uqam/ec canadian contribution to map d-phase r. mctaggart-cowan, m. desgagne, j. cote, s. gravel, c....
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UQAM/EC
Canadian Contribution to MAP D-PHASE
R. McTaggart-Cowan, M. Desgagne, J. Cote, S. Gravel, C. Girard, A. Erfani, J.
Milbrandt, C. JonesUniversity of Quebec at Montreal (UQAM) / Environment Canada,
Quebec, Canada
UQAM/EC
Outline
● Canadian motivation and support
● Description of the GEM modelling system
● Multiscale comparison of events in the MAP and Vancouver 2010 regions
– Dynamical and physical representation of heavy precipitation episodes in the model
● Opportunity for “proof of concept” and verification
UQAM/EC
Motivation for Involvement
● Regional experience from the original MAP project
– Identified problems by “stressing” the system
– Motivated improvements to model formulation
● Proof of concept for high resolution short-term forecasting in mountains – valuable for Vancouver Olympics 2010 project
– Venues are particularly sensitive to precip amount and species
UQAM/EC
Model Description
● Global Environmental Multiscale (GEM) model has been developed extensively since the MC2 was used in MAP
● GEM runs in global (uniform/variable reso) + LAM configuration – unified model structure
● Non-hydrostatic primitive equations solved using an Implicit SL scheme
Operational G
EM
R
egional stretched C
onfiguration
UQAM/EC
Model Description
● Self-nesting allows for a consistent use of physical parameterizations:
– Kong and Yau microphysics (2 liq, 2 ice) – upgrade to Milbrandt and Yau is possible
– TKE boundary layer closure
– Kain-Fritsch convection (10 km MAP-Regional domain only)
● This allows nesting of hydrometeor species – important to reduce spin-up
UQAM/EC
Predictability: Large Scale
● Synoptic scale patterns modulate the internal structure of the systems – they must be well-represented
MA
P IO
P-2 C
yclone enhanced IR
image 1200
UT
C 20 S
eptember 1999
Van
couv
er s
now
(35
cm
Cyp
rus)
enh
ance
d IR
imag
e 06
00 U
TC
8 M
arch
200
6
UQAM/EC
Predictability: Large Scale
● Despite satellite DA, useful predictability can be <6h on West Coast
● Ensemble techniques may be an approachObservation increm
ent from
AM
SU
-A brightness
temperatures 14 F
eb 2006
Obs
erva
tion
incr
emen
t of
radi
oson
de te
mpe
ratu
res
for
16 J
une
2006
x
UQAM/EC
Regional Modelling
● Use of an intermediate domain (10km) will promote development of mesoscale signal and permit hydrometeor nesting
UQAM/EC
High Resolution Modelling
● During MAP, MC2 ran with smoothed (approximately x5) orography – GEM will run with full resolution field
UQAM/EC
High Resolution Modelling
● MAP revealed problems with the MC2
– New vertical coordinate (Schar) developed
– Numerical inconsistency eliminated
● Reduction of GEM waves is a priority
GEM with standard background GEM with modified background
Vertical motion fields from the GEM for a cosine idealized mountain case (C~.5)
Model Dynamics
UQAM/EC
High Resolution Modelling● Advanced microphysics scheme is being
developed for GEM – 3 moment bulk with 2 liquid, 4 ice phases (Milbrandt and Yau)
10020 40 60 800
101
100
10-1
10-2
Multimoment bulk estimate of DSD
N(D
)
Diameter
Observed1 Moment Bulk3 Moment Bulk
● Accurate DSD shape prediction important for fall speed estim-ates and conversion rate calculations
Model Microphysics
UQAM/EC
High Resolution Modelling
Model Microphysics
CLOUD(CLW)
RAIN
ICE / SNOW
GRAUPEL / HAIL
Kon
g a
nd
Yau
1 M
om
en
t M
icro
ph
ysi
cs
1 Moment mass
Unobserved heavy precipon the lee side
Almost no graupel formed(low riming rates)
Pockets of liquid water are known to form in persistent terrain-induced updrafts and provide ideal regions for rapid riming growth of snow
UQAM/EC
RAIN
ICE(pristine crystal)
SNOW(large crystals / aggregates)
GRAUPEL HAIL(ice pellets)
CLOUD(CLW)
High Resolution Modelling
Model Microphysics
Milb
ran
dt
an
d Y
au
3 M
om
en
t M
icro
ph
ysi
cs
Windward and leeward precip in line with obs
Large graupel growthrates by riming
3 Moment mass
UQAM/EC
High Resolution Modelling● Multimoment microphysics scheme reduces
known accumulation and lee-side heavy precipitation problems with single moment schemes (e.g. IMPROVE case)
● High resolution in steep terrain will challenge the numerics of GEM
● High resolution verification data is hard to obtain but invaluable in scheme evaluation and further development
UQAM/EC
Verification and Development● MAP and MAP D-PHASE produce unique
verification datasets
● D-PHASE will also be useful for model intercomparison at very high resolution
– Quasi-operational status will yield statistically significant results on un-tuned cases
– May be able to address the question of how much resolution is really needed? (> 3km)