|
|
|
Climate
Roles |
|
Surface
Energy Balance |
|
Surface
Water Balance |
|
Sea Ice |
|
Land Ice |
|
|
|
|
greenhouse
gas emissions |
|
è affects
global energy and biogeochemical cycles |
|
creation
of aerosols |
|
è affects
global energy and water cycles |
|
surface
reflectivity (albedo) |
|
è affects
global energy cycle |
|
impacts
on surface hydrology |
|
è affect
global water cycle |
|
|
|
|
|
|
|
|
|
|
|
|
Vegetation Properties |
|
Type and density |
|
Soil Properties |
|
Depth and physical properties |
|
(e.g., moisture) |
|
|
|
|
Typical Height |
|
|
|
Leaf Area Index (LAI) |
|
Leaf
area index (LAI) is ratio of the total area of all leaves (one-side) on a
plant to the area of ground covered by the plant. |
|
|
|
It
defines the area that interacts with solar radiation and that is
responsible for carbon absorption and exchange with the atmosphere. |
|
|
|
|
|
|
|
|
Surface ice of any depth is a much more
effective reflector of solar radiation than the underlying surface. |
|
Sea ice is a good insulator and allows air
temperature to be very different from that of the seawater under the ice. |
|
At present, year-round ice covers 11% of the
land area and 7% of the world ocean. |
|
|
|
|
One
major climate effect of sea ice is to seal off the underlying ocean from
interaction with the atmosphere. |
|
Without
an sea ice cover, high-latitude oceans transfers large amount of heat to
the atmosphere, especially in winter. |
|
With an
sea ice cover, the heat flux into the atmosphere is stopped. In addition,
the ice surface absorbs little incoming solar radiation. Winter air
temperature can cool 30°C or more near a sea-ice cover. |
|
|
|
|
|
Ice cores retrieve climate records extending
back thousands of years in small mountain glaciers to as much as hundreds
of thousands of years in continental sized ice sheets. |
|
The antarctic ice sheet has layers that extend
back over 400,000 years. |
|
The Greenland ice sheet has layers that extended
back 100,000 years. |
|
|
|
|
Much of climate history is recorded in four
climate archives: |
|
(1)
Sediments |
|
(2)
Ice |
|
(3)
Corals |
|
(4)
Trees |
|
How are those records dated? |
|
Hoe much of Earth’s history each archive spans? |
|
What is the resolution of climate history
yielded by each? |
|
|
|
|
The Antarctic Ice Sheet holds the equivalent in
seawater of 66 meters of global sea level. |
|
The Greenland Ice Sheet holds the equivalent of
6 meters of global seawater. |
|
|
|
|
|
|
This hypothesis argues that millennial
oscillations were produced by the internal interactions among various
components of the climate system. |
|
One most likely internal interaction is the one
associated with the deep-water formation in the North Atlantic. |
|
Millennial oscillations can be produced from
changes in northward flow of warm, salty surface water along the conveyor
belt. |
|
Stronger conveyor flow releases heat that melts
ice and lowers the salinity of the North Atlantic, eventually slowing or
stopping the formation of deep water. |
|
Weaker flow then causes salinity to rise,
completing the cycle. |
|