Surface Albedo and Temperature Models for Surface Energy Balance Fluxes and Evapotranspiration Using SEBAL and Landsat 8 over Cerrado-Pantanal, Brazil.

The determination of the surface energy balance fluxes (SEBFs) and evapotranspiration (ET) is fundamental in environmental studies involving the effects of land use change on the water requirement of crops. SEBFs and ET have been estimated by remote sensing techniques, but with the operation of new sensors, some variables need to be parameterized to improve their accuracy. Thus, the objective of this study is to evaluate the performance of algorithms used to calculate surface albedo and surface temperature on the estimation of SEBFs and ET in the Cerrado-Pantanal transition region of Mato Grosso, Brazil. Surface reflectance images of the Operational Land Imager (OLI) and brightness temperature (Tb) of the Thermal Infrared Sensor (TIRS) of the Landsat 8, and surface reflectance images of the MODIS MOD09A1 product from 2013 to 2016 were combined to estimate SEBF and ET by the surface energy balance algorithm for land (SEBAL), which were validated with measurements from two flux towers. The surface temperature (Ts) was recovered by different models from the Tb and by parameters calculated in the atmospheric correction parameter calculator (ATMCORR). A model of surface albedo (asup) with surface reflectance OLI Landsat 8 developed in this study performed better than the conventional model (acon) SEBFs and ET in the Cerrado-Pantanal transition region estimated with asup combined with Ts and Tb performed better than estimates with acon. Among all the evaluated combinations, SEBAL performed better when combining asup with the model developed in this study and the surface temperature recovered by the Barsi model (Tsbarsi). This demonstrates the importance of an asup model based on surface reflectance and atmospheric surface temperature correction in estimating SEBFs and ET by SEBAL.

Ground and remote sensing-based measurements of leaf area index in a transitional forest and seasonal flooded forest in Brazil.

Leaf area index (LAI) is a key driver of forest productivity and evapotranspiration; however, it is a difficult and labor-intensive variable to measure, making its measurement impractical for large-scale and long-term studies of tropical forest structure and function. In contrast, satellite estimates of LAI have shown promise for large-scale and long-term studies, but their performance has been equivocal and the biases are not well known. We measured total, overstory, and understory LAI of an Amazon-savanna transitional forest (ASTF) over 3 years and a seasonal flooded forest (SFF) during 4 years using a light extinction method and two remote sensing methods (LAI MODIS product and the Landsat-METRIC method), with the objectives of (1) evaluating the performance of the remote sensing methods, and (2) understanding how total, overstory and understory LAI interact with micrometeorological variables. Total, overstory and understory LAI differed between both sites, with ASTF having higher LAI values than SFF, but neither site exhibited year-to-year variation in LAI despite large differences in meteorological variables. LAI values at the two sites have different patterns of correlation with micrometeorological variables. ASTF exhibited smaller seasonal variations in LAI than SFF. In contrast, SFF exhibited small changes in total LAI; however, dry season declines in overstory LAI were counteracted by understory increases in LAI. MODIS LAI correlated weakly to total LAI for SFF but not for ASTF, while METRIC LAI had no correlation to total LAI. However, MODIS LAI correlated strongly with overstory LAI for both sites, but had no correlation with understory LAI. Furthermore, LAI estimates based on canopy light extinction were correlated positively with seasonal variations in rainfall and soil water content and negatively with vapor pressure deficit and solar radiation; however, in some cases satellite-derived estimates of LAI exhibited no correlation with climate variables (METRIC LAI or MODIS LAI for ASTF). These data indicate that the satellite-derived estimates of LAI are insensitive to the understory variations in LAI that occur in many seasonal tropical forests and the micrometeorological variables that control seasonal variations in leaf phenology. While more ground-based measurements are needed to adequately quantify the performance of these satellite-based LAI products, our data indicate that their output must be interpreted with caution in seasonal tropical forests.

Macro-nutrientes no lençol freático em Floresta Intacta, Floresta de Manejo e Pastagem no norte de Mato Grosso / Macro-nutrients in the water sheet in Mature Forest, Management Forest and Pasture in the north of Mato Grosso

A remoção de uma cobertura florestal e sua substituição por outras formas de uso do solo tem sido uma constante no norte do estado de Mato Grosso podendo alterar os ciclos hidrológicos e biogeoquímicos dos ecossistemas. Neste contexto, o presente trabalho visou identificar a variação do fósforo e nitrogênio das águas do lençol freático em áreas de Floresta de Transição madura e intacta (Floresta Intacta), Floresta de Transição Manejada (Floresta Manejada) e Pastagem localizadas no norte de Mato Grosso. Foram realizadas mensalmente medidas do nível do lençol freático, de coletas de amostras de água para análises físico-químicas e medições de precipitação e temperatura do ar, no período de janeiro/2005 a novembro/2006. Verificou-se uma sazonalidade na precipitação e na temperatura do ar. No período de estiagem as águas do lençol freático apresentaram maiores teores de nitrogênio e de fósforo total nas três áreas em estudo. Os maiores valores de nitrogênio e fósforo foram detectados nos ecossistemas florestais (Florestas Intacta e Manejada) como indicativo da função da cobertura vegetal na ciclagem dos nutrientes.

Forest removal for other land uses has been a constant in the north of Mato Grosso and can alter the hydrological and biochemical cycles. In this context, the present work aims to identify the variation of phosphorus and nitrogen in the water sheet in areas of Mature Forest, Management Forest and Pasture in the north of Mato Grosso. The water level was measured monthly and water samples for analysis were collected monthly from January/2005 to November/2006. We verified the precipitation and the air temperature seasonality, and in the dry season the quality of the water sheet presented greater values of total phosphorus and total Kjeldhal nitrogen in the studied areas. The phosphorus and nitrogen presented greater values in forest ecosystems (Forest and Management Forest) as indicative of the function of the vegetal covering in the nutrient cycle.

Produção de serrapilheira no Cerrado e Floresta de Transição Amazônia-Cerrado do Centro-Oeste Brasileiro / Litterfall production in the Brazilian mid-western Amazonia-Cerrado transition forest

O presente trabalho teve como objetivo verificar a variação da produção de serrapilheira de diferentes biomas: Cerrado (com as fitofisionomias Cerrado sensu stricto e Cerradão) e Floresta de Transição Amazônia-Cerrado, em clima tropical. Para a determinação da produção de serrapilheira foram utilizados coletores de tela em náilon. Dados micrometereológicos foram coletados nas áreas de estudo. A produção de serrapilheira nos dois biomas mostrou acentuada sazonalidade, com as maiores produções ocorrendo durante a estação seca e menor durante a estação chuvosa. A maior produção de serrapilheira ocorreu na Floresta de Transição, seguida do bioma Cerrado. A fração de folhas foi mais representativa do que as frações de galhos, flores, frutos em ambas as áreas estudadas.

The objective of the present work was to verify the variation of litterfall production of different biomass: a cerrado ("savanna") with vegetation types Cerrado sensu stricto ("orchard-like vegetation") and Cerradão ("woodland-like vegetation") and Amazonia-Cerrado transition forest in a tropical climate. To determine the litterfall production, we used nylon screen traps. Micrometereologic data was collected in both areas of study. The litterfall in two biomass revealed themselves as seasonal, with the highest productions occurring during the dry season and the lowest during the wet. The biggest litterfall occurred in the Transition Forest, followed by the Cerrado biome. Leaf fraction was more representative than twigs, flowers, fruits in both areas studied.

[Study of the infection and morbidity of Chagas' disease in municipality of João Costa: National Park Serra da Capivara, Piauí, Brazil]. / Estudo da infecção e morbidade da doença de Chagas no município de João Costa: Parque Nacional Serra da Capivara, Piauí, Brasil.

In order to investigate aspects of the infection and morbidity of Chagas' disease in the municipality of João Costa, Piauí State, Brazil, we carried out a serological survey to detect anti-Trypanosoma cruzi antibodies in 2,080 individuals, by indirect immunofluorescence, indirect hemagglutination and ELISA. A total of 189 seropositive and 141 seronegative patients were evaluated by anamnesis, physical exam and electrocardiogram (EKG). The parasitaemia of 106 chagasic patients was evaluated by indirect xenodiagnosis and PCR (polymerase chain reaction). The total seropositivity was 9.8%, with intervals of 0.5% in patients younger than 10 years old, and 39.4% among patients older than 59 years old, independently of the sex. The PCR and xenodiagnosis were positive, respectively in 74.5% and 15.1% of the seropositive patients (p < 0.05). The rate of abnormal EKG was 41.3% in chagasic and 15.6% in non-chagasic patients (p < 0.05). In spite of the high prevalence of infection in the investigated population, the low rate of seropositivity among children is indicative of a possible decrease of the active transmission mediated by triatomines. The high proportion of the chagasic component on the cardiopathy prevalence is indicative of the high morbidity of Chagas' disease in the studied region.

Estudo da infecção e morbidade da doença de Chagas no municÝpio de João Costa: Parque Nacional Serra da Capivara, Piauí, Brasil / Study of the infection and morbidity of Chagas' disease in municipality of JoÒo Costa: National Park Serra da Capivara, Piauí, Brazil

In order to investigate aspects of the infection and morbidity of Chagas' disease in the municipality of JoÒo Costa, PiauÝ State, Brazil, we carried out a serological survey to detect anti-Trypanosoma cruzi antibodies in 2,080 individuals, by indirect immunofluorescence, indirect hemagglutination and ELISA. A total of 189 seropositive and 141 seronegative patients were evaluated by anamnesis, physical exam and electrocardiogram (EKG). The parasitaemia of 106 chagasic patients was evaluated by indirect xenodiagnosis and PCR (polymerase chain reaction). The total seropositivity was 9.8, with intervals of 0.5 in patients younger than 10 years old, and 39.4 among patients older than 59 years old, independently of the sex. The PCR and xenodiagnosis were positive, respectively in 74.5 and 15.1 of the seropositive patients (p < 0.05). The rate of abnormal EKG was 41.3 in chagasic and 15.6 in non-chagasic patients (p < 0.05). In spite of the high prevalence of infection in the investigated population, the low rate of seropositivity among children is indicative of a possible decrease of the active transmission mediated by triatomines. The high proportion of the chagasic component on the cardiopathy prevalence is indicative of the high morbidity of Chagas' disease in the studied region.

Doença de Chagas na populaçäo urbana do distrito sanitário de Rio Verde, Mato Grosso do Sul, Brasil / Chagas'disease on urban population of the sanitarian district of Rio Verde, Mato Grosso do Sul State, Brazil

Com o objetivo de avaliar alguns aspectos da doença de Chagas na populaçáo urbana dos 12 municipíos do distrito sanitário de Rio Verde, Mato Grosso do Sul em 1998 realizamos a pesquisa de IgG anti-T.cruzi pela imunofluorescência indireta em amostras de sangue obtidas em papel de filtro de 14.709 moradores, com posterior confirmação pelos testes de hemaglutinação indireta e ELISA em soros. A parasitemia foi avaliada por xenodiagnóstico indireto em 134 chagásicos crônicos e a cardiopatia por anamnese, exame físico e eletrocardiograma (ECG) em 19l pares de chagásicos/não-chagásicos. No total os resultados mostraram: soropositividade de 1,83 por cento (0,93 por cento em autóctones e 5,01 por cento em alóctones), positividade do xenodiagnóstico de 17,2 por cento (12,3 por cento em autóctones e 20,8 por cento em alóctones) e proporção de cardiopatia chagásica crônica de 24,6 por cento (19,1 por cento em autóctones e 27,8 por cento em alóctones). A análise dos dados indicou a população de alóctones como a principal responsável pelas características da infecção e morbidade da doença de Chagas na área estudada