RegionalGEM15 km
OPERATIONAL 48-h RUN (00 or 12 UTC)
EVENT
GEM-LAM2.5 km
GEM-LAM1 km
MC2-LAM250 m
T+5
T+12
T-1
T-3
36-h run
15-h run
6-h run
MicroscaleUrban flow
Models (urbanSTREAM)
IC + LBC
IC + LBC
IC + LBC
IC + LBCGlobalVariable resolution576 x 641Timestep = 7.5 min58 levels (for NWP)1D turbulence No TEB
LAM201 x 201Timestep = 60 s53 levels (two levels of packing near surface)1D turbulence TEB
LAM201 x 201Timestep = 30 s53 levels (two levels of packing near surface)1D turbulence TEB
LAM201 x 401 (long axis oriented along the low-level wind direction)Timestep = 10 s53 levels (two levels of packing near surface)3D turbulence TEB
From Mesoscale to MicroscaleFrom Mesoscale to Microscale
12 UTC 00 UTC 12 UTC
13 UTC
1. Coupling variables
2. Surface layer coupling
3. Lateral boundary conditions
4. 250-m vs 1-km results
Coupling Between Mesoscale and Microscale
GEM-LAM1 km
MC2-LAM250 m
T+5
T+12
T-1
T-3
15-h run
6-h run
MicroscaleUrban flow
Models (urbanSTREAM)
IC + LBC
IC + LBC
Inflow boundary conditions
•Horizontal wind
•Vertical motion
•Turbulent Kinetic Energy
•Boundary-layer height
Atmospheric model
zatm
Vegetated canopyUrban canopy
Flat surfaces
The Surface in GEM The Concept
FLUX AGGREGATION
SURFACE = TOP of CANOPY
First atmospheric level, about 50 m above the surface
Surface layer
zatm+zblg
zatm+(zblg-zveg)zatm
Vegetated canopy Urban canopyFlat surfaces
GEM’s Surface: How it connects with the Real World
Atmospheric model
First atmospheric level, about 50 m above the surface
Logarithmic wind profiles over each type of surfaces
1ln)( *
oz
z
k
uzV
W
zzzzVzV bldbld 2
exp)()(
GEM’s Vertical Wind Profiles vs Observations at Station ANL (IOP9)
RADAR
SODAR
GEM
GEM’s Vertical Wind Profiles vs Observations at Station ANL (IOP9)
RADAR
SODAR
GEM
NATURAL
CANYON
IOP9 (Night): Daytime turbulence IOP9 (Night): Daytime turbulence
26 July 2003 20 UTC 26 July 2003 21 UTC
More turbulent
Less turbulent
One hour later, the turbulence is more homogeneous
Automation and TestingAutomation and Testing
We propose to run the prototype in a fully automatic manner at a regular frequency (once a week or once a month?).
• Specify location of event (lat, lon)
• Generation of computational grids (250-m grid is oriented along the mean daytime low-level winds)
• Production of surface fields using an interpolation from pre-processed large grids (for Montreal, Toronto, Ottawa, and Vancouver)
• Integration of 2.5-km, 1-km, and 250-m runs
• Production of outputs for microscale models (with adaptation to local surface characteristics)
FULLY AUTOMATIC PROCESS
Computational CostComputational Cost
200 x 200 x 53 x 2160 (36h) 35 min with 200 cpus2.5 km
200 x 200 x 53 x 1800 (15h) 30 min with 200 cpus1 km
200 x 400 x 53 x 2160 (6h) 65 min with 400 cpus250 m
Total of 110 min
ni x nj x nk x nsteps Wall clock timeGrid size
On CMC’s current operational machine…
On new computer (early 2007), 2.5 times faster, i.e., 45 min.
CRTI-1 Further WorkCRTI-1 Further Work1. Urban cover classification
– finalize vector data (MTL and VAN)– examine hybrid approach? (satellite + vector)– other cities (TOR, Ottawa,?)– Pre-processing of large grids for selected cities (MTL, VAN, OTT, TOR)
2. Urban anthropogenic fluxes– generation for MTL (+ validation with Quebec Region data)– modify GEM inputs to include anthropogenic fluxes– sensitivity study on OKC: impact on mixing in boundary layer
3. Prototype – complete OKC and apply to MTL (with MUSE)– output adaptation for microscale modeling (coupling issue)– current prototype with MC2-250m (waiting for updated GEM vertical discretization)– start running prototype (e.g. once a week?)
4. 3D turbulence – finalize code validation with LES-type runs– impact study with 250-m runs
5. MUSE – continue analyses of MUSE-1 and MUSE-2 data
6. TEB – cascading of TEB prognostic variables (for initialization purpose)– snow treatment
7. Publications…
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