Most of us know only about El Nino Southern Oscillation (ENSO) which determine the rainfall in tropics and subtropics. Here is another oscillation which moves across the globe and determines the rainfall pattern of Australia, Maritime continent and India. It plays an important role in NEM of Tamil Nadu.

1. Doctoral Credit Seminar II
Chairman Dr. R. Krishnan Ph. D.,
Professor (Agronomy)
Members Dr. R. Karthikeyan Ph. D.,
Assistant Professor (Agronomy)
Dr. N. Muthukrishnan Ph. D.,
Professor (Agri. Entomology)
Dr. C. N. Chandrasekar Ph. D.,
Professor (Crop Physiology)
Student
Sowmiya. R
2018800207

2. Impact of Madden Julian Oscillation (MJO)
on Indian Rainfall

3. Outline
• Introduction
• Madden Julian Oscillation (MJO)
• Characteristics of MJO
• Structure of MJ wave
• Phases of MJO
• Relation between ENSO and MJO
• Effect of MJO on El Nino and La Nina
• How MJO affects Indian monsoon
• Effect of MJO on climate change
• Effect of MJO on agricultural productivity
• Conclusion

4. A Surprise Discovery
Discovered by Roland Madden
and Paul Julian in 1971 at the
American National Centre for
Atmospheric Research (NCAR)
Why tropics weather is not predictable as in mid-latitudes?
• MJO - Main intra-seasonal fluctuation in the tropics
Attention over MJO was paid
only after 1982 – 83

5. What is MJO?
• The Madden-Julian oscillation (MJO) is an equatorial traveling
pattern of anomalous rainfall that is planetary in scale.
MJO - 2 parts
 Enhanced
convective
phase
 Suppressed
convective
phase

6. Characteristics of MJO
• Intra-seasonal wave originating in the tropics
• Period of MJO is approximately 30 – 60 days.
• Also called as 30 – 60 day oscillation or 30 – 60 day wave or
intra seasonal oscillation.
• Eastward propagation of waves with a speed of 4-8 m/s
• Act on global scale. Observed mainly on Indian and W. Pacific
Oceans

7. Cont..
• It results in changes in atmospheric and oceanic variables
• Lower and upper level wind
• Sea surface temperature
• Cloudiness and tropical rainfall
• Sea level pressure
• Ocean surface evaporation
• Measured by an infrared sensor using the variations in OLR

8. Structure of Madden Julian Wave

9. Phases of MJO
1 - Convection over
W. Indian Ocean
2 & 3 - moves eastward
4 & 5 - reaches W. Pacific
6, 7 & 8 - moves further
east and vanishes over
Pacific

13. El Nino & La Nina

14. Difference between
MJO El Nino
Cause changes on weekly to
monthly basis
Changes monsoon on seasonal
to yearly basis
Travels around the globe Stationary one
Intra-seasonal variability Inter-annual variability
Observed in both Indian and
Pacific Oceans
Observed only in Pacific ocean

15. Effect of MJO on El Nino & La Nina
• MJO events can Trigger
El Nino events by
weakening the trade
winds.
• MJO moves from west to
east
• La Nina moves from east
to west
• This weakens the La Nina.

16. MJO and Indian Monsoon
• When MJO is over Indian Ocean amid the Monsoon season,
it brings great precipitation over the Indian subcontinent
• When it observes a more extended cycle and remains over
the Pacific Ocean, MJO brings terrible news for the Indian
Monsoon.
• Shorter the cycle of MJO, better the Indian Monsoon.
• Presence of MJO over the Pacific Ocean alongside an El Nino
is adverse for Monsoon downpours.

17. Combined effects of MJO, ENSO and IOD on the
Intraseasonal Variability of North East Monsoon
rainfall over South Peninsular India
• Rainfall during NEM is associated with various phases of MJO
life cycle.
• Positive rainfall anomaly over South India and Indian Ocean is
observed during the strong MJO phases (2,3 and 4)
• Negative rainfall anomaly during phases 5,6,7,8 and 1.
• During the fourth phase, positive rainfall anomaly is present all
over India and the entire east coast receives more rain.
Krishnamohan et al. (2012)
Sreekala et al., 2018

18. No of days and rainy days under various MJO phases during 1979 - 2009

21. The number of days and number of rainy days under various phases of MJO
during El Nino and La Nina years

22. Sensitivity of the Madden Julian Oscillation to
Ocean warming in a Lagrangian Atmospheric Model
a) Observed MJO b) control c) 3K warming d) 7K warming
Patrick Haertel (2018). Climate. 6,45.

23. Twofold expansion of the Indo-Pacific warm
pool warps the MJO life cycle
• Global warming (1981 – 2018) warped MJO life cycle
• Decreases residence time by 3 – 4 days in Indian ocean
• Increases over the Indo-Pacific Maritime Continent by
5 – 6 days
• Changes in the Indo-Pacific warm pool increases rainfall over
Southeast Asia
N. Australia
Southwest Africa
• Drying over West coast of the US, North India, East Africa.
Roxy, M.K et al. (2019). Nature 575, 647 – 651.

25. The Madden Julian Oscillation affects crop
yield around the world
• MJO affects crop yield variations throughout the tropics.
• In dry, hot environments the MJO forces crop failures
• In wetter, cooler environments, it bring an increase in crop
yields.
• Each MJO event affects final crop yields by 0.5 - 1% of
expected yields.
W. B. Anderson et al. (2020). Geophysics.

27. Kerala flood, 2018: The Reason Behind
• Heavy rainfall of 130 mm was recorded - Aug 14 – 16th, 2018.
• 10 times higher than the normal.

28. Chennai flood,
2015
• 2 factors
MJO
ENSO

30. • Cyclone travelled
from southwest BOB
to NE Arabian Sea
• Along with MJO,
anomalous warm
SSTs & favorable
ocean subsurface
temperatures led to
conducive
conditions caused
rapid intensification.

31. Cyclone Gaja & MJO

32. Reason
behind: The
dry
November
with extreme
wet spells

33. Summary and Conclusion
MJO
It is an
oscillation
Reason for intra-
seasonal weather
variations
Influences the
atm response
of ENSO
Reason behind
NEM of
S. India
Reason for
cyclogenesis
in IO and BOB
Alters the
global rainfall
pattern