Search

In the modern world, electric energy plays a pivotal role in sustaining life and driving technological, scientific, and human development. Consequently, the selection and availability of the energy sources used for electricity generation have become crucial elements of strategic planning for countries and economic blocks. Moreover, the impact of these choices extends beyond the mere energy demand/supply, affecting economies, societies and the environment across geographical boundaries. This study delves into the various factors influencing the composition and the recent expansion of the European electricity mix. It explores the interplay of environmental, climatic, political, economic, and external factors that shape Europe's energy choices. To conduct this analysis, we utilized data from the International Energy Agency on electricity generation and GHG emissions. Data mining techniques were employed to uncover patterns and trends in the monthly data from 2010 to 2022, from which political and economic milestones such as the shutdown of nuclear power plants and the European Union's increased reliance on natural gas imports from Russia were examined. The study also discusses the impact of using natural gas for power generation on increasing GHG emissions. Ultimately, this research reveals that the European Union choices in transitioning towards a cleaner electricity mix have not yet proven efficient. In fact, these choices may have inadvertently created favorable conditions for Russia's invasion of Ukraine, triggering, not only a humanitarian crisis, but also an economic downturn in Europe due to soaring energy prices. This crisis could potentially extend beyond Europe and impact the whole planet in 2023 and on, including developing countries that rely on stable energy prices for their sustainable growth. [ABSTRACT FROM AUTHOR]

The South Atlantic Convergence Zone (SACZ) is an atmospheric phenomenon, typical of summertime, in which a band of nebulosity may cause intense or persistent rainfall in many regions of Brazil. The association between this natural event and human interventions is a major factor for the occurrence of social and environmental impacts such as floods, flash floods, inundations, and landslides. In this work, we objectively quantify the relationship between the SACZ and the incidence of natural hazards in Southeast Brazil from 1995 to 2016. We use official records of disasters, from the digital archive of the Integrated Disaster Information System (S2ID) and time series of SACZ events, to calculate conditional probabilities of SACZ events, given the occurrence of disasters in the states of Southeast Brazil. We also analyze which types of natural disaster are most prevalent during SACZ events. The average probability of disaster occurrence, given the presence of the SACZ in the Southeast Brazil, is 24%, while the average conditional probability of SACZ occurrence, given a disaster in the Southeast, is 48%. For each state in Southeast Brazil, the probabilities are higher for Espírito Santo (60%), followed by Minas Gerais (50%), Rio de Janeiro (40%) and São Paulo (31%). These results evidence the vulnerability of Southeast Brazil associated with intense or persistent rainfall typical of the SACZ phenomenon. [ABSTRACT FROM AUTHOR]

To avoid crop failures and soaring power costs, Brazil needs to diversify sources, monitor soil moisture, model local hydroclimate dynamics and treat water as a national security priority. [ABSTRACT FROM AUTHOR]

In January 2011, the Mountainous Region of Rio de Janeiro state underwent one of the largest natural hazards in Brazil, affecting more than 300,000 people, causing more than 900 dead and irreparable human losses and enormous economic losses. From a hydrometeorological point of view, for the prevention of this type of disaster, alert systems are used worldwide, seeking to anticipate these phenomena by issuing warnings to the population, using tools such as hydrometeorological monitoring and modeling. This study evaluated the applicability of the hydrological soil moisture accounting procedure (SMAP) model with daily discretization as a flood prevention tool in Brazil. It was done by adjusting sub-watershed parameters in the semiautomatic calibration process, inserting observed data of precipitation and stream flow, as well as evapotranspiration in the calibration of the model, between 2008 and 2010. The model was validated twice, between the years of 2011 and 2013, and during the disaster period. The results show that the efficiency coefficient reached in the calibration stage was 1.713, with a relative error of 12% between the calculated and the observed stream flow, and in the validation, the results were 1.401 and 28%, respectively. In the validation of the disaster, the calculated stream flow was overestimated, with an average relative error of 53%. Flash flood prevention through the use of the daily SMAP model has shown promise for use in operational centers. [ABSTRACT FROM AUTHOR]

The South Atlantic Convergence Zone (SACZ) plays a key role in the South American monsoon system (SAMS) precipitation regime, and accounts for around 25% of the rainfall volume over Southeast Brazil between October and April, on average, with peaks of 56% in March and 41% in January. Due to its often varying position and multi-variable structure, diagnosing or quantifying SACZ episodes may lie on subjective criteria. The present study provides a climatological characterization of different SACZ types, based on their position, and differences in dynamics analysed from 19 SAMS wet periods. A cycle in SACZ configurations is identified during the rainy season: northernmost (southernmost) episodes are more likely to occur during the onset/demise (peak) months of the SAMS. Objective SACZ indices are developed taking the principal components of the dynamics of the SACZ as explanatory variables, not including precipitation. The most sensitive threshold proposed for the identification of mean SACZ type yields simultaneous true positive rate of 86%, false alarm rate of 28%, true negative rate of 72% and false negative rate of 15%, for example. The indices have potential to bring gains in predictability to SACZ-related precipitation in Southeast Brazil, apart from allowing the objective diagnosis of SACZ episodes. The indices are also correlated with the South American precipitation dipole and may be used to identify anomalous SAMS precipitation at longer time scales as well. [ABSTRACT FROM AUTHOR]

This paper aims to validate inflow simulations concerning the present-day climate at Água Vermelha Hydroelectric Plant (AVHP—located on the Grande River Basin) based on the Soil Moisture Accounting Procedure (SMAP) hydrological model. In order to provide rainfall data to the SMAP model, the RegCM regional climate model was also used working with boundary conditions from the MIROC model. Initially, present-day climate simulation performed by RegCM model was analyzed. It was found that, in terms of rainfall, the model was able to simulate the main patterns observed over South America. A bias correction technique was also used and it was essential to reduce mistakes related to rainfall simulation. Comparison between rainfall simulations from RegCM and MIROC showed improvements when the dynamical downscaling was performed. Then, SMAP, a rainfall-runoff hydrological model, was used to simulate inflows at Água Vermelha Hydroelectric Plant. After calibration with observed rainfall, SMAP simulations were evaluated in two different periods from the one used in calibration. During calibration, SMAP captures the inflow variability observed at AVHP. During validation periods, the hydrological model obtained better results and statistics with observed rainfall. However, in spite of some discrepancies, the use of simulated rainfall without bias correction captured the interannual flow variability. However, the use of bias removal in the simulated rainfall performed by RegCM brought significant improvements to the simulation of natural inflows performed by SMAP. Not only the curve of simulated inflow became more similar to the observed inflow, but also the statistics improved their values. Improvements were also noticed in the inflow simulation when the rainfall was provided by the regional climate model compared to the global model. In general, results obtained so far prove that there was an added value in rainfall when regional climate model was compared to global climate model and that data from regional models must be bias-corrected so as to improve their results. [ABSTRACT FROM AUTHOR]

In the last years, natural hazards related to flash floods have caused serious damage and losses to the population of the state of Rio de Janeiro. This research discusses the importance of implementing a methodology for the prevention of flash floods, by comparing the methods applied since 2013 in the city of Duque de Caxias, in the Baixada Fluminense region of the state of Rio de Janeiro, Brazil, and the major prevention actions suggested by the Flash Flood Early Warning System Reference Guide from the National Oceanic and Atmospheric Administration, questioning civil defense professionals about the importance of each method to vulnerable communities. Even without the occurrence of an extreme event that proves the effectiveness of the method between 2014 and 2016, the population will certainly be better prepared to face the risks of disasters in the city in the future. In addition, the study also underscores an approach of approximation between academic studies and operational activities, which is still very incipient in Brazil. [ABSTRACT FROM AUTHOR]

The South American monsoon system (SAMS) plays a fundamental role in the precipitation regime of the most populous and economically important regions in Brazil. The South Atlantic Convergence Zone (SACZ) is a main component of the SAMS, characterizing its active phase, and is often associated with intense rainfall events: Strong and persistent episodes cause severe floods and landslides, while weak and sparse episodes are associated with droughts. The variability of the convergence zone caused great natural disasters in Southeast Brazil, associated with extreme precipitation conditions: 3562 landslides killed 947 people in Rio de Janeiro state in 2011, while a shortage of water in São Paulo affected around 20 million people between 2014 and 2015. In the present study, we build SACZ configuration series for the period between January 2000 and June 2014 and use them as indicators for the SAMS to quantify its influence on several atmospheric variables. Based on a principal component analysis, we present indices that identify the configuration of the SACZ in a local scale. The indices reached strong accuracy rates, especially for identifying days of extreme rainfall events associated with the SAMS and may, thus, serve as decision-making tools to help prepare for their impacts. Furthermore, the indices are composed by common variables simulated by numerical weather and climate models, other than precipitation, which is often a not very reliable output. The applied methodology is easily reproducible and different variables may be used to compose indices for different regions-an advantage of this local-scale approach. [ABSTRACT FROM AUTHOR]