PPT: El Nino & La Nina- 2 | Geography for UPSC CSE PDF Download

 Page 1


How El Nino
impacts
monsoon
rainfall in
India
Page 2


How El Nino
impacts
monsoon
rainfall in
India
La Nina
? With a high positive SOI, there would be a zone of low
atmospheric pressure
archipelago.
? The rising air from this region deflects
in both directions towards Africa and South America.
? In Indian Ocean,
zone from where surface winds blow as
monsoon towards Indian sub
? During La-Nina Indian ocean branch
strengthen and surface winds are more intense.
? La-Nina condition is
monsoon.
With a high positive SOI, there would be a zone of low
atmospheric pressure over Australia and Indonesian
rising air from this region deflects in upper atmosphere
in both directions towards Africa and South America.
Indian Ocean, the air descends down at high pressure
zone from where surface winds blow as Southwest
towards Indian sub-continent in summers.
Nina Indian ocean branch of walker cell get
strengthen and surface winds are more intense.
condition is generally associated with good
Page 3


How El Nino
impacts
monsoon
rainfall in
India
La Nina
? With a high positive SOI, there would be a zone of low
atmospheric pressure
archipelago.
? The rising air from this region deflects
in both directions towards Africa and South America.
? In Indian Ocean,
zone from where surface winds blow as
monsoon towards Indian sub
? During La-Nina Indian ocean branch
strengthen and surface winds are more intense.
? La-Nina condition is
monsoon.
With a high positive SOI, there would be a zone of low
atmospheric pressure over Australia and Indonesian
rising air from this region deflects in upper atmosphere
in both directions towards Africa and South America.
Indian Ocean, the air descends down at high pressure
zone from where surface winds blow as Southwest
towards Indian sub-continent in summers.
Nina Indian ocean branch of walker cell get
strengthen and surface winds are more intense.
condition is generally associated with good
Indian Ocean
Dipole
Page 4


How El Nino
impacts
monsoon
rainfall in
India
La Nina
? With a high positive SOI, there would be a zone of low
atmospheric pressure
archipelago.
? The rising air from this region deflects
in both directions towards Africa and South America.
? In Indian Ocean,
zone from where surface winds blow as
monsoon towards Indian sub
? During La-Nina Indian ocean branch
strengthen and surface winds are more intense.
? La-Nina condition is
monsoon.
With a high positive SOI, there would be a zone of low
atmospheric pressure over Australia and Indonesian
rising air from this region deflects in upper atmosphere
in both directions towards Africa and South America.
Indian Ocean, the air descends down at high pressure
zone from where surface winds blow as Southwest
towards Indian sub-continent in summers.
Nina Indian ocean branch of walker cell get
strengthen and surface winds are more intense.
condition is generally associated with good
Indian Ocean
Dipole
Indian Ocean
Dipole
? It is defined by the difference in sea surface
temperature between
hence a dipole)
Sea (western Indian
in the eastern Indian Ocean south of Indonesia.
? The IOD involves
surface temperatures (SST), between
"positive", "neutral” and
It is defined by the difference in sea surface
temperature between two areas (or poles,
hence a dipole) – a western pole in the Arabian
western Indian Ocean) and an eastern pole
in the eastern Indian Ocean south of Indonesia.
IOD involves a periodic oscillation of sea-
surface temperatures (SST), between
neutral” and "negative" phases.
Page 5


How El Nino
impacts
monsoon
rainfall in
India
La Nina
? With a high positive SOI, there would be a zone of low
atmospheric pressure
archipelago.
? The rising air from this region deflects
in both directions towards Africa and South America.
? In Indian Ocean,
zone from where surface winds blow as
monsoon towards Indian sub
? During La-Nina Indian ocean branch
strengthen and surface winds are more intense.
? La-Nina condition is
monsoon.
With a high positive SOI, there would be a zone of low
atmospheric pressure over Australia and Indonesian
rising air from this region deflects in upper atmosphere
in both directions towards Africa and South America.
Indian Ocean, the air descends down at high pressure
zone from where surface winds blow as Southwest
towards Indian sub-continent in summers.
Nina Indian ocean branch of walker cell get
strengthen and surface winds are more intense.
condition is generally associated with good
Indian Ocean
Dipole
Indian Ocean
Dipole
? It is defined by the difference in sea surface
temperature between
hence a dipole)
Sea (western Indian
in the eastern Indian Ocean south of Indonesia.
? The IOD involves
surface temperatures (SST), between
"positive", "neutral” and
It is defined by the difference in sea surface
temperature between two areas (or poles,
hence a dipole) – a western pole in the Arabian
western Indian Ocean) and an eastern pole
in the eastern Indian Ocean south of Indonesia.
IOD involves a periodic oscillation of sea-
surface temperatures (SST), between
neutral” and "negative" phases.
? A positive phase sees greater
surface temperatures and greater precipitation in
the western Indian Ocean region, with a
corresponding cooling of waters in the eastern
Indian Ocean—
adjacent land areas of Indonesia and
? The negative phase of the IOD brings about the
opposite conditions
greater precipitation in the eastern Indian Ocean,
and cooler and drier conditions in the west.
A positive phase sees greater-than-average sea-
surface temperatures and greater precipitation in
the western Indian Ocean region, with a
corresponding cooling of waters in the eastern
—which tends to cause droughts in
adjacent land areas of Indonesia and Australia
negative phase of the IOD brings about the
opposite conditions, with warmer water and
greater precipitation in the eastern Indian Ocean,
and drier conditions in the west.