1. BIOMS: Major ecosystems
on Earth |
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| Physical Geography
SUN:
Source of energy for EarthShort wave radiation to upper level
atmosphere: 2 cal/sq cm/min
To surface: 50%
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| Back-radiation: long-wave (green-house effect) |
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Glass
~ large molecules
Greenhouse gases:
water (H2O), nitrous oxide (N2O), methane (CH4), and carbon dioxide
(CO2)
Aerosol particles (brown cloud)
Methane: 60% of global methane emissions are caused by human-related
activities
fossil fuel production, animal husbandry (enteric fermentation
in livestock and manure management), rice cultivation, biomass
burning, and waste management.
nitrous oxide: human-related sources of N2O are agricultural
soil management, animal manure management, sewage treatment, mobile
and stationary combustion of fossil fuel, and nitric acid production.
Naturally from a wide variety of biological sources in soil and
water, particularly microbial action in wet tropical forests.
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Brown cloud: aerosol particles from woodfire,
cars, factories
Ramanathan et al. 2007. Nature: abstract,
news
Measured aerosol concentration and solar fluxes directly by light
weight aeroplans.
Brown clouds enhanced atmospheric solar heating by 50%
Atmospheric brown clouds are mostly the result
of biomass burning and fossil fuel consumption. They consist of
a mixture of light-absorbing and light-scattering aerosols and
therefore contribute to atmospheric solar heating and surface
cooling. The sum of the two climate forcing terms—the net aerosol
forcing effect—is thought to be negative and may have masked as
much as half of the global warming attributed to the recent rapid
rise in greenhouse gases.... Here we use three lightweight unmanned
aerial vehicles that were vertically stacked between 0.5 and 3
km over the polluted Indian Ocean. ... We found that atmospheric
brown clouds enhanced lower atmospheric solar heating by about
50 per cent... . We propose that the combined warming trend of
0.25 K per decade may be sufficient to account for the observed
retreat of the Himalayan glaciers |
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Why are tropics hot?
Equator: sunlight perpendicular
More energy / unit on surface |
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are winters cold? Axis is tilted by 23,5 0.
Please read Fredrik Venold's essay on seasonal temperature changes
in Oslo (student
assignment)
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Air rises at Equator
Travels to Poles
Sinks at Poles
Travels back to Equator
Steady winds from the Poles?
No, not really...
What's going on here? |
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The Earth is rotating: Coriolis force
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Earth rotates on its axis fromWest to East
Air lags behind
Coriolis effect
Rotating Earth breaks up air currents into six coils
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Major
winds on Earth |
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Major warm and cold currents |
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Global warming causing ice-age in
Europe?
Read this BBC - OU article
http://www.open2.net/landscapemysteries/article2_pg2.htm
Picture shows the Great Conveyor belt transporting
energy to the North. See original pic and article here.
Student essay by Rickard Kohler here |
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| Generation of precipitation
Heat, Evaporation, Air rising, Cooling, Cool air
holds less humidity -> Precipitation |
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Uplift of air: cooling -> precipitation
Descending air (high pressure): no cloud formation |
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Mountains
Air is forced upward by mountain
Air cools
Precipitation
Dry air descents
Arid areas: deep in the continents, downwind of mountains
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Convective uplift: air warms
Orographic uplift: mountains drive the air
Frontal uplift: warm and cool air clashes |
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| Cold and hot winds meet
Hurrican:radar image
Eye of typhon
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| Biogeography |
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Global temperature: 21st February 2006
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| Annual precipitation |
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Warmth
and water: photosynthesis
Figure: satellite image of chlorophyl avareged for 8 years. |
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Major bioms (dependence on precipitation and temperature)
- TUNDRA
- BOREAL FOREST or TAIGA
- TEMPERATE BROADLEAF DECIDUOUS FOREST
- TROPICAL BROADLEAF EVERGREEN FOREST
- TROPICAL SAVANNA
- DESERTSCRUB
- TEMPERATE GRASSLANDS
- MEDITERRANEAN SCRUB
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| Please, note: you need to be able to fill in the blank graph |
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Bioms
and vegetation |
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Terrestrial bioms of Earth |
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| Tropical
Broadleaf Evergreen Forest: The Rainforest
Precipitation: 200 – 400
Temperature: 20-350C
High growth rate
Tall trees – shadow - levels
Forest floor, understory, canopy, emergent layer
High productivity
2 million species (50% of all)
more
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Why are tropics wet?
Although rain forests create most of their rain,
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| winds also bring humid air from oceans to rainforests |
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DESTRUCTION OF RAIN FORESTS
- Commercial logging
- Clearing land for grazing animals and for
- Subsistence farming
Shallow soil, low carrying capacity,agriculture cannot be sustained,
erosion
Carbon to atmosphere:adds to global warming
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SAVANNAS: tropical grasslands
Rainfall: 75-125 cmRain is seasonal
Temperature < 18 oC
Vegetation: perennial grasses (controlled by grazing – fire)
Fauna: greatest diversity of ungulates> 40 species more |
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| DESERT, DESERTSCRUB |
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Rainfall:
< 25 cm
more |
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TEMPERATE GRASSLANDS (Prairie, pampa, steppe, puszta)
Precipitation: 25-50 cm (rain and snow) more
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Vegetation.
Perennial grasses and perennial forbs
No grazing: invasive plants |
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TEMPERATE (MEDITARRANIAN) SCRUB: Chaparral
Precipitation: 40-100 cm (summers are dry!)
Vegetation: (evergreen) shrubs
more
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Regular
burns stabilize vegetation.
Global warming: frequent fires |
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| TEMPERATE BROADLEAF DECIDUOUS FOREST
Precipitation: 50 – 150 cm
Temperature: ~ 6 month growing season
More |
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| TAIGA OR BOREAL FOREST
Largest terrestrial biom
Rainfall: 40 – 100 cm (mostly snow) (but low evaporation, high
humidity)
Temperature: 50-100 frost free days
Vegetation: Needleleaf trees
Fauna: large herbivores, fur-bearing predators more
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Trillemarka area: the last unlogged landscape in Norway wiki
Temperate coniferous forests (taiga or boreal forest) |
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TUNDRA
Tundra: from Finnish „tunturia”= treeless plain
Temperature: extremely low (3-12 oC in summer)
Precipitation: variable (15 – 25 cm)
Arctic tundra
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extremely short growing season,
low primary production
More |
| Alpine tundra (mountains) |
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| HUMAN IMPACT |
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| Exponential growth during industrial phase |
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Mexico
city today and in 1628 |
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Human impact
greenhouse gases |
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insecticides: DDT
was banned (Stockholm
Convention), however, traces of DDT can be detected in YOUR
tissues.
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| Ozone hole |
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| IN THE NEWS (follow the links if interested) |
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- How to Buy Time in the Fight against Climate Change: Mobilize
to Stop Soot and Methane SciAm
- Sperm whale faeces 'offset CO2 emissions' BBC
Iron defecation by sperm whales stimulates carbon export in
the Southern Ocean html
- A new study from Toronto researchers suggests that the collapse
of a large portion of the Antarctic ice sheet would shift the
very axis of the Earth. here
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See aquatic bioms here
excellent pdf file on bioms here |
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