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The objective of this work was to characterize the soil cover in the western region of the Amazon (Rio Branco, Acre) in years of climatic contrasts (rainy, normal and dry). For this, a series of monthly precipitation data provided by the National Institute of Meteorology (INMET), from 1985 to 2014, was used. rainy year (2009) and a dry year (2005), using the Landsat 5-TM satellite platform of the National Institute for Space Research (INPE). The Normalized Difference Vegetation Index (NDVI) was calculated and the surface type categories were defined. These images were processed using open access software R 4.3. The results showed that 2005 was one of the driest years and 2009 was one of the rainiest. The year 2005 presented 66% of coverage with dense vegetation, while the year 2009 presented the highest percentage (87.4%), as a result of a considerable variation in the biomass of the forest in Rio Branco. Among the years analyzed, the drought that occurred in 2005 showed the highest percentages of sparse vegetation (29.8%) and exposed soil (4.1%). Therefore, the influence of precipitation in the region is reinforced, where in drier years (2005), there is a decrease in the resilience of the vegetation, which may have been intensified by the process of deforestation and/or fires.

O objetivo principal neste trabalho foi avaliar a estimativa da evapotranspiração pelo algoritmo SEBAL (surface energy balance algorithm for land) no semiárido brasileiro. Para isso foi feito um levantamento bibliográfico acerca do tema, para diagnosticar se há convergência sobre a eficiência da utilização do SEBAL na aplicação e planejamento dos recursos hídricos, fazendo-se análise comparativa de diversos estudos publicados no meio científico. Os principais resultados encontrados convergiram que o SEBAL é um bom método, pois o erro oscila suavemente comparado as estimativas convencionais, além de permitir larga escala geográfica, análise com alta resolução e baixo custo. Considera-se que o SEBAL, embora tenha limitações com interferências atmosféricas, pode ser utilizado, o que se recomenda é que admita a margem de erro e que se faça análises com séries históricas para validar estatisticamente os resultados.

The purpose of this study is to analyze the dynamic/thermodynamic features of the center and periphery of upper tropospheric cyclonic vortices (UTCV) in Northeast Brazil (NEB). An algorithm was developed to identify the vortex climatology using ERA-Interim, while rainfall impact was assessed using the Climate Prediction Center dataset, from 1980 to 2016. The algorithm was validated by comparison UTCV’s positions obtained by subjective analysis, showing good performance regarding positioning and seasonality. One of the preferential regions of UTCV occurrence was the semiarid region of NEB, which may indicate these systems have a strong influence on the water deficit in the region. Air subsidence and mass divergence at the center and upward motions and convergence on the periphery of the system were observed. Two conceptual skew-t diagrams were generated and the results bring a new perspective about UTCV thermodynamic features, some of which are: in the center, associated with subsidence, low convective available potential energy (CAPE) values and low humidity concentration were detected in a large atmospheric layer due to the subsidence generated by mass convergence at high levels. In contrast, the edge region presented high CAPE values and high atmospheric moisture content, related to the mass convergence in lower troposphere. The advances in knowledge about dynamic/thermodynamic characteristics of this meteorological system generate perspectives for better simulations, improving its predictability. In addition, the proposed algorithm is of great value for future climatological studies of UTCV.

We present a high-resolution air quality study over Sao Paulo, Brazil with the EURopean Air Pollution Dispersion - Inverse Model (EURAD-IM) used for the first time over South America simulating detailed features of aerosols. Modeled data are evaluated with observational surface data and a Lidar. Two case studies in 2016 with distinct meteorological conditions and pollution plume features show transport (i) from central South America, associated to biomass burning activities, (ii) from the rural part of the state of Sao Paulo, (iii) between the metropolitan areas of Rio de Janeiro and Sao Paulo (MASP) either through the Paraiba Valley or via the ocean, connecting Brazil's two largest cities, (iv) from the port-city Santos to MASP and also from MASP to the city Campinas, and vice versa. A Pearson coefficient of 0.7 was found for PM10 at MASP CENTER and EURAD-IM simulations vary within the observational standard deviation, with a Mean Percentual Error (MPE) of 10%. The model's vertical distributions of aerosol layers agree with the Lidar profiles that show either characteristics of long-range transported biomass burning plumes, or of local pollution. The distinct transport patterns that agree with satellite Aerosol Optical Death and fire spot images as well as with the ground-based observations within the standard deviations, allows us exploring patterns of air pollution in a detailed manner and to understand the complex interactions between local to long-range transport sources.

Although seasonally dry tropical forests are considered invaluable to a greater understanding of global carbon fluxes, they remain as one of the ecosystems with the fewest observations. In this context, ecological and ecosystem models can be used as alternative methods to answer questions related to the interactions between the biosphere and the atmosphere in dry forests. The objective of this study was to calibrate the simple tropical ecosystem model (SITE) and evaluate its performance in characterizing the annual and seasonal behavior of the energy and carbon fluxes in a preserved fragment of the Caatinga biome. The SITE model exhibited reasonable applicability to simulate variations in CO2 and energy fluxes (r &gt, 0.7). Results showed that the calibrated set of vegetation parameters adequately simulated gross primary productivity (GPP) and net ecosystem CO2 exchange (NEE). The SITE model was also able to accurately retrieve the time at which daily GPP and NEE peaked. The model was able to simulate the partition of the available energy into sensible and latent heat fluxes and soil heat flux when the calibrated parameters were used. Therefore, changes in the dynamics of dry forests should be taken into consideration in the modeling of ecosystem carbon balances.

The São Francisco River basin is one of the largest in the Brazilian territory. This basin has enormous economic, social and cultural importance for the country. Its water is used for human and animal supply, irrigation and energy production. This basin is located in an area with different climatic characteristics (humid and semiarid) and studies related to precipitation are very important in this region. In this scenario, the objective of this investigation is to present an assessment of rainfall estimated through the Integrated Multi-SatellitE Retrievals for Global Precipitation Measurement (IMERG) product compared with rain gauges over the São Francisco river basin in Brazil. For that, a period from of 20 years and 18 surface weather stations were used to evaluate the product. Based on different evaluation techniques, the study found that the IMERG is appropriate to represent precipitation over the basin. According to the results, the performance of the IMERG product depends on the location where the rain occurs. The bias ranged from −1.67 to 0.34 mm, the RMSE ranged from 5.36 to 10.36 mm and the values of the correlation coefficients between the daily data from the IMERG and rain gauge ranged from 0.28 to 0.61. The results obtained by Student t-test, density curves and regression analysis, in general, show that the IMERG is able to satisfactorily represent rain gauge data. The exception is the eastern portion of the basin, where the product, on average, underestimates the precipitation (p-value &lt, 0.05) and presents the worst statistical metrics.

Seasonally dry tropical forests are among the most important biomes regarding regional and global hydrological and carbon fluxes. Thus, the objective of this study was to evaluate the seasonal and interannual variability of evapotranspiration (ET) and its biophysical control and characteristics (surface conductance—Gs; decoupling coefficient—Ω; ratio between actual evapotranspiration and equilibrium evapotranspiration—ET/ETeq) in a preserved Caatinga Biome environment during two dry years in the Northeast Brazil region. A study on this subject with this level of detail in this biome is unprecedent. Measurements were carried out using an eddy covariance system during the period from 1st January 2014 to 31st December 2015. The lowest ET values were observed in the dry season of both experiment years (0.3 and 0.2 mm day−1) as a consequence of poor water availability, which favored partial stomatal closure and reduced Gs values (0.22 and 0.13 mm s−1). The opposite occurred in the wet season, when ET (2.6 and 1.7 mm day−1) and Gs (3.74 and 2.13 mm s−1) means reached higher values. Regarding annual values, differences between total annual rainfall in both years is the most probable cause for the differences observed in annual ET values. In 2014, annual ET was of 473.3 mm while in 2015 it was 283.4 mm, which incurred in an overall decrease in Gs, Ω and ET/ETeq values. Leaf senescence and extremely low Gs values during the dry season suggest that the trees of the Caatinga Biome are more resilient regarding the use of water and are avoiding water stress caused under low water availability

O excesso ou deficit de chuvas observados atraves das chuvas torrenciais e secas potencializam a situacao de pobreza vivenciada pelas populacoes que habitam na regiao Nordeste do Brasil onde localiza-se o Rio Grande do Norte. Uma consequencia da ocorrencia desses eventos e o possivel impacto adverso na saude dos seres humanos, com o aumento da incidencia das doencas endemicas. Objetiva-se nesse trabalho identificar areas susceptiveis as doencas consideradas clima-dependente, levando em consideracao regioes pluviometricamente homogenea no estado do Rio Grande do Norte. Os dados de saude utilizados no trabalho foram provenientes do Ministerio da Saude disponibilizados na pagina de internet do Sistema de Informacoes Hospitalares do SUS (SIH/SUS) do DATASUS. E os dados de precipitacao foram obtidos por meio de estimativas processadas por um metodo de MERGE no periodo de 2000 a 2016. Como o Rio Grande do Norte apresenta uma alta variabilidade climatica, optou-se por dividir o estado em regioes pluviometricamente homogeneas. Para a determinacao dessas regioes, utilizou-se da tecnica de Analise de Agrupamentos com a distância euclidiana, e o metodo de Ward, tendo-se como variavel a precipitacao acumulada de cada municipio. Utilizou-se tambem o teste de Analise de Variância para verificar se ha influencia da precipitacao nas taxas de internacao por grupos de causa consideradas clima-dependentes, segundo as regioes pluviometricamente homogenea. Os resultados obtidos mostraram a formacao de 4 distintos grupos (regiao 1, regiao 2, regiao 3 e regiao 4). Observou-se que a principal causa de internacao trata-se das doencas do aparelho respiratorio seguido das doencas infecciosas e parasitarias. Em relacao as regioes homogeneas, as regioes 1 e 2 revelaram as maiores taxas de internacao para doencas infecciosas e parasitarias e doencas respiratorias, porem, regiao 1 apresenta menores volumes de chuva, enquanto, a regiao 2 elevadas precipitacoes. Evidencia-se nos resultados a influencia do clima nos grupos de causas que se relacionam como doencas infecciosas e parasitarias, doencas respiratorias, circulatoria e digestiva.