JMA Monthly and Seasonal Forecast Systems Yuhei Takaya ytakaya@met.kishou.go.jp Climate Prediction Division Japan Meteorological Agency Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Outline Designing Operational Forecast Systems Targets (Phenomena, Time scales, Applications) Requirements/Limitations Current JMA Operational Systems Monthly (uncoupled) and Seasonal (coupled) forecast systems Practical Examples Future Directions Required Activities Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

“Designing” Operational Forecast Systems Operational Forecast Systems are to be oriented to phenomena, user applications. 10 102 103 104 Time scale (hours) Horizontal scale (km) 2 20 200 2,000 20,000 1d 10d 1m 3m Monsoon MJO ENSO Synoptic Weather Systems Teleconnections Seasonal EPS (CGCM TL95 180 km) Tropical Cyclone Monthly EPS , Early Warning on Extreme Events (TL159 110 km) Mesoscale Weather System Weekly /Typhoon EPS (TL319 60 km) Deterministic (JMA-GSM, TL959 20 km) Atmospheric convection JMA-NHM (5 km) LFM (2 km) Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Current JMA Sub-seasonal to Seasonal Prediction Systems 1 month 　　　　　　3 months 　　　　7 months　　 operated models Early warning information on extreme events 2 weeks AGCM TL159L60 50 member Issued on Tuesday/Friday 1-month forecast week 1 Week 2 Week 3&4 Issued on Friday 3-month forecast 1 month CGCM JMA/MRI-CGCM AGCM: TL95L40 OGCM: 0.3 -1 deg x 1 deg 51 member Issued every month 3 months Warm/cold season forecast 3 months (summer/winter) Issued in Feb. Sep. ENSO outlook ENSO, Indian Ocean SST Issued every month The seasonal forecast system and ENSO prediction system were integrated with an atmosphere-ocean coupled model in Feb. 2010. Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Requirements and Limitations Higher Resolution Higher Frequency More Members Computer Resources Costs & Benefits Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

JMA Monthly EPS SST X200 and Div Wind Precipitation, PSI200, WAF200 Z500&WAF200 T850

JMA Monthly EPS Precipitation, PSI200, WAF200 SST X200 and Div Wind Z500&WAF200 T850

Predictability in the Midst of Chaos - Predictability at SSS Time Scale- (Shukla 1998 Science ) Better Atmosphere, Ocean, Land, Sea-ice initialization Initial value problems (predictability of 1st kind) Inertia or memory (ocean heat content, snow…) External forcing (volcanic eruption, solar activity, green house gases…) Boundary condition problems (predictability of 2nd kind) Feedback between boundary conditions and atmospheric internal dynamics gives an additional predictability. Interaction between predictabilities of 1st and 2nd kind Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

JMA Monthly Forecast System Atmospheric I. C. Atmospheric perturbations Trop.&Ext.-trop. bred vector 25 members start from Wednesday. 25 members start from Thursday. 50 members in total Atmospheric General Circulation Model (JMA-GSM0803C) TL159L60 (~110km) JMA Global Data Assimilation System JMA Land Surface Analysis Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Arctic Oscillation during Dec. 2009-Feb. 2010 Jan. 2010 Feb. 2010 -300 -180 -60 0 60 180 300 [m] A negative phase of the Arctic Oscillation (AO) pattern was dominant through Winter 2009/2010.

Forecast Skill of Operational JMA Monthly Forecast Anomaly Correlation Week 1 Week 2 Week 3-4 Week 1-4 Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

AO index in Winter 2009/2010 Index of EOF1 score (500hPa GPH, DJF mean) (1) 2009/12/10 　 (2) 2010/1/28 The winter 2009/2010 was the most prominent period during 1979-2010. Spatial Pattern of GPH500 EOF1 (Area weighted Covariance, 22.6 %) Computed with 1979-2005 DJF mean 500-hPa GPH. Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Prediction for negative AO Case Initial Date: 2009/12/10 1-month （4-week） mean 500-hPa GPH Anomaly Analysis (JRA-25) Forecast 120 90 60 30 -30 -60 -90 -120 [m] 0.84 1-month (4-week) mean Anomaly Correlation 0.84 Week 1 0.93, Week 2 0.77, Week 3-4 0.56 Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

200-hPa Westerly Jet Initial Date: 2009/12/10 200-hPa Zonal Wind Anomaly 4-Week Mean Forecasts Analysis (12/12-1/8) Forecast I.C.; 2009/12/09 Forecast I.C.:2009/12/10 14 Strong Sub-tropical Jet Weak Polar Front Jet [m/s] Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

E-vector (Hoskins et al. 1983 JAS) Momentum Transport Diagnostics: E-vector E=(v’2-u’2, -u’v’) Cyclonic Circulation Anti-Cyclonic Circulation E Divergence Convergence Anti-Cyclonic Circulation Cyclonic Circulation Ian N. James (1994) “Introduction to Circulating Atmospheres” Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Divergence of E-vector Mid-latitude 30N-40N North Atlantic 30N-40N, 90W-0 x104 [m s-2] x104 [m s-2] ●　Hindcast (Initial Date: 10 Dec.) 　　 Operational Forecast (2009/12/10) ○　JRA-25/JCDAS Analysis North Pacific 30N-40N, 170E-120W x104 [m s-2]

JMA Seasonal EPS Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

JMA Seasonal EPS The seasonal forecast relies on the predictability that comes from the ENSO variability. The East Asian monsoon is essentially an ocean-atmosphere-land coupled system. Coupled models are suitable for predicting its variability at a seasonal time scale. The new JMA coupled forecast system has been up and running for the JMA ENSO prediction system since Feb. 2008, and was introduced to the JMA seasonal forecast in Feb. 2010. Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

New JMA Seasonal Forecast System coupler (w/ flux adjustment) Climate Data Assimilation JRA-25/JCDAS Atmosphere-Ocean Coupled model (JMA/MRI-CGCM) JMA GSM （TL95L40: ~180km） Ocean model (MRI.COM ) 1.0°×(0.3°-1.0°), 51 levels Ocean Data Assimilation System MOVE/MRI.COM-G Atmospheric perturbations Trop.&Ext. trop bred vector Atmospheric I. C. Oceanic I. C. Atmospheric BGM + Lagged Averaging Forecast Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Operational Schedule Ocean Data Assimilation Forecasts 9 members / 5 days LAF 10 days Window NINO3 SSTA Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

South China Flood in 2010 BBC News http://news.bbc.co.uk/2/hi/asia-pacific/4617891.stm Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Precipitation Forecasts for June 2010 (I.C. : May) Beijing ECMWF Exeter Melbourne Montreal Moscow Seoul Tokyo Toulouse Washington Observation; OLR anomaly Original data are provided by NOAA. (mm/day) WMO LC website http://www.wmolc.org/

JMA future plan on the next HPC Weekly EPS TL479L100 (~40 km) in 2013 Monthly EPS TL319L100 (~60 km) in 2013 Development of integrated Weekly EPS and Monthly EPS (Seamless system) is under discussion. Seasonal EPS AGCM: TL159L60 (80?) (~110 km) in 2014 OGCM: Tripolar grid, 1deg x 0.3-0.5 deg. 53 levels. Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Forecast Skill wrt Lead Time The lead time is important at a 1-month time scale. ACC (Daily 500-hPa GPH) ACC (7-day mean 500-hPa GPH) 50 ensembles 50 ensembles Scores if forecasts 3-day before used. Based on verification of real-time JMA operational forecasts in 2006. Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Toward “Seamless Prediction System” Week-1 Week-2 Week-3 Week-4 Weekly EPS (TL479L100) 2-Week EPS (Early Warning) Monthly EPS (TL319L100) reforecast FY2013- 2-Week EPS (TL479L100) reforecast Monthly EPS (TL319L100) FY ? FY ??? 2-Week EPS (TL479L100) reforecast Monthly EPS (TL319L100) Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Required Activities for Further Improvement of SSS time scale International research projects to investigate predictability at monthly time scale 　(extended TIGGE ???) International research projects for key processes of predictability, MJO, ENSO, etc… 　(CLIVAR MJO WG etc. ) Standard verification framework for operational forecasts at sub-seasonal (monthly) time scale. (under WMO, CBS? SVS?) Research community Operational Community Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Thank you for your kind attention. END Thank you for your kind attention. Hope this talk to help the coming discussion. Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec

EOF1(AO), REOF(PNA, NAO) Scores Initial Date: 2009/12/10 (a) EOF1 22.6 % AO, NAO, PNA Indices were well predicted. Red： Ensemble mean Blue： Analysis Grey： Each realization (b) REOF1 16.6 % (c) REOF2 16.1 %

High-Frequency Wave Activity Anomaly K=½(u’2+v’2)　Initial Date: 2009/12/10 K anomaly and U300 Anomalies Analysis (JRA-25 , 12/12-1/8) K anomaly and U300　Anomalies Ensemble Forecast ( I.C. 12/10) Contours: 300-hPa Zonal Wind Anomaly [m s-1] Colors: High-Frequent Wave Activity Anomaly x 10-5 [m2 s-2] Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Convergence of Momentum Flux ∂y (-u’v’) and U300 Initial Date: 2009/12/10 ∂y (-u’v’), U300 Anomaly Analysis (JRA-25 , 12/12-1/8) ∂y (-u’v’), U300 Anomaly Ensemble Forecast ( I.C. 12/10) Contours; Convergence of Eddy Momentum Flux by High-Frequency Variation ∂y (-u’v’) (contour interval: 2・10-4 [m s-2] ) Colors: 300-hPa Zonal Wind Anomaly [m s-1] Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Ensemble Perturbations The JMA monthly forecast system produces initial perturbations using the Bred Vectors, which is specially intended to obtain large-scale growing modes in the tropics. Chikamoto et al. 2007, GRL Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Tropical Bred Vector Perturbation The space-time spectrum of the 200-hPa velocity potential of the tropical bred vector averaged over the 10S–10N region. Hovmoeller diagrams of 200-hPa velocity potential averaged over the 10S–10N region for (a) the observed field, (b) the bred vector Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Perturbation (500-hPa GPH Spread) OLD NEW NEW-OLD Old Singular Vector with a simplified model (NH only) New Combination of BV method in the tropics and extra-tropics (NH only). [m] Courtesy: M. Hirai@JMA Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Perturbation and Spread-Skill Relationship N. H. S. H. New RMSE Old Spread Perturbations in tropics contribute to increase of the spread in extra-tropics. Courtesy: M. Hirai@JMA Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Precipitation in June 2010 Ratio to Normals Zhejiang 174 % Fuzhou 157 % Based on CLIMAT reports Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

Index of 1st Mode Index of the 1st Mode The 1st mode is well correlated with Wang and Fan Index (Wang and Fan ,1999). Wand and Fan Index : U850 (5-15N,90-130E) – U850 (22.5-32.5N,110-140E) Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

2009/12/10 Z500 Analysis (12/12-1/8) Forecast I.C.; 2009/12/10 Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

2009/12/10 T850 Analysis (12/12-1/8) Forecast I.C.; 2009/12/10 Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010

2009/12/10 SLP Analysis (12/12-1/8) Forecast I.C.; 2009/12/10 Workshop on “Sub-seasonal to Seasonal Prediction”, Exeter, UK, 1-3 Dec. 2010