Page 75 - Yucaipa Valley Water District - Board Workshop
P. 75
Workshop Memorandum No. 16-006 Page 8 of 8
(10 centimeters) above normal. The green areas indicate normal conditions. The height of the
ocean water relates, in part, to its temperature, and is an indicator of the amount of heat stored
in the ocean below.
Within this area, surface temperatures are greater than 86 degrees Fahrenheit (30 degrees
Celsius) in the central equatorial Pacific and near 70 degrees Fahrenheit (21 degrees Celsius) off
the coast of the Americas. This El Niño signal encompasses a surface area of 6 million square
miles (16 million square kilometers) -- more than twice as big as the continental United States.
While no one can predict the exact timing or intensity of U.S. El Niño impacts, for drought-stricken
California and the U.S. West, it's expected to bring some relief.
"The water story for much of the American West over most of the past decade has been
dominated by punishing drought," said JPL climatologi st Bill Patzert. "Reservoir levels have fallen
to record or near-record lows, while groundwater tables have dropped dangerously in many areas.
Now we're preparing to see the flip side of nature's water cycle -- the arrival of steady, heavy rains
and snowfall."
In 1982-83 and 1997-98, large El Niños delivered about twice the average amount of rainfall to
Southern California, along with mudslides, floods, high winds, lightning strikes and high surf. But
Patzert cautioned that El Niño events are not drought busters. "Over the long haul, big El Niños
are infrequent and supply only seven percent of California's water," he said.
"Looking ahead to summer, we might not be celebrating the demise of this El Niño," cautioned
Patzert. "It could be followed by a La Niña, which could bring roughly opposite effects to the
world's weather."
La Niñas are essentially the opposite of El Niño conditions. During a La Niña episode, trade winds
are stronger than normal, and the cold water that no rmally exists along the coast of South America
extends to the central equatorial Pacific. La Niña episodes change global weather patterns and
are associated with less moisture in the air over cooler ocean waters. This results in less rain
along the coasts of North and South America and along the central and eastern equatorial Pacific,
and more rain in the far Western Pacific.
El Niño events are part of the long-term, evolving state of global climate, for which measurements
of sea surface height are a key indicator.
For an animation of the evolution of the 2015 and 1997 El Niños, visit:
https://sealevel.jpl.nasa.gov/elnino2015/2015-animated.gif
For more information on how NASA studies El Niño, visit:
http://climatesciences.jpl.nasa.gov/enso
To learn more about NASA's satellite altimetry programs, visit:
http://sealevel.jpl.nasa.gov
For more information about NASA's Earth science activities, visit:
http://www.nasa.gov/earth
Yucaipa Valley Water District - January 12, 2016 - Page 71 of 279
(10 centimeters) above normal. The green areas indicate normal conditions. The height of the
ocean water relates, in part, to its temperature, and is an indicator of the amount of heat stored
in the ocean below.
Within this area, surface temperatures are greater than 86 degrees Fahrenheit (30 degrees
Celsius) in the central equatorial Pacific and near 70 degrees Fahrenheit (21 degrees Celsius) off
the coast of the Americas. This El Niño signal encompasses a surface area of 6 million square
miles (16 million square kilometers) -- more than twice as big as the continental United States.
While no one can predict the exact timing or intensity of U.S. El Niño impacts, for drought-stricken
California and the U.S. West, it's expected to bring some relief.
"The water story for much of the American West over most of the past decade has been
dominated by punishing drought," said JPL climatologi st Bill Patzert. "Reservoir levels have fallen
to record or near-record lows, while groundwater tables have dropped dangerously in many areas.
Now we're preparing to see the flip side of nature's water cycle -- the arrival of steady, heavy rains
and snowfall."
In 1982-83 and 1997-98, large El Niños delivered about twice the average amount of rainfall to
Southern California, along with mudslides, floods, high winds, lightning strikes and high surf. But
Patzert cautioned that El Niño events are not drought busters. "Over the long haul, big El Niños
are infrequent and supply only seven percent of California's water," he said.
"Looking ahead to summer, we might not be celebrating the demise of this El Niño," cautioned
Patzert. "It could be followed by a La Niña, which could bring roughly opposite effects to the
world's weather."
La Niñas are essentially the opposite of El Niño conditions. During a La Niña episode, trade winds
are stronger than normal, and the cold water that no rmally exists along the coast of South America
extends to the central equatorial Pacific. La Niña episodes change global weather patterns and
are associated with less moisture in the air over cooler ocean waters. This results in less rain
along the coasts of North and South America and along the central and eastern equatorial Pacific,
and more rain in the far Western Pacific.
El Niño events are part of the long-term, evolving state of global climate, for which measurements
of sea surface height are a key indicator.
For an animation of the evolution of the 2015 and 1997 El Niños, visit:
https://sealevel.jpl.nasa.gov/elnino2015/2015-animated.gif
For more information on how NASA studies El Niño, visit:
http://climatesciences.jpl.nasa.gov/enso
To learn more about NASA's satellite altimetry programs, visit:
http://sealevel.jpl.nasa.gov
For more information about NASA's Earth science activities, visit:
http://www.nasa.gov/earth
Yucaipa Valley Water District - January 12, 2016 - Page 71 of 279
