Transcript Ocean Literacy Principle 03

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OCEAN LITERACY
OCEAN LITERACY
Essential Principles & Fundamental Concepts of Ocean Science
PRINCIPLE 3
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REVISION HISTORY
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Aug 25, 2010
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ESSENTIAL PRINCIPLE 3
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The ocean is a major influence
on weather and climate
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3 | THE OCEAN IS A MAJOR INFLUENCE ON WEATHER AND CLIMATE
3(a) The ocean controls weather and climate by dominating the
Earth’s energy, water and carbon systems.
The Ocean Controls Weather & Climate
The sun and moon act on the ocean to form Earth’s winds, waves,
tides and currents, and to create special weather patterns. Over
longer time scales, these natural forces can also result in major
changes in the Earth’s climate.
The ocean dominates the Earth’s:
• Energy System – e.g. winds, waves
• Water System – e.g. Water Cycle
• Carbon System - e.g. Carbon Cycle
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3 | THE OCEAN IS A MAJOR INFLUENCE ON WEATHER AND CLIMATE
3(b) The ocean absorbs much of the solar radiation reaching Earth.
The ocean loses heat by evaporation. This heat loss drives
atmospheric circulation when, after it is released into the
atmosphere as water vapor, it condenses and forms rain.
Condensation of water evaporated from warm seas provides the
energy for hurricanes and cyclones.
Heat & Energy
• The ocean absorbs solar radiation from the Sun.
• The ocean loses that heat by evaporation.
• The heat loss drives atmospheric circulation.
• The water vapor rises, cools and condenses to form rain.
• The condensation provide the energy for hurricanes and cyclones.
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3 | THE OCEAN IS A MAJOR INFLUENCE ON WEATHER AND CLIMATE
3(c) The El Niño Southern Oscillation causes important changes in
global weather patterns because it changes the way heat is released
to the atmosphere in the Pacific.
El Niño-Southern Oscillation (ENSO)
El Niño-Southern Oscillation (ENSO) is a continual but irregular cycle of shifts
in ocean and atmospheric conditions that affect global weather patterns.
It’s effects vary widely. For people who live in Indonesia, Australia, or S.E.
Africa, El Niño can mean severe droughts and deadly forest fires. Ecuadorians,
Peruvians, or Californians, on the other hand, associate it with heavy rains that
can trigger devastating floods and mudslides. Severe El Niño events have
resulted in several thousand deaths worldwide, left thousands of people
homeless, and caused billions of dollars in damage. Yet residents on the N.E.
seaboard of the U.S credit El Niño with milder-than-normal winters and more
benign hurricane seasons.
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3 | THE OCEAN IS A MAJOR INFLUENCE ON WEATHER AND CLIMATE
3(d) Most rain that falls on land originally evaporated from the
tropical ocean.
Most Rain Originally Evaporated From The Tropical Ocean
The sun heats water in the ocean. Some of the water evaporates
into the air as water vapour. Ice and snow can also sublimate
directly into water vapour. Rising air currents take the water vapour
into the atmosphere along with water from evapotranspiration (water
transpired from plants and evaporated from soil).
Cooler temperatures here cause the vapour to condense into clouds.
As air currents move clouds around the globe, cloud particles
collide, grow, and fall from the sky as precipitation – i.e. rain, sleet or
snow.
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3 | THE OCEAN IS A MAJOR INFLUENCE ON WEATHER AND CLIMATE
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3(e) The ocean dominates the Earth’s carbon cycle. Half the primary productivity on Earth takes place in
the sunlit layers of the ocean and the ocean absorbs roughly half of all carbon dioxide added to the
atmosphere.
Carbon Cycle
Carbon dioxide
produced by
animals and from
humans burning
fossil fuels is
absorbed by
microscopic plants
and by chemical
processes in the
ocean.
Dead animals and
plants decay and
decompose over
millennia to
become fossils
and fossil fuels.
3 | THE OCEAN IS A MAJOR INFLUENCE ON WEATHER AND CLIMATE
3(f) The ocean has had, and will continue to have, a significant
influence on climate change by absorbing, storing, and moving heat,
carbon and water.
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3 | THE OCEAN IS A MAJOR INFLUENCE ON WEATHER AND CLIMATE
3(g) Changes in the ocean’s circulation have produced large, abrupt
changes in climate during the last 50,000 years.
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