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A general description of the Earth climate
system and its subcomponents: the
atmosphere, ocean, land surface, ice, and solid earth. |
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Week 1-2: Atmosphere (Chapters 3 and 4) |
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Global Energy Cycle |
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Basic Structure and Dynamics |
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General Circulation in the Troposphere |
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General Circulation in the Stratosphere |
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Week 3: Ocean (Chapter 5) |
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Basic Structure and Dynamics |
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Surface Ocean Circulation: Wind-Driven |
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Deep Ocean Circulation: Density-Driven |
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Week 4: land surface and Cryosphere (Handout) |
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Land Surface Properties (Soil and Vegetation) |
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Surface Energy and Water Balance |
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Sea Ice and Land Ice |
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Climate Roles of Land Surface and Ice |
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Global
Energy Balance |
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Basic
Dynamics |
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General
Circulation in the Troposphere |
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General
Circulation in the Stratosphere |
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Climate
Variability in the Troposphere and Stratosphere |
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Climate
Feedback Processes in the Atmosphere |
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Every
other year or so the normal winter pattern of a cold polar stratosphere
with a westerly vortex is interrupted in the middle winter. |
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The
polar vortex can completely disappear for a period of a few weeks. |
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During
the sudden warming period, the stratospheric temperatures can rise as much
as 40°K in a few days! |
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Basic
Dynamics |
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From atmospheric winds to oceanic currents |
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Ekman transport |
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Geostrophic Currents |
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Surface
Ocean Circulation: Wind-Driven |
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Subtropicl gyre |
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Boundary current |
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Deep
Ocean Circulation: Density-Driven |
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Thermohaline conveyor belt |
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Currents are in geostropic balance |
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Each gyre includes 4 current components: |
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two
boundary currents: western and eastern |
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two
transverse currents: easteward and westward |
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Western boundary current (jet stream of ocean) |
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the fast, deep, and narrow current moves warm water polarward (transport ~50 Sv or greater) |
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Eastern boundary current |
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the
slow, shallow, and broad current moves cold water equatorward (transport ~
10-15 Sv) |
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Trade wind-driven current |
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the moderately shallow and broad westward current (transport ~ 30
Sv) |
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Westerly-driven current |
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the wider and slower (than the trade wind-driven current) eastward
current |
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Climate
Role |
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Surface
Energy Balance |
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Surface
Water Balance |
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Vegetation (Canopy) |
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Soil
(moisture) |
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Surface ice of any depth is a much more
effective reflector of solar radiation than the underlying surface. |
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Sea ice is a good insulator and allows air
temperature to be very different from that of the seawater under the ice. |
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At present, year-round ice covers 11% of the
land area and 7% of the world ocean. |
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Internal
Structure of the Solid Earth |
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Theory of Plate Tectonics |
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History of Plate Tectonics |
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The faint young Sun paradox and its possible
explanation. |
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Why was Earth ice-free even at the poles 100 Myr
ago (the Mesozoic Era)? |
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What are the causes and climate effects of
changes in sea level through time? |
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What caused Earth’s climate to cool over the
last 55 Myr (the Cenozoic Era)? |
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Chemical weathering acts as Earth’s
thermostat and regulate its
long-term climate. |
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This thermostat mechanism lies in two facts: |
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(1)
the average global rate of chemical weathering depends on the state of
Earth’s climate, |
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(2)
weathering also has the capacity to alter that state by regulating the rate
which CO2 is removed from the atmosphere. |
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During active plate tectonic processes, carbon
cycles constantly between Earth’s interior and its surface. |
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The carbon moves from deep rock reservoirs to
the surface mainly as CO2 gas associated with volcanic activity
along the margins of Earth’s tectonic plates. |
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The centerpiece of the seafloor spreading
hypothesis is the concept that changes in the rate of seafloor spreading
over millions of years control the rate of delivery of CO2 to
the atmosphere from the large rock reservoir of carbon, with the resulting
changes in atmospheric CO2 concentrations controlling Earth’s
climate. |
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The uplifting weathering hypothesis asserts that
the global mean rate of chemical weathering is heavily affected by the
availability of fresh rock and mineral surfaces that the weathering process
can attack. |
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This hypothesis suggests that tectonic uplifting
enhances the exposure of freshly fragmented rock which is an important
factor in the intensity of chemical weathering. |
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This hypothesis looks at chemical weathering as
the active driver of climate change, rather than as a negative feedback
that moderates climate changes. |
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Climate Sensitivity and Feedback |
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Past Climate Change |
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El Nino-Southern Oscillation |
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Ozone Depletion |
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ENSO is a interannual (year-to-year) climate
variability in the eastern tropical Pacific Ocean. |
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ENSO is found to have profound impacts on global
climate. |
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