1. Director of Center for Climate Change and Air Quality – BMKG
Factors Influencing the Response of the Maritime Continent Climate to ENSO
Dr. Edvin Aldrian
Director of Center for Climate Change and Air Quality – BMKG
BMKG
Presented in XV WMO RA V Bali 30 April – 6 Mei 2010

2. Outline of Presentation
BMKG
The theory of El Nino
Predictability of the maritime continent
El Nino dan climate of the maritime continent
ENSO impact episode
The role of local sea surface current
El Nino and Indian Ocean Dipole
Impact of El Nino on the Climate system
El Nino and global warming
Positive and negative impact of El Nino

3. Theory: What is ENSO
BMKG
ENSO is the abbreviation of El Niño Southern Oscillation
The term El Nino means ‘Christ Child’ and was first used by Peruvian fishermen in the late 1800’s to describe the warm current appearing off the western coast of Peru around Christmas time.
Southern oscillation refers to a seesaw shift in surface air pressure at Darwin, Australia and the South Pacific Island of Tahiti. When the pressure is high at Darwin it is low at Tahiti and vice versa. El Nino, and its sister event – La Nina – are the extreme phases of the southern oscillation, with El Nino referring to a warming of the eastern tropical Pacific, and La Nina a cooling.

4. Theory: What is ENSO
BMKG
The El Nino is indicated by the movement of warm water mass under the surface of ocean from the warm pool region to the central equatorial Pacific
What is the warmpool region? Is the most warmest equatorial region located in the north of the Papua island and formed after the accumulation of flowing surface warm water in the Pacific Ocean.
Why the surface water in the Pacific flows?
Due to the earth rotation
Part of the Great Ocean Conveyor Belt
The world ventilation system in the ocean
Where the water mass in the warmpool ends? The accumulation of that water mass will from geostropically to the Indian Ocean as the Indonesian Throughflow

5. Theory: Why is ENSO Predictable?
BMKG
“… the time averages (monthly and seasonal means) for the tropics have more predictability. This is because they are largely determined by fluctuations of the seasonally varying boundary conditions of sea surface temperature and soil moisture. Under favorable conditions, they can contribute to the predictability of middle latitudes also.” Shukla, 1981
Atmospheric weather is IN PRINCIPLE not predictable more than 2 weeks or so;
Over the tropical oceans, the STATISTICS of atmospheric weather depends on the sea surface temperature (e.g. Rains over warm water);
Sea surface temperature CAN be predicted by a coupled atmosphere-ocean model if the internal state of the upper tropical ocean in known;
Skill is likely to be much less in mid-latitudes because the SST determines the statistics in the presence or much variability.

6. Climatology of regional rainfall
BMKG
Mainly monsoonal
Three distinct rainfall climate regions
Aldrian and Susanto, 2003, Intl J Climatol.
monsoonal
Semi-monsoonal
Anti-monsoonal

7. Interannual variability in Region A
BMKG
Aldrian et al, 2007, Theo. Appl. Climatol.

8. Interannual variability in Region B
BMKG
Aldrian et al, 2007, Theo. Appl. Climatol.

9. Interannual variability in Region C
BMKG
Aldrian et al, 2007, Theo. Appl. Climatol.

10. Wide range SST responses to rainfall in region A
BMKG
Weak response in spring, no ENSO influence
Strong two dipoles in SON (Walker cell)
Role of SPCZ in SON
Aldrian and Susanto, 2003, Intl J Climatol.

11. Wide range SST responses to rainfall in region B
BMKG
Weak response in all season, especially in spring
no ENSO influence and walker cell
Aldrian and Susanto, 2003, Intl J Climatol.

12. Wide range SST responses to rainfall in region C
BMKG
Weak response in spring
Strong two dipoles in SON (Walker cell) like region A
Role of SPCZ in SON like in region A
Aldrian and Susanto, 2003, Intl J Climatol.

13. Skills of monthly rainfall variability
BMKG
Response to ENSO
Negative responses to NINO3 SST
Significant in MJJAS
(similar to Hendon, 2003)
Variability in comparison to observations
(correlation values)
Strong responses in Region A and C
Spring is the least responsive season
ECHAM4 responds well to ENSO
Aldrian et al, 2007, Theo. Appl. Climatol.

14. The Indonesian Throughflow
BMKG
The Indonesian Throughflow

15. ENSO and ocean: Climate
BMKG
Normal condition
El Nino condition
La Nina condition

16. Decadal signals of the maritime continent
(Aldrian and Djamil 2008)
After monsoon and ENSO signals
BMKG

17. El Niño impact episode
BMKG
Ensemble El Niño events during against climatology

18. La Niña impact episode
BMKG
Ensemble La Niña events during against climatology

19. ENSO episodes between rainfall and NINO3 SST
BMKG
impact starts in April
No impacts on the peak of rainfall season in DJF
The ocean mechanism prevents the impact during the wet season
El Nino is in-phase to the dry season, thus worsen the case
La Nina has no impact in the peak of the dry season MJJ because they are out-of-phase

20. Monsoonal climatology of the Maritime Continent
BMKG

21. Surface sea current (Wyrtki 1962)
BMKG
June
December

22. Role of ocean circulation in limiting the ENSO impact
BMKG
Aldrian, Disertation thesis, 2003

23. FACTORS CONTROLLING RAINFALL IN INDONESIA
El Nino and other climate characters
FACTORS CONTROLLING RAINFALL IN INDONESIA
A S I A 1
Ags -Sep
Okt - Nov
EL NINO / LA NINA
DIPOLE MODE POSITIFVE/ DIPOLE MODE NEGATIVE 4 2
A F R I C A 3
INDONESIAN SST 1 4
MONSOONAL WINDS 3
1963
1972
1982
1997
EL NINO (ºC)
SEP 09
1.38/ Mod
OKT 09
1.95/ Mod
NOV 09
2.07/ Kuat
DES 09
1.94/ Mod 2
A S I A
Ags -Sep
Okt - Nov
DIPOLE MODE (ºC)
SEP 09
(+) 0.38/ Netral
OKT 09
(+) 0.40/ Netral
NOV 09
(+) 0.32/ Netral
DES 09
(+) 0.22/ Netral 4
A F R I C A 1 3
ARAH
ANGIN MUSIM
AGS – SEP TIMURAN
OKT– NOV BARATAN 2

24. Indian Ocean Dipole El Nino and other climate characters
BMKG
The Indian Ocean Dipole (IOD) is a coupled ocean-atmosphere phenomenon in the Indian Ocean. It is normally characterized by anomalous cooling of SST in the south eastern equatorial Indian Ocean and anomalous warming of SST in the western equatorial Indian Ocean. Associated with these changes the normal convection situated over the eastern Indian Ocean warm pool shifts to the west and brings heavy rainfall over the east Africa and severe droughts/forest fires over the Indonesian region.

25. Partial correlation between Indian Ocean and ENSO in the maritime continent
BMKG
Purwaningtyas and Aldrian 2008
Western pole - rainfall
Eastern pole - rainfall

26. Delineation of ENSO and Indian Ocean Dipole impacts
BMKG
Purwaningtyas and Aldrian 2008

27. EL NIÑO DAN DIPOLE MODE 1957 – 2007
Update
EL NIÑO DAN DIPOLE MODE 1957 – 2007
EL ÑINO
PERIOD
Anomali
Suhu Muka Laut (0 C)
Central Pasifik (El Nino)
Indonesian water
Indian Ocean (Dipole Mode)
JAS NDJ 1951/52
+ 0.8
-0.38
MAM 1957 – MJJ 1958
+ 1.7
-0.40
JJA 1963 – DJF 1963/64
+ 1.0
-0.51
+ 1.5
MJJ 1965 – MAM 1966
+ 1.6
-0.46
+ 0.13
OND 1968 – MJJ 1969
-0.16
- 0.12
ASO 1969 – DJF 1969/70
-0.30
+ 0.58
AMJ 1972 – FMA 1973
+ 2.1
-0.45 (cool)
(strg)
ASO 1976 – JFM 1977
-0.45
+ 0.92
ASO DJF 1977/78
-0.60
+ 0.5
AMJ 1982 – MJJ 1983
+ 2.3
-0.60 (cool)
(strg)
JAS 1986 – JFM 1988
+ 1.6
-0.05
+ 1.88
AMJ 1991 – JJA 1992
+ 1.8
-0.23
+ 1.56
AMJ 1994 – FMA 1995
+ 1.3
-0.52
+ 2.73
AMJ 1997 – AMJ 1998
+ 2.7 – 3.2
-0.29 (cool)
(strg)
AMJ 2002 – FMA 2003
+ 1.5
0.17 (neutral)
+ 0.96
MJJ 2004 – JFM 2005
+ 0.9
-0.06
- 0.19
JAS DJF 2006/07
+ 1.1
-0.25 (cool)
+ 1.59
Agustus 2009
19 Sept
+0.82
+0.65
0.6(warm)
+0.63
-0.3 (neutral)
-0.33
Sumber : NOAA
Level EN & DM
EN Kuat > 2.0 0C
EN Moderate 1.0 – 2.0 0C
EN Lemah 0.5 – 1.0 0C
Tahun 1972; 1982; 1997:
Pada tahun yang sama, 2 fenomena, El Nino & Dipole Mode terjadi bersama-sama  curah hujan di wilayah Indonesia berkurang banyak karena didorong dari:
Pantai barat Sumatera ke Afrika Timur
Wilayah perairan Indonesia ke Pasifik Tengah
Perhatikan: Kekuatan El Nino dan Suhu perairan
1997: EN Kuat
Suhu perairan Indonesia ; dingin
2009; EN Lemah – Moderate
Suhu Perariran Indonesia; hangat 27

28. Detecting El Nino from Indonesian seas
BMKG
Data from modeling Indonesian seas from the entrance and exit channel of the throughflow could be used as the precursor of the incoming El Nino up to 5 month in advance with high confidence level
During El Nino the climate predictability of the region is high

29. During La Nina (El Nino) the termocline layers will transport more (less) water mass due to ENSO modulations (Meyers, 1996). Large water mass transport is usually associated with a higher density or higher salinity water, thus whenever this layers is modulated, the water composition and density will change accordingly.
BMKG

30. El Nino and Indonesian climate
BMKG
During El Nino, the Indonesian water will be cooler  high surface pressure in the MC, winds from Australia will be diverted to the southtern coast of MC  create Ekman pumping and upwelling there  good for fishery there and western coast of Sumatera. Ironically cool SST will induce drought especially in the western part of MC or the eastern dipole of the Indian Ocean. Hence, most of El Nino will be associatively related to the positive Dipole Mode. Moreover El Nino usually shutdown the MJO potency in that year.

31. Climate Feedback and forest fire
BMKG
Aldrian 2007
annual SST
Aug-Dec SST
Kalimantan
Sumatera
0.94
0.83
0.95
0.93
0.90
0.80
0.77
0.75
0.84
0.85
0.87 1

32. ENSO & Fishery
BMKG
According to Hendiarti et al (2005) fishery catch in seas around Java is highly seasonal. Catch decrease during El Nino in Sunda Strait, but increase in east Java.

33. Impact of climate change and ENSO over the deep sea
BMKG
The global warming will increase surface temperature and its subsurface layer. Changes in temperature will largely occur in the mixing and thermocline layers. Subsequently marine acosystem will change due to comfort zone of living by ocean species.

34. Impact of climate change and ENSO over the deep sea
BMKG
Because of global warming or strong La Nina episodes and rising of surface temperature, the ocean species will swim deeper to find the same comfort zone as before global warming happens. As a result the fish catchment must go deeper. The reverse pattern is true during El Nino event when the fish catchment increase because fish swim in shallower layers.

35. Impact of global warming on the evolution of El Nino (higher frequency) (present decade and last 3 decade)
BMKG

36. Impact of global warming on the evolution of El Nino (higher intensity)
BMKG

37. Why El Nino intensifier due to global warming
BMKG
The Warm pool is formed due to global thermohaline circulation (the great ocean conveyor belt) and brings surface sea water from north, south and equatorial Pacific. Those surface water is notable warm because direct solar radiation. The warm pool is the main gate of water flow from the Pacific to the Indian Ocean
El Nino occurs during the movement of subsurface warm pool from north of Papua to central Pacific because the subsurface temperature gradient over the warm pool and central Pacific exceed the critical threshold. By classic fluid dynamics this condition will allow propagation of water masses, thus creating El Nino
Global warming will make faster warmer warm pool
With faster and warmer warm pool, the potency to exceed the threshold level will be faster and allowing propagation of water mass  El Nino

38. Competing feature of ENSO and global warming in the region
BMKG
As the earth surface temperature warmer, the evaporation rate over the tropics will increase  faster and higher water cycle
There is a tendency of wetter dry season over the maritime continent  case 2009
Aldrian and Susanto, 2003, Intl J Climatol.

39. Evidence of wetter climate
BMKG

40. Negative impacts of El Nino
BMKG
Long drought and strong potency of forest fire
Surface water deficit and water deficit in the reservoirs, lake, dams and rivers
Long drought means harvest failure especially in the paddy field
Major El Nino issues: rice import, water pump, irrigation and water resources

41. Positive impact of El Nino
BMKG
Fishery sector will be booming as the fish swim nearer to the surface
Salt industry will be booming due to longer solar radiation
Seaweed industry will be booming with cooler surface sea water

42. Positive impact of El Nino
BMKG
Transport sector  no weather extreme
Several agriculture commodities will gain better harvest such as onion, tabacco, teakwood, corn etc.
Construction sectors will gain better such as building development and the cement industry
Tourism sector will gain benefit due to longer solar radiation

43. CONCLUSIONS
BMKG
The maritime continent has high seasonal predictability from tropical and maritime characters
ENSO is the second largest influences of regional climate phenomena, whose influences are confined during the dry season due to monsoonal sea surface pattern.  event and impact are different
Indian Ocean dipole, monsoon and global warming are confounding factors affecting the impact of ENSO in the region
Global warming has intensifier the frequency and intensity of ENSO but on the other hand warmer and wetter the maritime sea and climate