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Le projet CRTI: d é veloppement d’un syst è me de mod é lisation à l’ é chelle urbaine. Jocelyn Mailhot Stéphane Bélair Mario Benjamin Najat Benbouta Bernard Bilodeau Gilbert Brunet Frédéric Chagnon Michel Desgagné Jean-Philippe Gauthier Bruno Harvey Richard Hogue. Michel Jean

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Le projet crti d veloppement d un syst me de mod lisation l chelle urbaine l.jpg

Le projet CRTI: développement d’un système de modélisation à l’échelle urbaine

Jocelyn Mailhot

Stéphane Bélair

Mario Benjamin

Najat Benbouta

Bernard Bilodeau

Gilbert Brunet

Frédéric Chagnon

Michel Desgagné

Jean-Philippe Gauthier

Bruno Harvey

Richard Hogue

Michel Jean

Aude Lemonsu

Alexandre Leroux

Gilles Morneau

Radenko Pavlovic

Pierre Pellerin

Claude Pelletier

Lubos Spacek

Linying Tong

Serge Trudel

Yufei Zhu

RPN / CMC / Région du Québec

Séminaire CMC / RPN – 24 février 2006

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Objectives and Context

  • Improve the representation of cities in Canadian meteorological models:

  • accurate prediction of urban flows and atmospheric dispersion over major North American cities.

  • improve urban surfaces and urban boundary layer in meso--scale and micro--scale (~ 20km down to 200m) atmospheric models

  • Part of a larger-scale project within CRTI:

  • development of an integrated multi-scale modeling system

  • to provide decision making framework to minimize consequences

  • injuries, casualties, and contamination

  • prototype for Environmental Emergency Response Division in 2007

  • Project partners:

  • R&D Defence Canada, AECL

  • Universities of Waterloo and Calgary

  • CFD microscale models (at street- and building-scales)

  • Lagrangian stochastic dispersion models

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Urban Modeling System

Off-line surface modeling

At 100-200 m

« Urbanized »

Regional-15 km


Built areas are parameterized, i.e., we need

  • TEB

  • Urban surfaces


1D (vertical) turbulence is sufficient

  • TEB

  • Urban surface databases

  • Anthropogenic heat sources

« Urbanized »

Meso--scale 2.5 km





« Urbanized »

Micro--scale 250 m


3D turbulence is required


still TBD



Microscale (CFD)


Built areas are resolved

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High-level management

(Jean, Hogue)

Scientific management

(Mailhot, Bélair)





Meso- and



Surface fields


Anthropo. heat sources



Regional NWP


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Urban Modeling System

  • Main features of the new urban modeling system:

  • High-resolution capability for micro-α scale applications (down to ~250m)

  • Urban processes with Town Energy Balance (TEB) scheme (Masson, 2000)

  • Generation of fields characterizing urban type covers (Lemonsu et al., 2006)

  • 3D LES-type turbulent diffusion scheme.

  • First validation of the urban modeling system:

  • Impact of urban processes on structure of urban boundary layer

  • Comparison against observations from the Joint Urban 2003 experimental campaign in Oklahoma City in July 2003 (Allwine et al., 2004)

  • Comparison against observations from MUSE-1 (March-April 2005) for cold conditions and snow melt period.

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TEB urban surface scheme

Town Energy Balance (Masson, 2000)

  • Urban canopy model parameterizing water and energy exchanges between canopy and atmosphere (based on urban canyon concept of Oke 1987)

  • Model specifically dedicated to the built-up covers

  • Three-dimensional geometry

    • Radiative trapping and shadow effect

    • Heat storage

    • Wind, temperature and humidity inside the street

    • Water and snow

  • Idealized urban geometry

    • Mean urban canyon: 1 roof, 2 identical walls, 1 road

    • Isotropy of the street orientations

    • No crossing streets




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Sea ice




Coupling with MC2 and GEM

To couple TEB with MC2 and GEM requires :

  • Implementing a new type of surface in the physics package in order to take into account the urban areas

  • Developing urban land-cover databases to document the spatial distribution and spatial variability of urban areas

  • Defining the heat and humidity releases due to human activities (Anthropogenic sources)

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Urban Land-Cover Classification


  • Based on joint analysis of satellite imagery (ASTER, Landsat-7) and digital elevation models (SRTM-DEM, NED, CDED1)

  • Produce 60-m resolution urban land-use land-covers

  • Methodology applied to major North American cities


  • Horizontal resolution adapted to micro-α-scale modeling

  • Number of urban classes (12) allowing the representation of urban variability

    Interest of the method:

  • Semi-automatic treatment

  • Limited number of data sources

  • Large availability of the databases

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Surface element identification

ASTER satellite image

15 m database

Building height estimation


10 m database

  • Water

  • Trees

  • Low vegetation

  • Grass

  • Bare soil and rocks

  • Roofs

  • Roads and parkings

  • Asphalt roads

  • Residential mixing

  • Veg/road mixing

  • Building height

  • Built fraction with elevation

Classification criteria

to describe the urban landscapes and identify urban classes

Aggregation at a lower resolution

to compute the statistics of selected criteria on the new grid

Decision tree

Regrouping pixels whose criteria are similar and identification of urban classes

Attribution of descriptive parameters

Town Energy Balance input data

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High buildings

Mid-high buildings

Low buildings

Very low buildings

Sparse buildings

Industrial areas


Roads and parkings

Road mix

Dense residential

Mid-density residential

Low-density residential

Mix of nature and built



Short grass

Mixed forest

Mixed shurbs



Urban classification


60-m resolution classification

Including 12 new urban classes

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High buildings

Mid-high buildings

Low buildings

Very low buildings

Sparse buildings

Industrial areas

Roads and parkings

Road mix

Dense residential

Mid-density residential

Low-density residential

Mix of nature and built



60-m resolution classification

Vancouver 60-m resolution classification

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Inclusion of Anthropogenic Heating

Anthropogenic sources:

  • importance of heat and humidity releases, especially during wintertime

  • based on estimates for a typical US city:

    • ~60% due to traffic

    • ~40% due to residential/industrial activities

    • a few % due to metabolism (neglected)

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Anthropogenic Heating:

Production of a database for Canada & USA

Current TEB:

  • uses constant forcing of fluxes due to traffic and industrial activities


  • under development for more realistic representation of anthropogenic fluxes

  • based on “top-down” approach of Sailor and Lu (2004)

  • estimates of diurnal, weekly and seasonal cycles

  • prototype and validation for Montreal

  • generalize to major North American cities

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Evaluation Of Anthropogenic Heating

Top-down approach (D. J. Sailor, USA, 2004)

Daily total energy released by 1 vehicle

  • ρpop(t) Population density [person/km2]

  • FV(t) Non-dimensional vehicle traffic profile

  • EVVehicle energy used per kilometer [Wkm-1]

  • DVD Distance traveled per person [km]

  • Analysis at the city scale

  • Hourly non-dimensional profile functions per capita

  • Spatial refinement through the hourly density of population profile

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Anthropogenic Heating:

Top-Down Approach, Vehicle Traffic Profile

Hourly fractional traffic profiles – fv(t) for various US cities and states (Sailor and Lu, 2004).

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Anthropogenic Heating: Top down approach

Production of a database for Canada & USA

  • Plan:

    • Search for data sources

    • Analysis of the data

    • Definition of the anthropogenic profiles per sector

    • Building of the anthropogenic heating database

  • Validation of the approach with detailed high resolution data

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Implementing 3D Turbulence

  • Current 1D (vertical) turbulent diffusion scheme parametrizes effects of large eddies in PBL

  • High-resolution models (< 1km) partly resolve large eddies

  • Adjustments needed to avoid “double-counting” of diffusion processes

  • Must also include XY contributions as grid resolution increases and move toward LES (quasi-isotropic 3D diffusion)

  • Cascade to LES-type model resolution (Large-eddy simulation - i.e. 10-50m) with Smagorinsky-Lilly approach

  • Smooth transition of diffusion intensity as function of model resolution

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Implementing 3D Turbulence

  • Included all XY components of the dynamic Reynolds stress tensor

  • Added TKE gradient terms

  • Horizontal corrections introduced in all remaining transport equations

  • Finite difference discretization on Arakawa-C grid and Charney-Phillips vertical staggering

  • Modified operator splitting technique used by TKE solver

  • Modified appropriate scale-dependent mixing length

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Vertical heat flux: published LES results

  • 30 m resolution

  • SB1 and SB2: strong shear + moderate convection

  • SGS (sub-grid-scale parameterization) model mostly active:

  • - lower levels (near surface)

  • -top of PBL (entrainment zone)

Moeng et al., J. Atmos.,Sci., 1994

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1D vs. 3D TKE profiles (OKC 16:00 CDT) CDT)

- “double-counting” problem -

40 m

200 m

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Modeling objectives CDT)

Current studies :

  • Offline modeling over OKC (Joint Urban 2003) to evaluate TEB over North American cities

  • 3D modeling over OKC (Joint Urban 2003) to study the impact of the urban parameterization on the boundary layer

    Future works :

  • Offline modeling over Montreal (MUSE period) to evaluate TEB under winter condition and to improve the snow parameterization

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In collaboration with our CRTI partners (U. of Waterloo, Defence R&D Canada)

The Joint Urban 2003 Experiment

Atmospheric dispersion study

28 June to 31 July 2003

  • Include the following meteorological measurements:

    • 22 surface met stations

    • 6 surface energy budget stations

    • 2 CTI windtracer lidars

    • 2 radiosonde systems

    • 4 wind profiler/RASS systems

    • 1 FM-CW radar

    • 3 ceilometers

    • 9 sodars

    • + Oklahoma mesonet

    • + NEXRAD radars of the US weather service

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Modeling configuration Defence R&D Canada)

  • Preliminary results based on Joint Urban 2003

  • IOP 3 (16 July 2003) - Clear sky / southerly winds

  • Cascade of grid nesting down to 1-km resolution

GEM/LAM 250 m

GEM/LAM 1 km

GEM/LAM 2.5 km

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Observations Defence R&D Canada)






Evaluation on Joint Urban 2003

  • Sensitivity tests conducted with 2 model simulations at 1-km:

  • CROPS = no TEB (city is replaced by crops resolved by ISBA)

  • URBAN = with TEB + urban land-cover classification (12 urban classes)

  • Rural sites (7 MESONET stations around OKC):

  • good agreement on day 1 between observations and model runs

  • model slightly too warm during nighttime and day 2

  • minor impact of TEB in rural areas (as expected)

  • Suburbs (PNNL stations) and urban sites (13 PWIDS stations in CBD):

  • marked positive impact of TEB during nighttime

  • significant overestimate during daytime with TEB (examination is underway)

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1500 LST Defence R&D Canada)

1200 LST

Evaluation on Joint Urban 2003

  • At 1200 LST well-mixed BL (with θ ~ 34°C) to about 1300 m at upwind site (PNNL south of OKC), with strong inversion. A few km downwind (ANL site), UBL is colder (by about 1°C) and reaches height of 1200 m.

    • The 1-km model run indicates a relatively good agreement, except at upper levels: too much mixing in the entrainment zone!

  • BL warms up in afternoon (~ 36°C). While the upwind BL stays relatively steady, the UBL top rises to 1650 m at the ANL site, likely as a result of the urban heat island plume.

    • The 1-km model run does not capture well this evolution of the BL structure.

  • Work underway to improve simulations with:

    • Higher horizontal (250 m) and vertical resolutions (especially in entrainment zone);

    • More appropriate vertical diffusion scheme (3D LES-type)

Evolution of the Urban Boundary Layer

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Preliminary results of the 2005 Defence R&D Canada)Montreal Urban Snow Experiment (MUSE-2005)

Objectives of MUSE-1

  • Document the evolution of surface characteristics and energy budgets in a dense urban area during the winter-spring transition

    • Evolution of snow cover from ~100% to 0% in an urban environment

    • Impact of snow on the surface energy and water budgets

    • Quantify anthropogenic fluxes in late winter and spring conditions

  • Evaluate TEB in reproducing the surface characteristics and budgets in these conditions (aspect not well examined so far)

  • Gain expertise in urban measurements

  • Prepare for a wider effort to be submitted to CFCAS

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Continuous measurements Defence R&D Canada)17 March to 14 April 2005

20 m tower

Radiative surface temperatures

IR camera in heated case

Incoming and outgoing radiation

CNR1 radiometer Kipp & Zonen

Turbulent fluxes by eddy covariance 10Hz

3D sonic anemometer CSAT3

H2O/CO2 analyzer Li-Cor 7500

Fine wire thermocouple ASPTC

Air temperature and humidity in canyons

Radiative temperature of walls

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Intensive observation periods Defence R&D Canada)

Evolution of snow cover

  • Clear skies and southwest winds

  • Four 26-hour IOPs (March 17-18, 22-23, 30-31, April 5-6)

  • Measurements:

    • Hourly radiative surface temperatures using IR thermometer

    • Albedo (5 daytime measurements)

    • Snow depth and density (5 daytime measurements)

    • Pictures to document snow cover, snow melt, wet fraction

March 22nd

March 17th

March 30th

April 5th

100 %

50 %

10 %

95 %

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Energy balance summary Defence R&D Canada)

Daily average in W/m²

1st sequence

With snow

2nd sequence

Without snow

Residual term = Radiative balance – (sensible heat + latent heat)

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The MUSE-2005 team Defence R&D Canada)

Project management:

Michel Jean, Operations Branch, CMC, Dorval

Jocelyn Mailhot, MRB, Dorval

Mario Benjamin, Quebec Region - MSC

Field work (installation and observations):

Bruno Harvey, Frédéric Chagnon, Stavros Antonopoulos, Najat Benbouta, Mario Benjamin, Olivier Gagnon,

Aude Lemonsu, Gilles Morneau, Radenko Pavlovic

Modelling team:

Stéphane Bélair, Aude Lemonsu, Claude Pelletier

External contributions from:

Prof Sue Grimmond, Indiana University

Prof Tim R. Oke, University of British Columbia

Prof James A. Voogt, University of Western Ontario

Sarah M. Roberts

This project was funded by CBRN Research and Technology Initiative as project # 02-0093RD

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Outlook Defence R&D Canada)

  • MUSE-2: follow-up

  • 10 February until end March 2006

  • Wintertime conditions

  • Similar location (Rosemont/Petite-Patrie) and instrumentation

  • Longer-term wider effort in Canada:

  • Development of a national observation network

  • Urban sites for surface and upper-air profiles

  • Monitoring of the urban boundary layer

  • Partnership with various organizations across Canada

  • Seek funding by CFCAS (Canadian Foundation for Climate and Atmospheric Sciences)

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CFCAS Urban Proposal Defence R&D Canada)

Network Grant Proposal to the Canadian Foundation

for Climate and Atmospheric Sciences


Co-Principal Investigators:

J.A. Voogt (The University of Western Ontario)

T.R. Oke (The University of British Columbia)

Total requested Budget: $1,447,000

February 10th, 2006

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CFCAS Urban Proposal Defence R&D Canada)

Table 1. Proposal participants.

* Obs:field observation acquisition and analysis, Mod: numerical modeling, RS: remote sensing, TEB: TEB-ISBA use.

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Forecasting Weather for Canadian Cities Defence R&D Canada)5 Major Objectives

Forecasting Weather for Canadian Cities

5 Major Objectives

  • Field observations (Montreal + Vancouver: urban / suburban / rural sites)

    • Oke, Benjamin, Strachan, Grimmond, Voogt

    • Detailed urban heat and water balances (continuous 2-year measurements)

  • Canadian optimized version of TEB-ISBA

    • Bélair, Lemonsu, Mailhot, Oke

    • Specifics of Canadian cities: building materials, vegetation, snow and cold winter conditions

  • Modeling studies of the urban boundary layer

    • Mailhot, Bélair, Lemonsu, Masson, Zawadzki

    • Impact of TEB on UBL and clouds/precipitation/types; urban-induced circulations

  • Urban component of off-line modeling system

    • Bélair, Lemonsu

  • Urban remote sensing

    • Voogt, Coops, Wang, Bélair, Lemonsu

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Presentations at conferences Defence R&D Canada)

  • Recently:

  • 39th Annual CMOS Congress: June 2005 in Vancouver (5 presentations)

  • Royal Met Society 2005 Conference: September 2006 in Exeter UK (1 presentation)

  • 6th Symposium on Urban Environment / AMS Annual Meeting: Jan. 2006 in Atlanta, GA (5 presentations)

  • Upcoming:

  • 17th Symposium on Boundary Layers and Turbulence: May 2006 in San Diego, CA (1 presentation)

  • 6th International Conference on Urban Climate: June 2006 in Göteborg, Sweden (4 presentations)

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Funding through… Defence R&D Canada)

CRTI Project # 02-0093RD

Advanced Emergency Response Systemfor CBRN Hazard Prediction and Assessment for the Urban Environment