Virnei Silva Moreira

Derivation of third-order vertical velocity turbulence moment in the convective boundary layer from large eddy simulation data: an application to the dispersion modeling

A new formulation for the vertical turbulent velocity third statistical moment in a convective boundary layer is proposed. The parameterization is based directly on the definition of this higher order moment, with velocity skewness and variance being calculated from large eddy simulation data. The formulation, included in a Lagrangian stochastic dispersion model, has been tested and compared with expressions for the third moment obtained from experimental data and reported in the literature, using concentration data from field experiments. The application of a statistical evaluation shows that the proposed parameterization has one of the best overall adjustments to the data.

INFLUENCE OF SOIL PROPERTIES IN DIFFERENT MANAGEMENT SYSTEMS: ESTIMATING SOYBEAN WATER CHANGES IN THE AGRO-IBIS MODEL

AbstractThe water balance in agricultural cropping systems is dependent on the physical and hydraulic characteristics of the soil and the type of farming, both of which are sensitive to the soil management. Most models that describe the interaction between the surface and the atmosphere do not efficiently represent the physical differences across different soil management areas. In this study, the authors analyzed the dynamics of the water exchange in the agricultural version of the Integrated Biosphere Simulator (IBIS) model (Agro-IBIS) in the presence of different physical soil properties because of the different long-term soil management systems. The experimental soil properties were obtained from two management systems, no tillage (NT) and conventional tillage (CT) in a long-term experiment in southern Brazil in the soybean growing season of 2009/10. To simulate NT management, this study modified the top soil layer in the model to represent the residual layer. Moreover, a mathematical adjustment to th...

ESTIMATION OF WATER INFILTRATION IN A FLOODPLAIN SOIL THROUGH THE GREEN-AMPT MODEL WITH ADJUSTMENT PARAMETERS

The need to find a model that describes the process of water infiltration into the soil which could be more closer to the reality is extremely important, especially considering the physical characteristics of a soil has, because a better understanding of this process is of fundamental importance for the efficient management of soil and water in agricultural crops. This study aims to validate the model of Green-Ampt in a rice-growing area. The experiment was conducted in the experimental site of Paraiso do Sul - RS, where soil samples were collected for physical analysis and used the double ring infiltrometer to obtain the values of cumulative infiltration. The results obtained through the Green-Ampt model did not generate acceptable results for application. With the development of the work, it was concluded that for the implementation of Green-Ampt model it is necessary to find a new parameter setting proposal that can describe the process of infiltration to the soil type studied.

ESTUDO DO COMPORTAMENTO DE VARIÁVEIS DE SOLO UTILIZANDO O MODELO NOAH PARA UMA CULTURA DE ARROZ IRRIGADO

This study aims to evaluate the performance of the land surface model Noah by simulating soil data and compare them with observed data in a region with rice in southern Brazil. From the results, it is observed that the Noah model needs adjustments, especially when analyzing the parameter volumetric soil moisture.

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.

DERIVAÇÃO DE UMA ESCALA DE TEMPO DE DESCORRELAÇÃO LAGRANGIANA PARA UMA CAMADA LIMITE ESTÁVEL

In the present study a new formulation for the lagrangian decorrelation time scale in the stable boundary layer (CBL) is proposed. This new model is compared with a well-known relation proposed by Sorbjan (1989).

ANÁLISE DAS COMPONENTES HÍDRICAS, PRECIPITAÇÃO, EVAPOTRANSPIRAÇÃO E UMIDADE NA SUPERFÍCIE DO SOLO REPRESENTADAS PELO MODELO CLIMÁTICO REGIONAL REGCM3, PARA UMA REGIÃO DE CULTIVO DE SOJA

Este trabalho tem por finalidade testar as componentes do Balanco Hidrico utilizando o modelo regional RegCM3 para uma regiao de cultivo de soja.