Ralf Gielow

Ciclo diário da precipitação estimada através de um radar banda S e pelo algoritmo 3B42_V6 do projeto TRMM durante a estação chuvosa de 1999 no sudoeste da Amazônia

The rainfall estimated with a S-band radar, and by the 3B42_V6 TRMM satellite algorithm, is evaluated by comparing it with rain gauge measurements during the 1999 rainy season in the Amazon Basin, with focus on the diurnal cycle. Statistic analyses based on contingency tables, skill scores, and harmonic analysis were used. The radar estimation is in agreement with the rain gauges measurements. The diurnal cycle exhibits a main maximum during the afternoon and a secondary one at night, which is associated to Squall Lines propagation over the Amazon Basin. It is also shown that the 3B42_V6 algorithm captured important features of the rainfall diurnal cycle: (i) the maximum at 2100 UTC (1700 LST); (ii) the nocturnal rainfall is strongest during Westerly regimes. These results are important for numerical weather and climate prediction model evaluation, especially when concerning the convection activity over the region.

La Influencia de la Altura de la Capa Límite Oceánica en la Región del Centro de Lanzamientos de Alcántara en Brasil

The influence of the height of the ocean boundary layer in the region where the Alcântara Space Center is located, was studied. The topography of the region is very complex and it includes a 50 m coastal cliff. A 2D numerical code was used, where the equations were written using the vorticityvelocity formulation. High order compact finite differences schemes were used for the spatial derivatives and the time integration was performed with a fourth-order Runge-Kutta scheme. The coastal cliff was specified through the immersed boundary method. The numerical results showed that the height of the ocean boundary layer influences the formation of the height of the internal boundary layer of the cliff, increasing the turbulence in the region.

Analysis of the Ocean Boundary Layer influence on the Mobile Tower Integration at the Alcantara Space Center

This work presents a numerical and experimental analysis of the Ocean Boundary Layer (OBL) influence on the formation of the Internal Boundary Layer (IBL) at the Alcantara Space Center (ASC), from where the Brazilian rockets are launched. The numerical simulation was carried out considering a two-dimensional flow with velocity-vorticity formulation for Navier Stokes equations. A 6th order compact finite differences scheme was used for spatial discretization and a 4th order Runge-Kutta scheme with temporal integration. The coastal cliff along the shoreline in the ASC neighborhood was specified trough the immersed boundary technique. The experimental analysis was carried out in a subsonic wind tunnel using a twodimensional Particle Image Velocimetry (PIV) system. The measurements were carried out considering the irregularity of the coastal cliff. The results confirmed that OBL height influences the height of Internal Boundary Layer that reaches the Mobile Integration Tower (MIT).

STUDIES USING WIND TUNNEL TO SIMULATE THE ATMOSPHERIC BOUNDARY LAYER AT THE ALCÂNTARA SPACE CENTER. doi:10.5028/jatm.2009.01019198

The Alcântara Space Center (ASC) region has a peculiar topography due to the existence of a coastal cliff, which modifies the atmospheric boundary layer characteristic in a way that can affect rocket launching operations. Wind tunnel measurements can be an important tool for the understanding of turbulence and wind flow pattern characteristics in the ASC neighborhood, along with computational fluid dynamics and observational data. The purpose of this paper is to describe wind tunnel experiments that have been carried out by researchers from the Brazilian Institutions IAE, ITA and INPE. The technologies of Hot-Wire Anemometer and Particle Image Velocimetry (PIV) have been used in these measurements, in order to obtain information about wind flow patterns as velocity fields and vorticity. The wind tunnel measurements are described and the results obtained are presented.

TRANSFERÊNCIAS DE MOMENTUM E PERFIS NOTURNOS DE VELOCIDADE DO VENTO NO INTERIOR DE FLORESTAS DA AMAZÔN

Transferencias de momentum e perfis noturnos develocidade do vento no interior de florestas da Amazon

IMPACTO DA ALTURA DAS FALÉSIAS NA GERAÇÃO DE TURBULÊNCIA

1. Introducao Existem muitas falesias espalhadas pelo mundo com as mais diversas formas e tamanhos. A existencia dessas falesias causa a alteracao das correntes de ar que passam sobre elas, gerando uma zona de recirculacao turbulenta, caracterizada como camada limite interna (CLI), conforme Fig. 1. E importante saber qual a dimensao dessa camada para entender as influencias que ela pode ocasionar quando ha, a jusante dessas falesias, cidades, balnearios, fabricas, aeroportos e outros. Esse trabalho mostra o comportamento do escoamento para o caso de falesias simples (ângulo de 90o) de ate 30 m de altura, com variacoes de velocidade do vento de 5 a 10 m s-1 a sua jusante (Figura 1).