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ENSO , PDO and Rainfall over Strong SST Gradients and Ocean Currents in Minerva Hindcasts

ENSO , PDO and Rainfall over Strong SST Gradients and Ocean Currents in Minerva Hindcasts. Bohua Huang Jieshun Zhu Mike Fennessy Xuelei Feng. Mean SST, November. 1-mon lead. 7-mon lead. SST Correlation Skill, November. 1-mon lead. 7-mon lead. SST RMSE, November. 1-mon lead.

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ENSO , PDO and Rainfall over Strong SST Gradients and Ocean Currents in Minerva Hindcasts

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  1. ENSO, PDO and Rainfall over Strong SST Gradients and Ocean Currents in Minerva Hindcasts Bohua Huang Jieshun Zhu Mike Fennessy XueleiFeng

  2. Mean SST, November 1-mon lead 7-mon lead

  3. SST Correlation Skill, November 1-mon lead 7-mon lead

  4. SST RMSE, November 1-mon lead 7-mon lead

  5. Hindcast for November, 7-mon Lead, 2000-2011

  6. ENSO Prediction Skill: • Based on May ICs during 1982-2011 • SST observations: OISST More ensembles or higher resolution (AGCM)?

  7. Jul Sep Nov

  8. Jul Sep Nov

  9. Prediction Skills of Nino 3.4 index (Lead Months)

  10. Using 5 Probability Bins • All three predictions are the same • “Overconfident”

  11. Forecasting PDO: Can we get anything in a region of low skill (low correlation and high RMSE)? What is predictable? Looking for predictable patterns while allowing bias

  12. Need larger ensemble size?

  13. Rainfall over Kuroshio and Gulf Stream Does higher AGCM resolution enhance the effects of warm western boundary currents and large SST gradients ? Do we needhigher OGCM resolution?

  14. Seasonal Climate, Precipitation & SST

  15. Seasonal Climate, Precipitation & SST

  16. Seasonal Climate, Precipitation & SST

  17. Seasonal Climate, Precipitation & SST

  18. Athena ERA40 Athena Minerva Minerva Athena

  19. ERA40 Athena Athena Minerva Athena Minerva

  20. Minerva Minerva

  21. Summary • SST prediction skill does not change significantly from T319to T639 (T1279). • Compared with T319, SST RMSE is reduced for T639 in the western equatorial Pacific. • Categorical estimate of the reliability does not change with resolution. • A PDO pattern can be predicted with skill up to 7 months (allowing for weaker strength). At same ensemble size, T639 shows better pattern and smaller spread. Larger ensemble size may be helpful. • CGCM improves precipitation over Kuroshionear coast. Higher AGCM resolution (T1279) enhances rainfall there, especially off the eastern coast of Japan. • AGCM produces stronger precipitation over Gulf Stream Extension and North Atlantic Current, implying stronger SST gradient forcing. • Model Kuroshioand Gulf Stream are comparable to GODAS but stay coastal too longer. Their extension flows are also weaker. High AGCM resolutions do not show a major impact.

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