Update of NMC/CMA Global Ensemble Prediction

System

Jing Chen, Hua Tian, Gou Deng

National Meteorological Center (NMC), CMA

Contents

• GEPS System Configuration• GEPS Update• Tigge relative research and use

T213L31

BGM perturbation method

Con.l Run

IC1+ IC1- IC2+ IC2-

Run all members.

Product processing

SSI+ATOVSObs

EPS Upgraded T213 GEPS System

model T213L31

Horizontal Resolution

0.5625

Vertical Resolution

31

Analysis system 3D SSI+ATOVS

Perturbation method

BGM

Perturbation region

Global

EPS members 15

forecast 10 days

Typhoonrelocation and vortex perturbation

T213 GEPS Configuration

Integration withModel T213

IC 1IC 2

First Guess 1

12 or 24 hrs

DIFF=FG1-FG2

Filtered DIFFGauss Filter, Remove waves no.>9

MASKRescalingProcess

Perturbation

Analysis

First Guess 2

EP mem1

EP mem2

1~10 days

GetiniconGetinicon.cmdcmd

GetrscalGetrscal..cmdcmd

ModelnModeln..cmdcmd

T213 GEPS Based on-BGM T213 GEPS Based on-BGM System Structure and Flow ChartSystem Structure and Flow Chart

Global EPS Upgrade Data assimilation from Optimal Interpolation 3DVAR +ATO

VS in 2008T213-EPS ACC (NH 500mb Height)

average for 20080801-20080831

00.10.20.30.40.50.60.70.80.9

1

1 2 3 4 5 6 7 8 9 10valid(day)

AC

C S

core

EPS_mean Control Skill line

ACC (NH 500mb Height)average for 20060601-20060831

00.10.20.30.40.50.60.70.80.9

1

1 2 3 4 5 6 7 8 9 10valid(day)

AC

C S

core

EPS_mean Control Skill line

CMA old EPSCMA upgraded EPS

Control run forecast skill improve from 5 to 6.5 day

Anomaly Correlation Coefficient (ACC)

New update in 2009 for Global TC ensemble prediction

Old TC EPS ： Perturbed TC environmentUpgrade TC EPS ： perturbed TC environment ＋ Vortex.

Old TC EPS New TC EPS Difference

The ensemble products update on the NMC’s webhttp://www.nmc.gov.cn/publish/nwp/eps-t213/probability/precipitation/index.htm

Tigge relative research and use

• Relative Research– Global EPS system upgrade;

– Typhoon EPS system development;

– Method for bias correction & combination, cluster;

– Numerical model error analysis and NWP Probability;

– Hydrology prediction drived by TIGGE data;

– Method for severe weather potential forecast;

– TIGGE-LAM researches

• Data operational use – Medium-range forecast with TIGGE data;

– CXML typhoon track EPS product;

Global TC track EPS CXML digital products

CXML ( Cyclone extensible Markup Language):

CMA ECMWF NCEP

JMA KMA UKMO

No.0817, HIGOS (2008)

Hydrology forecast based on downscaling TIGGE precipitation

TIGGE precipitation in watershed

CMA CMA

ECMWF ECMWF

NCEPNCEP

Period and flood runoff forecast based on EPS

data

Super EPS flood runoff probability prediction