Hans Rogério Zimermann

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.

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.

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.

Redução de escala de dados de vento de modelos regionais para Modelos de Dispersão Atmosférica

This paper discusses the development of a data interpolation scheme applicable to the regional numerical weather prediction models (i.e. BRAMS) output, allowing the coupling of these models with atmospheric dispersion models. To evaluate this tool, the BRAMS wind field is used as input to the Atmospheric Dispersion Model (Zimora) developed by the Laboratorio de Micrometeorologia of the Universidade Federal de Santa Maria (UFSM).

ESTIMATIVA DOS FLUXOS SUPERFICIAIS DE ENERGIA UTILIZANDO O MODELO DE SUPERFÍCIE NOAH

This study aims to compare the surface flows of energy (sensibleheat and latent) obtained from Candiota07 micrometeorologicalexperiment with the results estimated by the Noah surface model.According to the results, the Noah surface model presents a goodagreement with observed data, except for the flow of latent heat duringthe night.