Amauri Pereira de Oliveira

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Summer SchoolRio de JaneiroMarch 20092. PBL
PROPERTIES

• Amauri Pereira de Oliveira

Group of Micrometeorology
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Topics

1. Micrometeorology
2. PBL properties
3. PBL modeling
4. Modeling surface-biosphere interaction
5. Modeling Maritime PBL
6. Modeling Convective PBL

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PBL PROPERTIES
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Turbulent Boundary Layer (TBL)
Fluid is moving with velocity U
U
TBL
Rigid Surface
Monin. A.S. and Yaglom, A.M., 1971 Statistical
Fluid Mechanics, Vol. 1, Massachussets MIT
Press, 769 pp.
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Turbulent Boundary Layer
Scales characteristics d vertical
extension CLT ?/u length scale ?
kinematics viscosity of fluid (?ar 1.5 m2/s) u
velocity scale hi characteristic
length scale for the roughness elements of
the surface.
Monin and Yaglom, 1971.
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Internal and external TBL

• The TBL can be divided to layers using as a
  criteria the source of turbulence
• Internal layer (inner-region)
• Shear is intense and most of the turbulence is
  produced
• Characteristic length scale is ?/u
• External layer (outer-region)
• Shear is small and production of turbulence is
  also small
• Characteristic length scale is d.

Raupach, M.R., Antonia, R.A. and Rajagopalan, S.,
1991 Rough-wall turbulent boundary layers,
Applied Mechanics Reviews, 44, 1-25.
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Rough and smooth surfaces
A surface is aerodynamically smooth when the
vertical extension of roughness elements (hi)
are smaller than ?/u. In this case there is a
layer adjacent to the surface where the vertical
profile of mean velocity varies linearly with
height. It is frequently called viscous sub
layer. The region of turbulence production is
located in the viscous sub layer (internal or
inner layer).
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Canonical TBL Smooth surface

• Surface rigid and plane
• Horizontal pressure gradient null
• No thermal stratification (Neutral flow)
• Aerodynamically smooth surface
• Stationary flow

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Canonic TBL
Logarithmic profile
Linear profile
Monin. and Yaglom (1971).
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TBL Rough surfaces
Raupach et al., 1991.
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Planetary Boundary Layer

• Planetary Boundary Layer (PBL) is the region -
  adjacent to the surface - where turbulence
  promotes mixing and most of the exchange of
  energy, mass and momentum between the surface and
  atmosphere.

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PBL localization
Turbulent layer
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Diurnal evolution
Adapted from Stull (1988).
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Homogeneous and plane surfaces
Jatos de baixos níveis
Sem memória
Fernando, H.J.S., Lee, S.M., Anderson, J.,
Princevac, M., Pardyjak, E. and Grossman-Clarke,
S., 2001 Urban fluid mechanics air circulation
and contaminant dispersion in cities.
Environmental Fluid Mechanics, 1, 107-164.
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Convective PBL
Nieuwstadt, F.T.M. and Duynkerke, P.G., 1996
Turbulence in the boundary layer, Atmospheric
Research, 40, 111-142.
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Similarity Theory - CBL
Mixing Layer Similarity
Monin and Obukhov similarity
Free Convection Similarity
Nieuwstadt and Duynkerke, 1996.
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Monin-Obukhov Similarity
Characteristic length scale
 
Obukhov length scale
Nieuwstadt and Duynkerke, 1996.
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Mixing Layer Similarity
Nieuwstadt and Duynkerke, 1996.
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Stable Boundary Layer - SBL
Nieuwstadt and Duynkerke, 1996.
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Similarity theory for SBL
Nieuwstadt and Duynkerke, 1996.
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Local Similarity
Characteristic length scale
Local Obukhov length scale.
Nieuwstadt and Duynkerke, 1996.
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Vertical structure of SBL
Nieuwstadt and Duynkerke, 1996.
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PBL over heterogeneous surface
Urban Boundary Layer
Source Fernando et al. (2001).
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BPL Complex Topography
Source Hunt et al., 2003
Advection makes turbulence not local.
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Surface covered by vegetation

• Internal layer
• Inertial layer
• Roughness layer
• Canopy layer
• Canopy sub-layer.

Mahrt, L., 2000 Surface heterogeneity and
vertical structure of the boundary layer.
Boundary-Layer Meteorology, 96 33-62.
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Canopy layer turbulent fluxes
Finnigan, J., 2000 Turbulence in plant canopies.
Annu. Rev. Fluid Mech., 32, 519571.
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PBL over the ocean

• Inertial layer
• Roughness layer.

Sjöblom, A. and Smedam, A.-S., 2003 Vertical
structure in the marine atmospheric boundary
layer and its implication for the inertial
dissipation method, Boundary-Layer Meteorology,
109, 1-25
.
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Urban Boundary Layer

• Internal region
• Inertial
• Roughness layer
• Canopy layer
• Canopy sub-layer.

Fonte Fernando et al. (2001).
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UBL structure
Fernando et al., 2001.