Cléo Quaresma Dias-Júnior

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• PhD
• Professor at Federal Institute of Education, Science and Technology of Pará

The occurrence of coherent structures (CS) above the Amazon forest is analyzed. To perform this study, a large eddy simulation (LES) model is used, which has been improved by the introduction of a drag force which is representative of a typical Amazon forest canopy. The results show that the flow is sensitive to the presence of canopy and an inflex...

The structure of atmospheric turbulence is analyzed based on the existence of three different night-time turbulent regimes observed in the Amazon forest, classified according to Sun's criteria: regime 1: weak turbulence, low wind speed; regime 2: strong turbulence, with high wind speed, and regime 3: intermittent turbulence events. Next, we have in...

The main objective of this work is to better understand the increase of ozone (O3) in the surface by the influence of density currents formed by downdrafts from mesoscale convective systems, using as tool the JULES-CCATTBRAMS model. Initially, the superficial increases of O3 were investigated with the ECMWF Era-Interim reanalysis that showed a plum...

On the basis of measurements over different surfaces, an inertial sublayer (ISL), where Monin-Obukhov Similarity Theory (MOST) applies, exists above z = 3h, where h is canopy height. The roughness sublayer (RSL) is within h < z < 3h. Most studies of the surface layer (SL) above forests, however, are able to probe only a narrow region above h. There...

The goal of this work is to compare the main air turbulence characteristics of two common areas in the Amazonian landscape: a dense forest (rough surface) and a water surface (smooth surface). Using wind components data collected at high frequency by sonic anemometers located just above these surfaces, turbulence intensity and power spectra, tempor...

RESUMO Tornados são intensos vórtices atmosféricos produzidos por tempestades convectivas, capazes de produzir significativos danos sócio-econômicos. No Brasil, tais fenômenos ocorrem mais comumente ao sul de 20°S, em especial, nos estados do sul do país, porém ocasionalmente ocorrem ao norte desta latitude. Nas últimas duas décadas, o número de es...

In central Amazonia, aerosol sources, weather, and chemical processes create a highly variable aerosol population. The aerosols' optical properties, shaped by composition and size, determine sunlight interaction and the regional radiation budget. Previous studies observed differences in the particles' physical properties during smoke events and des...

Long-term and high-precision measurements of the mole fraction of greenhouse gases (GHG), together with their isotopic composition, are of fundamental importance to understand land-atmosphere interactions. Current flask monitoring programs have important information gaps in large regions of the Earth, particularly in the southern hemisphere and in...

The planetary boundary layer height (zi) is a key parameter in meteorology and climatology, influencing weather prediction, cloud formation, and the vertical transport of scalars and energy near Earth's surface. This study compares multiple machine learning (ML) models that predict zi from surface measurements at two sites in Central Amazonia—the A...

Studies on Convective Boundary Layer Height (CBLH) variability within the Amazon region are scarce. An alternative to obtaining CBLH values is to use reanalysis data, such as ERA5. This study used in situ temperature, humidity, and CO2 vertical profiles collected from 2010 to 2018 by small aircraft carried out within the scope of the CARBAM project...

Amazon forests play a significant role in the global C cycle by assimilating large amounts of CO2 through photosynthesis and by storing C largely as biomass and soil organic matter. To evaluate the net budget of C in the Amazon, we must also consider the amplitude and timing of losses of C back to the atmosphere through respiration and biomass burn...

In 2023, the biogeographic Amazon experienced temperature anomalies of 1.5°C above the 1991-2020 average from September to November. These conditions were driven by high sea surface temperature in the Atlantic and Pacific oceans, together with reduced moisture advection from the Atlantic, causing large vapor pressure and water deficits in the secon...

Data from three different heights (35, 50 and 81 meters) of one of the ATTO Project towers in the Amazon forest were used to calculate the TKE (turbulence kinetic energy) budget and some other statistics within the RSL (roughness sublayer). In addition, the results obtained from the data were compared with large eddy simulation (LES). The analyses...

The equation of turbulence kinetic energy (TKE) quantifies the intensity of turbulence, the mechanisms generating it, transporting it, and dissipating it. Given the well-known difficulty in applying Monin-Obukhov Similarity Theory in the roughness sublayer, the development of new approaches to understand the flow in this region of the atmosphere is nec...

A Camada Limite Atmosférica (CLA) é uma porção da baixa troposfera que interage e é influenciada pela superfície. É um parâmetro chave para micrometeorologia, química da atmosfera e outras áreas de estudos. Contudo, a estimativa da altura da camada limite noturna (CLN) não é nada trivial, e as técnicas que foram usadas até hoje nunca estimaram o to...

Winds can exceed the mechanical stability of trees, leading to snapping or uprooting. In large portions of the Amazon, storms propagating winds with destructive potential (WDP) are key drivers of tree mortality, affecting forest structure, biomass stocks, and species composition. Our understanding of WDP primarily comes from tree damage observation...

High‐frequency measurements obtained at two micrometeorological towers are investigated for a rare northward surging gust front that impacted the Amazon Tall Tower Observatory (ATTO), in central Amazon. The gust front originated from a decaying mesoscale convective system (MCS) during the morning hours of 27 December 2021 near Manaus, Amazonas stat...

Squall lines (SLs) are convective phenomena frequently occurring in the tropical atmosphere and have been widely investigated by the scientific community. In this work, satellite images of the central Amazon region were used to identify the occurrence of SLs between 2014, considered as a typical year, and 2015, characterize by a strong El Nino. Sub...

This study investigates the rain-initiated mixing and variability in the mixing ratio of selected trace gases in the atmosphere over the central Amazon rain forest. It builds on comprehensive data from the Amazon Tall Tower Observatory (ATTO), spanning from 2013 to 2020 and comprising the greenhouse gases (GHGs) carbon dioxide (CO2) and methane (CH...

How are rainforest photosynthesis and turbulent fluxes influenced by clouds? To what extent are clouds affected by local processes driven by rainforest energy, water and carbon fluxes? These interrelated questions were the main drivers of the intensive field experiment CloudRoots-Amazon22 which took place at the ATTO/Campina supersites in the Amazo...

Amazon forests play a significant role in the global C cycle by assimilating large amounts of CO2 through photo- synthesis and storing C largely as biomass and soil organic matter. To evaluate the net budget of C in the Amazon, we must also consider the amplitude and timing of losses of C back to the atmosphere through respiration and biomass burni...

Natural aerosol feedbacks are expected to become more important in the future, as anthropogenic aerosol emissions decrease due to air quality policy. One such feedback is initiated by the increase in biogenic volatile organic compound (BVOC) emissions with higher temperatures, leading to higher secondary organic aerosol (SOA) production and a cooli...

This study investigates the rain-initiated mixing and variability in the concentration of selected trace gases in the atmosphere over the central Amazon rain forest. It builds on comprehensive data from the Amazon Tall Tower Observatory (ATTO), spanning from 2013 to 2020 and comprising the greenhouse gases (GHG) carbon dioxide (CO2) and methane (CH...

A Camada Limite Planetária (CLP) é a região mais baixa da atmosfera e interage diretamente com a superfície. A altura da CLP é um parâmetro chave para várias áreas do conhecimento, especialmente para a previsão de tempo e clima, dispersão de poluentes e qualidade do ar. Neste trabalho foram usados dados de um ceilômetro localizado no sítio experime...

O objetivo deste trabalho foi avaliar a evolução temporal da energia cinética turbulenta sobre a ação de Jatos de Baixo Nível na Camada Limite Noturna do Pantanal, através dos fluxos de calor sensível e Momentum. A metodologia empregada foi um estudo de caso para a noite entre os dias 19 e 20 de Setembro de 1999, durante a estação seca na região. E...

Identificamos dois regimes turbulentos noturnos em diferentes alturas acima da Floresta Amazônica e sua variação com relação à proximidade do dossel. Analisamos dados de resposta rápida medidos na Reserva de Desenvolvimento Sustentável do Uatumã, Amazônia central, Brasil, durante os meses de setembro de 2021 a janeiro de 2022. Nossos resultados mos...

Neste trabalho, é realizada uma investigação da influência da topografia na estrutura da turbulência da floresta Amazônica. O modelo Parallelized Large Eddy Simulation Model (PALM) foi utilizado com o objetivo de compreender melhor como a topografia atua na organização da turbulência, nos fluxos turbulentos de energia e massa, dentro e acima do dos...

Data from two experimental sites in central Amazonia were used, one located in a forested region and the other in an urban region. The values of the radiation and energy balance components were measured at both sites. The observed components of the radiation balance in the forest, and urban areas were quite different. The city, the radiative (albed...

Foram investigados fenômenos atmosféricos extremos que se manifestam na forma de variações abruptas na velocidade do vento e na temperatura. Durante a ocorrência dessas variações e com o uso do método de Sinais de Alerta Antecipados (SAA), é possível a detecção da transição entre dois regimes de turbulência na Camada Limite Noturna (CLN). Os testes...

As linhas de instabilidade (LI) são um dos sistemas atmosféricos mais importantes e frequentes na Amazônia e no norte do Nordeste do Brasil. Podem ser entendidas como conjuntos organizados de cumulonimbus, com deslocamento simultâneo, responsáveis por índices elevados de precipitação e modificam a estrutura termodinâmica atmosférica perto da superf...

The ability of the relaxed eddy accumulation (REA) method to estimate the kinematic fluxes of temperature, water vapor and carbon dioxide was assessed for the dry season (3 months) at the ATTO (Amazon Tall Tower Observatory) site from turbulence measurements. The measurements were performed at 50 m above ground within the roughness sublayer. Non-co...

Isoprene emissions are a key component in biosphere–atmosphere interactions, and the most significant global source is the Amazon rainforest. However, intra- and interannual variations in biological and environmental factors that regulate isoprene emission from Amazonia are not well understood and, thereby, are poorly represented in models. Here, w...

The ability of the Relaxed Eddy Accumulation (REA) method to estimate the kinematic fluxes of temperature, water vapor and carbon dioxide was assessed for the dry season (3 months) at the ATTO (Amazon Tall Tower Observatory) site from turbulence measurements. The measurements were performed at 50 m above ground within the roughness sublayer. Non-co...

The height (zi) of the Atmospheric Boundary Layer (ABL) is a fundamental parameter for several areas of knowledge, especially for weather and climate forecasting, pollutant dispersion and air quality. In this work, we used data from a remote sensing instrument (ceilometer), located at the experimental site of the Amazon Tall Tower Observatory (ATTO...

The height (zi) of the Atmospheric Boundary Layer (ABL) is a fundamental parameter for several areas of knowledge, especially for weather and climate forecasting, pollutant dispersion and air quality. In this work, we used data from a remote sensing instrument (ceilometer), located at the experimental site of the Amazon Tall Tower Observatory (ATTO...

We investigated the influence of seasonality and proximity to the forest canopy on nocturnal turbulence regimes in the roughness sublayer of a Central Amazon forest. Since convective systems of different scales are common in this region, we also analyzed the effect of extreme wind gusts (propagated from convective downdrafts) on the organization of...

Isoprene is a chemical compound emitted naturally by soil, microorganisms, plants, and animals into the atmosphere. But plants are the largest emission source, and the amount of emission depends on plant species, weather conditions, and environmental conditions, including exposure to environmental stresses such as heat and drought. Isoprene is very...

Modification to the law-of-the wall represented by a dimensionless correction function $\phi_{RSL}(z/h)$ is derived using near-neutral atmospheric turbulence measurements collected at two sites in the Amazon in near-neutral stratification, where $z$ is the distance from the forest floor and $h$ is the mean canopy height. The sites are the Amazon Ta...

Abstract An experiment has been conductedto evaluate the agreement among the sonic anemometers deployed at theATTO project, before their final installation at a 325-m hightower. The experiment was conducted close to the tall tower location,in a small clearing. A total of 19 sonic anemometers were compared: Campbell Scientific InstrumentsCSAT3Bs an...

The atmospheric boundary layer height (zi) is a key parameter in the vertical transport of mass, energy, moisture, and chemical species between the surface and the free atmosphere. There is a lack of long-term and continuous observations of zi, however, particularly for remote regions, such as the Amazon forest. Reanalysis products, such as ERA5, c...

Observations of the vertical structure of the turbulent flow in different stability regimes above and within the Amazon Forest at the Amazon Tall Tower Observatory (ATTO) site have been presented in Part I. Here, the influence of stability on the inception and development of coherent structures is investigated. According to the mixing-layer analogy...

The influence of the topography at the ATTO site (Amazon Tall Tower Observatory) in the formation of Gravity Waves (GW) was investigated in this work. The role of these waves in gas transport on different heights in the nocturnal boundary layer, was also investigated. For this, were analyzed: experimental data of wind speed, temperature, humidity a...

During the dry season of 2014, the formation of a mesoscale convective system (MCS) caused intense precipitation and strong winds in the central Amazon region. In this period, cases of MCS that occurred during the days when there were higher concentrations of CO were analyzed. Through this criterion, a case of MCS occurred on August 16th, 2014 was...

Understanding the processes that govern the mixing and transport of scalars within and above the Amazon Forest is of great importance for many environmental applications. The impact of atmospheric stability on the roughness sublayer (RSL) as well as the influence on it by the processes in the overlying atmosphere are investigated using measurements...

Convection plays an important role in determining Amazon weather and climate. Variations in momentum fluxes and sensible heat associated with turbulence regimes influence the propagation of downdrafts, which have high destructive power and can cause damage and mortality from one to millions of trees. Windthrows are related to variations in tree spe...

The parallelized large-eddy simulation model (PALM) was used to understand better the turbulent exchanges of a passive scalar above and within a forested region located in the central Amazon. Weak (2 ms−1) and strong (6 ms−1) wind conditions were simulated. A passive scalar source was introduced to the forest floor for both simulations. The simulat...

We investigated the role of turbulent coherent structures (CS), gravity waves (GW) and low-level jet (LLJ) propagation in the flow dynamics of the Nocturnal Boundary Layer (NBL) within and above a forest canopy at the Amazon Tall Tower Observatory (ATTO), in Central Amazon. Seven levels of wind velocity and temperature measurements allowed the stud...

Squall lines (SLs) are convective systems that cause heavy precipitation and consequently modify the atmospheric thermodynamic structure near the surface. SLs generated along the northern coast of Brazil and their effect upon atmospheric structure during their westward displacement into the Amazon are studied. Satellite imagery was employed to iden...

In the period between 9 and 11 July 2014, a friagem event reached the Amazon region. On 11 July, the southwest flow related to the friagem converged with the easterly winds in the central Amazon. The interaction between these two distinct air masses formed a convection band, which intensified over the Manaus region and the Amazon Tall Tower Observa...

The Atmospheric Boundary Layer height () is an important quantity used in many parameterizations in surface flux calculations. However, to obtain this height, it is necessary to use atmospheric radiosonde, which can be expensive or even logistically unfeasible in some places in the Amazon. The objective of this work is to estimate through the spect...

We apply different methods for detection of extreme phenomena (EP) in air-turbulent time series measured in the nocturnal boundary layer above the Amazon forest. The methods used were: (a) a Morlet complex wavelet transform, which is often used in analysis of non-linear application processes. Through the use of the wavelet, it is possible to observ...

The most turbulent vortices that populate the forest-atmosphere interface have canopy height length scales. These vortices are mainly responsible for turbulent exchanges between inside and above canopy region. Thus, we used the vertical wind profiles obtained by 10 anemometers installed inside and above the forest canopy of the Rebio-Jarú experimen...

Observational data from two field campaigns in the Amazon forest were used to study the vertical structure of turbulence above the forest. The analysis was performed using the reduced turbulent kinetic energy (TKE) budget and its associated two-dimensional phase space. Results revealed the existence of two regions within the roughness sublayer in w...

In the period between July 9 th and 11 th , 2014 a Friagem event reached the central Amazon region causing significant changes in microclimate and atmospheric chemistry. On July 11 th , the southwest flow related to the Friagem converged with the easterly winds in the central Amazon region. The interaction between these two distinct air masses form...

Methane (CH4) atmospheric mixing ratio measurements are analyzed for the period between June 2013 and November 2018 at the Amazon Tall Tower Observatory (ATTO). We describe the seasonal and diurnal patterns of nighttime events in which CH4 mixing ratios at the uppermost (79 m a.g.l.) inlet are significantly higher than the lowermost inlet (4 m a.g....

Este estudo mostra uma análise em transformada em ondeleta cruzada e coerência em ondeleta aplicada a duas séries temporais, sendo uma delas precipitação e a outra temperatura do ar. O objetivo deste estudo é mostrar que esta técnica é uma ferramenta poderosa na análise de séries temporais climáticas, para isso à aplicamos a duas séries com relação...

Methane (CH 4) atmospheric mixing ratio measurements are analyzed for the period between June 2013 and November 2018 at the Amazon Tall Tower Observatory (ATTO). We describe the seasonal and diurnal patterns of nighttime events in which CH 4 mixing ratios at the uppermost (79 m a.g.l) inlet are significantly higher than the lowermost inlet (4 m a.g...

Resumo Analisou-se o ciclo diário da velocidade do vento dentro e acima do dossel em dois sitios experimentais na região amazônica. O objetivo desse trabalho foi aplicar um modelo simplificado para simular o comportamento do ciclo diário da velocidade do vento. Verificou-se que esse comportamento são semelhantes nos sítios em estudo, com pequenas d...

Resumo A altura da Camada Limite Atmosférica (z i) é uma importante grandeza utilizada em muitas parametrizações nos cálculos de fluxos de superfície. No entanto, para obter esta altura se faz necessário o uso de sondagens atmosférica, que podem ser dispendiosas ou até mesmo ser inviáveis, do ponto vista logístico, em alguns locais da Amazônia. O o...

Nesse trabalho recorreu-se ao LES (Large Eddy Simulation) para o melhor entendimento dos pro-cessos de troca de um escalar passivo, além das principais características de um escoamento estratificado neutro, dentro e acima do dossel florestal do sítio experimental do projeto ATTO (Amazon Tall Tower Observatory -Observatório da Torre Alta na Amazônia...

A descrição precisa da Camada Limite Noturna (CLN) é um dos grandes desafios aos pesquisadores da Camada Limite Atmosférica (CLA) na atualidade. Esta tarefa é complexa devido a interação de processos de múltiplas escalas. Na CLN é comum encontrar situações com turbulência fraca e extremamente intermitente. Neste tipo de condições, fenômenos não tur...

The most important individual source of methane globally is wetlands, which in the Amazon rainforest are abundant. Wetland emissions in the Amazon represent 15% of the global wetland emissions. Therefore, understanding the main drivers of methane emissions in this region is vital to constrain its global variability. At the Amazon Tall Tower Observa...

In the Amazon basin, high temperatures and drought unprecedented in records since 1900 occurred during the 2015/16 El Niño event. How tropical forests react to such extreme conditions in terms of volatile organic compound (VOC) emissions is of interest as the frequency of these events is predicted to increase through climate change. The diverse VOC...

The 2015/16 El Niño event caused unprecedented drought and warming in the Amazon basin. How tropical forests react to such extreme events in terms of volatile organic compound (VOC) emissions is of interest as the frequency of these events is predicted to increase through climate change. The diverse VOCs emitted can be significant for plants’ carbo...

Atmospheric turbulence characteristics within and above rain forest canopies are investigated at several sites located in the Amazon region of Brazil. Turbulence data provided by bi- and three-dimensional sonic anemometers, which were deployed at heights ranging from near the forest floor to about 80 m, are analyzed to describe the principal featur...

Resumo Analisou-se as situações em que o escoamento turbulento imediatamente acima e dentro de um dos-sel florestal amazônico estiveram acoplados, tanto para as situações de diferentes condições de estabilidade atmosférica quanto para diferentes intensidades de turbulência. Para tanto foram utilizados dados de resposta rápida das três componentes d...

The structure of atmospheric turbulence is analyzed based on the existence of three different nighttime turbulent regimes observed in the Amazon forest, classified according to Sun's criteria: regime 1: weak turbulence, low wind speed; regime 2: strong turbulence, with high wind speed, and regime 3: intermittent turbulence events. Next, we have inv...

In this work, we investigate the ozone dynamics during the occurrence of both downdrafts associated with mesoscale convective storms and non-classical low-level jets. Extensive data sets, comprised of air chemistry and meteorological observations made in the Amazon region of Brazil over the course of 2014–15, are analyzed to address several questio...

We analyzed the vertical wind profile measured at six experimental tower sites in dense forest in the Amazon Basin and examined how well two simple models can reproduce these observations. In general, the vertical wind profile below the canopy is strongly affected by the forest structure. From the forest floor to 0.65 h (where h = 35 m is the avera...

The aim of this study was to evaluate the different features of the vertical wind profile measured in different experimental sites in the Amazon, and also to test the ability of the two simple models to reproduce such features. We analyzed data from six measurement towers at dense forest areas. In general, the vertical wind profile below the canopy...

The present study considers the mean wind velocity profiles measured from a 60 m high tower in the Rebio-Jarú forest (10 ° 04.7 ′ S, 61 ° 52.0 ′ W), located in the Brazilian northwestern state of Rondônia. The data were collected during the wet season as part of an intensive campaign of the large scale biosphere–atmosphere experiment in Amazonia. N...

The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline reco...

Some conditions of occurrence of “rolls” coherent structures (CSs) above the Amazon forest are analyzed. As is well known, CSs are responsible for a significant fraction of the turbulent exchanges of momentum, heat and mass between the biosphere and the atmosphere. To perform this study, Large Eddy Simulation (LES) is used. The applied model has be...

Were investigated the structure of turbulent flow above the Rebio-Jarú forest reserve, located in the state of Rondônia. For this, we used data measured in micrometeorological tower, collected during the wet season, in daytime and nighttime periods, and also performed numerical modeling using Large Eddy Simulation (LES). For daytime conditions some...

The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It already has been changed significantly by human activities, and more pervasive change is expected to occur in the next decades. It is therefore essential to establish long-term measurement sites that provide a baseline record...

This work is based on Patton (1997) which uses a large eddy simulation (LES) model modified to include the aerodynamic effects of porous drag elements. Here the LES is used to investigate the interaction of the atmospheric surface layer with the Amazonian forest canopy. The influence of a plant canopy with a leaf area index set as five, as observed...

Environmental data measured in the nocturnal boundary layer (NBL) above a forest in Central Amazonia are used to detect the occurrence of gravity waves (GWs) and to identify under which situations they would be generated by terrain undulations. Thus, for each available situation, a “Scorer” number was calculated with meteorological data and a wave...