New Coupled Forecast System at the Japan Meteorological Agency

New Coupled Forecast System at the Japan Meteorological Agency

Yuhei Takaya1 ([email protected]), Tamaki Yasuda2, Satoshi Matsumoto2, Tosiyuki Nakaegawa2,

Hirotaka Kamahori1 and Tomoaki Ose2

1. Climate Prediction Division, Japan Meteorological Agency2. Meteorological Research Institute, Japan Meteorological Agency

NOAA 32nd Annual Climate Diagnostics and Prediction Workshop, October 22-26, 2007, Tallahassee, Florida

Japan

NOAA 32nd Annual Climate Diagnostics and Prediction Workshop, October 22-26, 2007, Tallahassee, FloridaAgencyMeteorological

MeteorologicalResearchInstitute

2

History of ENSO Monitoring and Forecast Service at JMA

1992

1996

1999

2003

2008

2010

The Second Version of JMA’s CGCM (JMA-CGCM02)

Launch of ENSO Monitoring Service

Start-up of Ocean Monitoring with the Operational Ocean Data Assimilation System (ODAS)Start-up of ENSO Forecast Service with the CGCM (JMA-CGCM)

The New Version of JMA’s Coupled Forecast System (MOVE-G/MRI.COM, JMA/MRI-CGCM)

Seasonal Forecast with a CGCM

Japan



3

Table of Contents

• Introduction of a new JMA’s coupled forecast system for ENSO forecast– New ocean assimilation system

(MOVE-G/MRI.COM)– New atmosphere-ocean coupled model

(JMA/MRI-CGCM)

• Forecast skill of ENSO and Asian summer monsoon

• Summary

Japan



JMA Forecast System for ENSO Prediction

Coupled model(JMA/MRI-CGCM)

Atmospheric model(JMA/MRI Unified AGCM)

Ocean model (MRI.COM)

Coupler

Ocean Data Assimilation System(MOVE/MRI.COM-G)

Atmospheric Analysis(JRA-25, JCDAS)

Japan



Ocean Data Assimilation System (MOVE-G/MRI.COM)

MOVE (Multivariate Ocean Variational Estimation) System

Usui et al. (2006)

• Ocean Model : MRI Community Ocean Model (MRI.COM)• 3D-VAR(T,S) Observation Data: T, S on GTS, SST (COBE-SST, Ishii et al. 2005), SSH (TOPEX/POSEIDON, JASON-1, ERS-1,2, ENVISAT)• Vertical Coupled Temperature-Salinity EOF modes　 Fujii and Kamachi(2003)

• Incremental Analysis Update (IAU)

Japan



Improvement of the thermocline variability

shade: dT/dzlines: isotherms of 20°C

The MOVE system represents the more realistic interannual variability of thermocline.TAO OBS.

MOVE-G CURRENT

Japan



Comparison of Temperature Climatology

The temperature climatology of MOVE system is relatively close to the climatology of WOA01.

Forget, Heimbach, and Menemenlis (2006)CLIVAR/GODAE Meeting on Ocean Synthesis Evaluation

Japan



Comparison of Salinity Climatology

Forget, Heimbach, and Menemenlis (2006)CLIVAR/GODAE Meeting on Ocean Synthesis Evaluation

The salinity climatology of MOVE system is relatively close to the climatology of WOA01.

Japan



New Coupled Model (JMA/MRI-CGCM)

AGCM JMA/MRI Unified AGCM

• TL95L40 (horizontal resol. ~ 180km)

OGCM MRI.COM

Ishikawa et al. (2005)

• 75S-75N, 0-360E

• horizontal resolution: lon 1.0°　, lat 0.3-1.0°• vertical resolution : 50 levels

(23 levels in the upper 200m)

Coupler • coupling interval : 1 hour

• flux adjustment for heat and momentum flux

Japan



Forecast Skill of SST in NINO3.4

ACC (NINO3.4) RMSE (NINO3.4)

Period: 1979-20051 member forecast started from the end of every month(NOT ensemble forecast)

red: JMA/MRI-CGCMblue: current operational modelblack: persistence

(°C )

Japan



Forecast Skill of SST in WTP

ACC (WTP) RMSE (WTP)

Period: 1979-20051 member forecast started from the end of every month(NOT ensemble forecast)

red: JMA/MRI-CGCMblue: current modelblack: persistence

(°C )

Japan



Experimental Setting of the Retrospective Seasonal Forecast

• 10-member ensemble forecasts are started from the end of January.(Two-tier AGCM forecasts are started from Feb. 10th.)

• Period of the retrospective forecast is 22 years (1984-2005).• CO2 concentration is updated during the retrospective forecast period.

• Initial data for land model are climatology.

JAN 10 membersAUG

7 months Jun.-Aug.

4-month lead

Japan



Forecast Skill of Precipitation (JJA, 4 months lead)

• 10-member ensemble forecast started from around the end of January.• Period of the retrospective forecast is 22 years (1984-2005).• JJA mean precipitation is verified with CMAP analysis.

The JMA/MRI-CGCM shows better skill than JMA’s two-tier operational model.

ACC (JMA/MRI-CGCM) ACC (Two-tier AGCM)

Japan



SST-Precipitation Relationship in WTP in Boreal Summer

• Why CGCMs can predict precipitation better than AGCMs ?

Temporal correlation coefficients between JJA mean precipitation and JJA mean SST from (a) CMAP and COBE-SST analysis, (b)JMA/MRI-CGCM, (c)JMA two-tier operational model.

(a) Observation (b) JMA/MRI-CGCM (c) Two-tier AGCM

eg. Wang et al. 2004, Wang et al. 2005, Kitoh and Arakawa 1999, Kobayashi et al. 2005

Negative Correlation

Japan



Forecast Skill of Webster-Yang Index (JJA, 4 months lead)

JMA/MRI-CGCM

Two-tier AGCM

ACC=0.64

ACC=0.47

Webster-Yang index: U850(EQ-20N, 40-110E) –U200(EQ-20N, 40-110E)

Webster and Yang (1992)

10-member ensembleInit: the end of Jan.Period:1984-2005Ref. : JRA-25JJA mean

(m/s)

(m/s)

Japan



Forecast Skill of East Asian Summer Monsoon (JJA, 4 months lead)

JMA/MRI-CGCM

Two-tier AGCM

ACC=0.58

ACC=0.04

DU2 index: U850(5-15N, 90-130E) -U850(22.5-32.5N, 110-140E)

Wang and Fan (1999)

10-member ensembleInit: the end of Jan.Period:1984-2005Ref. : JRA-25JJA mean

cf. Kug et al. (2007)

(m/s)

(m/s)

Japan



ROC Score of 850 hPa Temperature (upper tercile, JJA, 4 months lead)

• 10-member ensemble forecast started from around the end of January.• Period of the retrospective forecast is 22 years (1984-2005).• JJA mean temperature at 850 hPa is verified with JRA-25.

ROC (JMA/MRI-CGCM) ROC (Two-tier AGCM)

ROC Area (tropics) : 0.59ROC Area (tropics) : 0.65

cf. Graham et al. (2005)

Japan



Summary and Future Plans

• The JMA/MRI-CGCM shows better forecast skill of Nino3.4 SST than the current operational ENSO forecast model. (The ACC is more than 0.7 at a lead time of 6 months.)

• The JMA/MRI-CGCM shows better forecast skill of the Asian summer monsoon circulation (W-Y index and DU2 index) and precipitation compared with the current operational two-tier system.

• The JMA’s new coupled forecast system for ENSO prediction will be operated in early 2008.

• JMA now plans to improve the JMA/MRI-CGCM as a seasonal forecast model and start one-tier forecast in 2010.

Japan



Thank you for your kind attention.

JMA’s mascot “Harerun”

Japan



References

• Fujii, Y., and M. Kamachi (2003), Three-dimensional analysis of temperature and salinity in the equatorial Pacific using a variational method with vertical coupled temperature-salinity empirical orthogonal function modes, J. Geophys. Res., 108(C9), 3297, doi:10.1029/2002JC001745.

• Graham, R. J., M. Gordon, P. J. Mclean, S. Ineson, M. R. Huddleston, M. K. Davey, A. Brookshaw, R. T. H. Barnes (2005), A performance comparison of coupled and uncoupled versions of the Met Office seasonal prediction general circulation model, Tellus A, Volume 57, Number 3, May 2005 , pp. 320-339(20)

• Kitoh, A, O. Arakawa (1999), On overestimation of tropical precipitation by an atmospheric GCM with prescribed SST. Geophys. Res. Lett. 26:2965-2968

• Kobayashi, C., S. Maeda, A. Ito, Y. Matsushita and K. Takano (2005), Relation between SSTs and Predictability of Seasonal Mean Precipitation over the Western Tropical Pacific. JMSJ, Vol. 83, 919-929.

• Kug, J.-S., I.-S. Kang and D.-H. Choi (2007): Seasonal climate predictability with Tier-one and Tier-two prediction systems, Clim. Dyn., DOI 10.1007/s00382-007-0264-7

• Usui, N., S. Ishizaki, Y. Fujii, H. Tsujino, T. Yasuda, M. Kamachi (2006), Meteorological Research Institute Multivariate Ocean Variational Estimation (MOVE) System: Some early results. Adv. Space Res. 37, 806-822

• Wang, B. and Z. Fan (1999), Choice of South Asian summer monsoon indices. Bull. Amer. Meteor. Soc., 80, 629-638, 1999.

• Wang, B., I.-S. Kang and J. -Y. Lee (2004), Ensemble Simulations of Asian-Australian Monsoon Variability by 11 AGCMs. J. Climate, 17, 4, 803-818.

• Wang, B., Q. Ding, X. Fu, I.-S. Kang, K. Jin, J. Shukla, and F. Doblas-Reyes (2005), Fundamental challenge in simulation and prediction of summer monsoon rainfall, Geophys. Res. Lett., 32, L15711, doi:10.1029/2005GL022734.

• Webster, P. J. and S. Yang: Monsoon and ENSO (1992), Selectively interactive systems. Quart. J. Roy. Meteor. Soc., 118, 877-926.

Japan



Japan



22

History of ENSO Monitoring and Forecast Service at JMA

1992

1996

1999

2003

2008

2010

The Second Version of JMA’s CGCM (JMA-CGCM02)

Launch of ENSO Monitoring Service

Start-up of Ocean Monitoring with the Operational Ocean Data Assimilation System (ODAS)Start-up of ENSO Forecast Service with the CGCM (JMA-CGCM)

The New Version of JMA’s Coupled Forecast System (MOVE-G/MRI.COM, JMA/MRI-CGCM)

Seasonal Forecast with a CGCM

Japan



System design of MOVE/MRI.COM

Future

Past MRI.COM （ OGCM ）prediction

first-guessObservation・ temperature・ salinity・ SSH

Coupled T-S EOF

Climatology

3DVAR

Gridded analysis fields

IAU

predictionMRI.COM

POpULar

Assimilation

Assimilation

Japan



Vertical Coupled T-S EOF Modes

Domain

segmentation for

vertical coupled T-S

EOF modes

Vertical coupled

T-S EOF modes

for a red box region

Te

mp

era

ture

Sa

Iinit

y

1st 2nd 3rd 4th 5th

Fujii and Kamachi (2003)

Japan



Impact on the Warm Water Heat Content (WHC)

WHC: Heat

content in warm

water (>28 °C ）WHC decreases in the thick barrier layer area

because of bad barrier layer expression.

BLT (Color) at Eq.WHC=10 (Black line)

Difference of WHC (cal/cm2) (With S correction – without S correction)

Thick barrier layer area has good correspondence with the area of large WHC.

Japan



Salinity Impact on the Equatorial Undercurrent

With Salinity Correction 1993-2001 mean

Without Salinity Correction 1993-2001 mean

Eq-140W Sep96-Aug01 mean

Tao

With S

Without S

EUC is weak without S correction

The profile with S correction is closer to the observed profile

Japan



Forecast Skill of SST (JJA, started from JAN)


• 10-member ensemble forecast started from around the end of January.• Period of the retrospective forecast is 22 years (1984-2005).• JJA mean SST is verified with COBE-SST analysis.

MSSS (JMA/MRI-CGCM) MSSS (Two-tier AGCM)

Japan



Forecast Skill of SST (DJF, started from JUL)


• 10-member ensemble forecast started from around the end of July.• Period of the retrospective forecast is 22 years (1984-2005).• DJF mean SST is verified with COBE-SST analysis.


Japan



Forecast Skill of T2m (JJA, started from JAN)


• 10-member ensemble forecast started from around the end of January.• Period of the retrospective forecast is 22 years (1984-2005).• JJA mean T2m is verified with JRA-25.


Japan



Forecast Skill of T2m (DJF, started from JUL)


• 10-member ensemble forecast started from around the end of July.• Period of the retrospective forecast is 22 years (1984-2005).• DJF mean T2m is verified with JRA-25.


Japan



ROC Area of 2-m Temperature (JJA, upper tercile)

• 10-member ensemble forecast started from around the end of January.• Period of the retrospective forecast is 22 years (1984-2005).• JJA mean temperature at 2 m height is verified with JRA-25.

ROC Area (JMA/MRI-CGCM) ROC Area (Two-tier AGCM)



Japan



ROC Area of 2-m Temperature (DJF, upper tercile)

• 10-member ensemble forecast started from around the end of July.• Period of the retrospective forecast is 22 years (1984-2005).• DJF mean temperature at 2 m height is verified with JRA-25.




Japan



ROC Area of 850 hPa Temperature (JJA, upper tercile)

• 10-member ensemble forecast started from around the end of January.• Period of the retrospective forecast is 22 years (1984-2005).• JJA mean temperature at 850 hPa is verified with JRA-25.



Japan



• 10-member ensemble forecast started from around the end of July.• Period of the retrospective forecast is 22 years (1984-2005).• DJF mean temperature at 850 hPa is verified with JRA-25.



ROC Area of 850 hPa Temperature (DJF, upper tercile)

Japan



ROC Area of SLP (DJF, upper tercile)

• 10-member ensemble forecast started from around the end of July.• Period of the retrospective forecast is 22 years (1984-2005).• DJF mean temperature at 850 hPa is verified with JRA-25.



Japan



ROC of T850 (JJA, upper tercile)

• 10-member ensemble forecast started from around the end of Jan.• Period of the retrospective forecast is 22 years (1984-2005).• DJF mean temperature at 850 hPa is verified with JRA-25.

ROC (JMA/MRI-CGCM) ROC (Two-tier AGCM)

Documents

New Coupled Forecast System at the Japan Meteorological Agency