GRAPES Model Research Progresses at CMA Chen D.H., Wang J.J., Shen X.S. et al. Numerical Weather Prediction Center China Meteorological Administration h thanks to our colleagues who contribute to the presentation (The 4th THORPEX-ASIA Science Workshop and ARC-8 Meeting 30 Oct.~3 Nov., 2012, Kunming, China )
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GRAPES Model Research Progresses at CMA Chen D.H., Wang J.J., Shen X.S. et al. Numerical Weather Prediction Center China Meteorological Administration.
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GRAPES Model Research Progresses at CMA
Chen D.H., Wang J.J., Shen X.S. et al.Numerical Weather Prediction CenterChina Meteorological Administration
with thanks to our colleagues who contribute to the presentation
(The 4th THORPEX-ASIA Science Workshop and ARC-8 Meeting30 Oct.~3 Nov., 2012, Kunming, China )
Outline
• 1 Current Operational NWP Systems
• 2 Efforts for improving GRAPES_GFS
• 3 Progresses in GRAPES_VAR
• 4 Implementation of GRAPES_TYM
• 5 High resolution modeling activities
• 6 Future Plan
General Office
Numerical Weather Prediction Center of CMA
R&D Division
Dynamic process group
Physical process group
Regional model group
Parallel computing group
Observation data quality
control group
Data assimilation group
Ensemble prediction
Group
System & Operation Division
Typhoon prediction
group
System pre-operational test
group
Model version manage and information
technology group
Model verification group
Post process and products
development group
Director: Dr. WANG Jianjie Chief Engineer: Dr. CHEN Dehui
Deputy-directors: Dr. GONG Jiandong and Dr. SHEN Xueshun
The restructured organization of Numerical Prediction Center
1 Current Operational NWP Systems at CMA
Models specified
Global Spectral Model
(TL639L60)
Meso Scale Model (GRAPES_Meso)
Global Ensemble (T213L31)
Typhoon Ensemble forecast
Forecast Range
Global Medium-range forecast
Regional short-range foreecast
10 day forecast
Typhoon forecast
Forecast domain
Global China/East Asia(8340km5480km
)
Global
Horizontal resolution
TL639(0.28125o) 15km T213 (0.5625 o)
Vert. levels / Top
600.1hPa
3310hPa
3110hPa
Forecast hours (initial
time)
240hours(00, 12UTC)
72 hours(00, 12UTC)
240hours(00, 12UTC) 15members
240hours+BGS(00, 12UTC)15members
3310hPa
Initialization
Global GSI(NCEP)
GRAPES_3VAR Initial Perturb. by BGM
BGM+NCEP SSI + vortex relocation, intensity
adjustments
Current NWP Operational System in NMC
In general, there were no big changes in the operational NWP systems
GRAPES_TCM at Shanghai Typhoon Institute for East C.S.
• PhysicsPhysics– Cumulus : KF-eta
– PBL: YSU– Micro: NCEP cloud3– LSM: SLAB scheme
– Radia.: RRTM scheme
Fig: Topography of the domain of GRAPES_TCM
• ConfigurationConfiguration– Domain:
E90º~E170º,N0º~N50º – Hor. Res.: 0.25ºx0.25º
– Grids: 321x201– V. res.: 31(ztop: 35000m) (From Wang et al., 2010)
Assessment of TC forecast methods
• TRaP: extrapolating method based satellite-estimated precipitation
Forecast verification for Typhoon SINLAKUNumber of cases (21, 21,19,17)
0
2
4
6
8
10
12
14
16
Max
imum
win
d er
ror (
m/s
)
Forecast hour
Uncoupled
Coupled
(From Sun et al., 2012)
Forecast verification of Nine TC in 2011 Number of cases (72,72,56,56,49,44,44)
0
5
10
15
20
25
0 12 24 36 48 60 72
Mea
n m
inim
um se
a le
vel
pres
sure
err
or (h
pa)
Forecast hour
Uncoupled
Coupled
02468
10121416
0 12 24 36 48 60 72
Mea
n m
axim
um w
ind
erro
r (m
/s)
Forecast hour
UncoupledCoupled
(From Sun et al., 2012)
Minimum sea level pressure forecast GRAPES_tym
Minimum sea level pressure forecast Coupled model
Maximum wind forecast GRAPES_tym
Maximum wind forecast Coupled model
0
10
20
30
40
50
60
0 10 20 30 40 50 60
Fore
cast
Observation
T+0h
T+24h
T+48h
T+72h
Intensity forecast of Nine TC in 2011 Number of cases (72,72,56,44)
(From Sun et al., 2012)
5 High resolution modeling activities
5.1 High Resolution Modeling Activities at CMABased on GRAPES_Meso
Recent activities •Vertical coordinate from terrain-following Z to hybrid coordinate (Schar, 2002)•Inclusion of thermal expansion effect in continuity equation•Improve the interpolation accuracy in physics-dynamics interface•Refinement of 2-moment microphysics scheme•Some bug fix in land surface scheme•Refinement of back ground error covariance in 3DVAR
Modification of TF coordinate
• In order to design a new TF coordinate, we rewrite the formulation of Gal-Chen and Sommerville (1975) in a common formulation:
),(
),(ˆ
yxZZ
yxZzZz
sT
sT
),(ˆ yxZbzz s
with )ˆ
1(TZ
zb It is a decaying coefficient of the coordinate surface with
height. It is possible to use different “b” to accelerate the decaying.
(From Li et Chen, 2012)
New TF coordinates
• The different decaying coefficients “b” can be defined as:
)ˆ
1(TZ
zb (Gal-Chen and Sommerville, 1974)
]/sinh[
]/)ˆsinh[(*
*
hZ
hzZb
T
Th
2
1*
*
]/sinh[
]/)ˆsinh[(
i iT
iTH hZ
hzZb
c
c
n
cTC
zz
zzz
z
Z
zb
ˆˆ0
ˆˆˆ
ˆ
2cos
ˆ1
(similar to Klemp, 2011)“n>2”: an empirical
number; zc : a reference height from which the
coordinate surface becomes horizontal.
(Schar, 2002)h*: scale of ref-topography; h*1 and h*2: large and small-scale of ref-topogr.
G.C.S.
SLEVE1
SLEVE2
COS
(From Li et Chen, 2012)
•Test Objective : to compare the errors of PGF calculation of four coordinates in rest atmosphere over an artificial terrain.
•Test design:•Reference rest atmosphere :
•Classical algorithm used for PGF calculation
0
0
00
exp
g 9.81,T 287.0
exp ,
p
p
gz
C T
gzT
C T
ˆ ˆ ( ( , ))ˆp z p z p b z SC C C J b Z x yz
with z
zJ b
ˆ
(From Li et Chen, 2012)
-50000 0 50000-0.1
-0.050
0.050.1
-50000 0 500000
5000
10000
15000L2
-50000 0 50000-0.1
-0.050
0.050.1
-50000 0 500000
5000
10000
15000L10
-50000 0 50000-0.05
-0.0250
0.0250.05
-50000 0 500000
5000
10000
15000L20
-50000 0 50000-0.02-0.01
00.010.02
-50000 0 500000
5000
10000
15000L30
-50000 0 50000-0.005
-0.00250
0.00250.005
SLEVE2 coordinate
-50000 0 500000
5000
10000
15000L40
-50000 0 50000-0.1
-0.050
0.050.1
-50000 0 500000
5000
10000
15000L2
-50000 0 50000-0.1
-0.050
0.050.1
-50000 0 500000
5000
10000
15000L10
-50000 0 50000-0.05
-0.0250
0.0250.05
-50000 0 500000
5000
10000
15000L20
-50000 0 50000-0.02-0.01
00.010.02
-50000 0 500000
5000
10000
15000L30
-50000 0 50000-0.005
-0.00250
0.00250.005
SLEVE1 coordinate
-50000 0 500000
5000
10000
15000L40
-50000 0 50000 -0.1
-0.050
0.050.1
-50000 0 50000 0
5000
10000
15000L2
-50000 0 50000 -0.1
-0.050
0.050.1
-50000 0 50000 0
5000
10000
15000L10
-50000 0 50000 -0.05
-0.0250
0.0250.05
-50000 0 50000 0
5000
10000
15000
heig
ht
L20
-50000 0 50000 -0.02-0.01
00.010.02
-50000 0 50000 0
5000
10000
15000L30
-50000 0 50000 -0.005
-0.00250
0.0025 0.005
COS coordinate
-50000 0 50000 0
5000
10000
15000L40
-50000 0 50000-0.1
-0.050
0.050.1
-50000 0 500000
5000
10000
15000L2
-50000 0 50000-0.1
-0.050
0.050.1
-50000 0 500000
5000
10000
15000L10
-50000 0 50000-0.05
-0.0250
0.0250.05
pres
sure
gra
dien
t for
ce e
rror
-50000 0 500000
5000
10000
15000L20
-50000 0 50000-0.02-0.01
00.010.02
-50000 0 500000
5000
10000
15000L30
-50000 0 50000-0.005
-0.00250
0.00250.005
Gal.C.S coordinate
-50000 0 500000
5000
10000
15000L40
G.C.S SLEVE1 SLEVE2 COS
Errors of PGF calculation induced by using TF coordinates
bottom
top
On different vertical levels: L2, L10, L20, L30 and L40 from bottom to top(From Li et Chen, 2012)
1/ 2/ 100%Gal SLEVE SLEVE COS
Gal
E E
E
Vertical levels SLEVE1 SLEVE2 COS
L40 67% 99% 100%
L30 62% 99% 100%
L20 51% 99% 99%
L10 31% 95% 75%
L2 4% 30% 2%
R.R.E. is defined as:
Relatively Reduced Errors: SLEVE1(SLEVE2, COS) against GCS
(From Li et Chen, 2012)
2 1
2 1
1 5
( ) 10 sin 42
0 4
km z
z zu z km z z
z z
z km
20 0
0
cos ( ) 1( , ) 2
0 1 x z
rr x x z z
x z rR R
r
,
Initial wind:
Analysis density
distribution :
before mount over after mount
2D test design (cont.)
flow from L to R density distribution
(From Li et Chen, 2012)
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
k regular grid
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
e SLEVE2 coordinate
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
f SLEVE2 coordinate
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
c SLEVE1 coordinate
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
l regular grid
-75000 -50000 -25000 0 25000 50000 750000
2500
5000
7500
10000
12500
15000
x
he
ig
ht
a Gal.C.S coordinate
-75000 -50000 -25000 0 25000 50000 750000
2500
5000
7500
10000
12500
15000
x
he
ig
ht
b Gal.C.S coordinate
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
g COS coordinate(Zc=15km)
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
i COS coordinate(Zc=10km)
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
j COS coordinate(Zc=10km)
-75000 -50000 -25000 0 25000 50000 75000 0
2500
5000
7500
10000
12500
15000
x
he
ig
ht
h COS coordinate(Zc=15km)
-75000 -50000 -25000 0 25000 50000 750000
2500
5000
7500
10000
12500
15000
x
he
ig
ht
d SLEVE1 coordinate
left : density distribution at 0s,5000s,10000s right : the errors at 10000s after mountain
Advection test : air mass moves over a topographic obstacle
GCS
SLEVE1
SLEVE2
COS-zc=15km
COS-zc=10km
without topography
(From Li et Chen, 2012)
1 12 22 2
, , , ,1 1 1 1
2 12 22
, ,1 1 1 1
1 2
( ) ( ) ( ) ( )
( ) ( )
m n m n
i k num i k ana i k num i k anak i k i
m n m n
i k ana i k anak i k i
SLEVE SLEVE COS
1
2
wi thout terrai n
, , , ,
, ,1 2
( ) ( ) ( ) ( )
( ) ( )i k num i k ana i k num i k ana
i k ana i k anaSLEVE SLEVE COS
MAX MAX
MAX MAX
wi thout terrai n
、
left : temporal evolution of
计算误差
积分时间
Defining two parameters as following, according to Williamson (et.al,1992)
,( )i k num,( )i k anais numerical solution is analytical solution
The preliminary results with new TF coordinates in GRAPES_Meso
• The preliminary results with regional GRAPES (15km) are quite encouraging:
Monthly mean of 24h forecast of geopotential
height at 100hPa
(From Li et Chen, 2012)
The torrential rain-storm occurred on 21 Jul. 2012 in Beijing
24 h accumulated precipitation from 00UTC 21 Jul to 00UTC 22
Jul
“The torrential rain-storm occurred on 21 Jul. 2012 in Beijing area: the worst the city has seen in more than 60 years,
dumped an average of 215 millimeters of rain in 16 hours. Hebeizhen, a town in the suburban district of Fangshan
(South-West), saw 460 millimeters for the same period. ” 。 (From Chen et al., 2012)
Heavy rainfall event on Jul.21/2012 Beijing
Mean=190.3mm/24hrMax=460mm/24hr
00z21Jul2012-00z22Jul201200z21Jul2012-00z22Jul2012Initial: global analysisBC: global forecast
Grid size:3kmPhysics:
- microphysics: WSM6 - radiation : RRTM S&L
- pbl : MRF - land surface : NOAH
Initial: global analysisBC: global forecast
Grid size:3kmPhysics:
- microphysics: WSM6 - radiation : RRTM S&L
- pbl : MRF - land surface : NOAH
Fcst.
24-hour accumulated rainfall
Max=341mm/24hr
Beijing
Obs.
GRAPES_Meso-3km
ECMWF
(From Huanget al., 2012)
Comparison of precipitation every 6-hour forecasts against Obs.
Obs.0-6hr Obs.6-12hr Obs.12-18hr Obs.18-24hr
Fcst.0-6hr Fcst.6-12hr Fcst.12-18hr Fcst.18-24hr
(From Huanget al., 2012)
(GRAPES_Meso-3km)
5.2 other Research activities at CMA
– GRAPES Yin-yang dynamic core– SV-based GRAPES ensemble forecast system– New algorithms of dynamic core
Progress of GRAPES Yin-Yang gridThe Helmholtz equation of GRAPES in the Yin-Yang overset grid are solved.The transplant of the whole GRAPES dynamical core is finished. However,some bugs exist and it need to be debuged in the next step.
2 2 H Helmholtz equation:
(From Peng et al., 2012)
3D advection resultsalpha=0.
alpha=90.
alpha=45.
Instant image on the Yang grid
The tracer follow the wave motion and undergo Three oscillations in the vertical direction.
After one revolution(12 days), the tracer is backto the initial state.
200 , 60, 1.0z m nlev d
day12
( 12) ( 0)q day q day
1
2
3
4
5
6
7
8
9
10
(From Peng et al., 2012)
High order Multi-moment Constrained finite Volume (MCV) method
We define the moments within single cell, i.e. the cell-averaged value, the point-wise value and the derivatives of the field variable
Constraint conditons:
Approximate Riemann solvers
The unknowns (solution points) are updated in a fourth order mcv scheme, for example,
The same in multi-dimension, for example, y direction
Solution points
Constraint points
(From Li et al., 2012)
Height-based terrain-following vertical coordinate (Gal-chen & Somerville 1975) is used. is transformation Jacobian.
MCV4 results
A nonhydrostatic atmospheric governing equation sets in the Cartesion system