Claudio Alberto Teichrieb

Nocturnal Intermittent Coupling Between the Interior of a Pine Forest and the Air Above It

A 1-year set of measurements of CO2 and energy turbulent fluxes above and within a 25-m pine forest in southern Brazil is analyzed. The study focuses on the coupling state between two levels and its impact on flux determination by the eddy-covariance method. The turbulent series are split in their typical temporal scales using the multiresolution decomposition, a method that allows proper identification of the time scales of the turbulent events. Initially, four case studies are presented: a continually turbulent, a continually calm, a calm then turbulent, and an intermittent night. During transitions from calm to turbulent, large scalar fluxes of opposing signs occur at both levels, suggesting the transference of air accumulated in the canopy during the stagnant period both upwards and downwards. Average fluxes are shown for the entire period as a function of turbulence intensity and a canopy Richardson number, used as an indicator of the canopy coupling state. Above the canopy, CO2 and sensible heat fluxes decrease in magnitude both at the neutral and at the very stable limit, while below the canopy they increase monotonically with the canopy Richardson number. Latent heat fluxes decrease at both levels as the canopy air becomes more stable. The average temporal scales of the turbulent fluxes at both levels approach each other in neutral conditions, indicating that the levels are coupled in that case. Average CO2 fluxes during turbulent periods that succeed very calm ones are appreciably larger than the overall average above the canopy and smaller than the average or negative within the canopy, indicating that the transfer of air accumulated during calm portions at later turbulent intervals affects the flux average. The implications of this process for mean flux determination are discussed.

Monitoring the micrometeorology of a coastal site next to a thermal power plant from the surface to 140 m

AbstractA 140-m micrometeorological tower has been operating since August 2016 at 4 km from the coastline and 250 m from a thermal power plant that releases heat from its 20-m stacks in southeaster...

Quasi-Experimental Determination of Turbulent Dispersion Parameters for Different Stability Conditions from a Tall Micrometeorological Tower

AbstractTurbulent wind data measured by sonic anemometers installed at various heights on a 140-m-tall micrometeorological tower located at a coastal site are used to obtain vertical profiles of th...

EFFECTS OF A STRAW LAYER ON THE SOIL THERMAL BEHAVIOR

The presence of crop residue on the soil surface has an impact on evaporation, water storage, soil temperature and soil heat flux. Consequently, changes the energy transfer in the soil-atmosphere system. The objective of this work is study the influence of crop residues in the soil thermal variables. It was concluded that the thermal effect of a straw layer is large, leading to surface temperature differences around 10°C. With depth increasing, the effect of straw coverage decreases, leading to a temperature difference to 4°C of 5cm depth. The most important consequence of higher temperature on bare ground is an increase of soil heat flux. In stable weather conditions, this difference can reach 29 W/m 2 .

POST-CLOSURE OF THE ENERGY BALANCE METHOD TO EVALUATE OF THE FLUXES OF THE LAND SURFACE MODELS

In this work, an analysis of the uncertainty of energy flux resulting from post-closure methods of the energy balance: H Method, LE method and Bowen method for the data observed in native grass area of the Pampa biome, located in Santa Maria, RS, Brazil. From these three methods suggest a new one, which we call the Combined Method. This method takes into account the quality classes of eddy covariance to choose the correct method to be applied. The uncertainties of flux were obtained by the difference between the fluxes corrected by one of the post-closure methods and the raw fluxes. The maximum values of the uncertainties occur during the daytime. Regarding the combined method, the highest percentage of cases resulted in the application of correction by Bowen method, followed by the LE method and with less occurrence Method H. Thus, this method can be considered valid to evaluate the uncertainty of simulated fluxes over land surface models.

ANALISYS OF ATMOSPHERIC TURBULENCE IN THE NOCTURNAL BOUNDARY LAYER OVER THE AMAZON RAIN FOREST

In this study, turbulence data taken in different vertical levels in the Amazon rain forest are analyzed for two distinct nights: a night characterized by intense turbulent mixing, and a night which turbulence was intermittent. This is done using the multiresolution decomposition, which allows the identification of the turbulence and submeso contributions to spectra and cospectra.

COMPARATIVE ANALYSIS OF WATER AND THERMAL REGIME OF TWO EXPERIMENTAL SITES IN PAMPA

In the last 15-20 years has greatly increased research on the problem of climate change, necessitating a demand for reliable measurements of absorption and emission of carbon dioxide, methane, as well as the impact on water resources. In the biome Pampa are the largest continuous natural field extensions, requiring a monitoring of water and temperature regime on the ground. The water content of the soil has spatial and temporal variability affecting many hydrological processes and determining this is needed since the soil store and provide the water and nutrients for the plants, thus involving relationships water-soil-plant-atmosphere. In this work, we compared the water content behavior of the soil at depths of 10, 30 and 50 cm, the temperature of the soil at depths of 5, 15 and 30 cm, heat flux in soil installed 10 cm deep and the thermal conductivity was determined in two experimental sites in the Pampa biome, for the period 01.01.2015 to 06.31.2015. It was found that there are differences between the sites in the capacity to retain moisture in the soil and in the ability to store energy in the soil for the study period.

BALANÇO DE ENERGIA E TROCA LÍQUIDA DE CO2 PARA UM CICLO DA CULTURA DO MILHO NO MODELO AGRO-IBIS

Neste trabalho, e apresentado o balanco de energia e a troca liquida de CO 2 (NEE) para um ciclo da cultura do milho com o modelo Agro-IBIS. Os resultados indicam que o modelo representa bem as trocas entre o ecossistema e o ambiente na maior parte do ciclo, com excecao no periodo de senescencia foliar.

EFEITOS DA NEBULOSIDADE NA ABSORÇÃO DE CARBONO EM UMA CULTURA DE MILHO EM CRUZ ALTA, RS

Foram realizadas medicoes no periodo de 11 de novembro de 2010 a 19 de fevereiro de 2011 de variaveis meteorologicas e fluxo de dioxido de carbono (CO 2 ), atraves da tecnica de covariância dos vortices turbulentos, com o intuito de analisar a influencia da nebulosidade na absorcao do C em uma cultura de milho em Cruz Alta, RS. Observou-se maior absorcao de C a niveis intermediarios de cobertura de nuvens.

SIMULAÇÃO DO COMPORTAMENTO DA TEMPERATURA DO SOLO ATRAVÉS DA TEMPERATURA DO AR

A partir de dados observacionais de temperatura do solo e do ar, e obtida uma equacao para descrever a temperatura do solo a 5 cm de profundidade em funcao da temperatura do ar para uma regiao de cultivo de arroz irrigado. A regiao do estudo apresenta periodos de alagamento. A equacao obtida descreve de forma satisfatorio os periodos secos.