Recorded presentationJ23.1
Testing of a multi-layer urban canopy model with two boundary layer schemes in WRF
Alberto Martilli, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Madrid, Spain; and S. Grossman Clarke, F. Chen, and J. Dudhia
A multi-layer urban canopy model (UCM) was implemented in Weather
Research and Forecast (WRF) Version 3 and tested with two planetary
boundary layer (PBL) schemes, the Bougeault-Lacarre (1989) and the
Mellor-Yamada -Janjic (MYJ) scheme. The multi-layer urban scheme
solves the energy balance for roofs, roads and buildings at several
vertical levels within the urban canopy and provides source terms for
the prognostic equations for T, q, u, v and turbulent kinetic energy
(TKE) that are solved in the respective PBL schemes. Varying vertical
building density is considered in the model and this UCm is coupled
to the Noah land surface model, which calculates surface fluxes from
natural surfaces in urban areas.
The Bougeault-Lacarrere(1989) scheme calculates the TKE
prognostically and uses length scales (estimated from the vertical
profile of potential temperature and TKE) to calculate the
dissipation and the turbulent coefficients. The MYJ scheme
calculates changes in TKE due to shear, buoyancy and dissipation and
subsequently diffuses TKE vertically.
Results of the simulated wind and temperature fields as well the
structure of the planetary boundary layer for an idealized 2-d case
will be presented for both PBL schemes as well as with alternative
urban land cover parameterizations (the urbanized Noah LSM, and a
single-layer UCM). Also will be discussed are preliminary results
from applying this WRF/UCM to a case study during the TexAQS-2000
field experiment over the Greater Houston region.
Joint Session 23, Modeling and Forecasting Urban Areas—II
Thursday, 15 January 2009, 1:30 PM-3:00 PM, Room 124A
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