Subseasonal forecasting for Africa and tropical climate ... · PDF fileSubseasonal forecasting for Africa and tropical climate sensitive regions Wassila M. Thiaw Climate Prediction
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Subseasonal forecasting for Africa and tropical climate sensitive regions
Wassila M. Thiaw
Climate Prediction CenterNational Centers for Environmental Predictions
International TeamEndalkachew BekeleTom DiLibertoVadlamani KumarNicholas NovellaChalump OonariyaMiliaritiana Robjhon Acknowledgements: CFS Team, NMME Team
• Climate monitoring
• NWP tools – severe weather up to one week
• Subseasonal outlooks (week1, week2, week3, week4, monthly)
• Seasonal outlooks
Hazards Outlooks Basic Requirements
Approach to operational subseasonal forecasting
• Assess state of the MJO and forecasts– MJO active and projected to remain active
• MJO rainfall anomaly composites & NWP toolsGuidance to draw polygons of enhanced or suppressed
rainfall
Phase 4, 90% CI Phase 8, 90% CI
Phase 1, 90% CI Phase 5, 90% CI
MJO rainfall anomaly compositeMaritime Continent, DJF
NE Brazil, DJF
Phase 1, 90% CI Phase 5, 90% CI
Phase 1, 90% CI Phase 5, 90% CI
West Africa, JAS
East Africa, OND
MJO rainfall anomaly composite
Approach to operational subseasonal forecasting
• Assess state of the MJO and forecasts– MJO active and projected to remain active
• MJO rainfall anomaly composites & NWP toolsGuidance to draw polygons of enhanced or suppressed
rainfall
• NWP tools out to two weeks– Low and upper level winds– Low and mid‐level geopotential height– Mean sea level pressure – Ensemble precipitation forecasts
• Probability of exceedence• Bias corrected precipitation anomaly forecasts
Approach to operational subseasonal forecasting
• Assess state of the MJO and forecasts– MJO active and projected to remain active
• MJO rainfall anomaly composites & NWP toolsGuidance to draw polygons of enhanced or suppressed
rainfall
• NWP tools out to two weeks– Low and upper level winds– Low and mid‐level geopotential height– Mean sea level pressure – Ensemble precipitation forecasts
• Probability of exceedence• Bias corrected precipitation anomaly forecasts
• SST anomaly and SST tendency
Data•CFSv2 – 45 day hindcasts•NMME outputs, zero lead•TRMM
Methodology•Construct CFSv2 week1 to week4 P anomaly forecasts•Apply bias correction to the weekly forecasts•Obtain monthly CFSv2 forecasts•Calculate AC between forecasts and observations•Apply CCA correction to NMME forecasts•Evaluate NMME skill
CFS2 and NMME Subseasonal Forecast Skill
Week-1, with BC Week-2, with BC
Week-3, with BC
CFS2 Precipitation (bias corrected) forecast skill
Week-4, with BC
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