Observational Study of the Surface Layer at an Ocean–Land Transition Region

Authors

  • Luiz Eduardo Medeiros Divisão de Ciências Atmosféricas Instituto de Aeronáutica e Espaço
  • Roberto de Oliveira Magnago Universidade do Estado do Rio de Janeiro – Resende/RJ – Brazil
  • Gilberto Fisch Instituto de Aeronaútica e Espaço – São José dos Campos/SP – Brazil
  • Edson Roberto Marciotto Instituto de Aeronaútica e Espaço – São José dos Campos/SP – Brazil

Keywords:

Coast, Internal boundary layer, Sonic anemometer, Surface layer

Abstract

http://dx.doi.org/10.5028/jatm.v5i4.244

High-frequency measurements of wind, and temperature were made during the dry season of 2008 to study the development of an internal boundary layer at the main Brazilian space launching centre, Centro de Lançamento de Alcântara at Alcântara, Maranhão, Brazil. Turbulence measurements taken at the coast, in two different points 227 m apart show different daily cycles of turbulent kinetic energy friction velocity (u*), and buoyancy flux . Surface roughness change, surface heating change, and a gap in the natural vegetation seem to be the causes for the variation in these turbulent parameters. The mean wind cycle also shows distinct patterns. It seems that, first, internal boundary layers develop when the oceanic surface layer reaches the continent, and a second when the first internal boundary layer’s flow encounters the gap. A direct implication is that turbulence is not horizontally homogeneous and measurements taken at single places are not spatially representative. Knowing how turbulence varies spatially is necessary information to understand the diffusion of pollutants exhausted by rockets near the coast.

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Published

2013-11-23

Issue

Section

Original Papers