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The objective of this study was to propose bioclimatic zoning to classify human thermal comfort and discomfort in the state of Minas Gerais, Brazil; both historical and future scenarios are considered. Thus, historical series (1961 to 2017) of the effective temperature index as a function of the wind (ETW) were obtained as a function of the monthly average values of the minimum, mean, and maximum dry-bulb air temperatures (tdb,min, tdb,mean, and tdb,max, respectively), in addition to the mean relative humidity (RH , %) and mean wind speed (V , m s −1). The data were obtained from 34 weather stations and subjected to trend analysis by using the nonparametric Mann–Kendall test, thus enabling the simulation of future scenarios (for 2028 and 2038). Then, to define the thermal ranges of the bioclimatic zoning, maps of ETWmin, ETWmean, and ETWmax were created from geostatistical analysis. Overall, the results show warming trends for the upcoming years in Minas Gerais municipalities. All climatic seasons showed an increase in the frequency of new classifications in the upper adjacent classes, which indicates climate warming. Therefore, when considering future scenarios for the autumn and winter seasons, attention should be given to changes in predicted thermal sensation, especially in the Central Minas Gerais, Belo Horizonte Metropolitan, South/Southwest Minas, Campo das Vertentes, and Zona da Mata. [ABSTRACT FROM AUTHOR]

Interactions between land use and cover and a basin hydrological regime are complex and dynamics. The identification of trends and changes in rainfall and flow regimes in a region is relevant in water resources planning and management so that environmental, economic and social adversities are avoided. Thus, this study aims to identify possible trends in the historical series of rainfall and fluviometric stations in Rio das Mortes basin, Minas Gerais, Brazil, as well as to relate the modifications in the flow rate behaviour due to changes in land use and cover in the basin between the years of 1985 and 2017. For that, hydrological data were used from the Ibituruna-MG river station and 12 rainfall stations and orbital images from Landsat-5 and Sentinel satellites. Flow rate and precipitation behavior were performed using the nonparametric Mann-Kendall test and the Pettitt's test, while the land use and cover classification was performed in an eCognition Developer® 64 environment. Significant trends were observed in the average of total annual rainfall series and decreasing trends in the average of monthly flow rate series of lowest runoff over the years 1925 to 2014. There were changes in land use and cover in the studied region, however, these were not significant enough to modify the hydrological regime of Rio das Mortes basin during the analysed period. [ABSTRACT FROM AUTHOR]

Severe defoliation of mangrove species is reported in several parts of the world. We analyzed the effect of a severe defoliation event resulting from the attack of a lepidopteran caterpillar (an insect outbreak) on the litterfall production. The attack occurred between 2009 and 2010 in a mangrove in southeastern Brazil. Leaf litter production by different mangrove species between 2008 and 2019, was considered in the analysis. The infestation directly affected the species Avicennia schaueriana Stapf & Leechm in all physiographic types assessed, with a decrease in leaf litter production between 43% and 86% since the monitoring began (2009) until the year when defoliation reached the maximum (2011). A decrease in the impact of defoliation was observed along the tidal flooding gradient, with more pronounced effects in forests located in the transition zone with the salt-flat, and progressive decrease towards fringe forests. In fringe and basin forests, leaf litter production by Laguncularia racemosa (L.) decreased between 52% and 67% between 2009 and 2011, respectively, and increased 30% in transition forests. Contrarily, the contribution of Rhizophora mangle (L.) increased 7% in basin, became noticeable in transition, and decreased by 25% in the fringe forests. The time required for A. schaueriana to recover the level of debris production was 8 years, and still reflect the effect of the severe, selective defoliation process on the dynamics and ecological succession of mangrove forests. A model that determines the stages of defoliation and their direct and indirect impacts on litter was developed. • The Insect infestation directly affected the species Avicennia schaueriana. • Losses varied between 43% and 96% of the leaf litter production. • The level of impact of the infestation was dependent on the physiographic types. • Herbivory may change facilitative or competitive processes in mangrove systems. [ABSTRACT FROM AUTHOR]

ABSTRACT: This study examines the spatial and temporal surface (10 m) wind speed trend characteristics of Brazil during 1980–2014 using two in situ and three climate reanalysis datasets. Nonparametric regression is used to understand how mean seasonal and annual wind speeds change over space and time across Brazil. Overall temporal linear trends show that station and reanalysis products exhibit varying seasonal and annual wind speed trends. A geographic examination displays statistically significant (P < 0.05) positive (negative) mean wind speed trends for equatorial (southeastern and central) Brazil. Quantile regression is performed to interpret how wind speed changed across different percentiles. Results show that the largest positive and negative spatial wind speed trends occur for the upper percentiles (75 and 95%). The spatial and temporal trends and correlations described could be interconnected to possible changes developing with the location of Intertropical Convergence Zone and South Atlantic Anticyclone over the study region. Results have implications for optimizing renewable wind energy production and development across Brazil. [ABSTRACT FROM AUTHOR]

The main source of electricity in Brazil is from hydro, which has about 65.2% share of the country’s electric energy matrix. However, over the last decade the wind energy increased from 19 MW to 2.2 GW. Since wind is an intermittent energy source, heavily determined by the weather and climatic conditions, and important effects on wind power generation can be expected in the mid and long term, in particular related to the impacts of extreme winds. The IPCC AR5 (Intergovernmental Panel on Climate Change) indicates changes in wind speed at the surface in some regions of the world, and increased wind strength in mid-latitude regions. This study scrutinizes future scenarios of extreme winds in Brazil by applying trend analysis techniques on a 50-year historical series of observational wind speed and meteorological parameters at 10 m height in Brazil. Embracing techniques of cluster analysis it was possible to characterize six main regions with macro climatic similarities. To assess the goodness fit distribution, we designate two stations per homogenous region, taking as criteria the stations with better performance in the qualification process to determine the wind distribution pattern in each region applying the Kolmogorov-Smirnov test (KS) and the lowest standard error (SE). After evaluating the frequency distribution of wind speed, the best fit result for the frequency distribution of maximum wind speed is the Gumbel model. The analysis of climatic trends performed by Mann-Kendall test revealed that in minimum wind speed series is not conclusive because it shows disparate results between homogeneous regions. On the other hand, the analysis of climatic trends of maximum wind speed presents 100% positive trends in Group#1, an equal number of stations with not significant trends and positive trends for Group#2, 36.8% more stations with positive trends than negative trends for Group#3 and 20% of stations with more negative trends than stations with positive trends for Group#4. This way, based in these results, is possible assert that there are an increase in the maximum extreme wind in Brazil, mainly in mid-latitudes. [ABSTRACT FROM AUTHOR]

Using the Shannon entropy, the space–time variability of rainfall and streamflow was assessed for daily rainfall and streamflow data for a 10-year period from 189 stations in the northeastern region of Brazil. Mean values of marginal entropy were computed for all observation stations and entropy maps were then constructed for delineating annual and seasonal characteristics of rainfall and streamflow. The Mann-Kendall test was used to evaluate the long-term trend in marginal entropy as well as relative entropy for two sample stations. The marginal entropy values of rainfall and streamflow were higher for locations and periods with the highest amounts of rainfall. The entropy values were higher where rainfall was higher. This was because the probability distributions of rainfall and the resulting streamflow were more uniform and less skewed. The Shannon entropy produced spatial patterns which led to a better understanding of rainfall and streamflow characteristics throughout the northeastern region of Brazil. The total relative entropy indicated that rainfall and streamflow carried the same information content at annual and rainy season time scales. [ABSTRACT FROM AUTHOR]

A comprehensive dataset of daily rainfall covering the period from 1972 to 2002 was used to compute the climatology and trend of occurrence and intensity of heavy, weak and normal events of rainfall on Northeast Brazil (NEB). For selection of rainfall events, we used the technique of quantiles and the trend was identified using the nonparametric Mann-Kendall test. The heavy events are modulated by La Niña and El Niño occurrences and in general they presented negative trend concerning to number of episodes and positive trend to daily rainfall. [ABSTRACT FROM AUTHOR]

Abstract: The database from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) re-analysis project available for the period from 1948 to 2009 was used for obtaining long-term solar radiation for northeastern Brazil. Measurements of global solar radiation (Rs ) from data collection platform (DCP) for four climatic zones of northeastern Brazil were compared to the re-analysis data. Applying cluster analysis to Rs from database, homogeneous sub-regions in northeastern Brazil were determined. Long times series of Rs and sunshine duration measurements data for two sites, Petrolina (09°09′S, 40°22′W) and Juazeiro (09°24′S, 40°26′W), exceeding 30years, were analyzed. In order to exclude the decadal variations which are linked to the Pacific Decadal Oscillation, high-frequency cycles in the solar radiation and sunshine duration time series were eliminated by using a 14-year moving average, and the Mann–Kendall test was employed to assess the long-term variability of re-analysis and measured solar radiation. This study provides an overview of the decrease in solar radiation in a large area, which can be attributed to the global dimming effect. The global solar radiation obtained from the NCEP/NCAR re-analysis data overestimate that obtained from DCP measurements by 1.6% to 18.6%. Results show that there is a notable symmetry between Rs from the re-analysis data and sunshine duration measurements. [ABSTRACT FROM AUTHOR]