Climate

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Climate

• The average of the day-to-day weather over a long
  period of time at a specific place.
• The normals reported on television are really
  just climatological averages!
• Different parts of the world have different
  climates
• Orlando, Florida
• Point Barrow, Alaska

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Climate Variability

• Climate can change over time.
• There were once dinosaurs in Oklahoma.
• But we are really interested in a more short-term
  climate change.
• A change that can be observed over a few years,
  or at least in our lifetime.

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Short-term Climate Variability

• Changes in the solar output.
• The solar constant really isnt.
• Between 1981 to 1986, the solar output was
  measured to decrease by 0.018 per year.
• The total reduction was almost 0.1 in six years.
• Had this trend continued for another six years,
  the effects of the reduction in solar output may
  have had a noticeable effect on the global
  climate.

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Changes in the solar output.
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Short-term Climate Variability

• Changes in the number of sunspots.
• Sunspots are relatively large dark spots that
  appear on the surface of the sun.
• The temperature of the core of the sunspot is
  usually 4000 K compared to the 5800 K normal
  temperature of the surrounding solar surface.
• Sunspot numbers tend to fluctuate in an 11 year
  cycle (22 years if magnetic fluctuations are
  included).

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Sunspots
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Short-term Climate Variability

• There have been noted correspondence between
  sunspot number minima and colder temperatures on
  earth.
• Between 1645 and 1715 there was a period of few
  sunspots. This is called the Maunder Minimum.
• The Maunder Minimum corresponds to the little
  ice age where the average global temperature was
  estimated to be about 0.5oC cooler.

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Maunder Minimum
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Changes in the solar output.
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Short-term Climate Variability

• Volcanoes
• Large volcanic eruptions can have an impact on
  the climate of a region.
• Particles are ejected into the atmosphere that
  can alter the amount of radiation received at the
  surface.
• Sulfur compounds in ejected material can create
  sulfuric acid (H2SO4).
• This sulfuric acid absorbs solar radiation and
  increases the albedo.

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Short-term Climate Variability

• A year after the eruption of Tambura, New England
  experienced the year without a summer.
• Heavy snow in June
• Frost in July and August
• June mean temperatures were 3.5oC below normal
• August temperatures were 1-2oC below normal
• Cold weather was experience in England and Europe
• A year after the eruption of Pinatubo, the mean
  global air temperature dropped by almost 0.5oC
  compared to the previous 9-year average.

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Mt. Pinatubo
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Short-term Climate Variability

• Greenhouse Gasses
• Carbon Dioxide, Methane, Water Vapor, Nitrous
  Oxide, CFCs
• Increase CO2 and increase the temperature of the
  earths surface
• Do feedback mechanisms cancel this effect?

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El Ni?o

• El Niño refers to abnormally warm water in the
  tropical Pacific Ocean which usually first
  appears in March-May and lasts roughly until the
  same time the next year.
• The term "El Niño", meaning "little boy", refers
  to the Christ child, as the event typically shows
  warmest waters around Christmastime.
• At first, "El Niño" was used to refer to the warm
  waters along the equator off the coast of Peru,
  but now the term applies to the event which spans
  the entire tropical Pacific.

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El Ni?o

• El Niño brings drought to Hawaii 'This is the
  worst yet.
• The Fury Of El Nino
• IS IT EL NINO OF THE CENTURY?
• SHIFTING OCEAN CURRENTS IN THE PACIFIC COULD
  TRIGGER DRAMATIC SWINGS IN THE WORLD'S WEATHER

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El Ni?o

• Normally, there is relatively warm water (28C
  or 82F) in the far western Pacific.
• This warm water is a result of easterly winds
  which normally blow toward the west across the
  Pacific Ocean. These winds pile up water in the
  western Pacific Ocean which is heated by the sun.

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Easterly Equatorial Winds
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El Ni?o

• In the eastern Pacific, the easterly winds cause
  cold water to be drawn up from the ocean below.
• When water gets this warm, there are likely to be
  large areas of thunderstorms in the atmosphere
  above.

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El Ni?o
Normal Sea Surface Temperatures near the Equator
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El Ni?o
Normal Sea Temperatures at the Equator through a
depth of 500 m.
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El Ni?o
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El Ni?o
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Impacts of El Ni?o
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How often does El Ni?o Occur?

• 1902, 1905, 1911, 1914, 1918, 1923, 1925, 1930,
  1932, 1939, 1941, 1951, 1953, 1957, 1965, 1969,
  1972, 1976, 1982, 1986, 1991, 1994, 1997
• Usually El Niño events occur every 3 to 7 years,
  although they have been more frequent in recent
  decades than earlier in the century.
• El Niño events have been documented well back
  into the 1400's.

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More Impacts of El Ni?o
Anchovies in Peru

• The cold water off the coast of Peru has dramatic
  biological consequences. Namely, the catch of
  anchovies is greatly reduced.
• This can destroy the local fishing industry. So
  much, in fact, that the El Niño in 1972 appears
  to have permanently damaged the local ecology.
  Now, sardines have taken the place of anchovies
  in the ecosystem.

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Anchovies in Peru
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Mackerel and Salmon in the Northwest U.S.

• During an El Niño, it is not uncommon to have
  warm waters also stretching up the western coast
  of the U.S.
• This warm water confuses some of the fish in the
  region, altering their migration patterns.
• In the El Niños of 1982/83, 1991/92, and 1992/93,
  mackerel traveled farther north than usual.
• Being voracious predators which feed on young
  salmon, they severely reduced the salmon
  population.
• Some mackerel caught in 1992 and 1993 were found
  to have 6 to 8 young salmon in their stomachs!

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Mackerel and Salmon in the Northwest U.S.
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Human Health Effects

• Climate variability has profound effects on the
  Earth's living organisms.
• Changes in the incidence, duration, onset and
  intensity of storms, hurricanes, floods, and
  droughts greatly impact the life cycle of
  diseases of human, animals, and plants.

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Human Health Effects

• Because climate affects temperature, humidity,
  and precipitation, it influences human health via
  three interconnected pathways
• Distribution and quality of surface water
• Life cycle of disease vectors and host/vector
  relationships
• Predator/prey relationships which control
  populations of disease carrying animals.

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Human Health Effects

• El Niño has been associated with upsurges of
• Water-borne diseases such as hepatitis, shigella
  dysentery, typhoid, and cholera
• Vector-borne pathogens such as malaria, dengue,
  yellow fever, encephalitis, schistosomiasis,
  plague and hantavirus
• Agricultural pests such as rodents, insects,
  fungi, bacterium, and viruses.

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Impacts on the Military!!!

• EL NIÑO - ITS FAR-REACHING ENVIRONMENTAL EFFECTS
  ON ARMY TACTICAL DECISION AIDS
• To know the likely implications of an El Niño
  event in advance, will allow strategic and
  logistical planners to be better prepared in
  their efforts to diffuse chaos in the world's
  political and military arenas of tomorrow.

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The 1998 El Ni?o8 April 1998
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Last El Ni?o8 April 1998
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Last El Ni?o8 April 1998
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LastEl Ni?o 15 July 1998
Much Weaker!
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LastEl Ni?o 15 July 1998
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La Ni?a(Cold Episode)Effects