Products of the JMA Ensemble Prediction System (EPS) for Seasonal Forecast
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Transcript of Products of the JMA Ensemble Prediction System (EPS) for Seasonal Forecast
Products of the JMA Ensemble Prediction System (EPS)
for Seasonal Forecast
Shuhei MaedaClimate Prediction Division
Contents1. Introduction
2. Products of the EPS for one-month prediction
3. Products of the EPS for three-month outloo
k
4. Remarks
TCC Web pagehttp://cpd2.kishou.go.jp/tcc/
One-month prediction
Three-month outlook
2. Products of the EPS for one-month prediction
1) Outline of the EPS 2) Performance of the system 3) Examples of products
The EPS for one-month prediction
Atmospheric Model
(Atmosphere-Land)
SSTpersisted SST
anomaly
Initial
Atm
osp
here
Land
Oce
an
Products• Map• Verification・ GPV
Analysis
Boundary
C
ondit
ion
Horizontalresolution
T106 (about 1.125 º Gaussian grid ~110km)
Time integrationrange
34 days
Executingfrequency
Once a week
Ensemble size 26 membersSST persisted anomalyPhysicalprocesses
The same as those of short-and medium- range forecastmodel
7 day running mean Z500 normalized anomaly over the western North Pacific (40N,140E-170E)
Ensemble mean
Spread
Each member
Example of ensemble prediction
Initial
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ProductsKind Forecast
rangeParameter
Ensemble mean map
2-8day
9-15day
16-29day
2-29day
(NH)
Z500,Z500A
T850,T850A
PSEA
PSEAA
(60N-60S and Asia)
Z500,Z500A
SLP,SLPA
PSI200,PSI200A
PSI850,PSI850A
CHI200,CHI200A
T2m,T2mA
RAIN,RAINA,SSTA
*○○○ A: anomalies of ○○○
(continue) ProductsForecast range
Parameter
Spread map 2-8 day
9-15 day
16-29 day
2-29 day
Z500A
Large anomaly index* map
Time series
(each member)
7-day running mean
Circulation indices (Z500A)
Area averaged T850A
Area averaged spread (Z500A)
CHI200 in the equatorial region*Ratio of number of members whose anomaly is higher than 0.5SD to total number of ensemble menber at each grid point
2) Performance of the system
Example of one-month prediction verification charts
Anomaly correlation scores of ensemble mean forecast in 2001
28 day (2-29) mean 500hPa height fields over the Northern Hemisphere. Initial: 2001/1/4-2001/12/27
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RMSE of ensemble mean forecast in 2002
28 day (2-29) mean 500hPa height fields over the Northern Hemisphere. Initial: 2002/1/3-2002/12/27
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Example of verification of probabilistic one-month prediction
Reliability diagram for 7 day mean 500hPa field: day 9-15
2003 Spring (2003/2/27-5/29)
Frequency of occurrences where E was forecast within each of the probability category bins
Event (E)
Z500 anomaly is greater than 0
Forecast frequency distribution
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3) Examples of products
Prediction of
・ Arctic Oscillation
・ Rossby waves along Asia jet
・ Intra Seasonal Oscillation in the tropics (Madden Julian Oscillation (MJO))
Ensemble average forecast map ( Initial: 2002/10/24)
Northern Hemisphere Z500 and T850 ; 28day mean
Z500
analysis
Z500
forecast
T850
analysis
T850
forecast
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AO!
Example of one-month prediction products(1)
Large anomaly index map
Init:2002.10.24 28 day mean ( day:2-29)
Many members predict large Z500 anomaly (above 0.5*standard deviation)
Many members predict large Z500 anomaly (below 0.5*standard deviation)
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7 day running mean Z500 normalized anomaly over North western Pacific (40N,140E-170E)
Analysis and ensemble average
Analysis
Each member
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Normalized temperature anomalies
2002.1.11-15
Time sequences of temperature anomalies in Japan (5 day running mean)
2001.10-2002.1
Oct Nov Dec Jan
Example of one-month prediction products(2)
WWhat?
Ensemble average forecast map ( Initial: 2002/1/3)
PSI200 ; 7day mean (9-15 day forecast range)
PSI200
analysis
PSI200
forecast
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Prediction of the Rossby wave along Asia jet
1/12-1/18
Rossby wave guide along Asia jetDispersion relation of barotropic Rossby wave in U(y) is
ω = Uk-β * k/K2, here, β * = β-∂2U/ ∂y2 , K2 = k2+l2.
Therefore, total wave number of a stationary Rossby wave is
K = Ks =( β * /U)1/2.
Hoskins and Ambrizzi(JAS,1993,1661-) showed that if Ks has maximum at some latitude as figure 1, it works as “Rossby wave guide”
Schematic figure of Rossby wave guide
Climatological Ks in DJF (shade)
and
Analyzed stream function anomaly at 200hPa (2002.1.11-15)
latitude
Temperature anomalies, and Rossby wave along Asia jet
Normalized temperature anomalies
Longitude and height cross section of 20N-30N averaged stream function anomaly
2002.1.11-15
Stream function (200hPa) anomalies
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Time-longitude cross-section of stream function anomaly (20N-30N) at 200 hPa initial 2002.1.3
(left) analysis (right) ensemble mean forecast
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Spread among ensemble members
Spread among ensemble members ( Initial: 2003/10/16) Z500 ; 7day mean (9-15 day )
Predicted stream function (200hPa) anomalies and wave activity flux of two of 26 ensemble member
1 10 20 30
Example of one-month prediction products(3)
MAY 2003
Observed amount of daily precipitation in MAY 2003
96015
97430
98618
91425What ??
Eastward propagation of MJO
1-5 May
2003
6-10 May
11-15 May
16-20 May
OLR Velocity potential (200hPa)
longitude
da
y 1 May
20 MayW
Velocity potential (200hPa) in the equatorial region
Rui and Wang(1990)
Schematics of MJO 3-D structure over the Indian Ocean
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Prediction of MJO in May 2003
Observation 2nd week prediction ( 7 day mean)
Velocity potential anomalies (200hPa)
Stream function anomalies (200hPa)
Ensemble mean
Initial:2003/4/24
2003/5/3-5/9
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Velocity potential anomalies (200hPa)
Stream function anomalies (200hPa)
Observation 2nd week prediction
Ensemble mean
Initial:2003/5/1
2003/5/10-5/16
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Velocity potential anomalies (200hPa)
Stream function anomalies (200hPa)
2nd week predictionObservation
Ensemble mean
Initial:2003/5/8
2003/5/17-5/23
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Prediction of MJO in Oct. 2003
Velocity potential at 200hPa (CHI200)
Longitude
day
20 Sep
10 Oct
Obs.
Fcst
Init:10/9 2nd week
CHI200a
PSI850a
PSI200a
Prediction of MJO in July 1984-1993OBS FCST
CHI200A in the equatorial region
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