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El Niño/La Niña and its impact on
summer monsoon precipitation over Indian
subcontinent
Seminar: II Course: AGM-692
Speake...
Contents
Slide 1
• Some Technical terms related to El
Nino and La Nina
Introduction
• Historical chronology of eventsRevie...
Contents
Slide 2
•Introduction
•Review of Literature
•Objective
•Conclusion
•References
Introduction
Why is El Niño and La Niña are interesting??
Slide 3
Introduction
Why is El Niño and La Niña are interesting??
Global Impacts
Figure 1
Slide 3
http://www.physicalgeography.net...
Introduction
Why is El Niño and La Niña are interesting??
Global Impacts Mysterious history
Figure 1 Figure 2
Slide 3
http...
Introduction
1.Anomaly
The difference between
value of a climatic variable
(for e.g. Precipitation)
at a given location an...
Introduction
2.Climatology
Quantitative description
of values of a variable
(for e.g. Rainfall)
averaged over a long
perio...
IntroductionSome technical terms
3.Convection
Transfer of heat from one
place to another by
the movement of fluids.
More s...
IntroductionSome technical terms
4.Equatorial Upwelling
 Upward motion of
subsurface water toward the
surface of the ocea...
IntroductionSome technical terms
5.Thermocline
Thin but distinct layer in a
Ocean/Lake in which
temperature changes more
...
IntroductionSome technical terms
6.Trade winds/Equatorial
Easterlies
 Blowing from the subtropical
highs (30° latitude) t...
IntroductionSome technical terms
7.Teleconnections
Climate anomalies being
strongly and statistically
related to each othe...
El Niño La Niña
"El Niño“ in Spanish refers
to “the Christ Child”-
appear in Christmas
"La Niña" is Spanish
refers to "the...
El Niño La Niña
"El Niño“ in Spanish refers
to “the Christ Child”-
appear in Christmas
"La Niña" is Spanish
refers to "the...
El Niño La Niña
"El Niño“ in Spanish refers
to “the Christ Child”-
appear in Christmas
"La Niña" is Spanish
refers to "the...
Literature Review
Slide 14
•Introduction
•Review of Literature
•Objective
•Conclusion
•References
Author Work Findings
Eguigúren,
1894
Variety of primary and secondary sources.
1. Books: Histories and geographies of the
...
Author Work Findings
Eguigúren,
1894
Variety of primary and secondary sources.
1. Books: Histories and geographies of the
...
Author Work Findings
Eguigúren,
1894
Variety of primary and secondary sources.
1. Books: Histories and geographies of the
...
Author Work Findings
Bjerknes,
1969
Connection between the El Niño and the
Southern Oscillation.
1. Trade wind system over...
Author Work Findings
Bjerknes,
1969
Connection between the El Niño and the
Southern Oscillation.
1. Trade wind over the tr...
Author Work Findings
Kiladis &
Diaz, 1989
Temperature and precipitation (1877-1988)
anomalies of 1045 stations globally ar...
Author Work Findings
Kiladis &
Diaz, 1989
Temperature and precipitation (1877-1988)
anomalies of 1045 stations globally ar...
Author Work Findings
Kiladis &
Diaz, 1989
Temperature and precipitation (1877-1988)
anomalies of 1045 stations globally ar...
Objective
Slide 19
•Introduction
•Review of Literature
•Objective
•Conclusion
•References
To understand the mechanism of
development of El Niño and La Niña
1
Objective
Slide 20
To understand the mechanism of
development of El Niño and La Niña
1
To identify an El Niño/La Niña episode?2
Objective
Sli...
To understand the mechanism of
development of El Niño and La Niña
1
To identify an El Niño/La Niña episode?2
To visualise ...
To understand the mechanism of
development of El Niño and La Niña
1
To identify an El Niño/La Niña episode?2
To visualise ...
To understand the mechanism of
development of El Niño and La Niña
1
To identify an El Niño/La Niña episode?2
To visualise ...
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
wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over
wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over
wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over wester...
Mechanism (How??)What happens during these events?
Normal Year El Niño Year La Niña Year
Pressure
Low pressure over wester...
Cartoon of wind circulation during Normal/La Nina and El Niño
Mechanism (How??)What happens during these events?
Figure 20...
Cartoon of wind circulation during Normal, El Niño and La Niña condition
Mechanism (How??)What happens during these events...
Cartoon of upwelling, SST, and flow of water during Normal, El Niño and
La Niña condition
Tropical Atmosphere Ocean projec...
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...
Mechanism (Why??..Still a mystery)
Why does El Niño and La Niña occur??
Exact reason for why does they occur is still not...
Mechanism (Why??..Still a mystery)
Why does El Niño and La Niña occur??
Exact reason for why does they occur is still not...
Mechanism (Why??..Still a mystery)
Why does El Niño and La Niña occur??
Exact reason for why does they occur is still not...
Mechanism (Why??..Still a mystery)
Why does El Niño and La Niña occur??
Exact reason for why does they occur is still not...
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.co...
Different Nino regions
NINO1+2 (0-10S, 80-90W): Typically warms first
when an El Niño event develops.
NINO3 (5S-5N; 150W-9...
Different Nino regions
NINO1+2 (0-10S, 80-90W): Typically warms first
when an El Niño event develops.
NINO3 (5S-5N; 150W-9...
Different Nino regions
NINO1+2 (0-10S, 80-90W): Typically warms first
when an El Niño event develops.
NINO3 (5S-5N; 150W-9...
Year
Oceanic Nino Index (ONI): De-facto
standard, NOAA
ONI calculation:
Running 3-month mean SST anomaly
for the Niño 3.4 ...
Year
Oceanic Nino Index (ONI): De-facto
standard, NOAA
ONI calculation:
Running 3-month mean SST anomaly
for the Niño 3.4 ...
Year
Oceanic Nino Index (ONI): De-facto
standard, NOAA
ONI calculation:
Running 3-month mean SST anomaly
for the Niño 3.4 ...
Sustained negative value of SOI
below −8 : El Niño
Sustainted positive values of SOI
above +8 : La Niña
Identify an El Niñ...
Sustained negative value of SOI
below −8 : El Niño
Sustainted positive values of SOI
above +8 : La Niña
Long term average
...
Cartoon of global SST anomaly during El Niño(1997) and La Niña (1988) condition
El Niño La Niña
Identify an El Niña/La Niñ...
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...
El Niño La Niña
El Niño conditions tend to suppress the
development of tropical storms and hurricanes
in the Atlantic, but...
Global Impact of El Niño
Author Work Findings
Ropelewski
and Halpert,
1987
Global and Regional Scale Precipitation Pattern...
Global Impact of El Niño
Author Work Findings
Ropelewski
and Halpert,
1987
Global and Regional Scale Precipitation Pattern...
Global Impact of El Niño
Author Work Findings
Ropelewski
and Halpert,
1987
Global and Regional Scale Precipitation Pattern...
Global Impact of El Niño
Author Work Findings
Ropelewski
and Halpert,
1987
Global and Regional Scale Precipitation Pattern...
Author Work Findings
Sharon E.
Nicholson
and
Jeeyoung
Kim, 1997
Comprehensive study of the rainfall response
over Africa t...
Author Work Findings
Sharon E.
Nicholson
and
Jeeyoung
Kim, 1997
Comprehensive study of the rainfall response
over Africa t...
Author Work Findings
Sharon E.
Nicholson
and
Jeeyoung
Kim, 1997
Comprehensive study of the rainfall response
over Africa t...
Author Work Findings
Changnon,
1999
WMO, 1999
Impacts of the 1997–1998 El Niño-Generated
Weather in the US
Scientific and ...
Author Work Findings
Changnon,
1999
WMO, 1999
Impacts of the 1997–1998 El Niño-Generated
Weather in the US
Scientific and ...
Author Work Findings
Nicholson et
al. 2001
Identified characteristic differences between those
episodes during which droug...
Author Work Findings
Nicholson et
al. 2001
Identified characteristic differences between those
episodes during which droug...
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 Darw...
Sir G. Walker: Quantity of rainfall in the Indian subcontinent was
often negligible in the years of high pressure at Darw...
Sir G. Walker: Quantity of rainfall in the Indian subcontinent was
often negligible in the years of high pressure at Darw...
Sir G. Walker: Quantity of rainfall in the Indian subcontinent was
often negligible in the years of high pressure at Darw...
Plot of standardized, all-India summer monsoon rainfall and
summer Niño3 anomaly index. Severe drought and drought free
ye...
Plot of standardized, all-India summer monsoon rainfall and
summer Niño3 anomaly index. Severe drought and drought free
ye...
Plot of standardized, all-India summer monsoon rainfall and
summer Niño3 anomaly index. Severe drought and drought free
ye...
All-India summer monsoon rainfall (1871-2014)
http://www.tropmet.res.in/~kolli/MOL/Monsoon/Historical/aismr1871-2014.pdf
A...
El Niño Vs Drought, La Niña Vs Flood (1871-2014)
http://www.tropmet.res.in/~kolli/MOL/Monsoon/Historical/aismr1871-2014.pd...
El Niño Vs Drought, La Niña Vs Flood (1871-2014)
http://www.tropmet.res.in/~kolli/MOL/Monsoon/Historical/aismr1871-2014.pd...
Parameter
Indian Summer Monsoon Rainfall, 1880-2008
Deficit
< - 1.0
Below Normal
- 0.5 to 0.5
Near Normal
-0.5 to 0.5
Abov...
Parameter
Indian Summer Monsoon Rainfall, 1880-2008
Deficit
< - 1.0
Below Normal
- 0.5 to 0.5
Near Normal
-0.5 to 0.5
Abov...
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...
prediction tools of El Niño and La Niña
1. Computer models and
statistical/Numerical based methods
2. Ocean and atmosphere...
prediction tools of El Niño and La Niña
Example: TOPEX/Poseidon (T/P)
• August 10, 1992-Jan 18, 2006
• Must Successful: 19...
Summary
Slide 50
•Introduction
•Review of Literature
•Objective
•Summary
•References
 El Niño and La Niña both develop due to large-scale interaction of Ocean
and atmosphere. SST and Sea surface pressure ar...
 El Niño and La Niña both develop due to large-scale interaction of Ocean
and atmosphere. SST and Sea surface pressure ar...
 El Niño and La Niña both develop due to large-scale interaction of Ocean
and atmosphere. SST and Sea surface pressure ar...
 El Niño and La Niña both develop due to large-scale interaction of Ocean
and atmosphere. SST and Sea surface pressure ar...
 El Niño and La Niña both develop due to large-scale interaction of Ocean
and atmosphere. SST and Sea surface pressure ar...
 El Niño and La Niña both develop due to large-scale interaction of Ocean
and atmosphere. SST and Sea surface pressure ar...
References
Slide 52
•Introduction
•Review of Literature
•Objective
•Conclusion
•References
References
Bjerknes, J. (1969). Atmospheric teleconnections from the equatorial pacific 1.Monthly Weather Review, 97(3), 1...
Acknowledgement
Declaration
•This work is solely related to educational purpose
•I acknowledge all the website authorities...
El nino and la nina impact on monsoon rainfall of India- Jitendra Kumar Meher
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El nino and la nina impact on monsoon rainfall of India- Jitendra Kumar Meher

Includes
1. Preliminary to detail Idea about El Nino and La Nina
2. Impact of El Nino and La Nina at global scale
3. Impact of El Nino and La Nina on Indian summer monsoon
4. A must check literature review

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El nino and la nina impact on monsoon rainfall of India- Jitendra Kumar Meher

  1. 1. 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
  2. 2. 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
  3. 3. Contents Slide 2 •Introduction •Review of Literature •Objective •Conclusion •References
  4. 4. Introduction Why is El Niño and La Niña are interesting?? Slide 3
  5. 5. Introduction Why is El Niño and La Niña are interesting?? Global Impacts Figure 1 Slide 3 http://www.physicalgeography.net/fundamentals/7z.html
  6. 6. Introduction Why is El Niño and La Niña are interesting?? Global Impacts Mysterious history Figure 1 Figure 2 Slide 3 https://en.wikipedia.org/wiki/Late_Victorian_Holocausts
  7. 7. 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
  8. 8. 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
  9. 9. 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
  10. 10. IntroductionSome technical terms 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
  11. 11. IntroductionSome technical terms 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
  12. 12. IntroductionSome technical terms 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
  13. 13. IntroductionSome technical terms 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
  14. 14. El Niño La Niña "El Niño“ in Spanish refers to “the Christ Child”- appear in Christmas "La Niña" is Spanish refers to "the girl" IntroductionSome technical terms Figure 11Figure 10 Table 1 Slide 13
  15. 15. El Niño La Niña "El Niño“ in Spanish refers to “the Christ Child”- appear in Christmas "La Niña" is Spanish refers to "the girl" Periodic warming in SST across the central and east-central equatorial Pacific. Periodic cooling of SST across the central and east-central equatorial Pacific. IntroductionSome technical terms Table 1 Slide 13 Figure 11Figure 10
  16. 16. El Niño La Niña "El Niño“ in Spanish refers to “the Christ Child”- appear in Christmas "La Niña" is Spanish refers to "the girl" Periodic warming in SST across the central and east-central equatorial Pacific. Periodic cooling of SST across the central and east-central equatorial 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 IntroductionSome technical terms Table 1 Slide 13 Figure 11Figure 10
  17. 17. Literature Review Slide 14 •Introduction •Review of Literature •Objective •Conclusion •References
  18. 18. 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
  19. 19. 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 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
  20. 20. 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 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
  21. 21. Author Work Findings 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
  22. 22. Author Work Findings 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
  23. 23. Author Work Findings 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
  24. 24. Author Work Findings 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 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
  25. 25. Author Work Findings 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 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/
  26. 26. Objective Slide 19 •Introduction •Review of Literature •Objective •Conclusion •References
  27. 27. To understand the mechanism of development of El Niño and La Niña 1 Objective Slide 20
  28. 28. To understand the mechanism of development of El Niño and La Niña 1 To identify an El Niño/La Niña episode?2 Objective Slide 20
  29. 29. To understand the mechanism of development of El Niño and La Niña 1 To identify an El Niño/La Niña episode?2 To visualise the Global Impact of El Niño3 Objective Slide 20
  30. 30. To understand the mechanism of development of El Niño and La Niña 1 To identify an El Niño/La Niña episode?2 To visualise the Global Impact of El Niño3 To study the Impact of El Niño on monsoon rainfall of India 4 Objective Slide 20
  31. 31. To understand the mechanism of development of El Niño and La Niña 1 To identify an El Niño/La Niña episode?2 To visualise the Global Impact of El Niño3 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
  32. 32. Mechanism of development of El Niño and La Niña Objective 1 Slide 21
  33. 33. 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
  34. 34. 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 Figure 14
  35. 35. 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.htmFigure 14 Figure 15
  36. 36. 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. 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
  37. 37. 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. 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 http://www.chm.bris.ac.uk/webprojects2002/yung/mechanisms.htm Figure 16
  38. 38. 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. 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 http://www.chm.bris.ac.uk/webprojects2002/yung/mechanisms.htm Figure 16 Figure 17
  39. 39. 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. 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
  40. 40. 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. 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 Figure 19
  41. 41. 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. 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. 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
  42. 42. 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. 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. 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
  43. 43. Cartoon of wind circulation during Normal/La Nina and El Niño Mechanism (How??)What happens during these events? Figure 20 Slide 23 Normal Condition El Nino Condition http://klimat.czn.uj.edu.pl/media/archive/3294.gif
  44. 44. Cartoon of wind circulation during Normal, El Niño and La Niña condition Mechanism (How??)What happens during these events? Figure 21 Slide 24 http://www.pmel.noaa.gov/tao/proj_over/diagrams/
  45. 45. Cartoon of upwelling, SST, and flow of water during Normal, El Niño and La Niña condition Tropical Atmosphere Ocean project Mechanism (How??)What happens during these events? Figure 22 Slide 25 http://www.pmel.noaa.gov/tao/proj_over/diagrams/
  46. 46. Trends since 1982-2010 Figure 23Le and McPhaden, 2010 Slide 26
  47. 47. 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
  48. 48. Mechanism (Why??..Still a mystery) Why does El Niño and La Niña occur?? Exact reason for why does they occur is still not understood. They results from interaction between the surface layers of the ocean and the overlying atmosphere in tropical Pacific. Slide 26
  49. 49. Mechanism (Why??..Still a mystery) Why does El Niño and La Niña occur?? Exact reason for why does they occur is still not understood. They results from interaction between the surface layers of the ocean and the overlying atmosphere in tropical Pacific. It is the internal dynamics of the coupled ocean-atmosphere system that determine the onset and termination of El Niño events. Slide 26
  50. 50. Mechanism (Why??..Still a mystery) Why does El Niño and La Niña occur?? Exact reason for why does they occur is still not understood. They results from interaction between the surface layers of the ocean and the overlying atmosphere in tropical Pacific. It is the internal dynamics of the coupled ocean-atmosphere system that determine the onset and termination of El Niño events. 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
  51. 51. Mechanism (Why??..Still a mystery) Why does El Niño and La Niña occur?? Exact reason for why does they occur is still not understood. They results from interaction between the surface layers of the ocean and the overlying atmosphere in tropical Pacific. It is the internal dynamics of the coupled ocean-atmosphere system that determine the onset and termination of El Niño events. 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
  52. 52. How to identify which is an El Niño/La Niña episode? Objective 2 Slide 27
  53. 53. 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
  54. 54. Different Nino regions 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
  55. 55. Different Nino regions 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. 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. http://iridl.ldeo.columbia.edu/maproom/ENSO/ENSO_Info.html#tab s2 Slide 28 Figure 24
  56. 56. Different Nino regions 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. 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 http://iridl.ldeo.columbia.edu/maproom/ENSO/ENSO_Info.html#tab s2 Slide 28 Figure 24
  57. 57. 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
  58. 58. 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). Events: 5 consecutive overlapping 3-month periods at or above/below 0.50 anomaly as El Niño/La Niña. 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
  59. 59. 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). 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 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
  60. 60. Sustained negative value of SOI below −8 : El Niño Sustainted positive values of SOI above +8 : La Niña Identify an El Niña/La Niña episode? Figure 26 Slide 30 http://www.bom.gov.au/climate/glossary/soi.shtml
  61. 61. Sustained negative value of SOI below −8 : El Niño Sustainted positive values of SOI above +8 : La Niña Long term average 1933 to 1992 Identify an El Niña/La Niña episode? Figure 26 Figure 27 Slide 30 http://www.bom.gov.au/cli mate/glossary/soi.shtml
  62. 62. Cartoon of global SST anomaly during El Niño(1997) and La Niña (1988) condition El Niño La Niña Identify an El Niña/La Niña episode? Figure 28 Slide 31 https://www.nc-climate.ncsu.edu/climate/patterns/ENSO.html
  63. 63. Global impact of El Niño and La Niña Objective 3 Slide 32
  64. 64. Global Impact Brush Fire Hurricanes Anchovy population Flood Figure 29 Figure 31 Figure 30 Figure 32Table 4 Slide 33
  65. 65. 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
  66. 66. 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. Global Impact of El Niño Table 5 Slide 34
  67. 67. Global Impact of El Niño Author Work Findings 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
  68. 68. Global Impact of El Niño Author Work Findings 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 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
  69. 69. Global Impact of El Niño Author Work Findings 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 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. 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
  70. 70. Global Impact of El Niño Author Work Findings 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 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. 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
  71. 71. Author Work Findings 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 Global Impact of El Niño Table 6 Slide 36
  72. 72. Author Work Findings 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 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. Global Impact of El Niño Table 6 Slide 36
  73. 73. Author Work Findings 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 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. Supplee, 1999; WMO, 1999 Studied on the climatologically impact of 1997- 98 El Niño 1997-98 El Niño was also responsible for severe droughts in Papua New Guinea, Indonesia, Central America, and northeastern Brazil. Global Impact of El Niño Table 6 Slide 36
  74. 74. Author Work Findings 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. Global Impact of El Niño Table 6 Slide 37
  75. 75. Author Work Findings 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. Global Impact of El Niño Table 6 Slide 37
  76. 76. Author Work Findings 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) Global Impact of El Niño Table 6 Slide 38
  77. 77. Author Work Findings 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. Global Impact of El Niño Table 6 Slide 38
  78. 78. Impact of El Niño and La Niña on monsoon rainfall of India Objective 4 Slide 39
  79. 79. 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
  80. 80. 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). 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. ENSO relation with MSLP at Darwin and Tahiti Slide 40
  81. 81. 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). 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. 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 ENSO relation with MSLP at Darwin and Tahiti Slide 40
  82. 82. 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). 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. 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. ENSO relation with MSLP at Darwin and Tahiti Slide 40
  83. 83. 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
  84. 84. 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. 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
  85. 85. 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. 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
  86. 86. 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
  87. 87. El Niño Vs Drought, La Niña Vs Flood (1871-2014) http://www.tropmet.res.in/~kolli/MOL/Monsoon/Historical/aismr1871-2014.pdf 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
  88. 88. El Niño Vs Drought, La Niña Vs Flood (1871-2014) http://www.tropmet.res.in/~kolli/MOL/Monsoon/Historical/aismr1871-2014.pdf 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
  89. 89. 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
  90. 90. 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
  91. 91. Prediction tools of El Niño and La Niña Objective 5 Slide 46
  92. 92. 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
  93. 93. 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 • 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
  94. 94. prediction tools of El Niño and La Niña 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
  95. 95. Summary Slide 50 •Introduction •Review of Literature •Objective •Summary •References
  96. 96.  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
  97. 97.  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.  El Niño and La Niña can be identified from the ONI and SOI. Slide 51 Summary
  98. 98.  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.  El Niño and La Niña can be identified from the ONI and SOI.  Both of them have significant impact on a global scale due to teleconnection. The Impact are more devastating than fortunate. Slide 51 Summary
  99. 99.  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.  El Niño and La Niña can be identified from the ONI and SOI.  Both of them have significant impact on a global scale due to teleconnection. The Impact are more devastating than fortunate.  El Niño episode is characterised by deficient/less than normal rainfall in Indian subcontinent. Slide 51 Summary
  100. 100.  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.  El Niño and La Niña can be identified from the ONI and SOI.  Both of them have significant impact on a global scale due to teleconnection. The Impact are more devastating than fortunate.  El Niño episode is characterised by deficient/less than normal rainfall in Indian subcontinent.  La Niña episode is characterised by more than normal rainfall in the Indian subcontinent. Slide 51 Summary
  101. 101.  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.  El Niño and La Niña can be identified from the ONI and SOI.  Both of them have significant impact on a global scale due to teleconnection. The Impact are more devastating than fortunate.  El Niño episode is characterised by deficient/less than normal rainfall in Indian subcontinent.  La Niña episode is characterised by more than normal rainfall in the Indian subcontinent.  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
  102. 102. References Slide 52 •Introduction •Review of Literature •Objective •Conclusion •References
  103. 103. 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
  104. 104. 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

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