2.3. (9/2) Global climate & terrestrial biomes Flashcards
atmospheric and oceanic movement
Why is the equator warmer than the poles? What is differential heating?
- solar rays pass through less atmosphere at the equator
- beam hits a larger area at the pole
- the angle of the ray determines the reflection percent
- higher albedo at poles (more reflection b/c light)
What is albedo?
amount of solar radiation reflected instead of absorbed
What is the net solar radiation at the equator and poles?
there is a net surplus at the equator and a net loss at the poles
What do the differences in temperature/energy lead to?
movement
- drives circulation of ocean and atmosphere
How much is the Earth’s rotational axis tilted?
23.5 degrees relative to its path around the sun
What does the Earth’s tilt cause?
Shifts where you get the band of highest radiation
What is the solar equator?
the latitude receiving the most direct radiation (changes seasonally)
- point at which the radiation is directly hitting from the sun
How does the climate system equilibrate the difference in heating?
- move atmosphere (wind patterns)
- hurricanes (uneven distribution of energy) (movement of air horizontally and vertically)
what drives vertical movement of air?
heating at surface of planet, warm air is less dense, and raises
What is conduction?
the ability of heat to pass through a substance
what is convection?
transfer of heat by movement of air or water
What two things are related?
temperature and pressure
What is adiabatic cooling?
removing pressure causes air to rise, expand, and cool
What is adiabatic heating?
falling air has more pressure so the temperature rises (decreases in volume) (molecules bang more)
What is latent heat release?
energy (heat) released when water vapor turns to precipitation
What kind of air holds more water vapor?
warm air
what usually happens when you having falling air?
more evaporation
What is Hadley cell circulation?
at the equator: lots of heating, rising air, precipitation
the air goes north and south to descend at 30 degrees
Why do you have dry conditions at 30 degrees?
the falling air is heating up which means it can hold more water causing more evaporation
What is the intertropical convergence zone? (ITCZ)
Where the northerly and southerly air meets and rises
What is the Coriolis effect?
when the flow of air is deflected because of the Earth’s rotation
In what directions is the air deflected in the northern and southern hemispheres?
northern: right
southern: left
What are the trade winds?
east winds coming out of tropical areas
What is the doldrum area?
the region between the winds
- not a lot of wind
what is important in determining climate in the tropics?
relative position to the shifting solar equator that moves with the seasons
The Hadley cells explain tropic and subtropic atmospheric circulation, but what drives prevailing wind patterns outside of this region?
largeness of temperature gradient
- also determines the speed of westerly winds at mid-latitudes
What kind of pattern explains why we find rainforests and deserts where we do?
Hadley cell latitudinal patterns of moisture circulation
Why is there are rainforest at 30 degrees north in Asia?
Monsoon cycle
What are monsoons driven by?
the temperature differences between an ocean and a continent
- peak of winter and summer
At what speed do oceans temperatures/seasons change?
much slower response than a continent
What are the surface temperatures of the land and ocean during summer and winter?
in the summer the land is hotter than the adjacent ocean, and cooler in the winter
how does a monsoon work in the summer?
- hot land surface = rising air
- rising air-> less pressure -> cools
- cool = can’t hold moisture -> precipitation
- air descends over cool ocean -> pulled back into rising air (repeat)
* mini Hadley cell
how does a monsoon work in the winter?
- cool land/ warm ocean
- rising air over the ocean -> precipitation -> falling air over land (drier conditions)
Why does the northern hemisphere experience more variable temperature
more land
- southern hemisphere has the ocean to moderate temperature
What are the characteristics of deep continental interiors? coastal areas?
- drier, variable
- maritime climate
what is maritime climate?
stable in terms of temperature
What are rain shadows?
- modifier local climate
- forced air masses that go up or down (change in pressure/temperature/water carrying capacity)
- rain where a prevailing wind hits and dry on the other side of the mountain
What is lake-effect snow?
- modifier of local climate
- lake warmer than surrounding air (going into winter)
- cold air mass moves across lake -> evaporation -> moisture held -> warming air -> air mass hits the other cold side (can’t hold moisture anymore leading to dumped snow)
- 30 -50 miles from lake coast snow drives
What do prevailing winds cause in oceans?
ocean currents and gyres
What do oceans disperse?
tropical heat to mid/high latitudes
What are biomes?
the broadest way to classify communities and ecosystems
What is climate space?
*Whittaker classification
plotted distribution of biomes according to average annual temperature and precipitation
- triangle: warm-moist, warm-dry, cool-dry
What is a walter climate diagram?
- summer months in the middle
- average temperature and precipitation on y axis
- scaled 10-degree temperature = 20 mm precipitation
When is plant growth limited by temperature? (walter climate diagram)
when the precipitation line is above the temperature line
when is plant growth limited by precipitation? (walter climate diagram)
when the precipitation line is below the temperature line
what is a growing season? (walter climate diagram)
when temperatures are above 0*C
what is another way to categorize biomes?
soil profiles: foundation of terrestrial biomes
what is the O horizon?
lose vegetation, no decomposition
* thin
what is the A horizon?
organic rich, hummus, partially decomposed
*garden
what is the E horizon?
leached soil (minerals carried away)
What is the B horizon?
chemical resemblance to parent layer with leached minerals
What is the C horizon?
broken bedrock
What is the R horizon?
unaltered parent material (bedrock)
What is a soil?
a complex mixture of living and non-living materials
What is a temperate seasonal forest?
- Pennsylvania
- deciduous: maple, beech, oak
- wide distribution
- moderate temperature and precipitation
- warmer and drier part: southeast with pines
What is the temperate rain forest?
- higher precipitation
- restricted
- douglas fir and coast redwood (60-70m tall)
- mild winters, heavy winter rain, foggy summers
- extensive during Mesozoic era
What kinds of human impact have temperate forests experienced?
- cities
- logging
- few old growth deciduous forests (east of Mississippi, Adirondacks)
What are temperate grasslands?
- continental interior
- hotter, drier summers
- enough moisture deficit for no trees
- prairies, steppes
- tallgrass (more rain) vs short grass
- nutrient rich, low acidity
- Mollisols: light color, homogenous, thick/alkaline/rich humus
What kinds of human impact have temperate grasslands experienced?
- agriculture and livestock production (particularly in the wetter, tallgrass areas
What are Mediterranean woodlands and shrublands?
- dry summer
- cool, wet winter
- maritime
- sclerophyllous shrubs
- chaparral/fynbos
- year-round growing season
- coasts
- small areas
what are sclerophyllous shrubs?
leathery, thick, prevent moisture loss
What are chaparrals and fynbos?
drought-tolerant grasses and shrubs
What limits plant growth in Mediterranean woodlands and shrublands?
dry summer, cold winter, frequent fires
What is the subtropical desert?
- descending branch of Hadley cell
- high evaporation
- low organic matter (not much primary productivity)
- low abundance, high diversity
- no precipitation
- always hot
- 20% of land surface
- year-round growing season
What are boreal forests?
- average 5 to -5*C
- Taiga
- dominated by spruce
- high latitude (50-60*N, North America/Eurasia)
- variable temperature
- precipitation always above temperature
- 11% land area
- evergreen conifers (firs)
- precipitation does not evaporate
- Podsolization for competition
What is podsolization?
Conifer needles release hydrogen ions as they decompose decreasing the pH of the soil which bleaches out minerals like iron and aluminum immobilizing them as oxides
How have Taigas been affected by human activity?
historically low, but increasing
What are tundras?
- average less than -5*C
- not a lot of microbial activity
- frozen soil (thaw to 0.5-1 m in short summer)
- north of Arcitic Circle
- superficially similar systems occur in Alpine zones
- growing season has less than 60cm of precipitation
- saturated soil because of impeded drainage and low evapotranspiration
- dwarf, woody shrubs
- many native mammals
What are human affects on tundra?
- low
- scare resources
Why do polygons form in the tunra?
freeze thaw and density
What sets tropical climates apart?
- daily temperature variation greater than monthly
- no frost
- differences are determines by seasonal precipitation pattern (ITCZ)
What are tropical rainforests?
- 10* of equator
- lots of rain leaches nutrients
- available nutrients sucked up by plants
- year-round growth rate
- Mycorrhizae
- lianas
- various canopy layers -> promotes diversity
- epiphytes
- evergreens
- seasonally deciduous broad-leaved trees
- probably contain ~1/2 of world’s species
- soil laterization
What are mycorrhizae?
- mutualistic relationship
-different to fungi - help gather nutrients
what are epiphytes
plants that grow on other plants
What are lianas?
woody vines
How do humans impact tropical rainforests?
lumber, food, medicines
What is laterization?
breaking down of clay particles leaches silicon leaving iron and aluminum oxides to dominate
What are tropical dry forests?
- pronounced dry and wet seasons
- leaf loss at dry season
- richer in nutrients
- erode easily
- year-round growing season
- 10-30* latitude from equator
How have humans impacted tropical dry forests?
- heavily settled
- cleared for agriculture
What is a tropical savanna?
It is a type of tropical dry forest (it just has less trees)
How have tropical savannas been impacted by human activities?
grazing livestock
