Summer School Rio de Janeiro March 2009 6. MODELING CONVECTIVE PBL. Amauri Pereira de Oliveira. Group of Micrometeorology. Topics. Micrometeorology PBL properties PBL modeling Modeling surface-biosphere interaction Modeling Maritime PBL Modeling Convective PBL. Modeling Convective PBL.
Amauri Pereira de Oliveira
Group of Micrometeorology
Nieuwstadt, F.T.M. and Duynkerke, P.G., 1996: Turbulence in the boundary layer, Atmospheric Research, 40, 111-142.
Mixing Layer Similarity
Monin and Obukhov similarity
Free Convection Similarity
Holstlag and Neuiwastadt 1988.
Investigation of Carbon Monoxide in the city of Sao Paulo using LES
Codato, G., Oliveira, A.P., Soares, J., Marques Filho, E.P., and Rizza, U., 2008: Investigation of carbon monoxide in the city of São Paulo using large eddy simulation. Proceedings of 15th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA, 88th Annual Meeting, 20-24 January 2008, New Orleans, LA (CDROM).
Codato. G., 2008: Simulação numérica da evolução diurna do monóxido de carbono na camada limite planetária sobre a RMSP com modelo LES. Dissertação de Mestrado. Departamento de Ciências Atmosféricas, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, SP, Brasil, 94 pp.
60 km far from Atlantic ocean
Topography during winter
of São Paulo
Wind – Seasonal evolution during winter(1996 -2005)
Winds in São Paulo are weak.
Morning winds are weaker than
in the afternoon
Stronger SE wind in the afternoon is due to
LES Model during winter
The motion equation are filtered in order to describe only motions with a length scale larger than a given threshold.
Source: Marques Filho (2004)
( zi /L ~ - 800)
Source: Marques Filho (2004)
Fonte: Marques Filho (2004)
It was developed by Moeng (1984) and modified by Sullivan during winteret al. (1994):
Filtering all variables by
homogeneous during winter
Sullivan et al. (1994) subgrid parametrization
Turbulent diffisivity coefficients
LES Model- Moeng during winter
Surfaces Horizontally Homogeneous
Grid points during winter
(128, 128, 128)
(Lx, Ly, Lz)
(10 km; 10 km; 2 km )
5 K km-1
36000 time steps
0 ppm km-1
Initial Conditions – Vertical profiles during winter
Bθ = 0.209 K m s-1
t = time in hours
The amplitude of CO flux at the surface is based on the total emission of CO in the MRSP (1.48 million of tons per year) divided by number of days in one year and by the area representative of traffic in São Paulo (8,051 km2).
In reality the value of Bco was set equal to 1/6 of the value above. This was obtained by trial and error and there is no apparent reason.
BCO = 0.024 ppm ms-1
t1 = 9 hour
t2 = 19 hour
= 3 hour
Quasi-steady equilibrium after 1000 s during winter
Time evolution of turbulent kinetic energy per unit of mass volume-averaged in the PBL.
E= 0.5 (u´2+v´2+w´2).
PBL characteristic scales during winter
Potential temperature and sensible heat flux during winter