GMAO’s Seasonal-to-Interannual Forecasts & Potential contributions to MME Forecasts
description
Transcript of GMAO’s Seasonal-to-Interannual Forecasts & Potential contributions to MME Forecasts
30 Nov 2005
GMAO’s Seasonal-to-Interannual Forecasts &
Potential contributions to MME Forecasts
Max SuarezGlobal Modeling and Assimilation Office (GMAO)
Michele Rienecker, Randy Koster, Siegfried SchubertChristian Keppenne, Rolf Reichle, Shu-Chih Yang
CTB SAB MeetingAugust 28, 2007
30 Nov 2005
12 month Coupled Integrations: 6-30 ensemble members
AGCM (AMIP forced with Reynolds SST; NCEP Analyses)
Ocean DAS (Surface wind analysis, GPCP precipitation; Reynolds SST, Temperature profiles; synthetic salinity profiles; altimetry)
Ocean state estimate perturbations:’s randomly from snapshots or from EnKF
Atmospheric state perturbations: ’s randomly from previous integrations
AGCM: NSIPP1 AGCM, 2 x 2.5 x L34LSM: Mosaic (SVAT)OGCM: Poseidon v4, 1/3 x 5/8 x L27, with embedded mixed layer physicsCGCM: Full coupling, once per day
ODAS: Optimal Interpolation of in situ temperature profiles; Ensemble Kalman Filter“LDAS”: Offline forced land states (recalibrated)
CGCMv1 Ensemble Forecast SystemCGCMv1 Ensemble Forecast SystemCGCMv1 Ensemble Forecast SystemCGCMv1 Ensemble Forecast System
30 Nov 2005
CGCMv1 Forecasts initialized 1 Aug, 2007CGCMv1 Forecasts initialized 1 Aug, 2007CGCMv1 Forecasts initialized 1 Aug, 2007CGCMv1 Forecasts initialized 1 Aug, 2007
30 Nov 2005
1-month lead
3-month lead
6-month lead
EnKF OI-TS
Forecast skill (ACC) from CGCMv1SST anomaly
Initialized 1 March, 1993-2006
Forecast skill (ACC) from CGCMv1SST anomaly
Initialized 1 March, 1993-2006
30 Nov 2005
1-month lead
3-month lead
6-month lead
EnKF OI-TS
Forecast skill (ACC) from CGCMv1Heat content anomaly in upper 300m
Initialized 1 March, 1993-2006
Forecast skill (ACC) from CGCMv1Heat content anomaly in upper 300m
Initialized 1 March, 1993-2006
30 Nov 2005
July Forecast Anomaly Correlation
MAYstart
FEBstart
AUGstart
NOVstart
CNT Mean BV Mean BV1 Mean BV2
30 Nov 2005
GEOS-5 CGCM Forecast System - Status & PlansGEOS-5 CGCM Forecast System - Status & PlansGEOS-5 CGCM Forecast System - Status & PlansGEOS-5 CGCM Forecast System - Status & Plans
GEOS-5 AGCM, Catchment LSM, MOM4• Simulation for several decades, still tuning
Configuration• AGCM: 1° 1.25°72L• MOM4: 0.25° 0.5° 40L (telescoping grid in equatorial band - NCEP configuration)
Forecast Initialization• MOM4 initialized by ODAS-2 multivariate assimilation (EnKF) • LSM initialized by offline (LIS) forcing• AGCM initialized by reanalysis (NCEP, MERRA?)
Hindcast strategy• 1993-2007• Use low-resolution MERRA for atmosphere and also for ocean forcing• Coupled EnKF?
Ensemble Strategy possibilities• mimic NCEP, initialization every day• mimic NCEP (except initialization every 3days) + 3-member ensemble from breeding• all ensemble members initialized 1st of the month
30 Nov 2005
GEOS-5 CGCM- contributing to the MMEGEOS-5 CGCM- contributing to the MMEGEOS-5 CGCM- contributing to the MMEGEOS-5 CGCM- contributing to the MME
GEOS-5 timeline• Q2-FY08 Begin ODAS• Q3-FY08 Begin hindcasts• Q4-FY08 Contribute selected G5 hindcast months to CTB MME
Proposed Interim Strategy• Use CGCMv1 (ensembles initialized 1st month, 1993 - present)• Q1-FY08 contribute EnKF system for selected months as test of MME
30 Nov 2005
CGCMv1 Forecasts initialized 1 Aug, 2007CGCMv1 Forecasts initialized 1 Aug, 2007CGCMv1 Forecasts initialized 1 Aug, 2007CGCMv1 Forecasts initialized 1 Aug, 2007
30 Nov 2005
30 Nov 2005
• Forecast errors show a strong dependence on seasons/starting month
• Ensemble spread doesn’t have the season-dependent characteristic shown in forecast errors
• Ensemble spread is too small compared to the forecast error, especially at early months
SST ensemble spread vs. SST errorIn Nino3 region
Mean SST error in Nino3 SST Ensemble spread in Nino3
error
spread
Forecast month
Shu-Chih Yang
ACC in Nino3
Ensemble forecast system performanceEnsemble forecast system performanceEnsemble forecast system performanceEnsemble forecast system performance