ENSO effects on the relationship between aerosols and evapotranspiration in the south of the Amazon biome.

The effects of the El Nino-Southern Oscillation (ENSO) events have local, regional, and global consequences for water regimes, causing floods or extreme drought events. Tropical forests are strongly affected by ENSO, and in the case of the Amazon, its territorial extension allows for a wide variation of these effects. The prolongation of drought events in the Amazon basin contributes to an increase in gas and aerosol particle emissions mainly caused by biomass burning, which in turn alter radiative fluxes and evapotranspiration rates, cyclically interfering with the hydrological regime. The ENSO effects on the interactions between aerosol particles and evapotranspiration is a critical aspect to be systematically investigated. Therefore, this study aimed to evaluate the ENSO effect on a site located on the southern portion of the Amazonian region. In addition to quantifying and testing possible differences between aerosols and evapotranspiration under different ENSO classes (El Niño, La Niña and Neutrality), this study also evaluated possible variations in evapotranspiration as a function of the aerosol load. A highly significant difference was found for air temperature, relative humidity and aerosol load between the El Niño and La Niña classes. For evapotranspiration, significant differences were found for the El Niño and La Niña classes and for El Niño and Neutrality classes. Under the Neutrality class, the aerosol load correlated significantly with evapotranspiration, explaining 20% of the phenomenon. Under the El Niño and La Niña classes, no significant linear correlation was found between aerosol load and evapotranspiration. However, the results showed that for the total data set, there is a positive and significant correlation between aerosol and evapotranspiration. It increases with a quadratic fit, i.e., the aerosol favors evapotranspiration rates up to a certain concentration threshold. The results obtained in this study can help to understand the effects of ENSO events on atmospheric conditions in the southern Amazon basin, in addition to elucidating the role of aerosols in feedback to the water cycle in the region.

Hourly seasonal variability of thermal properties in haplic gleysol in northern of pantanal / Variabilidade sazonal horária das propriedades térmicas em gleissolo háplico no norte do pantanal

Researches about thermal dynamics of the wetlands soil has not been explored in order to have a better understanding of this dynamic in the region, making it necessary studies to explain their properties in order to contribute to the understanding of this biome. Thus, this study examined the variability of the average soil heat flow through a characteristic day of each season: rainy and dry, the region has a seasonal flood pulse and rainfall, affecting the exchange of energy between the surface and atmosphere. It was made analysis of the influence of thermal conductivity and thermal gradient in the values of heat flow in soil. It was observed variability of soil thermal components followed the flood pulse of the Pantanal region, because presence of water was essential for the seasonal variation of soil heat flux, temperature gradient and thermal conductivity of soil in the Pantanal.

Pesquisas envolvendo a dinâmica térmica do solo pantaneiro ainda não foram exploradas de forma que se tenha um maior conhecimento dessa dinâmica na região, tornando-se necessário estudos que discutam suas propriedades térmicas, de forma a contribuir com o entendimento desse bioma. Dessa maneira, o presente trabalho analisou a variabilidade média do fluxo de calor no solo de um dia característico de cada período: chuvoso e seco, uma vez que a região apresenta uma sazonalidade no pulso de inundação e pluviosidade, afetando as trocas de energia entre a superfície e a atmosfera. Foi feita uma análise da influência da condutividade térmica e do gradiente térmico nos valores do fluxo de calor no solo. Observou-se que a variabilidade dos componentes térmicos do solo acompanhou o pulso de inundação da região pantaneira, pois a presença de água foi determinante na variação sazonal do fluxo de calor no solo, do gradiente de temperatura e da condutividade térmica do solo no Pantanal.

Hourly seasonal variability of thermal properties in haplic gleysol in northern of pantanal / Variabilidade sazonal horária das propriedades térmicas em gleissolo háplico no norte do pantanal

Researches about thermal dynamics of the wetlands soil has not been explored in order to have a better understanding of this dynamic in the region, making it necessary studies to explain their properties in order to contribute to the understanding of this biome. Thus, this study examined the variability of the average soil heat flow through a characteristic day of each season: rainy and dry, the region has a seasonal flood pulse and rainfall, affecting the exchange of energy between the surface and atmosphere. It was made analysis of the influence of thermal conductivity and thermal gradient in the values of heat flow in soil. It was observed variability of soil thermal components followed the flood pulse of the Pantanal region, because presence of water was essential for the seasonal variation of soil heat flux, temperature gradient and thermal conductivity of soil in the Pantanal.

Pesquisas envolvendo a dinâmica térmica do solo pantaneiro ainda não foram exploradas de forma que se tenha um maior conhecimento dessa dinâmica na região, tornando-se necessário estudos que discutam suas propriedades térmicas, de forma a contribuir com o entendimento desse bioma. Dessa maneira, o presente trabalho analisou a variabilidade média do fluxo de calor no solo de um dia característico de cada período: chuvoso e seco, uma vez que a região apresenta uma sazonalidade no pulso de inundação e pluviosidade, afetando as trocas de energia entre a superfície e a atmosfera. Foi feita uma análise da influência da condutividade térmica e do gradiente térmico nos valores do fluxo de calor no solo. Observou-se que a variabilidade dos componentes térmicos do solo acompanhou o pulso de inundação da região pantaneira, pois a presença de água foi determinante na variação sazonal do fluxo de calor no solo, do gradiente de temperatura e da condutividade térmica do solo no Pantanal.

Utilização da análise de FOURIER no estudo de variáveis micrometeorológicas de uma floresta de transição do norte de Mato Grosso

In this work, we employed data collected in a transition forest, on the Maracaí farm, northwest of Sinop, MT, Brazil. The data was obtained by the eddy covariance method, using equipment installed on a 42m high tower. Its main purpose was to study the potentialities of Fourier analysis applied to data of latent (H) and sensible (Le) heat flux and the air temperature (T). We investigated the main frequencies presented by the data, and obtained mean values for the variables corresponding to every 3 hours, between 1999 and 2005. The main periods obtained with the Fourier method were 24; 12; 4 and 3.4 hours. The first two are attributed to the solar radiation and to the Earth rotation. The last two periods, as indicated by the data, are related to stomata dynamics. In this way, the results indicate that the main factors that predominantly influence the microclimatological variables during the day (frequencies between 10-5 a 10-4 Hz), were the solar radiation and the stomata dynamics. These results reinforce the importance of employing the Fourier method in studying microclimatic dynamics of ecosystems.

Este trabalho foi realizado utilizando dados coletados em uma Floresta de Transição, em uma área pertencente à Fazenda Maracaí no Noroeste de Sinop, MT, com dados micrometeorológicos obtidos com o sistema de correlação de vórtices turbulentos (Eddy Covarience) instalado numa torre de 40 metros. Teve como objetivo principal estudar as potencialidades da análise de Fourier aplicada a dados de fluxo de Calor Latente (LE), Calor Sensível (H) e Temperatura (T). Para os cálculos foram feitas médias de 3 em 3 horas para cada mês, ao longo do período de 1999 a 2005, para as variáveis estudadas. Os períodos dominantes encontrados foram de 24; 12; 4 e 3,4 horas. Os dois primeiros são atribuíveis ao movimento de rotação da Terra, ou seja, à periodicidade dia/noite. Quanto aos dois períodos menores, há indícios que estão relacionados com a dinâmica de abertura dos estômatos. Assim sendo, os resultados deste trabalho indicam que os fatores que influenciam predominantemente as variáveis microclimatológicas durante o dia (freqüências entre 10-5 a 10-4 Hz) são a radiação solar e a dinâmica de abertura dos estômatos, um resultado que destaca as potencialidades da aplicação do método de Fourier no estudo da dinâmica de microclimas em ecossistemas.