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Search Results: 1 - 10 of 270833 matches for " José Augusto P. Veiga "
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An Analysis of the Spectral Energetics for a Planet Experiencing Rapid Greenhouse Gas Emissions  [PDF]
André Ferreira Aranha, José Augusto P. Veiga
Atmospheric and Climate Sciences (ACS) , 2017, DOI: 10.4236/acs.2017.71009
Abstract: So far, energetics studies related to climate change have focused on the disturbed and undisturbed kinetic and potential energies, as well as their transformations, without dealing with the energetics involved in the phenomena of different spatial scales. Thus, the present work reports the first analysis of the spectral energetics for a condition of climate change, followed by the high-range emission scenario, RCP8.5, which originated from the new Max Planck Institute Earth System Model (MPI-ESM). The results showed that both types of generation (Go and Gn), baroclinic processes (Co and Cn), kinetic energies (Ko and Kn) and the barotropic process, Mn, significantly increase in the condition of a warming climate. Moreover, the results still reveal that in the most components of the energetics, is the planetary scale waves that are the most impacted under a climate change scenario. These results highlight that global warming can have different impacts on particular types of motions.
Impact of the Waves on the Sea Surface Roughness Length under Idealized Like-Hurricane Wind Conditions (Part II)  [PDF]
José Augusto P. Veiga, M?nica R. Queiroz
Atmospheric and Climate Sciences (ACS) , 2015, DOI: 10.4236/acs.2015.53025
Abstract: In this study the effect of the surface waves over sea surface roughness (z0) and drag coefficient (CD) is investigated by combining an ocean wave model and a simplified algorithm, which estimates z0 and CD with and without dependence on the sea state. This investigation was possible from several numerical simulations with the Wave-Watch-III (WW3) model for complex wind conditions. The numerical experiments were performed for idealized like-hurricanes with different translation speed (0, 5 and 10 m/s) and maximum wind speed (MWS) at the centre (35, 45 and 55 m/s). It is observed that z0 and CD are strongly dependent on the sea state, via substantial modification in Charnock parameterization (zch). As the hurricane translation speed increases more discrepancies in z0 and CD are observed in opposite quadrants around the region of MWS. As for instance, higher, longer and older (or more developed) waves, located in the front-right quadrant, produce lower values of z0 and CD. In the rear-left quadrant, where the waves are lower, shorter and younger (or less developed), higher values of z0 and CD are observed. In addition the difference between values on opposite quadrants increases as the hurricane intensity increases, showing the hurricane intensification dependence. Interesting aspects are observed in scatter plotting wave age versus Charnock coefficient. It is also observed that zch, which has a constant value of 0.0185, is modified by the sea state, where young waves produce higher values of zch, while old waves are related to lower values of zch when compared with zch without dependence on sea state.
Impact of the Waves on the Sea Surface Roughness under Uniform Wind Conditions: Idealized Cases for Uniform Winds (Part I)  [PDF]
José Augusto P. Veiga, M?nica R. Queiroz
Atmospheric and Climate Sciences (ACS) , 2015, DOI: 10.4236/acs.2015.53024
Abstract: The effect of the surface gravity waves over sea surface roughness length (z0) is investigated from several idealized numerical experiments with the Wave-Watch-III (WW3) model. The WW3 model is combined with a simplified model to estimate z0, CD, u* and U10 as function of the sea state. The impacts related to the presence of the ocean waves over z0 are obtained from conditions of growing (young waves) and mature seas (old waves). The wave spectrum is obtained from WW3 model for each idealized simulation under uniform wind conditions. Uniform wind experiments range from 15 to 45 m/s. The simplified algorithm determines z0, CD, u* and U10 for cases of young waves, old waves and by the Charnock method. The results show that when the ocean is characterized by young waves, both z0 and CD (drag coefficient) increase while U10 is reduced. In Charnock case, the values of z0, CD and U10 have no dependence with the presence of gravity waves. Experiments using winds higher than 30 m/s result in young waves’ CD values higher than the CD value for old waves. Even for young waves CD values are high for cases of strong winds. The results also show that in experiments using winds higher than 30 m/s the dependence between CD and wave age becomes stronger, which is in accordance with other studies.
A Global and Hemispherical Analysis of the Lorenz Energetics Based on the Representative Concentration Pathways Used in CMIP5
José Augusto P. Veiga,Tercio Ambrizzi
Advances in Meteorology , 2013, DOI: 10.1155/2013/485047
Abstract: So far, only a few studies have evaluated the impact of greenhouse gases emissions on the global and limited area energetics. Furthermore, all of them have concentrated on the increasing of CO2. As new climate projections are now available from a number of climate models under the MPI-ESR-MR experiment, the present study analyses the global and hemispherical energetics under the increase of greenhouse gas forcings that follow Representative Concentration Pathways (RCP26, RCP45, and RCP85). The results have shown a reduction in the LEC intensity as the concentration of greenhouse gases increases, with the RCP85 scenario generating the strongest decrease. For both global and hemispherical domains, zonal kinetic energy is the only energy reservoir which increases in a warmer environment, whereas the conversion between eddy kinetic energy and zonal kinetic energy ( ) is the only energy flux also experiencing an increase. A quantitative analysis of the inner processes involved in the conversion terms shows important changes in the horizontal and vertical eddy-transport of momentum and sensible heat. In the case of both vertical and horizontal eddy-transports of momentum play an important role in the increase of zonal kinetic energy for the global domain. 1. Introduction After Lorenz [1] has derived a set of equations to quantify the energy cycle for the whole atmosphere, many studies have applied the technique to quantify and understand the dynamical processes involved in the energetics of the planet (e.g., [2–9]) and those who are considering just a piece of the atmosphere (e.g., [10–19]). In particular, they differ from each other depending upon the purpose of use and the energetics formalism (space domain, time domain, and mixed space-time domain energetics, see [5]). As discussed in Lorenz [2] and Oort [4], although the absolute value produced by each technique differs from each other, the energy fluxes are qualitatively similar. In general, studies of energetics considering closed domain highlight the maintenance of the general circulation, while studies involving open domain stress the dynamics related to the life cycle of individual atmospheric disturbances. The increasing of greenhouse gas emissions has amplified the greenhouse efficiency effect by trapping more heat in the mid- and lower troposphere and consequently altering the atmospheric circulation pattern [20]. The consequences of this can be felt through the changes in a broad spatial and temporal-scale of disturbances around both hemispheres as observed in the cases of cyclones and
The Energy Cycle Associated to the Pacific Walker Circulation and Its Relationship to ENSO  [PDF]
José Augusto P. Veiga, Alexandre B. Pezza, Tercio Ambrizzi, V. Brahmananda Rao, Sergio H. Franchito, Marcos C. Yoshida
Atmospheric and Climate Sciences (ACS) , 2013, DOI: 10.4236/acs.2013.34065
Abstract:

In this paper we study the Lorenz energy cycle of the Walker circulation associated with ENSO. The robust formulation of the energetics allows drawing a clear picture of the global energy and conversion terms associated with the three dimensional domains appropriate to qualify the large scale transfers that influence, and are influenced by, the anomalies during ENSO. A clear picture has emerged in that El Nino and La Nina years have approximately opposite anomalous energy fluxes, regardless of a non-linear response identified in the potential energy fields (zonal and eddy). During El Ninos the tropical atmosphere is characterized by an increase of zonal available potential energy, decrease of eddy available potential energy and decrease of kinetic energy fields. This results in weaker upper level jets and a slowingdown of the overall Walker cell. During La Ninas reversed conditions are triggered, with an acceleration of the Walker cell as observed from the positive anomalous kinetic energy. The potential energy in the Walker circulation domain during the cold phase is also reduced. An equally opposite behavior is also experienced by the energy conversion terms according to the ENSO phase. The energetics-anomalous behavior seem to be triggered at about the same time when ENSO starts to manifest for both the positive and negative phases, suggesting a coupled mechanism in which atmospheric and oceanic anomalies interact and feed back onto each other.

A Space Domain Energetics Study for CO2 Increasing Based on SRES-A2 Emission Scenario
José Augusto P. Veiga,Tercio Ambrizzi,Alexandre B. Pezza
Advances in Meteorology , 2013, DOI: 10.1155/2013/697105
Abstract: This work presents a detailed investigation of the changes in the global pattern of energetics under a prescribed temporal evolution of CO2 concentration as proposed by the A2 IPCC forcing scenario (SRES-A2) using a combination of reanalysis and climate models. A validation climatology is computed using the classic Lorenz energetic formulation, with generation and dissipation components estimated as residuals. The results show a good agreement overall between models and reanalysis for the present day climate, noting that the models generally give more zonal energy and less eddy energy when compared to the reanalysis. Spatial analysis translates the above results as models depicting greater energy associated with the subtropical jet streams than effectively observed. This pattern is observed regardless of season or hemisphere. The projections for future climate scenarios suggest a further increase in the zonal kinetic energy, with a slight average reduction in all other terms. This pattern is seen in association with a substantial decrease in the conversion term mainly associated with sensible heat transport (CA) under a warmer climate. In agreement with recent work in the literature, our results suggest an overall reduction of the global energetics under increasing CO2. 1. Introduction Recent studies have shown that the tendency for planetary temperature increase observed in the 20th century has caused a global change on the earth-atmosphere energy balance and consequently altered the atmospheric disturbances behavior in a broad range of spatial and temporal scales. The cause of the changes has been majorly attributed to a gradual and continued increase of greenhouse gas emissions to the atmosphere [1–3]. According to the fourth IPCC report [4], the fossil fuel burning process, demanded by the human energy consumption, land use, and agricultural activities are anthropogenic components responsible for the CO2 concentration increasing, as well as NH4 and N2O (hereafter called GHGs). The rising of the GHGs atmospheric concentration amplifies the greenhouse effect efficiency by trapping more heat in the atmosphere, and as a consequence the atmosphere has its circulation pattern altered and adjusted to the additional heating as to establish a new equilibrium condition. However, the consequences for the atmospheric circulation patterns can be felt trough the changes in a broad spatial and temporal scale of eddy disturbances. For example, the author in [1] investigated the linear relation between the frequency of cyclones and anticyclones with the Northern
Projecting Extreme Changes in Summer Rainfall in South America by the Middle of the 21st Century  [PDF]
Paula Andrea M. Fonseca, José Augusto P. Veiga, Francis Wagner S. Correia, Adriane L. Brito, M?nica R. Queiroz, André A. Lyra, Sin Chan Chou
Atmospheric and Climate Sciences (ACS) , 2014, DOI: 10.4236/acs.2014.44067
Abstract:

Extreme rainfall events can be considered a natural manifestation of the environment in which they are embedded and foreknowledge about their future behavior is very important, especially for decision makers. In this context, we aimed to explore the future behavior of extreme rainfall intensity through numerical simulations with the ETA model. The model was forced with a scenario of high greenhouse gas emissions for the middle of the 21st Century as described for A1B emission scenario. We detailed the main changes in accumulated rainfall produced by heavy events, very heavy events and rare events over a broad area of South America with a focus on the tropical sector. The methodology applied here is capable of separating extreme events and establishing the quantity of rainfall yielded by them. We have found that in the near future (2041-2050) rare events will tend to increase over the Amazon basin, followed by reductions in heavy and very heavy events. Conversely, heavy, very heavy and rare events are expected to decline over north-east Brazil. Furthermore, increases were found for heavy, very heavy and rare events over southern Brazil.

Extreme Rainfall Events over the Amazon Basin Produce Significant Quantities of Rain Relative to the Rainfall Climatology  [PDF]
Adriane Lima Brito, José Augusto Paix?o Veiga, Marcos Cezar Yoshida
Atmospheric and Climate Sciences (ACS) , 2014, DOI: 10.4236/acs.2014.42021
Abstract:

Although much effort has been made to characterize and understand extreme rainfall’s causes and effects, little is known about their frequency and intensity. Moreover, knowledge about their contribution to the total rainfall climatology is still minimal, especially over the Amazon where rainfall data are very scarce. In this paper we propose to classify extreme rainfall events by type and analyze their frequency and intensity over South America with a focus on the Amazon basin. Gridded daily data from the MERGE/CPTEC product over a period of 15 years (1998–2013) was used. An adaptation of Rx5d climate index was applied to select different kinds of extreme rainfall for the purpose of quantifying their frequency and intensity as well as their contribution to the accumulated rainfall climatology. According to the results, all kinds of extreme rainfall events can be observed over the studied area. However, the quantity of rainfall produced by each type is different, and consequently their percent contributions to the total accumulated rainfall climatology also differ. For example: in the Amazon region EET-I is responsible for 15% - 40% of the total accumulated rainfall. Moreover, in the Brazilian northeast there are regions where EET-I exceeds 40% of the total rainfall. In northeast Brazil EET-II is responsible up to 30% of the total accumulated rainfall. EET-III is responsible for 5% - 15% in the Amazon basin, 25% - 45% in northeast Brazil and 10% - 45% over Roraima State. Area-mean time variation shows that the quantity of rainfall extremes over the Amazon basin was reduced during the El Nino years of 2002, 2005, 2007 and 2010, while during the La Ni?a episodes of 1999, 2008

Fundamentos conceituais da demonstra??o dos fluxos de caixa: significado, vantagens e limita??es. Algumas evidências
Braga, Roberto;Marques, José Augusto Veiga da Costa;
Caderno de Estudos , 1996, DOI: 10.1590/S1413-92511996000200002
Abstract: uma das discuss?es, ainda presente no cenário contábil nacional, diz respeito à suposta melhor qualidade da informa??o divulgada pela demonstra??o do fluxo de caixa em face à doar usual. neste sentido, as principais alega??es ressaltam sua relativa simplicidade e facilidade de interpreta??o no atendimento às necessidades dos usuários; em especial, aqueles externos à entidade. a exposi??o do confronto entre recebimentos e pagamentos oriundos das três atividades fundamentais do negócio - opera??es, financiamentos e investimentos - em principio, permitiria um melhor subsídio para as decis?es de investimento, haja vista sinalizar de modo mais claro e objetivo a situa??o de liquidez e solvência da empresa. todavia, a despeito de, presumivelmente, evitar rateios de custos e, assim, inibir a "maquilagem" dos relatórios financeiros, essa alega??o favorável à demonstra??o n?o se verifica na prática, uma vez que o relatório pode camuflar atrasos deliberados de pagamentos e antecipa??es planejadas de recebimento, com o beneficio de um exercício social em detrimento dos outros(s). em adi??o, a existência de discrepancias em alguns de seus itens integrantes, no tocante às varia??es mostradas no balan?o, parece representar uma desvantagem fundamental, notadamente por "violar" determinados princípios contábeis. seria conveniente que a provável substitui??o da doar resultasse em debates, sobretudo com a exposi??o das deficiências inerentes ao novo relatório contábil, que venha a substituí-lo.
Planos de incentivos baseados em op??es de a??es: uma exposi??o das distin??es encontradas entre as demonstra??es contábeis enviadas à CVM e à SEC
Nunes, Alexssander de Antonio;Marques, José Augusto Veiga da Costa;
Revista Contabilidade & Finan?as , 2005, DOI: 10.1590/S1519-70772005000200006
Abstract: stock option plans are one form of variable compensation in which the employee is given the opportunity to participate in the company as a stockholder. this kind of stimulus can mean advantages for employees and companies. accounting is responsible for measuring and disclosing the amounts involved. both fasb and iasb present specific rules in this respect. in brazil, this subject has been discussed in opinions and recommendations by cvm and ibracon. this article presents the foundations of stock options for employees and existing rules for the accounting treatment of these plans. 14 national publicly-traded companies were selected for the empiric study. the collected information demonstrates that there are differences between what is disclosed to regulators and the capital market in brazil and in the international context.
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