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RESEARCH AND DEVELOPMENT

IN PROGRESS. Started in:
2015

CLIMATE NETWORK: SUBNET RENEWABLE ENERGY - SUBPROJECT WATER, FOOD AND ENERGY SAFETY

Subproject of the Climate Network research program on global climate change, within the subnet of Renewable Energies, facing the construction of scenarios on the theme of energy security and its relations with other sectors of society.

Coordenadores: Dr. Luiz Pinguelli Rosa / Dr. Marcos Aurélio Vasconcelos de Freitas

Funders: CNPq / FINEP / FAPESP

SPECTRAL EVALUATION OF SOLAR IRRADIANCE ON SURFACE OF THE BRAZILIAN TERRITORY AND SCENARIOS FOR THE USE OF SOLAR ENERGY

The spectral response of the solar radiation at the surface varies between regions of the country depending on the atmospheric constituents. this project aims to study this variability and its impact on solar photovoltaic generation technologies.

Coordinator: Dr. Fernando Ramos Martins (UNIFESP)

Funder: CNPq

STUDY OF THE AVAILABILITY AND VARIABILITY OF SOLAR AND WIND ENERGY RESOURCES AND DEVELOPMENT OF SCENARIOS FOR THESE ENERGY SOURCES INSERTION IN THE BRAZILIAN ENERGY MATRIX

The knowledge of the variability of energy resources as a function of climate variability is relevant not only to the country's energy planning, as well as for the evaluation of the economic feasibility and technical details of projects and investments in the production and insertion of these renewable sources in electricity distribution system. The economic feasibility studies and energy planning should take into account the climatic and environmental impacts in the short, medium and long terms, as, for example, resulting from the increase or decrease of precipitation, increased frequency of storms or changes in ground cover. The increased speed of the winds above the tolerance values specified in the design of a wind farm can prevent energy production because of the risk of damage to the mechanical system of the installed wind turbines. As a result, economic and technical losses will occur if this increase is not considered during the development of the project.

Coordinator: Dr. Fernando Ramos Martins (UNIFESP)

Funder: CNPq

2011

SHORT-TERM FORECASTING OF GRID­CONNECTED SOLAR PHOTOVOLTAIC GENERATION

The project aims at the enhancement of the capabilities of using meteorological forecasts for improving the control of renewable energy systems and thus to ease the integration of these technologies to the grid for energy supply of the countries. Building on the experiences of the partners in the field of renewable energy systems, meteorology and metrology in solar and wind energy applications, a comprehensive scheme should be developed for an optimized use of meteorological forecast information, for system control and better grid integration. This should comprise, on one hand, the combined schemes for the improvement of the numerical weather forecasts by post­processing with the inclusion of space and time information on historic forecast errors. On the other hand, the remaining forecast errors must be characterized by their distribution function in order to obtain reliable intervals. This information must be the input to an optimal plan for probabilistic control of renewable energy systems.

Coordinator: Dr. Ricardo Rüther (UFSC)

Funder: CNPq

2009

INCT - CLIMATE CHANGE: SUBPROJECT RENEWABLE ENERGY

The subproject aims to conduct a study on the impact of various scenarios of global climate change on the flow of incoming solar radiation and the wind regime and thus estimate how these changes will alter their energy potential in Brazil in the long, medium and short deadlines.

Coordinator: Dr. Enio Bueno Pereira

Funder: CNPq

2002

SONDA/PETROBRAS

Project linked to research on climate and meteorology, focusing on support to energy sector activities, especially renewable energy. The project aims at setting up a high reliability environmental data collection system that addresses the needs of the sectors of society involved in the research, development, planning and investment in the use and applications of renewable energy, mainly solar and wind energy. For this, the following targets were established:

  1. implementation of a network for collecting meteorological, environmental and solar and wind energy resources data
  2. development of a database that integrates socio-economic information, climate and environmental data and availability of solar and wind resources
  3. providing the database to the public via the project's website, so that it is possible to conduct research through the association of several available variables with the purpose of producing information in accordance with the user's needs
  4. preparation of human resources through technical training and academic education

Coordinator: Dr. Enio Bueno Pereira

Funders: FINEP / PETROBRÁS

COMPLETED. Ended in:
2014

WIND FORECASTING IN WIND FARMS IN NORTHEASTERN BRAZIL

2010-2014

The project aimed to the development of methodology for short-term wind energy forecasting in the Brazilian Northeast region based on numerical predictions operationally available in the country and compatible with the tropical climate, thus allowing the wind farms acquire greater competitiveness and the electrical system be managed optimally. One of the biggest difficulties for the development of research on wind to exploitation purposes is the existing anemometric database. In addition to the scarcity of data, there is a gap in the knowledge of the atmospheric boundary layer (CLA), especially in the area of greatest potential (Northeast). For realization of the project, a partnership was formed between three institutions: UFAL, INPE and CTA.

Coordinator: Dr. Roberto Lyra (UFAL)

Funder: CNPq

2013

NOPA PROGRAMME - DEVELOPMENT OF METHODS FOR SURVEYING OF SOLAR AND WIND POWER

2011-2013

The project had as main objective the establishment of long-term partnership between the groups of renewables and bioenergy of the CCST/INPE and Meteorology of Energy at the University of Oldenburg (EnMetOL), Germany, for the development of methods and tools of meteorology applied specifically to the demands of the energy sector with respect to spatial and temporal variability of the energy potential of solar and wind sources. The results and products generated by this partnership will help to boost the integration of solar and wind renewable sources in the energy matrix. In the scope of this project with duration of 2 years, was given emphasis in the qualification and training of human resources through the exchange of researchers and PhD students, establishment of a joint agenda of research activities and the development of methods and tools to provide services to the energy sector.

Coordinator: Dr. Enio Bueno Pereira

Funder: CAPES

SOLAR RESOURCE ASSESSMENT IN CHILE

2010-2013

The project aimed to create a model of radiative transfer in the atmosphere which enables to estimate the solar radiation incident on the national territory of Chile with the processing of satellite images, taking into account their geographical and climatic conditions. To do this, the BrasilSR model of the INPE has been modified and adapted to conditions in Chile.

Coordinator: Dr. Rodrigo Escobar (Universidade do Chile)

Funder: Comisión Nacional de Investigación Científi ca y Tecnológica (Chile)

THE IMPACTS OF GLOBAL CLIMATE CHANGE ON THE NATIONAL POTENTIAL OF SOLAR AND WIND POWER

2010-2013

The project aimed to estimate the impacts of future climate change resulting from global warming in the potential of solar and wind energy in the country for periods of 2010-2040, 2040-2070 and 2070-2100. The project also aimed to provide predictions of these impacts for three scenarios of greenhouse gas emissions: A2, B2 and A1B, according to the classification presented in the IPCC reports.

Coordinator: Dr. Fernando Ramos Martins (UNIFESP)

Funder: CNPq

WIND ENERGY RESOURCES ASSESSMENT OVER HYDROELECTRIC RESERVOIRS (AREEHIDRO)

2011-2013

This project aimed to consolidate the potential of wind energy utilization research in hydroelectric reservoirs considering the current scenario and future scenarios designed by the IPCC, given the influence of climate change. This study (pilot) was performed to four important hydroelectric reservoirs in the State of Minas Gerais: Furnas, Três Marias, Itumbiara (on the border of Minas Gerais and Goiás) and Estreito (on the border of Minas Gerais and São Paulo).

Coordinator: Dr. Arcilan Treviseu (UNIFEI)

Funder: FAPEMIG

2011

ENHANCING INFORMATION FOR RENEWABLE ENERGY TECHNOLOGY DEPLOYMENT IN BRAZIL, CHINA, AND SOUTH AFRICA

2009-2011

The project promoted the development of a wind forecasting methodology in spatial scale of hundreds of meters, based on outputs for Mesoscale Meteorological models (MM5, WRF, BRAMS and others), aiming at wind potential assessment (micrositing).

Coordinator: Dr. Enio Bueno Pereira

Funder: UNEP

2010

CLIMATE NETWORK: CLIMATE CHANGE AND RENEWABLE ENERGY SUBPROJECT

2007-2010

The overall objective of this project was to develop studies of climate change impacts in the renewable energy sector in the country, mainly wind power and biomass, to 2015/2030/2100, in addition to providing a database with projections of climate change for two emissions scenarios of greenhouse gases for long-term planning of the oil industry. The activities were:

  1. identify the main lines of work on energy and climate in the major research centers in the country;
  2. structure an agenda for appropriate subnet to the country's commitments on climate change;
  3. monitor the development and implementation of the National Plan on Climate Change in the energy sector, with emphasis on renewable resources;
  4. follow the main actions of the national groups and their international interface issues of mitigation of greenhouse gas (GHG) emissions and climate vulnerability and the energy sector.

Coordinator: Dr. Luiz Pinguelli Rosa

Funder: CENPES

2009

SWERA PROGRAMME – SOLAR AND WIND ENERGY RESOURCE ASSESSMENT

2001-2009

The primary objective of the program was to facilitate the inclusion of renewable energy sources in the energy matrix of developing countries. Thirteen countries were involved, divided into three regional groups: Africa, Latin America and Asia. The Center for weather forecast and Climatic Studies (CPTEC/INPE) through the Climate and Environment Division (DMA) was responsible for coordinating activities to Latin America. The main goals set for the development of the project were:

  1. development of a consistent, reliable and accessible database to various sectors of society, governmental and non-governmental agencies, investors and private companies from the energy sector, research institutions and universities, with the aim of disseminating scientific knowledge on the extent and location of areas with greatest potential for harnessing solar and wind energy;
  2. integration of renewable energy resources database with other information bases such as available infrastructure, socio-economic data, climatic and environmental parameters in order to reduce uncertainties associated with planning and investment in the use of sources of solar and wind energy;
  3. development, validation and application of data collection models of solar radiation and wind on a regional scale.

In Brazil, implementation, validation and operation of the radiative transfer model to determine the solar radiation on the surface with geostationary satellite employment generated "Brazilian Atlas of Solar Energy," published in 2006.

Coordinator: Dr. Enio Bueno Pereira

Funder: UNEP

2006

PREVENTO - SHORT-TERM WIND FORECAST

2004-2006

The objective of the project was the development of wind forecasting methodology to allow the creation of tools for the insertion of wind systems analysis on generator matrix of CHESF, incorporating short-term forecast of wind speed. Was developed on coparticipation with Eletrobrás/CEPEL.

Coordinator: Dr. Enio Bueno Pereira

Funder: ANEEL

IN PROGRESS. Started in:
2015

Application of solar technologies for electricity generation in the São Francisco river basin in Nexus water, energy and food approach

In a scenario of global climate change and depletion of ecosystems, the growing demand for natural resources implies adopting new practices in human activities. The Nexus concept reads the interrelationship between Water, Energy and Food and how actions can systematically affect the three elements. It proposes appropriate management, based on information and governance, to ensure availability and access to resources in the long term.

In Brazil, the São Francisco river basin is emblematic territory for the Nexus concept, where water is demanded in energy generation, food production and direct use by the population. The periods of drought intensify the dispute over water, with social, economic and political effects. At the same time, solar irradiation is an abundant resource in the region, with an average level above 5 kWh / m² / day. Underutilized until now, its use to generate electricity has the potential to reduce water reserves, with the possibility of changing the region's sustainability index.

In this context, the research aims to analyze scenarios of application of solar source technologies to generate electricity in different functional, economic, spatial and land use arrangements. Nexus and Life Cycle Assessment will be methodological tools used to compose scenarios and quantify resource indicators. The scenarios will aim to provide information to decision making and subsidize governance and public policies focused on water, energy and food security in a region with an asymmetry in resource use.

Aluno: Érica Ferraz de Campos

Grau: Doutorado

Orientadores: Dr. Enio Bueno Pereira

Financiador: CAPES

ANALYSIS OF THERMAL PERFORMANCE OF URBAN SURFACES IN BRAZIL

The research is to analyze the spectral characteristics of the materials that make up the urban areas in Brazil, their relationship to the land use and energy demand. Aims to provide technical information that results in alleviating the phenomenon of warming of urban areas, called heat Island. The methodology consists of analyzing the phenomenon on the scale of the building and on the scale of cities and through models and simulations promote interaction with actual data: materials, construction methods, climate and use. The result of this project it is intended to complement information about the factors that determine the energy efficiency of cities, human well-being and environmental preservation and provide subsidies for the implementation of urban-related parameters.

Student: Fabiana Lourenço e Silva Ferreira

Degree: PhD

Advisors: Dr. Enio Bueno Pereira

Funder: CAPES

PERFORMANCE EVALUATION OF PHOTOVOLTAIC MODULES CONSIDERING THE SPECTRAL VARIATION

The photovoltaic modules in general have been evaluated in very well controlled conditions taking into account the solar spectrum according to ASTM G 173-03 standard prepared with data from North America. Considering that North American climate is particular of that region and the spectrum in field tends to vary during the year, we can say that such evaluation may not be representative for the conditions found throughout the Brazilian territory. So, this work aims to carry out a preliminary assessment of the effect of spectral variations in the performance of photovoltaic modules of six different technologies in a particular region of Brazil.

Student: Guilherme Marques Neves

Degree: PhD

Advisors: Dr. Enio Bueno Pereira / Dr. Waldeir Amaral Vilela

Funder: CAPES

COMPLETED. Ended in:
2018

STUDY OF THE CLOUDS VARIABILITY AND ITS APPLICABILITY IN THE SOLAR ENERGY SECTOR

The variability of solar energy is one of the most important issues in the integration of solar energy into the power grid. The development of methods for assessing the movement of clouds and the resulting buoyancy in power generation make this study of great importance to the Brazilian energy sector. In this way, the work aimmed to classify and study the clouds in different regions of the Brazilian territory, using sky imagers, for a regional climatological knowledge and possible short-term forecasts of the cloud movement.

Student: Eduardo Weide Luiz

Degree: PhD

Advisor: Dr. Enio Bueno Pereira

Funders: CAPES / CNPq

2017

EVALUATION OF SIMULATIONS WITH CODE "LES" IN THE STUDY OF THE SYSTEM OF WINDS IN SHORT AND MEDIUM TERM IN NORTHEASTERN BRAZIL

The objective of this work was to carry out a careful evaluation for estimation and prediction of short term and high resolution of the wind power potential at high spatial resolution through simulations with two versions of the WRF model (WRF-Real and WRF-LES) for some regions of Northeastern Brazil.

Student: Lucía Iracema Chipponelli Pinto

Degree: PhD

Advisor: Dr. Enio Bueno Pereira

Funder: CAPES

FEASIBILITY OF THE INCLUSION OF SOLAR ENERGY IN THE BRAZILIAN ENERGY MATRIX

Being of knowledge that Brazil has enormous resource potential of solar energy, this project proposed to develop a methodology for the seasonal forecast of solar irradiance, aimed at commercial exploitation of photovoltaic plants, with the aim of contributing to the country's energy planning, reducing the need for operation of thermoelectric plants that use fossil fuels and alleviate national energy security risks. This will be done through an approach involving the treatment of historical data, numerical modeling and utilization of artificial neural networks in order to get a joint analysis of the information obtained.

Student: Maria Francisca Azeredo Velloso

Degree: PhD

Advisor: Dr. Enio Bueno Pereira

Funder: CAPES

2015

IMPACTS OF VARIATIONS AND CLIMATE CHANGE ON EXTREME WINDS AND THEIR EFFECTS IN THE BRAZILIAN ELECTRIC SECTOR

A study was conducted for climate variability and change of the minimum and maximum extreme winds to 10 m starting from the Brazilian airfields database of 10 m wind along with the downscaling of the HadCM3 global model made by ETA regional climate model to South America targeting the future scenario of the 2010 to 2100 of the IPCC AR4 scenario A1B 2100. It was also made the bias correction of the EtaHadCM3 model using the method of Artificial Neural Networks.

Student: Marcelo Pizzuti Pes

Degree: PhD

Advisors: Dr. Enio Bueno Pereira / Dr. José A. Marengo

Funders: INCT / CAPES

SOLAR RADIATION FORECAST IN NORTHEAST BRAZIL USING THE MODEL "WRF" SET FOR ARTIFICIAL NEURAL NETWORKS

The WRF model was used to generate forecasts of surface solar radiation to the Northeast of Brazil, which were adjusted by statistical models based on multiple linear regression and artificial neural networks.

Student: Francisco José Lopes Lima

Degree: PhD

Advisor: Dr. Enio Bueno Pereira

Funders: CAPES / CNPq

2014

DEVELOPMENT OF METHODOLOGIES FOR CLOUD COVER ESTIMATE

The research aimed to develop methodologies for estimating parameters of cloud cover using data from long-wave radiation incident on the surface, along with weather data measured in surface stations in two localities, Brasília (DF) and Petrolina (PE). The first methodology employed atmospheric physics concepts to estimate the fraction of cloud coverage and presented behavior similar to the climatology of the localities studied. The second method proposed the use of Artificial Neural Networks for estimating the Effective Cloud Coverage and featured good correlation with satellite measurements. In addition, the method was able to evaluate the non-linearities of the estimate, when compared with linear methods such as Multiple Linear Regression.

Student: Eduardo Weide Luiz

Degree: Master

Advisor: Dr. Enio Bueno Pereira

Funder: CAPES

ESTIMATES OF INCIDENT SOLAR RADIATION ON THE NORTHEASTERN BRAZIL EMPLOYING INTERPOLATION AND RADIATIVE TRANSFER MODEL

Estimates of surface solar irradiance fields were made for the territory of Northeast Brazil in the years 2008 to 2011. For this, it was employed a estimating method based on interpolation by kriging. For evaluation of his performance, it was made an inter-comparison of the values estimated by interpolation with values measured in sampling points represented by Data Collection Platforms (DCPs) and estimates performed by the physical model of radiative transfer BRASIL-SR. The evaluation was performed through statistical indexes allied to cross-validation method and the visual analysis of maps of spatial variability of solar irradiance.

Student: Roque Magalhães Brito dos Santos

Degree: Master

Advisor: Dr. Enio Bueno Pereira

Funder: CAPES

2013

VARIABILITY OF THE CLOUD COVER COEFFICIENT OVER BRAZIL AND ITS RELATIONSHIP WITH THE PHENOMENA OF GLOBAL DIMMING AND BRIGHTENING

Several studies have shown, over the past few decades, that in fact the solar radiation that reaches the Earth's surface does not remain unchanged over the decades, but suffers increases and decreases known as solar dimming and solar brightening, respectively. However, the shortage of solar radiation data measured in the surface on long-term in Brazil is still a problem for the evaluation of the occurrence of these phenomena. Given this, this study proposed to assess trends in cloudiness, main factor modulator of solar radiation, through the study of spatio-temporal variability of the coefficient of cloud cover, determined through satellite images. For this, it were developed methods of estimation of irradiances of clear sky and overcast, necessary for the estimation of the coefficient of effective cloud coverage. The clear sky radiance is determined by the histogram of visible radiance frequencies measured by satellites, by assigning to it the value more often observed in a given area of the images within one quarter. The radiance of overcast skies, in turn, is determined by a setting that relates texture in the cloudtops, through the standard deviation of the visible radiance whose infrared measurement exceeds 280 K, with the sun-pixel-satellite geometry. The cloud cover was estimated for all the images of GOES-8 satellite, GOES-10 and GOES-12, in 1145, 1445, 1745 and 2045 GMT, in the period from 1999 to 2012. The trends of these coefficients were then evaluated through the use of non-parametric test of Mann-Kendall, with a significance level of 5%.

Student: Márcio Cecconi

Degree: Master

Advisor: Dr. Enio Bueno Pereira

Funder: CAPES

2012

INFLUENCE OF ATMOSPHERIC AEROSOLS IN SOLAR ENERGY RESOURCE MEASUREMENT: EXPERIMENTS IN RADIATIVE TRANSFER MODEL

The influence of atmospheric aerosols in quantifying of the solar resource was assessed from three data sources of horizontal visibility: climatological base model, the interpolation of the values of visibility of 105 airports in South America and visibility estimates obtained through the optical thickness of the aerosols from the CATT-BRAMS model. The simulations that used the data of horizontal visibility observed at airports showed significant improvements in estimates of global irradiation values, while the results of the simulations with the base of horizontal visibility estimated showed best performance in months and in regions where there was a high load of aerosols, with specific bias and RMSE decreases of up to 11%. Even when the new bases did not indicate improvements, error values were close to those obtained in the model integrations using horizontal climatological visibility.

Student: Rodrigo Santos Costa

Degree: PhD

Advisors: Dr. Enio Bueno Pereira / Dr. Fernando Ramos Martins

Funders: CAPES / CNPq

2011

REFINEMENT OF STATISTICAL WIND FORECASTS FROM THE ETA MODEL APPLIED TO THE AEOLIC-ELECTRIC SECTOR OF THE NORTHEAST BRAZIL

The ETA model outputs have been adjusted by statistical models based on multiple linear regression and artificial neural networks for the forecast of wind in surface (50 m). The results showed a significant gain in the correlations and reduction of errors in the forecast of wind in a horizon of 36 hours.

Student: André Rodrigues Gonçalves

Degree: Master

Advisors: Dr. Enio Bueno Pereira / Dr. Fernando Ramos Martins

Funder: CAPES

2010

MODELING AND REPRESENTATION OF ATMOSPHERIC PATTERNS IN THE IMAGES OF THE SYNOPTIC OBSERVATION SYSTEMS

The work has developed a new methodology of analysis, knowledge representation and classification of atmospheric patterns from the values of the pixels of images obtained on the surface. The methodology aims to replace the synoptic observers (SO) that classify the sky from tacit knowledge and subjective criteria. The methods of analysis raised in specialized literature and in commercially available equipment use a binary approach of the results and mathematical simplification. The proposed methodology establishes an appropriate task domain to map the data represented by the values of the pixels in knowledge, necessary for the classification of standards based on the theory of atmospheric physics. Preliminary results indicated that the methodology proposed is superior to the main technique existing in specialized literature in the following aspects: more rigorous mathematical modeling, precise breakdown of the atmospheric patterns observed in the images, invariance with respect to solar incidence angle (brightness), comparison of the images with solar radiation sensors and the identification of other weather phenomena from the same images.

Student: Sylvio Luiz Mantelli Neto

Degree: PhD (Engineering and Knowledge Management)

Advisors: Dr. Aldo von Wangenheim / Dr. Enio Bueno Pereira

2009

STUDY OF AEOLIC ENERGY FOR MARAJÓ ISLAND (PARÁ STATE, BRAZIL)

Marajó island, in the State of Pará, North Brazil, shows a low level of economic development compared to other regions of the country. Among other factors that limit this development is the low availability of energy which, today, is produced exclusively by thermoelectric plants in isolated systems. This work aimed to make a preliminary survey on the feasibility of wind power generation in the region. The results indicated that the best winds occur in the months of September to November along the coastal region, on the north-northwest of the island. For this region there was an average wind power density of 151 W / m², and a form factor of 1.7. Based on wind data obtained by the ETA model and using the commercial package WasP wind systems analysis, was developed a scenario of use of wind energy in cogeneration scheme with the thermoelectric plants today installed in the region.

Student: Eliude Introvini da Cruz Segundo

Degree: Master

Advisor: Dr. Enio Bueno Pereira

Funder: CNPq

STUDY OF THE IMPACT OF CLIMATE CHANGE ON THE WIND POTENTIAL IN THE STATE OF RIO GRANDE DO SUL FOR THE PERIODS OF 2010 TO 2040 AND 2070 TO 2100

The work consisted of developing a methodology for assessing the impacts of climate change on the wind potential in the southern region of Brazil. For this study were used observational climatic series, ERA40 reanalysis from 1960 to 2007 and projections of the climatic ETA HadCM model from CPTEC, for the climatic scenario A1B until 2100.

Student: Marcelo Pizzuti Pes

Degree: Master

Advisor: Dr. Enio Bueno Pereira

Funder: CAPES

2006

USE OF ARTIFICIAL NEURAL NETWORKS AND MULTIPLE LINEAR REGRESSION IN THE REFINEMENT OF SOLAR RADIATION FORECAST FROM ETA MODEL

The ETA model outputs have been adjusted by statistical models based on multiple linear regression and artificial neural networks for the forecast of solar radiation at the surface, showing gains in the application of statistical models in post processing of atmospheric models.

Student: Ricardo André Guarnieri

Degree: Master

Advisor: Dr. Enio Bueno Pereira

Funder: CNPq

2005

DEVELOPMENT OF AN AUTOMATIC MAPPING SYSTEM OF THE CLOUD COVER FRACTION

The work describes the development of a prototype of an automatic mapping system of the fraction of cloud cover and the first results obtained. It was used a system consisting of a digital Pixera brand camera, model PCS20232, operating in the range of visible radiation, along with a wide angle lens FCE8, Nikon's manufacturing, with a nominal opening of 178°. The results were compared with the atmospheric transmittance (Kt) and the ratio of global and diffuse solar radiations (Kd), besides the BRASIL-SR model, which estimates the solar radiation at the surface. It were employed, comparatively, as input to the model, the clouds fractions generated by the new imager system and data obtained by the GOES-8 satellite. The results showed important differences that have been attributed to the fact that the data obtained by the imager does not contain information on the optical depth of the clouds.

Student: Mariza Pereira de Souza Echer

Degree: PhD (Space Geophysics)

Advisor: Dr. Enio Bueno Pereira

Funder: CNPq

2001

INFLUENCE OF THE PROCESS OF CLOUD COVER DETERMINATION AND AEROSOLS OF BURNING IN THE PHYSICAL MODEL OF RADIATION BRASIL-SR

In this study it were evaluated, developed and implemented in the BRASIL-SR model parameterizations of cloud cover index and aerosols released into the atmosphere in events of burning, seeking the improvement of estimates of solar irradiation. Two techniques were proposed for the composition of images of clear sky and overcast. The visual analysis of the compositions of images showed that the reason IR/VIS offers greater efficiency in identifying pixels with persistent conditions. The technique implemented for parameterization of aerosol from burning adopted optical properties obtained with the use of "Global Aerosol Data Set" and showed good agreement with values obtained in TRACE-A and SCAR-B missions. The studies showed that, with more appropriate parameterization for the determination procedures of cloud cover and the influence of aerosols, model performance is improved.

Student: Fernando Ramos Martins

Degree: PhD

Advisor: Dr. Enio Bueno Pereira

Funder: FAPESP

DEVELOPMENT OF METHODOLOGY FOR THE ESTIMATION OF CLOUD COVER USING A SURFACE CAMERA AND COMPARING WITH THE SATELLITE IMAGES

The paper presents a method to increase the precision of estimates of cloud cover made from the surface and compare it with satellite images. Were used: an inexpensive digital camera from the surface, image processing algorithms, an atmospheric physical model for the calculation of solar radiation on the surface, solar irradiation data, synoptic data and images from the GOES-8 satellite. The proposed methodology concluded that the interpretation of the estimates of cloud cover can not be binary, assigning a pixel of an image corresponding representation of a cloud or not, with a range of intermediate values ​​of transparency. This classification can lead to misinterpretation, as there are in the sky a series of physical manifestations as scattering and atmospheric turbidity that, despite representing clear sky, can confuse an automated interpretation system to due to proximity of intensity values with a small cloud optical depth (such as cirrus and the edges of other types of clouds), super sizing the final amount of cloud cover. This finding was possible only after using anisotropic diffusion on the images of clouds.

Student: Sylvio Luiz Mantelli Neto

Degree: Master (Computer Science)

Advisors: Dr. Aldo von Wangenheim / Dr. Enio Bueno Pereira

1999

DEVELOPMENT OF A NEW METHODOLOGY FOR DETERMINATION OF CLOUD COVERAGE

The new method described in work employs a database obtained in surface through a digital camera with sensor type Charge Coupled Device (CCD), in the range of visible radiation and acquiring images in red, green and blue (RGB). To analyze the collected images it was developed an algorithm whose function is to classify the pixels based on a decision process established empirically by field observers, determining the fraction of the sky covered by clouds. RGB attributes were transformed to Intensity, Hue and Saturation (IHS) using the saturation (S) in the separation of the pixels that match the sky and the clouds. The methodology was tested on images collected in the Antarctic Brazilian Station "Comandante Ferraz" and the results showed that the technique is suitable for the proposed work. The hit percentage for the pixels classified as clear sky was among 94% and 99% and classified as fully covered between 99.96% and 100%. The hit percentage to partially overcast sky presents a great difficulty in validating due to the very subjective characteristic of the visual identification process, usually employed in weather stations. The evaluation of the results of the automatic classification method was obtained by analysis of case studies based in various sky coverage states. These cases were chosen in order to represent: (1) sky with cloud cover patterns well defined (outlines of clouds well defined) and (2) sky with vague patterns and large amount of cloudiness (clouds with poorly defined edges and / or indefinite coverage states). To these conditions the recognition program also displays response consistent with the subjective process of classification based on visual inspection. Images collected for different Zenithal angle values and states of cloud cover were classified by the method. The sorting algorithm divided the results in three separate cases: (1) effectively clouds (11% to 82.93%); (2) indefinite state (10% to 23.41%) and (3) clear sky (13.82% to 85.32%). All groups were tested with a confidence level of 99.73%.

Student: Mariza Pereira de Souza Echer

Degree: Master (Space Geophysics)

Advisor: Dr. Enio Bueno Pereira

Funder: CNPq

 

INPE - National Institute for Space Research / CCST - Earth System Science Center

MCTIC / INPE

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