Impact of El Niño & La Niña on Indian Monsoon Rainfall

El Niño/La Niña and its impact on
summer monsoon precipitation over Indian
subcontinent
Seminar: II Course: AGM-692
Speaker: Jitendra Kumar Meher, Ph.D. 4th Semester
Department of Agricultural meteorology and Physics
Faculty of Agriculture
Bidhan Chandra Krishi Viswavidyalay
West Bengal-741252, India

Contents
Slide 1
• Some Technical terms related to El
Nino and La Nina
Introduction
• Historical chronology of eventsReview of Literature
• Development, identification, Global
Impact, Impact on monsoon rainfall of
India, Prediction tools
Objective
• SummarySummary
• References
References and
Acknowledgement

Contents
Slide 2
•Introduction
•Review of Literature
•Objective
•Conclusion
•References

Introduction
Why is El Niño and La Niña are interesting??
Slide 3

Introduction
Global Impacts
Figure 1
Slide 3
http://www.physicalgeography.net/fundamentals/7z.html

Introduction
Global Impacts Mysterious history
Figure 1 Figure 2
Slide 3
https://en.wikipedia.org/wiki/Late_Victorian_Holocausts

Introduction
1.Anomaly
The difference between
value of a climatic variable
(for e.g. Precipitation)
at a given location and its
long term average at that
location.
2014 1961-1990
X Average of variable=Y
• Anomaly of 2014= (x-y)
Some technical terms
Figure 3
Slide 4
https://www.ncdc.noaa.gov/sotc/global/201013

Introduction
2.Climatology
Quantitative description
of values of a variable
(for e.g. Rainfall)
averaged over a long
period of time
Year Average Daily rainfall
1979 x1
1978 x2
. .
. .
2010 X30
climatology= Average(x1,x2,…,x30)
Some technical terms
Figure 4
Slide 5
https://climatedataguide.ucar.edu/climate-data/gpcp-monthly-global-precipitation-climatology-project

IntroductionSome technical terms
3.Convection
Transfer of heat from one
place to another by
the movement of fluids.
More specifically, it refers to
motion associated with a
rising current of air.
Figure 5
Slide 6
http://www.esrl.noaa.gov/psd/outreach/education/science/convection/Sky.html

4.Equatorial Upwelling
 Upward motion of
subsurface water toward the
surface of the ocean.
 This is often a source of cold
and nutrient rich water.
 Strong upwelling occurs
along the equator where
easterly winds are present.
Figure 6
Slide 7
http://www.lternet.edu/research/keyfindings/upwelling-matters

5.Thermocline
Thin but distinct layer in a
Ocean/Lake in which
temperature changes more
rapidly with depth than it does
in the layers above or below
Forms when water at the
surface of an ocean or lake is
heated up, while the water
below stays cool
Figure 7
Slide 8
http://staff.concord.org/~btinker/GL/web/water/water_temperatures.html

6.Trade winds/Equatorial
Easterlies
 Blowing from the subtropical
highs (30° latitude) toward the
low pressure region of the
equator.
 Northern Hemisphere:
NE Trade Winds
Southern Hemisphere:
SE Trade Winds
Figure 8
Slide 9
https://www.aip.org/history/climate/xGenCirc.htm

7.Teleconnections
Climate anomalies being
strongly and statistically
related to each other at large
distances (typically
thousands of kilometers).
Example: Linkage of sea-level
pressure at Tahiti(Pacific)
and Darwin, Australia, which
defines the Southern
Oscillation.
Figure 9
Slide 10
http://eesc.columbia.edu/courses/ees/climate/lectures/enso.html

El Niño La Niña
"El Niño“ in Spanish refers
to “the Christ Child”-
appear in Christmas
"La Niña" is Spanish
refers to "the girl"
Figure 11Figure 10
Table 1
Slide 13

El Niño La Niña
appear in Christmas
Periodic warming in SST
across the central and
east-central equatorial
Pacific.
Periodic cooling of SST
Pacific.
Table 1
Slide 13
Figure 11Figure 10

El Niño La Niña
appear in Christmas
Periodic warming in SST
Pacific.
Periodic cooling of SST
Pacific.
El Niño occurs every 3 to 5
years and lasts about 1
year
La Niña appear every 4-
5 years and last for 1-2
years
Table 1
Slide 13
Figure 11Figure 10

Literature Review
Slide 14
•Introduction
•Objective
•Conclusion
•References

Author Work Findings
Eguigúren,
1894
Variety of primary and secondary sources.
1. Books: Histories and geographies of the
New World written by Spanish colonists and
scholars.
2. contemporary descriptions of the coastal
areas of northern Peru.
Analysed reports of rains in northern Peru
Provided: Intensity index of these events for
the period 1791–189
Connection between rainfall and the warm El
Niño current
Literature Review
Table 2
Slide 15

Eguigúren,
1894
scholars.
Niño current
Walker,
1924
The relation/Teleconnection between Southern
Oscillation and mean summer monsoon rainfall
over India.
El Niño or warm Pacific event : India tends to
experience a below-normal monsoon
La Niña or cold Pacific event: Above-normal
monsoon.
Literature Review
Table 2
Slide 15

Eguigúren,
1894
scholars.
Niño current
Walker,
1924
The relation/Teleconnection between Southern
Oscillation and mean summer monsoon rainfall
over India.
El Niño or warm Pacific event : India tends to
experience a below-normal monsoon
La Niña or cold Pacific event: Above-normal
monsoon.
Walker and
Bliss, 1932
Interannual variation of atmospheric patterns in
connection with variations of the Indian
monsoons.
Southern Oscillation
Pressure:
High over the pacific ocean
Low over the Indian Ocean and converse.
Literature Review
Table 2
Slide 15

Bjerknes,
1969
Connection between the El Niño and the
Southern Oscillation.
1. Trade wind system over the tropical Pacific
Ocean driven in part by the large-scale gradient
of SST, cold in the east and warm in the west.
2. Warm water is normally driven westward by the
surface winds. Warm surface water in the west
promote ascending motion and convective
rainfall, and the cold surface in the east
promotes subsidence and stability in the
atmosphere.
Literature Review
Table 2
Slide 16

Bjerknes,
1969
Connection between the El Niño and the
Southern Oscillation.
1. Trade wind over the tropical Pacific Ocean
driven by the large-scale gradient of SST, cold in
the east and warm in the west.
2. Warm water: driven westward by the surface
winds.
Warm western Pacific: Ascending motion of air and
convective rainfall
Cold eastern Pacific: Subsidence and stability in the
atmosphere
Quinn et al.
1978
El Niño type events and their intensities for
the period 1861-1976. SOI record was used
along with environmental data
1. Heavy precipitation: central and western
equatorial Pacific
2. Droughts: Indonesia
Closely associated with El Niño type events.
Literature Review
Table 2
Slide 16

Kiladis &
Diaz, 1989
Temperature and precipitation (1877-1988)
anomalies of 1045 stations globally are
calculated during various stage of an event in
the southern oscillation.
El Niño is a local warming of surface waters that
takes place in the entire equatorial zone of the
central and eastern Pacific Ocean of the
Peruvian coast and which affects the
atmospheric circulation worldwide
Literature Review
Table 2
Slide 18

Kiladis &
Diaz, 1989
McPhaden,
1999
Identifying why it is so strong challenges our
understanding of the physical mechanism
responsible for El Niño.
Pacific Decadal Oscillation, the Madden-Julian
Oscillation/the chaotic nature of atmosphere
might produce ENSO
Literature Review
Table 2
Slide 18

Kiladis &
Diaz, 1989
McPhaden,
1999
Identifying why it is so strong challenges our
understanding of the physical mechanism
responsible for El Niño.
Pacific Decadal Oscillation, the Madden-Julian
Oscillation/the chaotic nature of atmosphere
might produce ENSO
McPhaden
et al., 1999
Genesis and Evolution of the 1997–1998 El Niño
TOGA (Tropical Ocean Global Atmosphere)
The greatest success of TOGA program was the
successful prediction and monitoring of the
1997-1998 El Niño.
Literature Review
Table 2
Figure 13
Slide 18
https://johncarlosbaez.wordpress.com/2014/08/18/el-
nino-project-part-7/

Objective
Slide 19
•Introduction
•Objective
•Conclusion
•References

To understand the mechanism of
development of El Niño and La Niña
1
Objective
Slide 20

1
To identify an El Niño/La Niña episode?2
Objective
Slide 20

1
To visualise the Global Impact of El Niño3
Objective
Slide 20

1
To study the Impact of El Niño on monsoon
rainfall of India
4
Objective
Slide 20

1
To study the Impact of El Niño on monsoon
rainfall of India
4
5 To study the prediction tools of El Niño and La
Niña
Objective
Slide 20

Mechanism of development
of El Niño and La Niña
Objective 1
Slide 21

Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over
western Pacific.
High pressure over
South America.
Pressure change =SO
Higher pressure over
western Pacific.
Lower pressure over
South America.
Lower than normal air
pressure over the western
Pacific.
Higher than normal air
pressure over South
America.
Table 3
Slide 22
http://www.chm.bris.ac.uk/webprojects2002/yung/mechanisms.htm

Pressure
Low pressure over
western Pacific.
High pressure over
South America.
Pressure change =SO
western Pacific.
Lower pressure over
South America.
Pacific.
pressure over South
America.
Table 3
Slide 22
Figure 14

Pressure
Low pressure over
western Pacific.
High pressure over
South America.
Pressure change =SO
western Pacific.
Lower pressure over
South America.
Pacific.
pressure over South
America.
Table 3
Slide 22
http://www.chm.bris.ac.uk/webprojects2002/yung/mechanisms.htmFigure 14 Figure 15

Pressure
Low pressure over western Pacific.
High pressure over South America.
Pressure change =SO
Higher pressure over western Pacific.
Lower pressure over South America.
Lower than normal air pressure over the western Pacific.
Higher than normal air pressure over South America.
Flow of trend
wind
Trade winds blow
east to west.
Trade winds weaken or
blow west to east.
Trade winds increase in
strength and blow even
stronger than normal from
east to west
Table 3
Slide 22

Pressure
Pressure change =SO
Flow of trend
wind
Trade winds blow
east to west.
blow west to east.
east to west
Table 3
Slide 22
Figure 16

Pressure
Pressure change =SO
Flow of trend
wind
Trade winds blow
east to west.
blow west to east.
east to west
Table 3
Slide 22
Figure 16
Figure 17

Pressure
Pressure change =SO
Flow of trend wind Trade winds blow east to west. Trade winds weaken or blow west to east. Trade winds increase in strength and blow even stronger than
normal from east to west
Position of
thermocline
Shallow
thermocline along
South America.
Deeper thermocline
near western
Pacific.
Deep themocline along
South America
Shallow thermocline
along western Pacific.
Shallow thermocline along
South America
More than normal deeper
thermocline near western
Pacific.
Table 3
Slide 22
http://www.physicalgeography.net/fundamentals/7z.html
Figure 18

Pressure
Pressure change =SO
Position of
thermocline
Shallow
thermocline along
South America.
Deeper thermocline
near western
Pacific.
Deep themocline along
South America
Shallow thermocline
along western Pacific.
Shallow thermocline along
South America
More than normal deeper
thermocline near western
Pacific.
Table 3
Slide 22
http://www.physicalgeography.
net/fundamentals/7z.html
Figure 18 Figure 19

Pressure
Pressure change =SO
Position of thermocline Shallow thermocline along South America.
Deeper thermocline near western Pacific.
Deep themocline along South America
Shallow thermocline along western Pacific.
Shallow thermocline along South America
More than normal deeper thermocline near western Pacific.
Upwelling lots of upwelling,
cold water at
surface.
little upwelling, warmer
water at surface
More than normal
upwelling brings
cold, nutrient-rich waters to
the surface.
Table 3
Slide 22

Pressure
Pressure change =SO
Position of thermocline Shallow thermocline along South America.
Deeper thermocline near western Pacific.
Deep themocline along South America
Shallow thermocline along western Pacific.
Shallow thermocline along South America
More than normal deeper thermocline near western Pacific.
Upwelling lots of upwelling, cold water at surface. little upwelling, warmer water at surface More than normal upwelling brings cold, nutrient-rich waters to
the surface.
Temperature
of surface
water Warm ocean
waters, clouds and
moisture are
pushed away from
North America
Western Pacific Ocean:
Colder
Eastern Pacific near the
coast of South America:
Warmer
Warm surface water
sloshes back along
equatorial Pacific
Western Pacific Ocean:
Warmer
Eastern Pacific near the
coast of South America:
Colder
Warm ocean waters, clouds
and moisture are pushed
away from North America
Table 3
Slide 22

Cartoon of wind circulation during Normal/La Nina and El Niño
Figure 20
Slide 23
Normal Condition El Nino Condition
http://klimat.czn.uj.edu.pl/media/archive/3294.gif

Cartoon of wind circulation during Normal, El Niño and La Niña condition
Figure 21
Slide 24
http://www.pmel.noaa.gov/tao/proj_over/diagrams/

Cartoon of upwelling, SST, and flow of water during Normal, El Niño and
La Niña condition
Tropical Atmosphere Ocean project
Figure 22
Slide 25
http://www.pmel.noaa.gov/tao/proj_over/diagrams/

Trends since 1982-2010
Figure 23Le and McPhaden, 2010
Slide 26

Mechanism (Why??..Still a mystery)
Why does El Niño and La Niña occur??
Exact reason for why does they occur is still not understood.
Slide 26

They results from interaction between the surface layers of the ocean
and the overlying atmosphere in tropical Pacific.
Slide 26

It is the internal dynamics of the coupled ocean-atmosphere system
that determine the onset and termination of El Niño events.
Slide 26

The physical processes are complicated, but they involve unstable air-
sea interaction and planetary scale oceanic waves. The system oscillates
between warm (El Niño) to neutral (or cold) conditions with a natural
periodicity of roughly 3-4 years.
Slide 26

The physical processes are complicated, but they involve unstable air-
sea interaction and planetary scale oceanic waves. The system oscillates
between warm (El Niño) to neutral (or cold) conditions with a natural
periodicity of roughly 3-4 years.
External forcing from volcanic eruptions (submarine or terrestrial) have
no connection with El Niño. Nor do sunspots as far as we know. TAO
Slide 26

How to identify which is an
El Niño/La Niña episode?
Objective 2
Slide 27

Different Nino regions
NINO1+2 (0-10S, 80-90W). Typically warms first
when an El Niño event develops. http://iridl.ldeo.columbia.edu/maproom/ENSO/ENSO_Info.html#tab
s2
Figure 24
Slide 28
https://www.ncdc.noaa.gov/teleconnections/enso/indicators/sst.php

NINO1+2 (0-10S, 80-90W): Typically warms first
when an El Niño event develops.
NINO3 (5S-5N; 150W-90W): Largest variability in
sea-surface temperature on El Niño time scales.
http://iridl.ldeo.columbia.edu/maproom/ENSO/ENSO_Info.html#tab
s2
Slide 28
Figure 24

NINO3.4 (5S-5N; 170W-120W)
• Closer (than NINO3) to the region where
changes in local sea-surface temperature are
important for shifting rainfall
• Typically located in the far western Pacific.
s2
Slide 28
Figure 24

NINO3.4 (5S-5N; 170W-120W).
• Closer (than NINO3) to the region where
changes in local sea-surface temperature are
important for shifting rainfall
• Typically located in the far western Pacific.
NINO4 (5S-5N: 160E-150W): Changes of SST lead
to 27.50C.
27.50 :Important threshold in producing rainfall
s2
Slide 28
Figure 24

Year
Oceanic Nino Index (ONI): De-facto
standard, NOAA
ONI calculation:
Running 3-month mean SST anomaly
for the Niño 3.4 region (i.e., 5oN-5oS,
120o-170oW).
El Niño and La Niña events
since 1950 to 2015, 8-El
Niños and 5 El-Niñas
Identify an El Niña/La Niña episode?
Slide 29
Figure 25

Year
standard, NOAA
ONI calculation:
120o-170oW).
Events:
5 consecutive overlapping 3-month
periods at or above/below
0.50 anomaly as El Niño/La Niña.
since 1950 to 2015, 8-El
Slide 29
Figure 25

Year
standard, NOAA
ONI calculation:
120o-170oW).
Events:
5 consecutive overlapping 3-month
periods at or above/below
0.50 anomaly as El Niño/La Niña.
Categorised by SST anomaly
Weak: 0.5 to 0.9
Moderate: 1.0 to 1.4 SST anomaly
Strong: 1.5 to 1.9 SST anomaly
Very Strong: ≥ 2.0 SST anomaly
since 1950 to 2015, 8-El
Slide 29
Figure 25

Sustained negative value of SOI
below −8 : El Niño
Sustainted positive values of SOI
above +8 : La Niña
Figure 26
Slide 30
http://www.bom.gov.au/climate/glossary/soi.shtml

Sustained negative value of SOI
below −8 : El Niño
Sustainted positive values of SOI
above +8 : La Niña
Long term average
1933 to 1992
Figure 26
Figure 27
Slide 30
http://www.bom.gov.au/cli
mate/glossary/soi.shtml

Cartoon of global SST anomaly during El Niño(1997) and La Niña (1988) condition
El Niño La Niña
Figure 28
Slide 31
https://www.nc-climate.ncsu.edu/climate/patterns/ENSO.html

Global impact of El Niño
and La Niña
Objective 3
Slide 32

Global Impact
Brush Fire
Hurricanes Anchovy population
Flood
Figure 29 Figure 31
Figure 30 Figure 32Table 4
Slide 33

El Niño La Niña
El Niño conditions tend to suppress the
development of tropical storms and hurricanes
in the Atlantic, but increase the number of
tropical storms over the eastern and central
Pacific Ocean.
La Niña's cooling of the
equatorial Pacific tend to favor
hurricane formation in the
western Atlantic
Global Impact of El Niño
Table 5
Slide 34

El Niño La Niña
El Niño conditions tend to suppress the
development of tropical storms and hurricanes
in the Atlantic, but increase the number of
tropical storms over the eastern and central
Pacific Ocean.
La Niña's cooling of the
equatorial Pacific tend to favor
hurricane formation in the
western Atlantic
Increased rainfall across the southern tier of
the US and in Peru, destructive flooding, and
drought in the West Pacific, Monsoon failure
in India, sometimes associated with
devastating brush fires in Australia
La Niña usually brings colder
winters to the Canadian west
and Alaska, and drier, warmer
weather to the American
southeast.
Table 5
Slide 34

Ropelewski
and Halpert,
1987
Global and Regional Scale Precipitation Patterns
Associated with the El Niño/Southern Oscillation
El Niño years generally bring drought in
northeastern Brazil, southern Africa, and the
western Pacific, and wetter conditions to southern
Brazil, Uruguay, Peru, and equatorial East Africa
Table 6
Slide 35

Ropelewski
and Halpert,
1987
Canby, 1984 Studied on multiple cyclones stroked to French
Polynesia on 1982-83
In the South Pacific during the 1982–1883 El Niño,
ocean surface warming allowed six cyclones to strike
French Polynesia, a region not usually prone to
experiencing intense tropical storms.
Table 6
Slide 35

Ropelewski
and Halpert,
1987
Glantz, 2001 El Ni˜no’s Impact on Climate and Society (Book) collapse of the Peruvian anchoveta fishery following
the 1972–1973 El Niño
Table 6
Slide 35

Ropelewski
and Halpert,
1987
Glantz, 2001 El Ni˜no’s Impact on Climate and Society (Book) collapse of the Peruvian anchoveta fishery following
the 1972–1973 El Niño
Table 6 Figure 33
Slide 35

Sharon E.
Nicholson
and
Jeeyoung
Kim, 1997
Comprehensive study of the rainfall response
over Africa to ENSO episodes in the Pacific for
the period 1901-1990
ENSO modulates rainfall over much of the
African continent. The strongest signals are in
the areas of eastern equatorial and south-
eastern Africa.
ENSO episodes that influence rainfall over
Africa are those which are manifested as SST
variation in the low-latitude Atlantic & western
Indian Oceans
Table 6
Slide 36

Sharon E.
Nicholson
and
Jeeyoung
Kim, 1997
eastern Africa.
Indian Oceans
Sponberg,
1999
Studied on the climatologically impact of 1997-
98 El Niño
Weather-related disasters and disease
outbreaks during 1997-98 El Niño claimed over
2.2 Lakh lives worldwide and caused US$36
billion dollars in economic losses.
Table 6
Slide 36

Sharon E.
Nicholson
and
Jeeyoung
Kim, 1997
eastern Africa.
Indian Oceans
Sponberg,
1999
98 El Niño
Weather-related disasters and disease
outbreaks during 1997-98 El Niño claimed over
2.2 Lakh lives worldwide and caused US$36
billion dollars in economic losses.
Supplee,
1999;
WMO, 1999
98 El Niño
1997-98 El Niño was also responsible for severe
droughts in Papua New Guinea, Indonesia,
Central America, and northeastern Brazil.
Table 6
Slide 36

Changnon,
1999
WMO, 1999
Impacts of the 1997–1998 El Niño-Generated
Weather in the US
Scientific and Technical Retrospective on 1997-98
El Niño
For the US as a whole, the 1997–1998 El Niño
produced a net economic gain of about $16 billion
dollars and resulted in 650 fewer deaths than
would have otherwise occurred
Atlantic hurricanes significantly reduced to 1.
US Midwest and grate lakes: Mildest (Warmer)
winter in over 100 year, Reduced heating bills.
Shrimp catch increased off the coast of Ecuador,
with export revenues rising by 40% in 1997.
Table 6
Slide 37

Changnon,
1999
WMO, 1999
Impacts of the 1997–1998 El Niño-Generated
Weather in the US
Scientific and Technical Retrospective on 1997-98
El Niño
For the US as a whole, the 1997–1998 El Niño
produced a net economic gain of about $16 billion
dollars and resulted in 650 fewer deaths than
would have otherwise occurred
Atlantic hurricanes significantly reduced to 1.
US Midwest and grate lakes: Mildest (Warmer)
winter in over 100 year, Reduced heating bills.
Shrimp catch increased off the coast of Ecuador,
with export revenues rising by 40% in 1997.
McPhaden,
2000
Causes and Global Consequences of El Niño and La
Niña
La Niña weather impacts include an increased
probability of unusually rainy conditions in
southern Africa and northeastern Brazil, and in
the monsoon regions of India, Indonesia and
Northern Australia.
Table 6
Slide 37

Nicholson et
al. 2001
Identified characteristic differences between those
episodes during which drought occurs and those in
which it does not occur over Botswana
Evolution of the Southern Oscillation index (SOI)
and of SSTs in key sectors of the Atlantic, Pacific, and
Indian Oceans during ENSO episodes between 1946
and 1992 is examined.
In the Pacific there is weaker and less consistent
warming in the wet Botswana composite than in the
dry Botswana composite, especially in the central
and western Pacific
probability of a wet season is very low at any time
during the second half of an ENSO episode, but it is
particularly low for the April–June (AMJ) season (i.e.,
AMJ of the post-ENSO year)
Table 6
Slide 38

Nicholson et
al. 2001
Identified characteristic differences between those
episodes during which drought occurs and those in
which it does not occur over Botswana
Evolution of the Southern Oscillation index (SOI)
and of SSTs in key sectors of the Atlantic, Pacific, and
Indian Oceans during ENSO episodes between 1946
and 1992 is examined.
In the Pacific there is weaker and less consistent
warming in the wet Botswana composite than in the
dry Botswana composite, especially in the central
and western Pacific
probability of a wet season is very low at any time
during the second half of an ENSO episode, but it is
particularly low for the April–June (AMJ) season (i.e.,
AMJ of the post-ENSO year)
Wang et al.
2007
The impacts of El Niño and La Niña on the U.S. climate
during northern summer (1901-2004).
Continental-scale anomalous high dominates
over most of North America during La Niña
events and leads to hot and dry summers over
the central United States. However, the impacts
of El Niño over North America are weaker and
more variable.
Table 6
Slide 38

Impact of El Niño and La
Niña on monsoon rainfall of
India
Objective 4
Slide 39

Sir G. Walker: Quantity of rainfall in the Indian subcontinent was
often negligible in the years of high pressure at Darwin (and low
pressure at Tahiti).
ENSO relation with MSLP at Darwin and Tahiti
Slide 40

Conversely, low pressure at Darwin bode well for the precipitation
quantity in India. Thus he established the relationship of Southern
Oscillation with quantities of Monsoon rains in India.
Slide 40

The ENSO is known to have a pronounced effect on the strength of
SW Monsoon over India with the Monsoon being weak (causing
droughts in India) during the El Niño years
Slide 40

The ENSO is known to have a pronounced effect on the strength of
SW Monsoon over India with the Monsoon being weak (causing
droughts in India) during the El Niño years
La Niña years had particularly good Monsoon strength over India.
Slide 40

Plot of standardized, all-India summer monsoon rainfall and
summer Niño3 anomaly index. Severe drought and drought free
years during El Niño events (standardized Niño3 anomalies >1) are
shown in red and green, respectively
Years with moderate to extreme cold
states (Niño3 index < -1), have had
abundant monsoon rains without
exception. On the other hand, years of
moderate to extreme warm states
(Niño3 Index > -1) have not been
reliably dry.
Figure 34
Slide 41
Gadgil, 2014

reliably dry.
The six leading droughts since 1871
have occurred along with a
standardized Niño3 index > +1, but the
presence of El Niños has not
guaranteed drought.
Figure 34
Slide 41
Gadgil, 2014

reliably dry.
The six leading droughts since 1871
have occurred along with a
standardized Niño3 index > +1, but the
presence of El Niños has not
guaranteed drought.
No simple association describes the
relation between the Indian monsoon
and Niño3 SSTs when moderate to
strong El Niño conditions exist
Figure 34
Slide 41
Gadgil, 2014

All-India summer monsoon rainfall (1871-2014)
http://www.tropmet.res.in/~kolli/MOL/Monsoon/Historical/aismr1871-2014.pdf
All-India area-weighted mean summer monsoon rainfall, based on a
homogeneous rainfall data set of 306 rain gauges, developed by the IITM, Pune
Figure 35
Slide 42

El Niño Vs Drought, La Niña Vs Flood (1871-2014)
Drought Year (El Niño)
1873, 1877, 1899, 1901, 1904, 1905, 1911, 1918, 1920, 1941, 1951,
1965, 1966, 1968, 1972, 1974, 1979, 1982, 1985, 1986, 1987, 2002,
2004, 2009.
Exception: El Niño still no deficit of rainfall
1900, 1944, 1976, 1997, 1906
Slide 43

El Niño Vs Drought, La Niña Vs Flood (1871-2014)
Drought Year (El Niño)
1873, 1877, 1899, 1901, 1904, 1905, 1911, 1918, 1920, 1941, 1951,
1965, 1966, 1968, 1972, 1974, 1979, 1982, 1985, 1986, 1987, 2002,
2004, 2009.
Exception: El Niño still no deficit of rainfall
1900, 1944, 1976, 1997, 1906
Flood Year (La Niña)
1874, 1878, 1892, 1893, 1894, 1910, 1916, 1917, 1933, 1942, 1947,
1956, 1959, 1961, 1970, 1975, 1983, 1988, 1994.
Exception: La Niña still not more than normal rainfall
1999, 2000
Slide 43

Parameter
Indian Summer Monsoon Rainfall, 1880-2008
Deficit
< - 1.0
Below Normal
- 0.5 to 0.5
Near Normal
-0.5 to 0.5
Above Normal
0.5 to 1.0
Excess
> 1.0
Total
El Niño
7 5 5 0
1
18
Normal 14 13 39 14 6 86
La Niña
0 0 7 7 10 24
Total 21 18 51 21 17 128
Niño /La Niño association with all-India summer monsoon rainfall
anomalies during 1880-2008.
Table 7
Slide 44

Parameter
Indian Summer Monsoon Rainfall, 1880-2008
Deficit
< - 1.0
Below Normal
- 0.5 to 0.5
Near Normal
-0.5 to 0.5
Above Normal
0.5 to 1.0
Excess
> 1.0
Total
El Niño
7 5 5 0
1
(1944)
18
Normal 14 13 39 14 6 86
La Niña
0 0 7 7 10 24
Total 21 18 51 21 17 128
Niño /La Niño association with all-India summer monsoon rainfall
anomalies during 1880-2008.
Table 7
Slide 45

Prediction tools of El Niño
and La Niña
Objective 5
Slide 46

prediction tools of El Niño and La Niña
1. Computer models and
statistical/Numerical based methods
2. Ocean and atmosphere measuring
devices
• For example : Moored and drifting buoys
and satellites.
Measures...
• Air and SST
• Water currents
• Winds
• Salinity
• Air pressure
Figure 36
Slide 47

1. Computer models and
statistical/Numerical based methods
2. Ocean and atmosphere measuring
devices
• For example : Moored and drifting buoys
and satellites.
Measures...
• Air and SST
• Water currents
• Winds
• Salinity
• Air pressure
• Oceans: 70% of the earth’s surface
• Ships, buoys and other in situ
instruments can’t possible cover
that much space
• Measure wind, waves, temperature
of the sea surface, ocean color,
ocean surface currents, and tides.
Figure 30 Figure 37
Slide 48

Example: TOPEX/Poseidon (T/P)
• August 10, 1992-Jan 18, 2006
• Must Successful: 1997-98 El Niño
• Joint satellite mission between NASA and
CNES, the French space agency, to map ocean
surface topography.
• Covers earth in 10 days
• Measures: Satellite's distance from the
ocean's surface and tells about the ocean's
surface currents, winds, and wave heights.
• Jason-2 (Successor of T/P), June 20, 2008-Till
data
Figure 38
Slide 49

Summary
Slide 50
•Introduction
•Objective
•Summary
•References

 El Niño and La Niña both develop due to large-scale interaction of Ocean
and atmosphere. SST and Sea surface pressure are the main drivers of
these processes.
Slide 51
Summary

these processes.
 El Niño and La Niña can be identified from the ONI and SOI.
Slide 51
Summary

these processes.
 Both of them have significant impact on a global scale due to
teleconnection. The Impact are more devastating than fortunate.
Slide 51
Summary

these processes.
 El Niño episode is characterised by deficient/less than normal rainfall in
Indian subcontinent.
Slide 51
Summary

these processes.
 La Niña episode is characterised by more than normal rainfall in the
Slide 51
Summary

these processes.
 La Niña episode is characterised by more than normal rainfall in the
 Prediction of El Niño and La Niña can be easily done by modern
techniques such as Bouys and Satellites as well as numerical models.
Slide 51
Summary

References
Slide 52
•Introduction
•Objective
•Conclusion
•References

References
Bjerknes, J. (1969). Atmospheric teleconnections from the equatorial pacific 1.Monthly Weather Review, 97(3), 163-172.Canby, T Y (1984). El Niño’s Ill Wind, Natl.
Geogr., 165(2), 144–183
Changnon, S A (1999). Impacts of the 1997–1998 El Niño-Generated Weather in the US, Bull. Am. Meteorl. Soc., 80, 1819–1827.
Diaz, K and Markgraf, V. (1998). Flood Data, in El Niño – Historical and Paleoclimatic Aspects of the Southern Oscillation, eds Cambridge University Press, Cambridge,
119–149.
Eguigúren, V. (1894). Las lluvias en Piura. Bol. Soc. Geogr. Lima, 4, 241–258.
Glantz, M H (2001). Currents of Change: El Niño’s Impact on Climate and Society, Cambridge University Press, Cambridge, 1–252.
Kiladis, G. N., & Diaz, H. F. (1989). Global climatic anomalies associated with extremes in the Southern Oscillation. Journal of Climate, 2(9), 1069-1090.
McPhaden, M J (1999). Genesis and Evolution of the 1997–1998 El Ni˜no, Science, 283, 950–954
McPhaden, M. J. (1999) El Niño and La Niña: Causes and Global Consequences, The Earth system: physical and chemical dimensions of global environmental change,
1:pp 353–370
McPhaden, M. J. (1999). El Niño: The child prodigy of 1997-98. Nature, 398(6728), 559-562.
Nicholson, S. E., & Kim, J. (1997). The relationship of the El Niño-Southern oscillation to African rainfall. International Journal of Climatology, 17(2), 117-135.
Nicholson, S. E., Leposo, D., & Grist, J. (2001). The relationship between El Niño and drought over Botswana. Journal of Climate, 14(3), 323-335.
Quinn, W H (1992). A Study of Southern Oscillation-related Climatic Activity for AD 622–1900 Incorporating Nile River
Quinn, W H, Neal, V T, and Antunez de Mayolo, S E (1987). El Niño Occurrences over the Past Four and a Half Centuries, J. Geophys. Res., 92, 14 449–14 461.
Quinn, W. H., D. O. Zorf, K. S. Short, and R. T. W.Kao Yang, (1978). Historical trends and statistics of the Southern Oscillation, El Niño, and Indonesian droughts. Fish.
Bull., 76, 663–678.
Ropelewski, C F & Halpert, M (1987). Global and Regional Scale Precipitation Patterns Associated with the El Niño/Southern Oscillation, Mon. Weather Rev., 115,
1606–1626
Sponberg, K (1999). Compendium of Climatological Impacts, National Oceanic and Atmospheric Administration, Washington DC, 62
Sulochana Gadgil, 2014. El Niño and the summer monsoon of 2014. CURRENT SCIENCE. 106:10.
Supplee, C (1999). El Niño/La Niña, Nat. Geo., 195(3), 72–95.
WALKER, G. T. (924). World Weather II. Mem. India Meteor. Dep. 24:275-332
Walker, G. T., & Bliss, E. W. (1932). World weather. V. Mem. Roy. Meteor. Soc., 4, 53
Wang, Z., Chang, C. P., & Wang, B. (2007). Impacts of El Niño and La Niña on the US climate during northern summer. Journal of climate, 20(10), 2165-2177.
WMO (1999). The 1997–1998 El Niño Event: a Scientific and Technical Retrospective, WMO No. 905,World Meteorological Organization, Geneva, Switzerland, 93
Lee, T., & McPhaden, M. J. (2010). Increasing intensity of El Niño in the central‐equatorial Pacific. Geophysical Research Letters, 37(14).
Slide 53

Acknowledgement
Declaration
•This work is solely related to educational purpose
•I acknowledge all the website authorities from
where the figures and tables are taken.
•The works or scientific papers cited in this
presentation are highly acknowledged for making
them online.
Slide 54

Impact of El Niño & La Niña on Indian Monsoon Rainfall

Impact of El Niño & La Niña on Indian Monsoon Rainfall

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