Rainfall in Western South America: The “traditional El Niño” versus “Global ENSO”

1. Rainfall in Western South America: The “traditional El Niño” versus “Global ENSO” C F Ropelewski and L Goddard IRI The Earth Institute, Columbia University (With thanks to Yamina Silva, Instituto Geofisico Del Peru) The 28th Climate Diagnostics and Prediction Workshop Reno NV, 20-23 October 2003

2. Traditional El Niño versus Global ENSO El Niño – The maximum in mean annual cycle of sea surface temperature along the west coast of South America i.e. anomalies with respect to the annual mean ENSO – Defined here as the positive displacement of the mean annual cycle of sea surface temperature in the equatorial Pacific i.e. anomalies wrt the mean annual cycle.

4. ENSO, El Niño and Climo

5. ENSO Composite Years 57 –58 (e.g. Jan 57 to Dec 58) 65 - 66 68 – 69 72 – 73 82 – 83 86 – 87 90 – 91 94 – 95 97 – 98

6. All Nino3 ,3.4, 1+2 Thanks to Vern Kousky

7. Event-to-Event Variability of SST Anomalies (El Niño)

8. SST Anomalies (1983-2003) (Source CPC/NOAA)

9. Annual Cycle-Precipitation and Temperature (80.75S, 5.25W, New et al 1999)

10. Sea surface temperature correlations with FMA precipitation in Peru

11. -0.5 – -0.3 -0.3 – 0.3 0.3 – 0.5 0.5 – 0.7 0.7 – 1.0 Correlations Nino1+2 Thanks to Yamina Silva, Instituto Geofisico Del Peru

12. Precip Vs NINO12 Thanks to Yamina Silva, Instituto Geofisico Del Peru

13. -0.5 – -0.3 -0.3 – 0.3 0.3 – 0.5 0.5 – 0.7 0.7 – 1.0 Correlations Nino 3.4 Thanks to Yamina Silva, Instituto Geofisico Del Peru

14. Composite precipitation in tercile classes for western South America tropics

15. Occurrence Nino34

16. Occurrence Nino1+2

17. Meridional and Vertical Winds Mean (1971-2000) FMA Circ Comps 10N EQ 10S Composite Anomaly Nino1&2 10 warmest

18. NINO1&2 – 4 Cases NINO3.4 – 4 Cases Both – 6 Cases

22. NINO1&2 – 4 Cases NINO3.4 – 4 Cases Both – 6 Cases

23. NINO1&2 WARM MARCH 1953 1957 1965 1972

24. NINO3.4 Only March 1966 1969 1973 1995

25. 1958 1992 1993 1983 1998 1987 March of years with both warm NINOP1&2 and NINO3.4

26. Summary • Rainfall in near equatorial regions of Ecuador and Peru are sensitive to the “local” sst anomalies (NINO1&2 here) in FMA. • Correlations i.e. teleconnections with central and western Pacific sst anomalies are weaker during the same season. • Most large “local” FMA sst anomalies occur in conjunction with the larger scale ENSO phenomenon. • There are some notable exceptions including: 1953, 1957, 1965, 1972 and most recently 2001 and 2002.

28. Nino 3.4 Thanks to Vern Kousky

29. Nino 1+2 Thanks to Vern Kousky

30. -0.5 – -0.3 -0.3 – 0.3 0.3 – 0.5 0.5 – 0.7 0.7 – 1.0 Correlations Nino 4.0 Thanks to Yamina Silva, Instituto Geofisico Del Peru

31. -0.5 – -0.3 -0.3 – 0.3 0.3 – 0.5 0.5 – 0.7 0.7 – 1.0 Correlations Nino 3

32. JanuaryN12 Precip Vs NINO12 Thanks to Yamina Silva, Instituto Geofisico Del Peru

33. March N12 Precip Vs NINO12 Thanks to Yamina Silva, Instituto Geofisico Del Peru

36. February N12 Precip Vs NINO12 Thanks to Yamina Silva, Instituto Geofisico Del Peru