced by examining the chlorophyll-normalised rate of organic carbon production. Mean NCP In the spring and dry season was 46.5 and 147 mg c m ˉ² h ˉ¹, which agreed well with the literature. There were clear discrepancies between box model and ECoS-derived nutrient export to the Atlantic ocean. The definitions of constituent uptake and remineralisation processes between the two approaches were examined In the context of biogeochemical modelling and environmental management of the Rias Bajas.

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Aravamudhan, Shyam. "Development of micro/nanosensor elements and packaging techniques for oceanography." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002219.

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22

Andrén, Hanna. "Tillförlitligheten hos översvämningskartering : Utbredningsjämförelse med översvämningen i Hallsberg 2015." Thesis, Karlstads universitet, Institutionen för miljö- och livsvetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-43608.

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Blomgren, Axel. "Stockholms grundvattenkvalitet : Bidrag till övergödningen av ytvattendrag och sjöar i Stockholmsområdet." Thesis, KTH, Industriell ekologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189125.

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Övergödning är ett av Sveriges mest allvarliga miljöproblem. Genom utsläpp till följd av antropogen verksamhet läcker näringsämnen ut i vattnet. Den senaste undersökningen av Stockholms stads grundvatten har kartlagt halterna av kväve och fosfor. Eftersom grundvatten är en del utav det hydrologiska kretsloppet, och efter en viss omsättningstid övergår till ytvatten, påverkar kvalitén hos grundvattnet recipienten samt det ekosystem som denna ingår i. Rapporten ämnar undersöka halterna av kväve och fosfor i grundvattnet utifrån befintliga bedömningsgrunder samt kartlägga huruvida grundvattnet bidrar till övergödning av Stockholms kommuns ytvattenförekomster. Detta är av vikt för kommunens vattenförvaltning i linje med EU:s vattendirektiv och mål om god status för vattenförekomster, men även för att verka mot landets miljökvalitetsmål. Miljöförvaltningens undersökning av grundvattenkvaliteten visar på höga halter av fosfor samt ammoniumkväve. Halterna av nitrat samt nitrit är enbart höga i vissa av provpunkterna. Halterna av främst fosfor och ammoniumkväve kan enligt bedömningsgrunder ha övergödande effekt på ytvattendrag. En översiktlig undersökning baserad på grundvattnets strömningsriktning visar att kommunens vattenförekomster får ett tillskott av vatten via grundvattnet inom kommunen. Detta finns representerat i kvalitetsundersökningen av grundvattnet varpå slutsatsen dras att ytvattenförekomsterna inom kommunen påverkas negativt av grundvattnet.
Eutrophication is one of Sweden’s most severe environmental issues. Due to emissions through anthropogenic activity nutrients are added to aquatic systems. The latest analysis of the Stockholm municipality groundwater has examined the levels of nitrogen and phosphorus. Due to the fact that the groundwater is part of the hydrological cycle and will eventually reach the surface water, the condition of the groundwater will affect the recipient and correlating ecosystem. This report aims to analyze the levels of nitrogen and phosphorus in the groundwater of Stockholm based on current national quality standards, and to identify whether the groundwater is contributing to the eutrophication of the surface water bodies in the municipality of Stockholm. This is of significance regarding the water management in Stockholm municipality, based on the EU water framework directive, and the target of achieving good status for all water bodies. It is also of great importance regarding the Swedish environmental quality objectives. The groundwater quality analysis indicates high levels of phosphorus and ammonium. The nitrate and nitrite levels are only excessive in certain cases. Primarily, the levels of phosphorus and ammonium may, according to national quality standards, have eutrophic effect on surface water bodies. A cursory examination based on the flow directions of the groundwater, indicates that the municipality’s surface waters are supplied with water from the municipality’s groundwater. This correlation is represented in the analysis of groundwater quality and it is therefore concluded that the groundwater has a negative impact on the surface water bodies within the municipality.

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Wiborgh, Hanna. "Where do the nutrients come from? : A case study from the agricultural landscape of Sibou village." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-126479.

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This study investigates the source of nutrients in an agricultural landscape in Kenya. Kapshoi furrow has its intake from Embobut River and flows through the village of Sibou until it reaches the plots in the lowland in Keu. The pH, electrical conductivity (EC), sediment transport, total nitrogen (N) mass flux and total phosphorus (P) mass flux all change when the furrow flows through the village. The most possible cause for the nutrients peaks is the farmers' goats, sheep and cows that walk freely in and around the furrow. This is counter to some existing local theories. The likely cause for the pH decrease and the EC increase are inflow of groundwater (springs) to the furrow. To secure safe drinking water it would be good to uphold the old rules in Sibou of (1) not to live in close proximity of the furrows and (2) not to bathe or do the dishes in the furrow water. This might be difficult due to a fast growing population.

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Schuh, Carina. "Influence of soil moisture content and infiltration on ground temperature and active layer depth in a river terrace in Adventdalen, Svalbard." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-121459.

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The active layer constitutes an important subsystem of permafrost environments. Thermal andhydrological processes in the active layer determine local phenomena such as erosion, hydrologicaland ecosystem changes, and can have implications for the global carbon-climate feedback.Despite their importance for environmental and climate change, active layer dynamics are stillonly poorly understood. The importance of hydrology for active layer processes is generallywell acknowledged on a conceptual level, but the physical interdependencies between soil moisture,subsurface water flows and active layer depth are largely unresolved. This thesis usedstate-of-the-art numerical modeling to study the influence of ground surface temperature, soilmoisture content and advective heat flow on near-surface permafrost temperatures and activelayer depths. The investigation was performed for a dry, loess-covered river terrace in centralAdventdalen, Svalbard, and fed by high-resolution hydro-climatic field data for the period2000-2014. Nine scenarios were considered in order to independently test the influence ofdifferent initial soil moisture contents (6%, 12%, and 19%) and infiltration patterns (no infiltration,constant infiltration, and early summer peak infiltration). Results indicated that the permafrost-hydrological system at the study site is largely influenced by cryosuction processes due tostrong capillarity of the highly unsaturated soil. Zones of increased ice content developedprimarily near the permafrost table, creating a ‘transition zone’ between the lower part of theactive layer and the upper permafrost. Infiltration based on snow melt and summer precipitationwas found to be negligible for the seasonal active layer development. The active layer depthgenerally decreased with increasing initial soil moisture content due to a higher consumption oflatent heat. However, cryosuction into the permafrost table and water percolation could potentiallycounterbalance latent heat effects, at least in systems characterized by higher soil moisturecontents. Both model simulations and field observations showed a clear tendency of increasingactive layer depth during the study period, whereas inter-annual variations in active layer depthwere comparably small. Given the moisture migration into the ‘transition zone’, the modelresults further suggested that the site might be capable to buffer thaw and thus obscure increasingground surface temperatures to a certain degree. This could have implications for the suitabilityof active layer depth as a proper indicator for climate change.

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Girons, Lopez Marc. "Modelling Climatic and Hydrological Variability in Lake Babati, Northern Tanzania." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-114009.

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A good understanding of the local and regional water cycle and how it is modified by landscape changes may help policymakers take the pertinent decisions in order to avoid adverse effects of future hydro–climatic changes. This knowledge is of particular interest in the most vulnerable areas of the world such as the African continent. In this context the aim of this project is to model hydrological responses to possible changes in climatic conditions in Lake Babati, northern Tanzania. For this reason a water balance model specially designed to simulate lake level changes was adapted to Lake Babati and calibrated with the available local meteorological and hydrological data record covering the last decades. The necessary ambient condition changes to produce a dry–out and an overflow of the lake were investigated and the response of the system to future IPCC climate change projections was studied. The results show that for instance a temperature change of less than 3ºC or a precipitation change of around 100 mm/year could eventually bring the lake from a dry–out situation to an overflow situation. Furthermore, the IPCC derived scenarios show a clear tendency of the lake to increase its volume and reach the overflow level in a relatively short time.

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Lindgren, Carl. "Estimating groundwater changes in the Rufiji basin by using data from the GRACE satellites." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-105999.

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Ekstedt, Karin. "Local water resource assessment in Messinia, Greece." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-93033.

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Messinia is a region in Greece renowned for its rich nature, olive agriculture and water availability. In the light of increasing anthropogenic and climatic pressure, this study assessedlocal water resources in catchments in south western parts of the region. The main objectives were to evaluate the balance between supply and demand, the sustainability of current waterconsumption, capacity of further land use intensification and to review local water management. The method was dual with both quantitative (water balance calculations and linear modeling) and qualitative (interviews and a questionnaire survey) approaches.It was confirmed that, on an annual basis, rainfall is comparatively high, there is a surplus of water leaving the catchments and aquifers are “superfluous”. The climate however, brings seasonal imbalance and notable shortages during summer that affect operation of local actors, especially with agriculture and tourism being the principal water users. Unofficial sources indicated that current consumption may not be sustainable, either because of over-exploitation or climatic changes, but further studies are required to draw reliable conclusions. Modeling showed the importance of land management, that unconsidered water consumption may impact the water balance substantially but also that, while minimizing evapotranspiration,there is capacity of intensification if water withdrawals are increased. Considering accessibility, competitive interests and sustainability however, such development is not necessarily feasible.The municipal water management appeared to be well established and, given that measures are taken concerning for example stakeholder integration and regulation of private and agricultural consumption, there is capacity of handling increasing water stress. Finally, stressing the crucial role of freshwater availability, the study highlighted the importance of further hydrological research and thus the need for improved data quality, particularly regarding river discharge.

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Joodaki, Saba. "Application of the Reflection SeismicMethod in Monitoring CO2 Injection in aDeep Saline Aquifer in the Baltic Sea." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-200179.

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Time-lapse reflection seismic methods have proven effective fordetecting and monitoring the injection and spreading of geologicallystored CO2. These methods are based on interpreting changes in themedia’s elastic properties that result from replacing the native salinewater by the injected CO2, which in turn affects the seismic velocitiesof the media. Since applications of these methods in the field areexpensive, and the interpretation process is time consuming, pre-studyinvestigations should be done in order to determine whether or notreflection seismic surveys can successfully be applied to monitor theCO2 plume in the case of interest.In the present study, CO2 injection and migration in a deep salineaquifer based on a structure situated below the south-western part ofthe Baltic Sea was modeled. To determine the CO2 saturationdistributions at different times, the injection was numericallysimulated using TOUGH2/ECO2N. A radial-symmetric model withhomogeneous and isotropic properties was assumed and two differentinjection rates were studied, with the results analyzed at differenttimes after the start of the injection.The saturation and density values resulting from the TOUGH2simulation were converted to seismic velocities using the Biot-Gassmann model. A synthetic velocity model was built based on bothTOUGH2 and Biot-Gassmann models and synthetic seismic responsefields before and after injection were generated. The results show thatthe amplitude changes in the seismic response are detectable even forsmall amounts of injected CO2, while noticeable signs of velocitypushdown, as a signature of the CO2 substitution, could only beobserved if the injection rate is high enough.

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Lundgren, Sandra. "Efficiency of two wastewater treatment plants situated in Zomba, Malawi." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-201901.

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Gallon, Evelina, and Sanna Lindberg. "Where does the stream begin? : Stream initiation under variable wetness conditions in a boreal landscape." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-227045.

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The understanding of where the streams begin is an important factor in both hydrology and geomorphology, as well as for land use activities. Despite this, only a few research projects have been done in a snowmelt-dominated boreal landscape. The main objective in this study is to see if one could predict where a stream initiates by knowing possible controlling factors. Data points from stream initiation points in the boreal landscape of Krycklan, situated 50 km Northwest of Umeå, were analyzed. Krycklan is a well-known research area and a lot of research projects have been done here. The landscape is diverse and most of the streams have been modified by human impact. The data points were collected with help of a Global Positioning System (GPS) during three different sampling campaigns; May 2012, May 2013 and August 2013. Maps were made from a Digital Elevation Model (DEM) showing slope, elevation and contributing areas for the stream heads. No clear relationship between the contributing area and slope could be found in this area, although it has been demonstrated in more semi-arid climates. The results show that other factors than the contributing area, elevation and slope seem to have a greater impact for the initiation of streams in a boreal landscape. The results were expected because of the modifications done for the streams.

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Amvrosiadi, Nino. "Temporal Dynamics of Total Organic Carbon Export Rates in Swedish Streams : Importance of discharge conditions and seasonal effects." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-175716.

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The amount of total organic carbon (TOC) in water is a rough indicator of the waterquality. Driven by the question how the TOC concentration would vary acrossstreams in Sweden under different climate conditions (e.g. more extreme dischargeevents), the temporal dynamics of TOC were examined for different stream subgroupswith six orders of magnitude catchment area span. In addition, the relationshipbetween dissolved inorganic carbon (DIC) export (both downstream and evasion) anddischarge conditions was also studied. Another question addressed was if the amountof TOC exported can be affected by export conditions dominating the previousseason. TOC export followed closely the discharge, which is in agreement withprevious studies, and all 42 catchments studied across Sweden were described by thispositive relationship regardless their size. A linear TOC export response to dischargewas identified during extreme discharge conditions. Furthermore, the TOC export wassignificantly related to the antecedent TOC export conditions for approximately halfof the 18 studied catchments with areas ranging between 2.5·10-3 and 67 km2.

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Harney, Pawel. "Evaluation of the use of a Dynamic versus a Simple Correction Model to correct for systematic errors in Swedish Precipitation Data." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-142905.

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A Dynamic Correction Model (DCM) was implemented to correct daily precipitation data from the network of precipitation gauges hosted by the Swedish Meteorological and Hydrological Institute (SMHI). The goal was to determine whether the DCM could be used to improve estimates of the influence of systematic errors on precipitation observations compared to a previous assessment made on the SMHI dataset using a Simple Correction Model (SCM). While the SCM in question only takes into account station exposure and temperature, reflecting the yearly average gauge level wind speed and the monthly average probability of snow respectively, the DCM would take into account sub-daily and daily observations of precipitation intensity, wind speed and temperature to correct precipitation according to the observed conditions at the time of the precipitation event. DCM corrections were performed on precipitation data from 165 stations throughout Sweden.The long term average result of aggregating daily DCM corrected precipitation was compared to the previous SCM correction for 24 stations while the daily corrected solid precipitation was evaluated against snow depth observations for 59 stations throughout Sweden.Since the systematic errors almost exclusively cause an underestimation of ground true precipitation the correction was expected to produce an increase in total precipitation. Since this undercatch is greater during solid precipitation, a pattern of higher correction was expected to be found in winter months compared to summer months, a pattern which could be expected to be stronger the further north in the country one looked. Furthermore, superimposed on this, areas which are more exposed to wind can be expected to require a larger correction due to the undercatch being also strongly correlated to wind speed. At the sub monthly time scale a variation in the undercatch could be expected when using the DCM with increased corrections required on days when precipitation falls as snow and on days when wind speeds are higher.For the comparison with previous SCM estimates the expectation was that long term totals (30 year average corrected precipitation) would be similar if the two methods are assumed to be equally valid. The DCM was further expected to improve correlations between newly fallen snow and change in snow depth.While the qualitative patterns in the corrections found met the expectations, large differences in the quantitative results of using the two different methods were found; the DCM had a tendency to overcorrect compared to the SCM, especially for the more exposed stations. This calls into question the assumption that both methods are equally valid and differ only in their temporal resolution, and further raises the question which if any of the methods is more valid and why. The evaluation of DCM corrected solid precipitation using snow depth showed a decrease in the correlation between precipitation and change in snow depth which was contrary to expectations. The greatest uncertainty in the DCM was attributed to the methods for assessing gauge level wind speeds.

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Åhlén, Imenne. "Connecting Hydrological Processes to the Hypersaline Conditions of the Wetland Complex of Ciénaga Grande de Santa Marta, Colombia." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-136655.

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Wetlands and coastal wetlands are important ecosystems for many aquatic and terrestrial flora and fauna as well as for the sustainable development of humans. Unfortunately, many of the world’s wetlands and coastal wetlands are subjected to degradation due to both natural processes and human activities changing the hydrodynamics of the area. As such, many coastal wetlands have been affected by hypersaline conditions consequently contributing to the degradation of both flora and fauna. This has also been true for the wetland complex of Ciénaga Grande de Santa Marta (CGSM), Colombia, where hypersalinity has been associated to constructions reducing freshwater inputs to the lagoon. As hydrological processes build up wetlands, it is crucial to understand how these processes impact wetlands and specifically the occurrence of hypersaline conditions. At the same time, not much is known about the hydrological conditions of wetlands, which is also the case for the wetland complex of CGSM. As such, this study focuses on disentangling the hydrological processes affecting the salinity levels of the wetland complex of CGSM by analysing the seasonal salinity patterns in both time (from the year of 2000 until 2015) and space. The analysis of the temporal pattern of salinity was also analysed statistically in relation to climatological data. The results from the temporal pattern of salinity showed a minor trend in increased salinity levels for the wetland in general, and by season, throughout the studied period. A rather strong correlation between salinity and climatological factors could also be identified. Moreover, the salinity for some areas within the wetland complex were higher during the wet season for some years, compared to the dry season. The results from the spatial patterns of salinity showed that the salinity of the wetland was generally higher further away from the fresh water sources, by the outlet to the open sea, and especially for the area of Ciénaga de Ahuyama. The salinity patterns in space changed as the rain period started creating a division of the wetland complex into a high-salinity western area (main lagoon) and a low-salinity eastern area. This could be due to the relatively higher amount of fresh water inputs from rivers fed by precipitation on the mountains of Sierra Nevada de Santa Marta, east of the wetland complex, compared to the relative small amount of freshwater from the channel of Aguas Negras in the western part of the wetland complex. Lack of correlation between salinity and channel dredging efforts questions the effectiveness of ongoing remediation strategies in the western section of the CGSM, while salinity levels in the eastern section are mainly regulated naturally via unrestricted freshwater inputs.

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Amland, Sølvi. "Hvor er de markene i Sverige som er mest sensitive ovenfor forsuring og nitrogentap?" Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-177377.

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Several factors affect whether the ground is prone to acidification and nitrogen loss. Removal of biological materials is an important factor that can trigger this. In Sweden, three dominant forest tree species are spruce, pine and birch trees. For forestry purposes, these trees are being logged at their potimal harvesting ages which are averaged at 70 years of age. This is of interest beacuse the forest ages can be used to predict future forestry practices, specifically in Dalarna, Sweden. The forest ages were observed at a catchment based level so that the effects of forestry can easily be measured. It was found that cathcments in the north of Dalarna consist of higher percentages of forest over the age of 70 in comparsion to the south and areas surrounding lakes. From this, it is expected that forestry will occur in the near future in the north. Hopefully the work that has been done in Dalarna, can be used as a model for the rest of Sweden.
Flere faktorer virker inn på om marken er utsatt for forsuring og nitrogenlekkasje. Fjerning av biologisk materiale er en viktig faktor som kan trigge nettopp dette. Finner man de områdene som har mest skogshugst, kan man få et svar på problemet. I Sverige er de tre dominerende treartene gran, furu og bjørk. For at skogsbruket skal få en størst mulig økonomisk gevinst, blir trærne kuttet når de er 70 år. Dette er av interesse fordi skogsalderen kan bli brukt til å prediktere fremtidig skogsbruk, spesielt i Dalarna, Sverige. Skogens alder ble observert i nedbørsfelt som var mindre enn 3 km2 , fordi markens respons på skogsbruk lettere kan måles i mindre områder. Det ble funnet at nedbørsfelt nord i Dalarna har høyest prosentandel av skog over 70 år, sammenlignet med de sørlige områdene og områder rundt innsjøer. Disse resultatene viser at vi kan forvente at områdene nord i Dalarna, er mest sensitive ovenfor forsuring og nitrogenlekkasjede neste ti til tyve årene. Det arbeidet som er for å finne sensitive områder i Dalarna, kan bli brukt som en modell for resten av Sverige.

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Ronquist, Christina. "Lateral och longitudinell dispersion hos grundvatten i en grusås." Thesis, Uppsala universitet, Naturgeografiska institutionen, 1987. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-433611.

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I denna uppsats har den laterala och den longitudinella dispersionen studerats i en grusås, (Finnerödjaåsen) med hjälp av spårämnesmärkning. Spårämnet, NaI injicerades i ett grundvattenrör. Jodidkoncentrationen i grundvattnet mättes i injiceringsröret, i sju grundvattenrör placerade tvärs över åsen och i ett rör 50 meter nedströms injiceringsröret. För att bestämma den laterala och den longitudinella dispersionskoefficienten användes en förenklad modell som förutsätter laminärt flöde i ett homogent medium. Modellen visade god överensstämmelse med försöksresultaten från Finnerödjaåsen. Den laterala dispersionen beräknades till 2.4 m2/dygn. Den longitudinella dispersionen visade sig vara mycket större i åsens kärna, ända upp till 260 m2/dygn än någon meter från kärnan ut mot åskanten där dispersionen i genomsnitt var 16 m2/dygn. Hastigheten hos grundvattnet i åsens kärna var ungefär dubbelt så stor som i övriga åsen och troligtvis transporteras största delen av flödet i en liten del av åsens mitt.
The lateral and longitudinal dispersion of groundwater was studied in a gravel ridge, (Finnerödjaåsen) in the central part of southern Sweden. NaI was injected into a groundwater tube. The iodine concentration in the groundwater was then measured in the injection tube, in seven groundwater tubes placed in a transverse row 1,5-4 m apart 20 m downstream the injection tube and in one tube 50 m downstream the injection tube. The coefficients of lateral and longitudinal dispersion were determined by using a model assuming laminate flow in a homogeneous medium. For the gravel ridge examined, there was a good fit between the experimental data and this model. The lateral dispersion was found to be 2,4 m2/day. The longitudinal dispersion was much larger in the narrow passage in the middle of the ridge, 260 m2/day, than in the marginal zones of the ridge, 16 m2/day. The flow velocity of the groundwater in the middle of the ridge was about twice as large as the flow velocity in the rest of the ridge, i.e. the bulk flow of groundwater occured in the middle of the ridge.

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Edström, Magnus. "Syre-18-halt hos markvatten extraherat genom centrifugering och destillering av jordprover." Thesis, Uppsala universitet, Institutionen för geovetenskap, 1993. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-392964.

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Vid hydrologiska studier är det ofta nödvändigt att känna till flödesvägar och uppehållstider för markvattnet. Syreisotopen 18O kan användas som ett konservativt hydrologiskt spårämne för att bestämma vattnets rörelse. Vid extrahering av markvatten från jordprover för 18O-analys används ofta en destillationsmetod. En enklare och snabbare metod för att extrahera markvatten är att använda en höghastighetscentrifug. Problemet är att allt markvatten i ett jordprov inte extraheras med denna metod. Det är därför möjligt att vatten extraherat genom centrifugering inte har en 18O-halt som är representativ för markvattnet. I den här undersökningen jämfördes 18O-halterna i vatten extraherat genom centrifugering och destillering. Markvatten extraherades från ostörda jordprover och från torkade jordprover mättade med vatten av känd 18O-halt. Extraktionerna gjordes både genom centrifugering vid olika hastigheter följt av destillation och genom enbart destillation. Samtliga jordprover torkades sedan. Skillnaden i 18O-halt mellan vatten extraherat genom centrifugering vid olika hastigheter var små. 18O-halten för destillaten var, med ett undantag, lägre än för centrifugaten. Torkningen av jordproverna visade dock att allt markvatten inte hade extraherats vid destillationen. Detta kan vara en förklaring till den lägre 18O-halten hos destillaten. På grund av ofullständig destillation kunde inte den här undersökningen avgöra i vilken grad 18O-halterna i centrifugaten var representativa för den del av markvattnet som är hårdast bunden till marken. För att karaktärisera 18O-halten i det rörligaste markvattnet, är dock centrifugering inte bara en snabbare metod, utan också en metod med färre felkällor än destillationsmetoden.
In hydrological studies it is often necessary to know the ﬂow pathways and residence time of soil water. The oxygen isotope 18O can be used as a conservative hydrological tracer to help determine water´s movement. To extract soil water from soil samples for 18O analysis, a distillation method is often used. An easier and faster method for extracting soil water is high speed centrifugation. All soil water, however, is not extracted from a soil sample by this method. It is therefore possible that the water extracted by centrifugation does not have an 18O content that is representative of the soil water. In this study, the 18O values of water extracted by distillation and centrifugation are compared. Soil water was extracted from undisturbed soil samples and from oven-dried soil samples saturated with water of a known 18O content. The extractions were done both by centrifugation at different speeds followed by distillation and by distillation only. All of the samples were then oven-dried. The differences in 18O content between water extracted by centrifugation at different speeds were small. The 18O content in the water extracted by distillation was, with one exception, more depleted in 18O than the water extracted by centrifugation. From the oven-drying it was seen that the distillations did not succeed in extracting all soil water. This might be a reason for the depletion in 18O content of the water extracted by distillation. Due to incomplete distillation, this study was not able to determine how well the 18O content in water extracted by centrifugation represents the water bound most strongly to the soil. For characterizing the 18O content in the least bound soil water, however, centrifugation is not only faster, but also less prone to error than distillation.

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38

Widén, Britta. "Nitrification and denitrification in seagrass communities in Chwaka bay, Zanzibar." Thesis, Uppsala universitet, Institutionen för geovetenskap, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-393143.

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As a response to the environmental degradation of many coastal areas in east Africa research have been initiated aiming towards the understanding of the coastal ecosystems and the interactions between them. The sediment of three seagrass communities were investigated with regard to nitrification, denitrification, pore water nutrient content, organic content and physical character. The aim was to estimate the magnitude and importance of nitrification and denitrification and correlate those to any difference in organic load. Total organic carbon and total nitrogen decreased while C:N ratio increased with distance from the mangroves indicating a larger organic load closer to the mangroves. There was however no significant difference between the sites regarding ammonium and nitrate + nitrite concentrations in the porewater; nor regarding denitrification. Recalculated to ambient nitrate concentrations denitrification was less than 157 nmol N m-2h-1. No trend could be seen for nitrification either. Nitrification ranged from 0-12.0 µmol N m-2h-1, but the method used may underestimate the rates. Denitrification, and especially nitrification rates, varied considerably within each site indicating an extremely patchy environment. Considering that nutrient regeneration rates in tropical environments are usually high, nitrification and denitrification seemed to be minor pathways in the nitrogen cycle irrespective of organic load. The study also suggests that nitrification and denitrification may be of less importance in Chwaka bay compared to other areas studied.
Som svar på den försämrade miljön i flera kustområden i Östafrika har forskning påbörjats inriktad på förståelsen av kustliga ekosystem samt samspelet dem emellan. Sedimentet i tre sjögräsområden undersöktes med avseende på nitrifikation, denitrifikation, näringshalt i porvattnet, organisk halt samt fysikalisk karaktär. Syftet var att uppskatta storleken och betydelsen av nitrifikation och denitrifikation samt att korrelera dessa med organisk belastning. Totala halten organiskt kol och totala halten kväve minskade medan C:N kvoten ökade med avståndet till mangroven vilket tyder på en större organisk belastning närmare mangroven. Det var däremot ingen signifikant skillnad mellan områdena beträffande ammonium- eller nitrat + nitrit koncentrationen i porvattnet; inte heller beträffande denitrifikation. Omräknad till föreliggande nitratkoncentrationer var denitrifikationen mindre än 157 nmol N m-2h-1. Nitrifikationen varierade från 0-12.0 µmol N m-2h-1, men den använda metoden kan ha underskattat hastigheterna. Någon trend i nitrifikationen syntes inte heller. Denitrifikationen och speciellt nitrifikationen varierade avsevärt inom varje område vilket tyder på en extremt omväxlande miljö. Med tanke på att regenerationen av näringsämnen ofta är hög i tropiska miljöer så verkade nitrifikationen och denitrifikationen vara mindre betydelsefulla delar i kvävecykeln oavsett organisk belastning. Denna studie tyder också på att nitrifikation och denitrifikation är mindre betydelsefulla i Chwaka bay än i andra studerade områden.

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39

Jaedicke, Christian. "Lake Evaporation Estimation by Isotope, Energy Balance and Bulk Aerodynamic Methods." Thesis, Uppsala universitet, Institutionen för geovetenskap, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-393212.

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Lake evaporation from a shallow lake in central Sweden has been estimated using three independent methods from measurements during summer 1995. The applied isotope method is a combination of the water and isotope mass balance. Its main feature is that inflows need not to be measured. Only knowledge of their isotopic content is sufficient. For calculations by the bulk aerodynamic method a computer program was applied, which takes into account the different conditions of stratification. The energy balance of the lake was determined by using the short and long wave radiation, heat storage and advective heat energy. Measurements were done on a small island and at a mast in the middle of the lake. Evaporation estimated by all the methods varied from -1.1 to 5.0 mm/d during the summer months 1995. Values estimated by the energy balance method agreed well with those from the bulk aerodynamic method. Evaporation estimates from the isotope method a showed fairly good agreement with the two other methods, excepting a few periods. It was found that both the isotope as well as the energy balance method are sensitive to errors in lake volume. Both methods carry some uncertainty due to their dependence on water balance components, some of which are difficult to determine. The bulk aerodynamic method is independent of the water balance of the lake. A good accuracy can be achieved using only four variables i.e. wind speed, relative humidity, skin and air temperature.
Avdunstningen från den grunda sjön Tämnaren i centrala Sverige bestämdes med tre oberoende metoder ur mätningar från sommaren 1995. Den använda isotopmetoden är en kombination av vatten- och isotopbalansen. Dess viktigaste fördel är att inflödet inte behöver mätas, utan att kännedom om isotophalten är tillräcklig. För beräkningarna med den bulk-aerodynamiska metoden användes ett datorprogram som tar hänsyn till atmosfärens stabilitet. Energibalansen beräknades ur kort- och långvågsstrålningen, värmelagringen och den tillförda energin. Mätningarna utfördes dels på en liten ö och dels vid en mast mitt i sjön. Avdunstningen varierade mellan -1.1 mmd-1 till 5.0 mmd-1. Resultaten från energibalansmetoden överenstämde bra med resultaten från den bulk-aerodynamiska metoden. Även resultaten från isotopmetoden överenstämde bra med resultaten från de två andra metoderna, med undantag av några få perioder. Både isotop- och energibalansmetoden var känsliga för feluppskattningar av sjövolymen. Båda metoderna innehåller osäkerheter som en följd av deras beroende på vissa av vattenbalansens komponenter, som är svåra att bestämma. Den bulk-aerodynamiska metoden är oberoende av sjöns vattenbalans och en bra noggranhet kan uppnås med mätningar av endast de fyra variablerna vindhastighet, relativ fuktighet, yt- och lufttemperatur.
Die Verdunstung von einem ﬂachen See in Zentralschweden wurde mit Hilfe von drei unabhängigen Methoden bestimmt. Die Messungen wurden im Sommer 1995 durchgeführt. Die angewandte Isotopenmethode ist eine Kombination aus Wasserbilanz and lsotop-Massenbilanz. Das besondere Merkmal dieser Methode ist es, daß Zuflüsse nicht gemessen werden müssen. Es genügt, ihre isotopische Zusammensetzung zu kennen. Für die Berechungen mit der bulk-aerodynamischen Methode wurde ein Computerprogamm verwendet, das die unterschiedlichen atmosphärischen Schichtungen berücksichtigt. Die Energiebilanz des Sees wurde mit Hilfe der kurz- und langwelligen Strahlung, der gespeicherten Energie im See und der durch Zuflüsse und Niederschlag zugeführten Energie bestimmt. Die Messungen wurden auf einer kleiner Insel und an einem Mast in der Mitte des Sees durchgeführt. Die Verdunstung reichte von -1.1 mmd-1 bis 5.0 mmd-1 während der Sommermonate 1995. Die Ergebnisse der Energiebilanz stimmten gut mit den Ergebnissen der bulk-aerodynamischen Methode überein. Die Ergebnisse der Isotopenmethode stimmten relativ gut mit den Ergebnissen der beiden anderen Methoden überein, mit Ausnahme einiger Perioden. Es wurde festgestellt, daß sowohl die Isotopenmethode als auch die Energiebilanzmethode sensibel auf Fehler im Seevolumen reagieren. Beide Methoden enthalten einige Unsicherheiten wegen ihrer Abhängikeit von Wasserbilanzkomponenten, die z.T. schwer zu bestimmen sind. Die bulk-aerodynamische Methode dagegen ist unabhängig von der Wasserbilanz des Sees. Gute Ergebnisse können mit nur vier zu messenden Variablen erreicht werden (Windgeschwindigkeit, relative Luftfeuchtigkeit, Wasseroberflächen- und Lufttemperatur).

Parts of the thesis work later published as:

Saxena, R., Jaedicke, C., & Lundin, L. C. (1999). Comparison of lake evaporation estimated by isotope mass-balance, bulk-aerodynamic and bowen ratio methods. Phys. Chem Earth (B), Vol. 24, No. 7, pp. 851–859.

and

Saxena, R., & Jaedicke, C. (1997). Estimation of vapour flux from a shallow lake by oxygen -18 mass balance. Isotope Techniques in the Study of Environmental Change, 225–237. Vienna: IAEA-SM-349/23.

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40

Jönsson, Anders. "Neural networks and interpolation of metal concentrations in a polluted river." Thesis, Uppsala universitet, Institutionen för geovetenskap, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-395743.

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In all areas of hydrology, where one or several variables are measured as a function of time, it might be necessary to interpolate the measured variable(s). There is a form of artiﬁcial intelligence (AI) called neural networks, which seem to be appropriate for this application. In an environmental project in Bolivia, where, among others, the concentrations of arsenic (As), cadmium (Cd) and lead (Pb) in the polluted Huanuni river was measured, a data set appropriate for application of the neural network method was available. Several neural networks with different conﬁgurations were used to interpolate concentration values of the three sampled metals. The neural networks interpolated concentrations at time steps where actual, measured, values existed so that an estimate of the method’s capacity could be obtained. The neural networks’ interpolating capability were compared to that of linear interpolation and linear equations derived by multiple regression. In the case of cadmium, the linear interpolation was the best method, whereas the neural network method was best at interpolating arsenic and lead concentrations. The conclusions of this study are that the neural network method was the most succesful method; that this method was the most complicated to implement; that this method was not fully optimised; and that, to evaluate the neural network method’s general applicability as an interpolation method in hydrology, further studies have to be conducted.
Inom alla områden av hydrologin, där man mäter en eller ﬂera variabler som funktion av tid, kan det ﬁnnas ett behov av att interpolera glesa tidsseriedata. Det ﬁnns en form av artiﬁciell intelligens (AI) som kallas för neurala nät, vilken verkar vara lämplig att applicera på detta problem. Genom ett miljöprojekt i Bolivia, där bl.a. arsenik-, bly-, och kadmiumkoncentrationer i den förorenade ﬂoden Huanuni mättes, blev data lämpliga för applicering av den neurala nätmetoden tillgängliga. Flera neurala nät med olika konﬁgurationer användes för att interpolera koncentrationsvärden av de tre metallerna. De neurala näten interpolerade värden längs tidssteg där verkliga, uppmätta, koncentrationsvärden fanns, så att en uppskattning av metodens kapacitet kunde göras. Dess kapacitet jämfördes med kapaciteten hos två andra metoder: linjär interpolation och linjära ekvationssystem härledda med hjälp av multipel regression. Den linjära interpolationsmetoden var bäst i fallet kadmium, medan den neurala nätmetoden var bäst i de två andra fallen. Slutsatserna av den här studien är att den neurala nätmetoden var den bästa; att denna metod var den mest komplicerade att använda; att denna metod inte var helt optimerad, och att det krävs ytterligare studier för att utvärdera den neurala nätmetodens allmänna lämplighet som metod att interpolera glesa hydrologiska tidsseriedata.

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41

Booth, Charles W. Gutsch Barbara J. "Military applications of intranet technology : Fleet Numerical Meteorology and Oceanography Center /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA337406.

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Thesis (M.S. in Information Technology Management) Naval Postgraduate School, Sept. 1997.
Thesis advisors, James C. Emery, Frank L. Barrett. Includes bibliographical references (p. 145-146). Also available online.

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42

Nieves, Calatrava Verónica U. "Multiscale techniques in turbulence: application to geophysical fluids and operational oceanography." Doctoral thesis, Universitat Politècnica de Catalunya, 2008. http://hdl.handle.net/10803/21617.

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43

Syahailatua, Augy BEES UNSW. "Biological oceanography of larval fish diversity and growth off eastern Australia." Awarded by:University of New South Wales. BEES, 2005. http://handle.unsw.edu.au/1959.4/22791.

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Fish larvae in Australian waters have been studied progressively in the last 2-3 decades including the distribution and abundance of taxa, growth and age, their prey and predators. However, the effect of nutrient limitation on ichthyoplankton is unstudied, particularly in the oligotrophic Australian waters. My study was aimed to examine the effect of natural or anthropogenic nutrients on the abundance, distribution, growth and condition of fish larvae along-shore of the NSW coast (latitude 30-34S), where the East Australian Current departs the NSW coast and generates local upwelling of cool nutrient-rich water. This study shows no significant difference in the total abundance or diversity of either larval fishes amongst the 112 taxa (111 families and 1 order), among regions within or upstream of the upwelling. However in both months, there were distinctive ichthyoplankton assemblages at the family level. The Carangidae, Labridae, Lutjanidae, Microcanthidae, Myctophidae and Scombridae were more abundant in the EAC or oceanic water masses, while the Callionymidae, Clupeidae, Platycephalidae, Sillaginidae and Terapontidae were mostly found in the surface or deep upwelled/uplifted water masses. This pattern is observed in other ichthyoplankton studies and may be a general and useful method to determine mixing of water masses. Larvae of silver trevally (Pseudocaranx dentex) and yellowtail scad (Trachurus novaezelandiae) were generally larger and less abundant in the topographically induced upwelling region, than north of the region in pre-upwelled conditions of the East Australian Current. Both species were mostly at the preflexion stage (less than 4.3 mm in body length and less than 10 days old) in the pre-upwelled conditions, particularly during November, and proportionally more larger and older larvae in the upwelled waters (mostly post-flexion, greater than 4.3 mm in body length and greater than 10 days old). Ages from sagittal otoliths ranged from 2-25 increments (~days) and exhibited linear growth for both species and months over the size range (3-15 mm standard length). The otolith radius-length relationship and the growth rates were similar between species and months, despite the 3-4C difference between months. Overall growth rates of the younger larvae were uniform throughout the entire sampling area (0.5-0.6 mm.d-1), while older larvae grew significantly faster in the upwelled water (0.41 mm.d-1) compared to the non-upwelled conditions (0.34 mm.d-1). Both species tended to be depleted in 13C in the upwelling region (from ???18.5 to ???19.0), consistent with expected ratios from deeper water, whereas the 15N composition tended to increase in Pseudocaranx, but decrease in Trachurus indicating different diets and possibly trophic level. The early life history of both species indicates spawning in pre-upwelled waters, but larval transport into upwelled waters is necessary for faster growth in the post-flexion stage. The assemblage of larval fishes did differ between the upwelled region and a region south of Sydney???s deepwater outfalls, but the difference was ascribed to a latitudinal effect and the EAC. Both larval carangids were enriched in 15N, possibly due to the enriched dissolved organic matter of primary treated sewage. In summary, this study found that the larval fish community can provide a biological means to trace water masses, and estimate their degree of mixing. Remarkably there was no significant effect of upwelling or sewage addition to the abundance or diversity of larval fish, in the nutrient poor waters of the East Australian Current. Larval carangids and pilchards were abundant in late spring off northern NSW, and their early life histories were inferred. Both larval carangid species seem to be spawned in the EAC waters, but as post-flexion larvae grew faster in the upwelled zone. Pre-flexion (less than 10 day old) larval carangids of both genera indicated spawning in the EAC, and the rarer post-flexion (greater than 10 days old) carangids grew faster in the upwelled waters. Here, both genera had stable isotope signatures characteristic of upwelled waters for carbon, but had different nitrogen signatures, indicative of different diets and trophic level status. Larval pilchards actually grew more slowly in the upwelling region, as observed in coastal waters off Japan, and their nursery grounds may be further offshore in the Tasman Front, analogous to their early life history in the Kuroshio Extension.

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44

Nieves, Calatrava Veronica Ursula. "Multiscale techniques in turbulence: application to geophysical fluids and operational oceanography." Doctoral thesis, Universitat Politècnica de Catalunya, 2008. http://hdl.handle.net/10803/21617.

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45

Le, Quéré Corinne. "Physical oceanography of the Baie des Chaleurs, Gulf of St. Lawrence." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56761.

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Time series of temperature and salinity from current meters moored in 1988 and 1990 along the north shore of Baie des Chaleurs were analyzed to characterize the frequency of upwelling events. Upwelling was found to propagate cyclonically with speeds of 40 to 85 km per day. Moderate correlations between $ sigma sb{ rm t}$ and zonal wind stress were found. The interaction of buoyancy, topography, and oscillating wind stress simulated the upwelling in a reduced gravity model. The dominant frequencies of the upwelling events were approximately 4.5 to 10 days.
Three water masses, one between the surface and the thermocline, one straddling the thermocline, and one at the bottom, were found to describe nicely the TS properties of the water column, as observed from the 1991 CTD data.
The observed circulation, from August to October 1990, was cyclonic, with baroclinicity observed in the bottom two layers, and at two stations in the top layers.

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46

Booth, Charles W., and Barbara J. Gutsch. "Military applications of intranet technology: Fleet Numerical Meteorology and Oceanography Center." Thesis, Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/8677.

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Approved for public release; distribution is unlimited
Intranets are rapidly becoming a corporate internal information- sharing medium. Intranet technology is the same robust, proven, industry standard technology that is used on the Internet. The technical aspects of implementing the technology are simple. The organization and management aspects are significant and are key to its successful implementation. This internal use of Internet technology is easy, inexpensive, and has produced savings and benefits for corporate organizations. This thesis reviews corporate and government intranets and examines the feasibility of implementing this technology and benefiting from it, in a military organization. Specific applicability of Intranet technology was examined at Fleet Numerical Oceanographic and Meteorology Center, while maintaining the vision of its applicability to other military organizations. Fleet Numerical Oceanographic and Meteorology Center has the requisite technical and organizational infrastructure necessary to successfully implement Intranet technology. The management and technical skill sets necessary to successfully implement this technology at any military command operating a computer network should be available, or easily trained. Fleet Numerical Oceanographic and Meteorology Center and the U.S. Military should establish the organizational plans and infrastructure to implement and exploit this empowering information sharing medium.

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47

Addison, Victor G. "The physical oceanography of the northern Baffin Bay-Nares Strait region." Thesis, Monterey, California. Naval Postgraduate School, 1987. http://hdl.handle.net/10945/22417.

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Approved for public release; distribution is unlimited
A dense network of conductivity-temperature-depth measurements was conducted from Baffin Bay northward to 82 deg 09 min N at the entrance to the Lincoln Sea, in the most comprehensive physical oceanographic survey ever performed in the northern Baffin Bay-Nares Strait region. These data indicate Nares Strait Atlantic Intermediate Water and Arctic Basin Polar Water to be derived from Arctic Basin waters via the Canadian Archipelago, whereas the West Greenland Current (WGC) is the source of the comparatively dilute West Greenland Current Atlantic Intermediate Water and West Greenland Current Polar Water fractions. Baffin Bay Surface Water is found seasonally throughout northern Baffin Bay. Recurvature of component branches of the WGC, which attains a maximum baroclinic transport of 0.7 Sv, occurs primarily in Melville Bay (0.2 Sv), south of the Carey Islands (0.1 Sv) and ultimately in Smith Sound (0.2 Sv). The Baffin Current originates as an ice-edge jet in Smith Sound and is augmented by net outflow from Smith, Jones and Lancaster Sounds at rates of 0.3 Sv, 0.3 Sv and 1.1 Sv, respectively. Circulation in Smith, Jones and Lancaster Sounds can be described in terms of the Geostrophic Estuarine Circulation Model. The North Water is caused by the combined influences of near-surface layer enthalpy and mechanical ice removal. KeywordsL Sea water temperature; Oceanographic data; Straits; Sounds(Waterways); Ocean currents

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48

MacTavish, Flora Pamela. "The application of adaptive mesh techniques to convective processes in oceanography." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/11616.

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Idealised numerical simulations of two oceanographic processes, salt finger formation and the restratification phase of open ocean deep convection, are considered. These processes are modelled using the Imperial College Ocean Model (Fluidity-ICOM). This is a finite element code with the novel capability to perform mesh adaptivity. The mesh is triangular/tetrahedral and can be unstructured. If mesh adaptivity is used, all the fields are periodically interpolated onto a new mesh that has been optimised from the previous mesh. The new mesh is designed to represent one or more of the solution fields as accurately as possible by putting more nodes in regions where the Hessians of the fields being adapted to are higher. The first process to be presented is the formation of salt fingers in double diffusive convection. A secondary instability is observed to form. Due to the unstructured mesh, the fingers start off slightly different lengths from each other and this difference is observed to grow with time. A new set of simulations are run in which the secondary instability is initialised from a perturbation in the initial condition. These results are used to compare between fixed and adaptive mesh results. Evidence is obtained to show that adaptive mesh is able to produce the same results as the fixed mesh with fewer computational nodes because the resolution is used in the regions where is it most needed. The second process is the restratification after open ocean deep convection. In order to run ocean scale simulations the model must be able to accurately represent geostrophic and hydrostatic balance on a high aspect ratio domain. In order to do this with an unstructured mesh it is shown that it is necessary to constrain the nodes to be aligned in the vertical. This type of mesh is known as a 2+1 mesh and it can be adapted in both the vertical and the horizontal in order to resolve the solution fields more accurately. The model is able to reproduce previous results for a simple restratification test case using mesh adaptivity. The representation of balance is investigated using different types of mesh and different finite element shape functions. A more complex restratification test case in which baroclinic eddies form is then examined. The results obtained are compared to other models with different numerical schemes. Fixed and adaptive results are compared. These results demonstrate that Fluidity-ICOM is able to represent balance and model relatively complex processes on ocean scale, high aspect ratio domains whilst using mesh adaptivity.

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49

Reddy, Tasha Elise. "Oceanography of the Ross Sea : ocean circulation, sea ice, and phytoplankton /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

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50

Coppini, Giovanni <1974&gt. "Development of operational oceanography applications: environmental indicators and decision support systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2996/1/Coppini_Giovanni_tesi.pdf.

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