Climate Scale Interactions in the Indo-Pacfic Tropical Basins

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1 Climate Scale Interactions in the Indo-Pacfic Tropical Basins Jean-Philippe Boulanger, Albert Fischer, Julie Leloup, Matthieu Lengaigne and many co-auhors Role of an MJO event in the termination of the Indian Dipole Event Role of the March 1997 WWE in El Niño onset WWE activity and ENSO dynamics Conclusions

Role of an MJO event in the termination of the 1994-1995 Indian Dipole Event

2 Role of an MJO event in the termination of the Indian Dipole Event Interannual anomalies of SST and Taux during the and Dipole events

3 Role of an MJO event in the termination of the Indian Dipole Event Strategy : 1- Study the impact of the Nov 1994 MJO in an ocean model (OPA model) 2- Study the atmospheric sensitivity to the oceanic impact of the Nov 1994 MJO (LMDZ)

Role of an MJO event in the termination of the 1994-1995 Indian Dipole

4 Role of an MJO event in the termination of the Indian Dipole Event OPA model response at the equator to the MJO zonal wind stress signal

5 Role of an MJO event in the termination of the Indian Dipole Event

6 Role of an MJO event in the termination of the Indian Dipole Event

Role of an MJO event in the termination of the 1994-1995 Indian

7 Role of an MJO event in the termination of the Indian Dipole Event LMDZ Atmospheric response to the simulated OPA SST patterns

8 Role of an MJO event in the termination of the Indian Dipole Event LMDZ Atmospheric response to the simulated OPA SST patterns LMDZ Indian Ocean zonal wind mean and ensemble 4 N m -2 Dec Jan TAUX REF nowwb E 60E 80E 100E Indian Ocean zonal wind index (70-90E 2S-2N) time evolution S O N D J F M A M J

9 Role of an MJO event in the termination of the Indian Dipole Event LMDZ Atmospheric response to the simulated OPA SST patterns LMDZ Indian Ocean zonal wind mean and ensemble 4 N m -2 2 Dec 0-2 REF nowwb Jan E 60E 80E 100E

10 Role of the March 1997 WWE in El Niño onset

11 Role of the March 1997 WWE in El Niño onset Observations Apr 98 (a) Observed SST (b) Observed SST Anomaly 29.0 Jan Oct Time Jul Apr Jan o E 180 o 140 o W 100 o W 140 o E 180 o 140 o W 100 o W (c) Observed Zonal Wind Stress (d) Observed Zonal Wind stress Anom Apr 98 Jan Oct Time Jul Apr Jan o E 180 o 140 o W 100 o W 140 o E 180 o 140 o W 100 o W Figure 11

12 Role of the March 1997 WWE in El Niño onset Zonal and meridional wind stress on March, 14th, N Zonal Meridional 10N Latitude 0 10S 20S 140E 160E W 140W 120W 100W 80W Longitude 140E 160E W 140W 120W 100W 80W Longitude

13 Role of the March 1997 WWE in El Niño onset Strategy : 1- Study the impact of the March 1997 WWE in an ocean model (OPA model) 2- Study the atmospheric sensitivity to the oceanic impact of the March 1997 WWE (Hadam) 3- Study the impact of the March 1997 WWE in a coupled model (HadOPA)

14 Role of the March 1997 WWE in El Niño onset (a) REF (SST) (b) REF-NWE (SST) Three oceanic responses in SST (1) warming along the Kelvin wave path (2) large warming along the EEWP (3) cooling in the western Pacific May 97 Apr 97 Mar E 160E May 97 Apr W 140W 120W 100W 80W (c) REF (SSS) E 160E W 140W 120W 100W 80W (d) REF-NWE (SSS) Strong zonal currents at the EEWP associated to anon-linear response of the thermo-halodynamical front and the windforced zonal currents Mar 97 Mar Feb E 160E W 140W 120W 100W 80W (e) REF (Surface current) May 97 Apr E 160E W 140W 120W 100W 80W E 160E W 140W 120W 100W 80W (f) REF-NWE (Surface current) E 160E W 140W 120W 100W 80W 0.2

15 -40 Role of the March 1997 WWE in El Niño onset Atmospheric response to the simulated SST patterns May 97 3 (a) REF OLR+SST (b) NWE OLR+SST Strong convection near 160 E in REF Apr 97 Mar (c) REF OLR+TAUX (d) NWE OLR+TAUX Large westerly winds near 160 E in REF May 97 Apr Time -40 Mar E W 100W E W 100W

16 Role of the March 1997 WWE in El Niño onset 0.12 (a) (b) Stronger WWE activity in REF than in NWE: positive feedback Zonal Wind Stress Intensity (N/m2) April May June April May June Time

17 Role of the March 1997 WWE in El Niño onset Eastern Pacific warming leads to a reduction of the Trade Winds Zonal Wind Stress Intensity (N/m2) REF NWE NKW -6 April May June Time

18 Role of the March 1997 WWE in El Niño onset HadOPA coupled model experiments HadOPA Nino3.4 SST Anomaly [year 45-75] SST Anom (C) Jan 45 Jan 50 Jan 55 Jan 60 Jan 65 Jan 70 Time (a) CREF mean SST (b) CWWE mean SST (c) CWWE-CREF mean SST pr Jan 63 Oct 62 Jul 62 pr 62 Jan o E 180 o 140 o W 100 o W 140 o E 180 o 140 o W 100 o W 140 o E 180 o 140 o W 100 o W

19 Role of the March 1997 WWE in El Niño onset (a) CSTA Nino34 SST Anomaly Jan 62 Jan 63 (b) CWWE Nino34 SST Anomaly WWE -2 Jan 62 Jan 63 Time

20 Role of the March 1997 WWE in El Niño onset Oct 62 (a) Location of the Eastern Edge of the Warm Pool Jul 62 Apr 62 Jan 62 WWE 140 o E 160 o E 180 o 160 o W 140 o W (b) Zonal Extension of the Trade Winds Oct 62 Jul 62 Apr 62 Jan 62 WWE 140 o E 160 o E 180 o 160 o W 140 o W

21 Role of the March 1997 WWE in El Niño onset Anomalie de SST C) ( CRE CWE CWN Anomalie de SST C) ( Mar Jun Sep CRE CWE CEP Mar Jun Sep

22 Role of the March 1997 WWE in El Niño onset CRE CWE CWN CEP CW2 2 0 Neutral Moderate warming Strong warming

23 Role of the March 1997 WWE in El Niño onset (a) CRE_Cold CWE_Cold Jun Sep Dec (b) CRE_Cold CWE_Cold Jun Sep Dec

24 Role of the March 1997 WWE in El Niño onset

26 WWE activity and ENSO dynamics

27 WWE activity and ENSO dynamics

28 WWE activity and ENSO dynamics

29 WWE activity and ENSO dynamics Recent changes in ENSO characteristics

30 Conclusions 1- Clear impact of an MJO in the termination of the Dipole event in the IO. Questions: -what favors the occurrence of such an MJO in 94 and not in 97? Is it stochastic or are there any large scale conditions favoring such an occurrence?

31 Conclusions 2- Strong impact of the March 1997 wind event on El Niño -Positive feedbacks (more WWE activity) -Large dispersion (is it model dependent or does it reveal a «natural» sensitivity of the coupled system?) -Can we define criteria associated to a risk of extreme El Niño occurrence? -What is the exact role of the MJO? Is it a real contributor to ENSO or one of the mechanisms by which a strong WWE can occur? In such a case, as much efforts should be put in modelling the other mechanims (e.g. cold surges, cyclones, etc ) as in modelling MJO.

32 Conclusions 3- WWE and ENSO: Is the change in dynamics observed with the Event related to a different impact/sensitivity of IntraSeasonal Activity in the Pacific?

ENSO Cycle: Recent Evolution, Current Status and Predictions. Update prepared by Climate Prediction Center / NCEP 8 March 2010

ENSO Cycle: Recent Evolution, Current Status and Predictions Update prepared by Climate Prediction Center / NCEP 8 March 2010 Outline Overview Recent Evolution and Current Conditions Oceanic Niño Index