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El Niño-Southern Oscillation and regional rainfall of Vietnam Ramasamy Suppiah 10 December 2012.

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Presentation on theme: "El Niño-Southern Oscillation and regional rainfall of Vietnam Ramasamy Suppiah 10 December 2012."— Presentation transcript:

1 El Niño-Southern Oscillation and regional rainfall of Vietnam Ramasamy Suppiah 10 December 2012

2 Sea surface temperature anomalies for El Niño and La Niña conditions ENSO-Vietnam rainfall| Ramasamy Suppiah 2 |

3 Temporal pattern of the ENSO : SST anomalies ENSO-Vietnam rainfall| Ramasamy Suppiah 3 |

4 Temporal pattern of the Southern Oscillation Index ENSO-Vietnam rainfall| Ramasamy Suppiah 4 |

5 Decadal variations in ENSO characteristics ENSO-Vietnam rainfall| Ramasamy Suppiah 5 |

6 SST anomalies for La Niña and El Niño events ENSO-Vietnam rainfall | Ramasamy Suppiah 6 |

7 Sea surface temperature anomalies and circulation patterns during Normal, El Niño and La Niña conditions ENSO-Vietnam rainfall| Ramasamy Suppiah 7 | Normal Pacific pattern. Equatorial winds gather warm water pool toward west. Cold water upwells along South American coast El Niño Conditions. Warm water pool approaches South American coast. Absence of cold upwelling increases warming La Niña Conditions. Warm water is farther west than usual Normal patternLa Niña patternEl Niño pattern

8 ENSO indices and Climatic seasons of Vietnam ENSO-Vietnam rainfall| Ramasamy Suppiah 8 | ENSO Indices: Southern Oscillation Index (SOI) (1979-2011) NINO3.4 Index (1979-2011) Seasons: First Intermonsoon season (April-May) Southwest monsoon season (June-September) Second Intermonsoon season (October-November) Northeast monsoon season (December-March)

9 Mean rainfall during First Intermonsoon (FIM) and Southwest (SWM) monsoon seasons ENSO-Vietnam rainfall| Ramasamy Suppiah 9 | FIM (April-May)SWM (June-September) mm/day Latitude

10 Mean rainfall during Second Intermonsoon (SIM) and Northeast (NEM) monsoon seasons ENSO-Vietnam rainfall| Ramasamy Suppiah 10 | SIM (October-November) NEM (December-March) mm/day Latitude

11 Rainfall regions of Vietnam ENSO-Vietnam rainfall| Ramasamy Suppiah 11 | R1: Northwest region R2: Northeast region R3: Red river delta region R4: North central region R5: South central region R6: Central highlands region R7: Southern region

12 Relationship between the Southern Oscillation Index (SOI) and rainfall of Vietnam ENSO-Vietnam rainfall| Ramasamy Suppiah 12 | SOI/Rainfall First Inter monsoon Season (April- May) Southwest monsoon season June- September Second Inter monsoon Season (October- November) Northeast monsoon season December to MarchANNUAL Region1 0.34-0.240.150.030.01 Region2 0.060.080.00-0.14-0.06 Region3 0.02-0.270.22-0.10 Region4 0.230.020.400.350.44 Region5 0.38-0.080.610.510.58 Region6 0.41-0.350.620.410.30 Region7 0.55-0.290.560.650.33 Statistically significant values are shown by bold letters

13 Relationship between NINO3.4 index and rainfall of Vietnam ENSO-Vietnam rainfall| Ramasamy Suppiah 13 | NINO3.4 SSTA/Rainf all First intermonsoon Season (April- May) Southwest monsoon season June- September Second intermonsoon Season (October- November) Northeast monsoon season December to MarchANNUAL Region1 -0.320.18-0.08-0.03-0.02 Region2 -0.07-0.060.040.060.03 Region3 -0.200.17-0.22-0.01-0.03 Region4 -0.430.16-0.57-0.28-0.43 Region5 -0.520.29-0.64-0.48-0.50 Region6 -0.480.35-0.60-0.36-0.28 Region7 -0.760.12-0.46-0.52-0.37 Statistically significant values are shown by bold letters

14 Relationship between seasonal rainfall variability at region 7 and ENSO ENSO-Vietnam rainfall| Ramasamy Suppiah 14 | Southern Oscillation-RainfallNINO3.4-Rainfall

15 Interannual variations of First and Second intermonsoon seasons’ rainfall at Region 7, SOI and NINO 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 15 |

16 Interannual variations of Southwest and Northeast monsoon seasons’ rainfall at Region 7, SOI and NINO 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 16 |

17 Variations of Annual and Seasonal rainfall at Region 7 and the relationship between annual rainfall and, SOI and NINO 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 17 |

18 Relationship between seasonal rainfall variability at region 4 and ENSO ENSO-Vietnam rainfall| Ramasamy Suppiah 18 | Southern Oscillation-RainfallNINO3.4-Rainfall

19 Interannual variations of First and Second intermonsoon seasons’ rainfall at Region 4, SOI and NINO 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 19 |

20 Interannual variations of Southwest and Northeast monsoon seasons’ rainfall at Region 4, SOI and NINO 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 20 |

21 Variations of Annual and Seasonal rainfall at Region 4 and the relationship between annual rainfall and, SOI and NINO 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 21 |

22 Relationship between seasonal rainfall variability at region 1 and ENSO ENSO-Vietnam rainfall| Ramasamy Suppiah 22 | Southern Oscillation-RainfallNINO3.4-Rainfall

23 Interannual variations of First and Second intermonsoon seasons’ rainfall at Region 1, SOI and Niño 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 23 |

24 Interannual variations of Southwest and Northeast monsoon seasons’ rainfall at Region 1, SOI and Niño 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 24 |

25 Variations of Annual and Seasonal rainfall at Region 1 and the relationship between annual rainfall and, SOI and Niño 3.4 Indices ENSO-Vietnam rainfall| Ramasamy Suppiah 25 |

26 Conclusion ENSO-Vietnam rainfall| Ramasamy Suppiah 26 | The link between ENSO variations and regional and seasonal rainfall variations of Vietnam indicates the following patterns: There are significant differences in the relationship between regional and seasonal rainfall of Vietnam and ENSO phenomenon. The relationship between ENSO variations and rainfall of regions 4,5 6 and 7 is strong, but the relationship is weak between ENSO and rainfall of regions 1,2 and 3. The relationship is positive (negative) between rainfall and the SOI (NINO3.4) during the First intermonsoon, Second intermonsoon and northeast monsoon seasons. Above (below) normal rainfall during La Niña (El Niño) years. The relationship is negative (positive) between rainfall and the SOI (NINO3.4) during the Southwest monsoon season. Above (below) normal rainfall during El Niño (La Niña) years in some regions.

27 Suppiah Ramasamy CSIRO Marine and Atmospheric Research, Aspendale, Vic. 3195 t+61 3 9239 4554 esuppiah.ramasamy@csiro.au Thank you

28 ENSO and global sea level change Presentation title | Presenter name 28 |


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