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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Teleconnection, Modeling, Climate Anomalies Impact and Forecasting of Rainfall and Streamflow of the Upper Blue Nile River Basin

Elsanabary, Mohamed Helmy Mahmoud Moustafa Unknown Date
No description available.
222

Installation and Operation of Air-Sea Flux Measuring System on Board Indian Research Ships

Kumar, Vijay January 2017 (has links) (PDF)
Exchange of mass (water vapor), momentum, and energy between atmosphere andocean has profound influence on weather and climate. This exchange takes place at the air-sea interface, which is part of the marine atmospheric boundary layer. Various empirical relations are being used for estimating these fluxes in numericalweather and climate models but their accuracies are not sufficiently verified or tested over the Indian Ocean. The main difficulty is that vast areas of open oceans are not easily accessible. The marine environment is very corrosive and unattended long term and accurate measurements are extremely expensive. India has research ships that spend most of their time over the seas around India but that opportunity is yet to be exploited. To address this, an air-sea flux measurement system for operation on board research ships was planned. The system was tested on board Indian Research Vessels ORV SagarKanya during its cruise SK-296 in the Bay of Bengal (BoB) in July-August 2012, and NIO ship Sindhu Sadhana in June-July 2016. The complete set included instruments for measuring wind velocity, windspeed and direction, air and water temperature, humidity, pressure, all components of radiation and rainfall. In addition, ship motion was recorded at required sampling rate to correct for wind velocity. The set up facilitates the direct computation of sensible and latent heat fluxes using the eddy covariance method. In this thesis, design and installation of meteorological and ship motion sensors onboard research ships, data collection and quality control, computation of fluxes of heat, moisture and momentum using eddy covariance method and their comparison with those derived from bulk method are described. A set of sensors (hereafter, flux measuring system) were mounted on a retractable boom, ~7 m long forward of the bow to minimize the flow disturbance caused by the ship superstructures. The wind observed in the ship frame was corrected for ship motion contaminations. During the CTCZ cruise period true mean wind speed was over 10 m/s and true wind direction was South/South-Westerly. True windspeedis computed combiningdata from the anemometer a compass connected to AWS and a GPS. Turbulent fluxes were computed from motion-corrected time-series of high frequency velocity, water vapor, and air temperature data. Covariance latent heat flux, sensible heat flux, and wind stress were obtained by cross-correlating the motion-corrected vertical velocity with fast humidity fluctuations measured with anIR hygrometer, temperate fluctuation from sonic anemometer and motion-corrected horizontal windfluctuations from sonic anemometer, respectively. During the first attempt made in July-August 2012 as part of a cruise of CTCZ monsoonresearch program, observations were mainly taken in the North Bay of Bengal. The mean air-temperature and surface pressure were ~28 Deg C and ~998 hPa, respectively. Relative humidity was ~80%. Average wind speed varied in the range 4-12 m/s. The mean latent heat flux was 145 W/m2 , sensible heat flux was ~3 W/m2 and average sea-air temperature difference was ~ 0.7°C. The Bay of Bengal boundary layer experiment (BoBBLE) was conducted during June-July 2016 and the NIO research ship Sindhu Sadhana was deployed. The same suite of sensors installed during CTCZ were used during BoBBLE. During daytime, peaks of hourly net heat fluxes (Qnet ) were around 600 Wm-2(positive if into the sea), whereas, night time values were around -250 W m-2. Sea surface temperature was always >28°C and maximum air temperature exceeded 29°C. During the experimental period the mean Qnet was around -24 Wm-2 from both eddy covariance and conventional bulk methods, but there are significant differences on individual days.The new flux system gives fluxes which are superior to what was available before.
223

Monitoramento ambiental da costa do Rio Grande do Norte com base em sensoriamento remoto e geod?sia de precis?o

Ferreira, Anderson Targino da Silva 16 September 2013 (has links)
Made available in DSpace on 2015-02-24T19:48:45Z (GMT). No. of bitstreams: 1 AndersonTSF_TESE_ Capa_ate_pag22.pdf: 11459625 bytes, checksum: fd30a979bc39cf6180f782c772106ee3 (MD5) Previous issue date: 2013-09-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This paper presents models of parameters of Sea Surface Layer (SSL), such as chlorophyll-a, sea surface temperature (SST), Primary Productivity (PP) and Total Suspended Matter (TSM) for the region adjacent to the continental shelf of Rio Grande do Norte (RN), Brazil. Concentrations of these parameters measured in situ were compared in time quasi-synchronous with images AQUA-MODIS between the years 2003 to 2011. Determination coefficients between samples in situ and bands reflectance sensor AQUA-MODIS were representative. From that, concentrations of SSL parameters were acquired for the continental shelf of the RN (eastern and northern) analyzing the geographic distribution of variation of these parameters between the years 2009-2012. Geographical and seasonal variations mainly influenced by global climate phenomena such as El Ni?o and La Ni?a, were found through the analysis of AQUA-MODIS images by Principal Components Analysis (PCA). Images show qualitatively the variance and availability of TSM in the regions, as well as their relationship with coastal erosion hotspots, monitored along the coast of the RN. In one of the areas identified as being of limited availability of TSM, we developed a methodology for assessment and evaluation of Digital Elevation Models (DEM) of beach surfaces (emerged and submerged sections) from the integration of topographic and bathymetric data measured in situ and accurately georeferenced compatible to studies of geomorphology and coastal dynamics of short duration. The methodology consisted of surveys with GNSS positioning operated in cinematic relative mode involved in topographic and bathymetric executed in relation to the stations of the geodetic network of the study area, which provided geodetic link to the Brazilian Geodetic System (GBS), univocal , fixed, and relatively stable over time. In this study Ponta Negra Beach, Natal / RN, was identified as a region with low variance and availability of MPS in the region off, as characterized by intense human occupation and intense coastal erosion in recent decades, which presents potential of the proposed methodology for accuracy and productivity, and the progress achieved in relation to the classical methods of surveying beach profiles / Este trabalho apresenta modelos de par?metros da Camada Superficial do Mar (CSM), tais como: Clorofila-a, Temperatura da Superf?cie do Mar (TSM), Produtividade Prim?ria (PP) e Material Particulado em Suspen??o (MPS), para a regi?o adjacente a plataforma continental do Rio Grande do Norte (RN), Brasil. Concentra??es desses par?metros medidos in situ foram comparadas em tempo quase-s?ncronos com imagens AQUAMODIS entre os anos de 2003 at? 2011. Coeficientes de determina??o foram representativos entre as amostras in situ e as bandas de reflect?ncia do sensor AQUAMODIS. A partir disso, concentra??es de par?metros da CSM foram adquiridos para a plataforma continental do RN (Plataforma Oriental e Setentrional) analisando a distribui??o geogr?fica da varia??o desses par?metros entre os anos de 2009-2012. Varia??es geogr?ficas e sazonais influenciadas principalmente por fen?menos clim?ticos globais como o fen?meno El Ni?o e La Ni?a, foram constatadas atrav?s das an?lises das imagens AQUA-MODIS por an?lise de Principais Componentes (PC). As imagens apontam de maneira qualitativa a vari?ncia e disponibilidade do MPS nas regi?es, assim como sua rela??o com hotspots de eros?o costeira, monitorados ao longo do litoral do RN. Em uma das regi?es identificadas como sendo de pouca disponibilidade de MPS, foi desenvolvida uma metodologia para levantamento e avalia??o de Modelos Digitais de Eleva??o (MDE) de superf?cies praiais (setores emersos e submersos) a partir da integra??o de dados topogr?ficos e batim?tricos mensurados in situ e georreferenciados com precis?o compat?vel aos estudos de geomorfologia e din?mica costeira de curta dura??o. A metodologia desenvolvida consistiu de levantamentos com posicionamentos GNSS operados no modo relativo cinem?tico envolvidos nos levantamentos topogr?ficos e batim?tricos executados em rela??o ?s esta??es da rede geod?sica da ?rea de estudo, que forneceram referencial geod?sico vinculado ao Sistema Geod?sico Brasileiro (SGB), o qual ? un?voco, fixo e relativamente est?vel no tempo. No estudo foi apresentado a Praia de Ponta Negra, Natal/RN, identificada como uma regi?o com baixa vari?ncia e disponibilidade de MPS ao largo, assim como, caracterizada por intensa ocupa??o antr?pica e intensa eros?o costeira nas ?ltimas d?cadas, no qual s?o apresentadas as potencialidades da metodologia proposta, quanto ? acur?cia e produtividade, al?m dos avan?os alcan?ados em rela??o aos m?todos cl?ssicos de levantamento de perfis de praia
224

Influence of River Discharge on Climate in A Coupled Model

Sharif, Jahfer January 2013 (has links) (PDF)
River discharge can affect ocean surface temperature by altering stratification within the oceanic mixed layer. A hitherto unexplored aspect of present climate is the feedback of river runoff onto climate. This thesis presents an investigation of the impact of global river runoff on oceans and climate using a fully coupled global climate model, Community Climate System Model (CCSM). Two model simulations for a period of 100 years have been carried out: 1) a reference run (CTRL) that incorporates all the features of a global coupled model with river runoff into the ocean embedded in it, and 2) a sensitivity run (NoRiv) in which the global river runoff into the ocean is blocked. Comparison of model climate devoid of fluvial discharge with the reference run reveals the significance of fluvial discharge in the present climate. By the end of 50 years of NoRiv experiment, salinity growth slows down and reaches a quasi-stable state. Regions close to river mouths exhibited maximum salinity rise that can potentially alter local density and stratification. On an average, denser and saltier waters in the NoRiv run annihilate barrier layer and form a deeper mixed layer, compared to CTRL run. Density gradient created by the modulation in salinity set forth anomalous currents and circulation across coastlines that carries coastal anomalies to open ocean, preventing local salinity buildup. Arctic Ocean, Bay of Bengal, northern high latitude Pacific and the Atlantic are the most affected regions in terms of changes in salinity and temperature. Model simulations demonstrate that major transformation in Arctic freshwater budget can have potential impact on northern Pacific and Atlantic climate. In the absence of runoff, global average sea surface temperature (SST) rise by about ~ 0.5oC, with major contribution from northern higher latitude oceans. In the Pacific, high latitude warming is related to deepening of mixed layer as well as the northward transport of low latitude warmer waters. Substantial cooling in the central equatorial Pacific (~1oC during winter) can alter large-scale ocean-atmosphere circulation, including El Niño-Southern Oscillation (ENSO). The reinforcement of Pacific and Atlantic western boundary currents aids the transport of warm saline water from low latitudes to higher latitudes. The results suggest that the river runoff can have potential impact on oceanic climate. Response of Indian summer monsoon rainfall to global continental runoff is also examined. In the NoRiv run, average summer monsoon rainfall over India increased by ~ 0.55 mm day−1. Consistent with the increase in annual average Indian monsoon rainfall, all other northern hemispheric monsoon systems showed an increase, while southern hemispheric monsoons weakened. Associated with enhanced monsoon, the periodicity of ENSO in the NoRiv run changes as a result of cooling tendency in the equatorial Pacific, a sign of consistent La Niña. Equatorial Pacific cooling, in spite of a global ocean warming trend, is found to be primarily because of the enhanced local easterly winds and resultant strong equatorial upwelling. Cold anomaly due to upwelling spread entire equatorial Pacific basin within a span of 50 years. The La Niña situation in the Pacific favored increased monsoon rainfall over Indian subcontinent. Another surprising result of this study is the strengthening of ENSO-monsoon relationship in the NoRiv run. This suggests that the river discharge can be considered as a dampening force in the ENSO-monsoon relationship. Northern hemisphere showed a clear warming in the NoRiv simulation compared to CTRL, the result of which is an enhanced trans-hemispheric gradient. Cross-equatorial winds triggered by this gradient blow from southern hemisphere and shift the Inter Tropical Convergence Zone (ITCZ) northward, increasing the precipitation in the northern hemisphere. The cooling in the eastern equatorial Indian Ocean and the warming in the west, reflected in the increase in number of positive Indian Ocean Dipole (IOD) events (9 positive and 5 negative IOD events in the last 50 years), also favored summer-time rainfall over India.
225

A Hydroclimatological Change Detection and Attribution Study over India using CMIP5 Models

Pattanayak, Sonali January 2015 (has links) (PDF)
As a result of increase in global average surface temperature, abnormalities in different hydroclimatic components such as evapotranspiration, stream flow and precipitation have been experienced. So investigation has to be carried out to assess the hidden abnormality subsisting in the hydroclimatological time series in the form of trend. This thesis broadly consists of following four parts. The first part comprises of a detailed review of various trend detection approaches. Approaches incorporating the effect of serial correlation for trend detection and interesting developments concerning various non parametric approaches are focused explicitly. Recent trends in annual, monthly, and seasonl (winter, pre-monsoon, monsoon and post-monsoon) Tmax and Tmin have been analyzed considering three time slots viz. 1901-2003, 1948-2003 and 1970-2003. For this purpose, time series of Tmax and Tmin of India as a whole and for seven homogeneous regions, viz. Western Himalaya (WH), Northwest (NW), Northeast (NE), North Central (NC), East coast (EC), West coast (WC) and Interior Peninsula (IP) were originally considered. During the last three decades significant upward trend in Tmin is found to be present in all regions considered either at annual or seasonal level. Sequential Mann Kendall test revealed that most of the significant upward trends both in Tmax and Tmin began after 1970. The second part discusses about numerous climate models from both Coupled Model Inter comparison Project-5 and 3 (i.e. CMIP5, CMIP3) and their skills in simulating Indian climate and assessing their performance using various evaluation measures. Performances of climate models were evaluated for whole of India and over all the individual grid points covering India. The newly defined metric symbolized as Skill_All is an intersection of the three metrics i.e. Skill_r, Skill_s and Skill_rmse, is used for overall model evaluation analysis. A notable enhancement of Skill_All for CMIP5 over CMIP3 was found. After overall model evaluation study, Compromise Programming, a distance based decision making technique, was employed to rank the GCMs gridwise. Entropy method was employed to obtain weights of the chosen indicators. Group decision making methodology was used to arrive at a consensus based on the ranking pattern obtained by individual grid points. In the third part, a detailed detection and attribution (D&A) analysis is performed to determine the causes of changes in seasonal Tmax and Tmin during the period 1950-2005. This formal D&A exercise helps in providing better insight (than trend detection analysis) into the nature of the observed seasonal temperature changes. It was noticed that the emergence of observed trend was more pronounced in Tmin compared to Tmax. Although observed changes were not solely associated with one specific causative factor, most of the changes in Tmin are above the bounds of natural internal climate variability. Finally in the fourth part, to understand the climate change impact on the hydrological cycle, a spatiotemporal change detection study of potential evapotranspiration (PET) along with Tmax and Tmin over India has been performed. Climatology patterns for PET confirmed a greater PET rate during the month of March, April, May and June. A significant increasing trend in both Tmax and Tmin (Tmin being more) was observed in more number of grid points compared to PET. Significant positive trends in Tmax, Tmin and PET were observed over most of the grid points in the IP region. Heterogeneities existed in the spatiotemporal variability of PET over all India. This spatio-temporal change detection study would be helpful for present and future water resources management.
226

Příspěvek k realizaci nákladově a energeticky úsporných rodinných domů / Contribution to the construction of cost and energy efficient family houses

Čech, Josef Unknown Date (has links)
Dissertation focuses on the verification of construction family houses made of concrete shell block with internal thermal insulation system. The construction technology is transferred to the Czech Republic from France. The work focuses on building envelope. The suitability of implementation is assessed on the basis of verification selected thermal technical requirements placed on building envelope. Requirements are specified by legislation in force in the ČR. The verification was performed by using software simulations and measurements on realized buildings. Critical areas of construction technology were identified on the basis software simulations and measurements on site. It was suggested solution, in which critical areas comply the thermal technical requirements. The building envelope was checked also using the thermography imaging on site. Continuous measurement of interior temperature was used to evaluate thermal comfort in the room. In the completed buildings was tested airtightness of the building envelope, which revealed other critical areas of the building envelope. Critical areas are necessary to solve with sufficient care. The economic cost of implementing each variants of exterior walls made of concrete shell block with internal thermal insulation were compared with the economic costs of implementing external walls made of burnt clay hollow blocks and made of burnt clay hollow blocks with external thermal insulation system ETICS. Subsequently, the economic return was calculated for individual variants of external walls made of concrete shell blocks with internal thermal insulation. From the environmental viewpoint was made comparison of production greenhouse gas CO2 and SO2 (cause acid rains) during the life cycle of the individual variations of exterior walls made of concrete shell blocks with system of internal thermal insulation, exterior walls made of burnt clay hollow blocks and burnt clay hollow blocks with external thermal insulation syst
227

Tepelně technické vlastnosti rámu okenní výplně a připojovací spáry / Thermal properties of the window frame and the connection joints

Hejný, Lukáš January 2015 (has links)
This thesis deals with the solution problem of fitting a window in the wall, especially for passive houses. It provides options to optimize the window connection joints, improve the thermal transmittance of the window frame, thereby reducing the total heat loss through the window. In the first part of the thesis is a research literature on the windows and heat technical and physical mechanisms. Are described equations and physical processes taking place in the windows and related building structures. This section describes the basic points in history, technical description of windows, etc. and present ways of assembly Installation the window and the influence of the thermal properties of the heat loss. The next part deals with the description of the work and the results obtained in the course of doctoral study. Describes the main objectives of the dissertation thesis, calculations and simulations of temperature fields and the results of the calculated values. Furthermore are described and analyzed measurement data and compared with the calculated values. At the end dissertation thesis are given opportunities to improve the current solution regarding the heat transfer coefficient of the frame, the optimal way of installation fillers windows in the perimeter wall and improve the thermal properties of the connecting joint.
228

Incorporating the effect of heterogeneous surface heating into a semi-empirical model of the surface energy balance closure

Wanner, Luise, Calaf, Marc, Mauder, Matthias 01 March 2024 (has links)
It was discovered several decades ago that eddy covariance measurements systematically underestimate sensible and latent heat fluxes, creating an imbalance in the surface energy budget. Since then, many studies have addressed this problem and proposed a variety of solutions to the problem, including improvements to instruments and correction methods applied during data postprocessing. However, none of these measures have led to the complete closure of the energy balance gap. The leading hypothesis is that not only surface-attached turbulent eddies but also sub-mesoscale atmospheric circulations contribute to the transport of energy in the atmospheric boundary layer, and the contribution from organized motions has been grossly neglected. The problem arises because the transport of energy through these secondary circulations cannot be captured by the standard eddy covariance method given the relatively short averaging periods of time (~30 minutes) used to compute statistics. There are various approaches to adjust the measured heat fluxes by attributing the missing energy to the sensible and latent heat flux in different proportions. However, few correction methods are based on the processes causing the energy balance gap. Several studies have shown that the magnitude of the energy balance gap depends on the atmospheric stability and the heterogeneity scale of the landscape around the measurement site. Based on this, the energy balance gap within the surface layer has already been modelled as a function of a nonlocal atmospheric stability parameter by performing a large-eddy simulation study with idealized homogeneous surfaces. We have further developed this approach by including thermal surface heterogeneity in addition to atmospheric stability in the parameterization. Specifically, we incorporated a thermal heterogeneity parameter that was shown to relate to the magnitude of the energy balance gap. For this purpose, we use a Large-Eddy Simulation dataset of 28 simulations with seven different atmospheric conditions and three heterogeneous surfaces with different heterogeneity scales as well as one homogeneous surface. The newly developed model captures very well the variability in the magnitude of the energy balance gap under different conditions. The model covers a wide range of both atmospheric stabilities and landscape heterogeneity scales and is well suited for application to eddy covariance measurements since all necessary information can be modelled or obtained from a few additional measurements.
229

Variations actuelles du niveau de la mer / Present day sea level variations

Dieng, Habib Boubacar 10 January 2017 (has links)
Depuis le début des années 1990 on suit l'évolution globale du niveau de la mer grâce aux satellites altimétriques. Ils observent une hausse du niveau moyen global de la mer (GMSL) de 3.4 ± 0.4 mm/an sur la période 1993-2016 (ce qui représente le double de ce qui a été observé au cours du 20ème siècle par les marégraphes, hausse à 1.7 mm/an entre 1900 et 1990). Le GMSL présente aussi des fluctuations interannuelles qui peuvent atteindre quelques millimètres, surtout pendant les épisodes ENSO. Cette hausse n'est pas régionalement uniforme : elle a été 3 fois plus rapide que la hausse moyenne globale dans certaines zones entre 1993 et 2016. Au cours du 21ème siècle, on s'attend à une hausse accrue du GMSL pouvant aller jusqu'à 1 m à l'horizon 2100, avec une forte variabilité régionale. Il est donc important de comprendre l'évolution actuelle du niveau des océans qui constitue une menace sérieuse pour de nombreuses régions côtières basses souvent très peuplées. Cette thèse s'inscrit dans le contexte du projet niveau de la mer CCI (Climate Change Initiative) de l'Agence Spatiale Européenne (ESA) ayant pour objectif de fournir de meilleurs produits du niveau de la mer combinant les missions Topex/Poseidon, Jason-1/2, ERS-1/2 et Envisat. L'objectif premier de cette thèse est de valider ces produits SL_CCI du niveau de la mer en utilisant différentes approches, en particulier par l'étude du bilan (comparaison du GMSL observé avec la somme des différentes contributions : composante stérique, fonte des glaces continentales et transferts d'eau depuis les terres émergées). Un autre objectif est d'estimer les composantes du niveau de la mer mal connues, et tout particulièrement le contenu thermique de l'océan profond non mesurable par le système Argo, et la contribution du stock d'eau sur les continents. Ces travaux ont montré que la contribution de l'océan profond en dessous de 2000m est faible sur la période 2005-2013 et contenue dans la barre d'incertitudes des données (erreurs qui proviennent essentiellement, (1) des produits niveau de la mer altimétriques et des lacunes de la couverture géographique des données Argo dans la région Indonésienne pour la tendance et (2) des produits GRACE et Argo pour la variabilité interannuelle). Nos résultats et la méthode utilisée montrent que le niveau de la mer et ses composantes sont encore entachés d'erreurs importantes. Dans la deuxième partie, nous avons analysé l'influence du phénomène ENSO (El Niño et La Niña) sur les variations interannuelles du GMSL. Nous montrons que lors des évènements La Niña comme celui de 2010-2011, le déficit de précipitations sur l'océan (et l'excès sur les continents) conduit à une baisse temporaire de la masse de l'océan global et donc du niveau de la mer. C'est essentiellement la variation de masse de l'océan qui explique la variabilité interannuelle du niveau de la mer lors des évènements ENSO, et le déficit (La Niña) ou excès (El Niño) de masse se trouve confiné dans l'océan Pacifique tropical Nord. Pour finir, nous analysons l'évolution de la température moyenne de l'air et de l'océan en surface sur la période du "hiatus" (2003-2013). Nous montrons que ce hiatus, c'est à dire le ralentissement récent de la hausse de la température moyenne globale de la Terre est un phénomène quasi global, même si le Pacifique tropical Est s'est fortement refroidi. Cette "supposée" pause récente s'explique par la variabilité naturelle interne du climat. La Terre est toujours en état de déséquilibre énergétique dû à l'accumulation de gaz à effet de serre. Nous mettons en évidence le rôle de la variabilité naturelle à court terme sur les changements à plus long terme associés au réchauffement climatique anthropique. / Since the early 1990s sea level is routinely measured using high-precision altimeter satellites. These observe a rise in global mean sea level (GMSL) of 3.4 ± 0.4 mm/yr over the 1993-2016 period (which is twice what has been observed during the 20th century by the tide gauges, with a rise of 1.7 +/- 0.3 mm/yr). The interannual variability in the GMSL can reach several millimeters, especially during ENSO events. The rate of sea level rise is not regionally uniform. During the altimetry era, it was three times faster than the global mean in some areas. During the 21st century, we expect a greater rise of the GMSL than today, up to 1 m in 2100, with strong regional variability. It is therefore important to understand the current evolution of the sea level, since it represents a serious threat to many low coastal areas, often densely populated of the planet. My thesis research deals with the Sea Level CCI (Climate Change Initiative) project of the European Space Agency (ESA) which objective is to provide improved sea level products combining several altimetry missions, including Topex/Poseidon, Jason-1/2, ERS-1/2 and Envisat. The primary objective of my thesis was to validate the CCI sea level products using different approaches, in particular the sea level budget approach. It consists of comparing the observed GMSL with the sum of different contributions : the steric component, melting of continental ice and transfers of water between the land surface and oceans. Another objective was to estimate the poorly known components to sea level rise, in particular the heat content of the deep ocean not measurable by Argo, and the contribution of water storage on the land. My work has shown that the contribution of the deep ocean below 2000m to the rising sea level is small over the 2005-2013 periods and not significant compared to the data uncertainties. The main uncertainties come from: (1) -in terms of trend- the altimetry sea level products and gaps in the geographical coverage of Argo data in the Indonesian region, and (2) -in terms of interannual variability- the GRACE and Argo products. My results and the method used show that the sea level and its components are still affected by important errors. In the second part, I analyzed the influence of ENSO (El Niño and La Niña) on the interannual variations of the GMSL. I showed that during La Niña events, like that of 2010-2011, the rainfall deficit over the ocean (and excess over the continents) leads to a temporary decrease in the global ocean mass and therefore in the GMSL. This is essentially the ocean mass variation that explains the interannual variability of the GMSL during ENSO events. Furthermore, the deficit (La Niña) or excess (El Niño) ocean mass is confined in the north tropical Pacific Ocean. Finally, I analyzed the evolution of the average temperature of air and ocean surface over the period of the "hiatus" (2003-2013). I showed that this hiatus, i.e. the recent slowdown in the rise of the global mean Earth's temperature is an almost global phenomenon, though cooling of the tropical eastern Pacific has slightly contributed. This recent pause is attributable to natural internal climate variability. The Earth is indeed still in a state of energetic imbalance due to the accumulation of greenhouse gases. I highlighted the role of the natural variability that is superimposed to the anthropogenic global warming.
230

Vliv obtokového součinitele na návrh a geometrii přímého výparníku pro chladící jednotku / The Effect of the Bypass Factor on Design and Geometry of the Evaporator for the Cooling Unit

Vytasil, Michal January 2016 (has links)
Diploma thesis focuses on effect of the bypass factor on design and geometry of the evaporator for the cooling unit of data centre. Effect of the bypass factor on individual design parameters is solved in detail. All dependendecies are captured by using graphs in which s placed a cement on that parameter. In part C, mathematical and physical solutions are demonstrated calculations and processes leading to the design of the exchanger. In the end, evaluation of the calculations is done and there is also showed possible improvements for the practise.

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