Long-range communication proves to be a challenge due to the Earth’s curvature, since electromagnetic waves propagate away from the Earth’s surface in a free atmosphere. A possible solution to beyond line-of-sight communication is the atmospheric phenomenon known as the evaporation duct. Ducting occurs when the refractive index of the atmosphere rapidly decreases with height, which leads to ray trajectories bending inward towards the surface of the Earth, effectively creating a waveguide and enabling long-distance communication. In this work, the models by Paulus-Jeske and Babin-Young-Carton are investigated and implemented in MATLAB for calculation of the evaporation duct height and for modelling the refractive index of the atmosphere. The rapid decrease in refractive index giving rise to evaporation ducts occurs due to evaporation of water within the atmosphericsurface layer (<100 m over the surface), which is the domain of turbulent mixing in the atmosphere. With atmospheric data from a Weather API by Meteomatics, Monin-Obukhov similarity theory for the atmospheric surface layer is combined with a bulk flux parameterization scheme from the COARE experiment to determine the air-sea fluxes in the lower troposphere. The surface layer variables with stability functions from Businger-Dyer, Beljaars-Holtslag, Cheng-Brutsaert, and the SHEBA experiment are used in the evaporation duct models proposed by Paulus-Jeske and Babin-Young-Carton to calculate the evaporation duct height, finding that the latter is a valid method with Monin-Obukhov stability functions based on the SHEBA experiment. The modelled refractive index is inserted into an already existing wave propagation model to investigate and validate the findings. / Långdistanskommunikation är en utmaning på grund av jordens krökning, eftersom elektromagnetiska vågor sprider sig bort från jordens yta vid propagering i fri atmosfär. En möjlig lösning för kommunikation bortom siktlinjen är det atmosfäriska fenomenet som kallas avdunstningskanal. Det uppstår när atmosfärens brytningsindex snabbt minskar med höjden, vilket leder till att strålbanorna böjer sig inåt mot jordens yta, vilket i praktiken skapar en vågledare och möjliggör långdistanskommunikation. I detta arbete undersöks och implementeras modeller beskrivna av Paulus-Jeske och Babin-Young-Carton i MATLAB för beräkning av avdunstningskanalens höjd och för modellering av atmosfärens brytningsindex. Den snabba minskningen av brytningsindexet som ger upphov till avdunstningskanaler beror på avdunstning avvatten i det atmosfäriska ytskiktet (<100 m över ytan), som är det område där den turbulenta blandningen i atmosfären sker. Med atmosfäriska data från Weather API av Meteomatics kombineras Monin-Obukhovs likvärdighetsteori för det atmosfäriska ytskiktet med ett parametriseringsschema för bulkflöden från COARE-experimentet för att bestämma luft- och havsflödena i den nedre troposfären. Variablerna för ytskiktet med stabilitetsfunktioner från Businger-Dyer, Beljaars-Holtslag, Cheng-Brutsaert och SHEBA-experimentet används i de modeller för avdunstningskanaler som föreslagits av Paulus-Jeske och Babin-Young-Carton för att beräkna avdunstningskanalens höjd, varvid det konstateras att den sistnämnda metoden är en giltig metod med Monin-Obukhovs stabilitetsfunktioner baserade på SHEBA-experimentet. Det modellerade brytningsindexet införs i en redan befintlig vågutbredningsmodell för att undersöka och validera resultaten.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-08T23:18:13Z No. of bitstreams: 1 AllanRodriguesSilva_TESE.pdf: 23816481 bytes, checksum: d4554a5a05635c895c42dfbae3c3ff21 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-08T23:44:04Z (GMT) No. of bitstreams: 1 AllanRodriguesSilva_TESE.pdf: 23816481 bytes, checksum: d4554a5a05635c895c42dfbae3c3ff21 (MD5) / Made available in DSpace on 2016-06-08T23:44:04Z (GMT). No. of bitstreams: 1 AllanRodriguesSilva_TESE.pdf: 23816481 bytes, checksum: d4554a5a05635c895c42dfbae3c3ff21 (MD5) Previous issue date: 2015-12-21 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A estabiliza??o da oferta de energia no Brasil tem sido um desafio para o planejamento do Sistema Interligado Nacional, diante das varia??es hidrol?gicas e clim?ticas. Termoel?tricas s?o utilizadas como fonte emergencial no per?odo de escassez h?drica. Por?m a utiliza??o de combust?veis f?sseis tem elevado o custo de produ??o, da energia el?trica. Por outro lado, a energia e?lica em alto mar (offshore) vem ganhando import?ncia no cen?rio internacional, e tornando-se competitiva a ponto de tornar-se uma possibilidade futura de gera??o no Brasil. Nesse sentido, o objetivo principal desta tese foi investigar a magnitude e distribui??o dos recursos e?licos offshore, verificando tamb?m possibilidades de complementaridade com a fonte h?drica. Para isto, foi utilizado uma s?rie de dados de precipita??o do Climatic Research Unit (CRU) e conjunto de dados satelit?rios de velocidade de vento do projeto Blended Sea Winds da National Climatic Data Center (NCDC/NOAA). De acordo com crit?rios estat?sticos foi encontrado tr?s tipos de complementaridade presentes no territ?rio brasileiro: h?drica h?drica, e?lica e?lica e h?drica e?lica. Notou-se que houve complemento bastante significativo (r=-0,65) entre as fontes, h?drica e e?lica, principalmente das bacias hidrogr?ficas do sudeste e centro oeste com os ventos do Nordeste. Com intuito de refinar a extrapola??o dos ventos sobre o oceano, foi utilizado m?todo baseado na teoria de Monin-Obukhov para modelar a estabilidade da camada limite atmosf?rica. Foi utilizado o conjunto de dados de fluxos de calor, temperatura e umidade do Projeto Objectively Analized Air-Sea Flux (OAFLUX), al?m de dados de press?o ao n?vel do mar do projeto NCEP/NCAR e o modelo de relevo global ETOPO1 da National Geophysical Data Center (NGDC/NOAA). Verificou-se um bom recurso em ?guas rasas, entre 0-20 metros, estimados em 559 GW. A contribui??o do recurso e?lico em um reservat?rio, foi investigada com um modelo h?brido e?lico-hidr?ulico simplificado que permitiu o c?lculo do n?vel dos reservat?rios a partir de dados de vaz?o afluente, defluente e produ??o de turbina. Notou-se que o sistema h?brido evita os per?odos de estiagem, poupando continuamente ?gua dos reservat?rios atrav?s da produ??o e?lica. Assim, a partir dos resultados obtidos, ? poss?vel afirmar que os bons ventos das costa brasileira podem, al?m de diversificar a matriz el?trica, estabilizar as flutua??es h?dricas evitando racionamentos e apag?es, reduzindo o uso das t?rmicas que eleva o custo de produ??o e emite gases poluentes. Pol?ticas p?blicas voltadas ao incentivo da energia e?lica offshore ser?o necess?rias para seu pleno desenvolvimento. / The stabilization of energy supply in Brazil has been a challenge for the operation of the National Interconnected System in face of hydrological and climatic variations. Thermoelectric plants have been used as an emergency source for periods of water scarcity. The utilization of fossil fuels, however, has elevated the cost of electricity. On the other hand, offshore wind energy has gained importance in the international context and is competitive enough to become a possibility for future generation in Brazil. In this scenario, the main goal of this thesis was to investigate the magnitude and distribution of offshore wind resources, and also verify the possibilities of complementing hydropower. A data series of precipitation from the Climatic Research Unit (CRU) Blended Sea Winds from the National Climatic Data Center (NCDC/NOAA) were used. According to statistical criteria, three types of complementarity were found in the Brazilian territory: hydro ? hydro, wind ? wind and hydro ? wind. It was noted a significant complementarity between wind and hydro resources (r = -0.65), mainly for the hydrographical basins of the southeast and central regions with Northeastern Brazil winds. To refine the extrapolation of winds over the ocean, a method based on the Monin-Obukhov theory was used to model the stability of the atmospheric boundary layer. Objectively Analyzed Air-Sea Flux (OAFLUX) datasets for heat flux, temperature and humidity, and also sea level pressure data from NCEP/NCAR were used. The ETOPO1 from the National Geophysical Data Center (NGDC/NOAA) provided bathymetric data. It was found that shallow waters, between 0-20 meters, have a resource estimated at 559 GW. The contribution of wind resources to hydroelectric reservoir operation was investigated with a simplified hybrid wind-hydraulic model, and reservoir level, inflow, outflow and turbine production data. It was found that the hybrid system avoids drought periods, continuously saving water from reservoirs through wind production. Therefore, from the results obtained, it is possible to state that the good winds from the Brazilian coast can, besides diversifying the electric matrix, stabilize the hydrological fluctuations avoiding rationing and blackouts, reducing the use of thermal power plants, increasing the production cost and emission of greenhouse gases. Public policies targeted to offshore wind energy will be necessary for its full development.

This work is dedicated to structural parameter of the refractive index in the atmosphere Cn2 and his various models. For comparison the models are simulated only for one area and only for one day. The work represented the influence of atmospheric turbulence on the communication environment and on the individual models. In addition this work is for selected areas and for the input conditions created program for modeling of structural parameters and meteorological data in the atmosphere