Struggle For Existence Part 4 Flashcards
Most important environment variable
Temperature
single most important source of ecological variation for life on earth arises
from latitudinal gradient in temperature
- hot near equator
- cold at poles
pattern comes form uneven distribution of radiant electromagnetic energy from sun
Why would the distribution would not be uneven if the earth was cylinder rather than sphere?
Sphere = sun hits earth at diff angles at diff latitudes. sun is far from earth enough that we consider incoming photon flux uniform stream of sun
- Density light = highest at equator (surface of earth is perpendpuclr 90 degrees to the vector of the incoming
Photon density per unit area declines as we move toward the poles because the angle of inci-dence declines from 90° to 0°, eventually reaching a tangent, where the rays skim parallel to the ground at the poles, not delivering any energy to the surface but instead zinging ineffectually off into space.
True
Earth axises titled ____ degrees off vertical
23.5
At spring and fall equinoxes, sun directly
overhead at noon
Northern hemisphere summer solstice, directly over_______ and Winter Solstice , directly over ______
1) 23.5 degree N
2) 23.5 degree S
Annual shift in angle are gradual but their effects on day length and on heat inout are profound
True
Tropic of Cancer
23.5 degree N
Tropic of Capricorn
23.5 degree S
Tropical region
Belt bounded by tropics
Solar equator
The lines of latitude closest to the sun
Solar equator socialites between _________, making one cycle per year
2 tropic lines
A photon heading for Toronto makes a longer transit through air than for the equator and the differences in the atmospheric transit length is non-trivial. Why?
Most of the energy reaching earth from sun is in the spectral range of light and the wavelength pass through air without giving up much of energy to air molecules. Light is hardly absorbed by air (air is transparent)
How does the incoming solar light energy transfer so much heat to the earth?
Light hits the surface other than air, solid surfaces (dark ones absorb more heat)
- When photons heat surfaces, they are absorbed and reradiated at longer infrared wavelengths
Light = heat (converted)
Therefore, solar energy heats earths surface
- surface heats air near surface
- heats the air at the bottom of the atmosphere, not the air at the top that is closest to the sun. And this heating is strongest near the equator.
Delivery of solar derived heat to bottom of atmosphere has consequences rather than top. What is it?
2) Why does it boil over?
Examples;
pot of water
- place heat source above pot, pointing down at water = nothing violent happens (water at surface heat up and start to evaporate and eventually all the water to vapour)
- place heat at bottom = bubbles as water in bottom starts to vapour (water set to increasingly violent motion as a simmer tune into a boil, boil into rolling boil and eventually boils over)
2) Boil over:
- circulation happens because heating from the bottom makes lower layers of water LESS DENSE
- Packets of hotter, LOW Density water MORE buoyant than Colder water above them, so they propelled upward and colder water sinks
Convection
Packets of hotter, low -density water are more buoyant than the colder water above them, so they are propelled upward and the colder water sinks
solar heating of the bottom of the atmosphere sets up
Atmospheric Circulation
Atmospheric pressure
weight of a column of air compresses against Kathy by gravity
Reduction in density causes
1) meteorological low pressure zone
2) heated air to rise above solar equator
What happens to air that rises?
As air rises, creates a particle vacuum beneath it and suction causes surface air to wards solar equator from both north and south
New air: heats up and rises
- sets continuer flow of air that rises
Why can’t air keep rising forever?
it bumps up against top of atmosphere and pushed way form solar equator moving to N and S
As air rises, why does it expand more?
less atmosphere above to compare it
Adiabatic lapse rate
relationship of temp drop to altitude gain
BY the time air reaches upper atmosphere, what is air like?
for a 1km rise, air temp drops 5 Celusis
no longer warm and buoyant
it becomes cold and heavy
Air masses at earths surface moved _______ equator, air masses at HIGHER altitude move in ________ equator
1) toward
2) farther from
Intertropical convergence Sone ITCZ
zone of rising, heated air
intertropical: solar equator moves between the 2 tropic lines over the course of a year
What are the 2 circulation hoops that moves to solar equator over a year?
Hadley Cells (British meteorologist who explained trade winds)
Hadley cells effects what? 1) and 2)
1) set prevailing winds in motion
2) effects precipitation
what is the air in Hadley cells like?
humid, heavily laden with water vapour
What happens to air in Hadley cells that rises? what places are there?
As it rises and cools, must of WV (water vapour) condense into liquid water cloud and falls as rain (equatorial tropical regions very rainy)
- rainforest, teaming with life
Hadley cells:
What happens to air by the time it reaches the upper atmosphere?
When that are descends, what happens?
- lost moisture
- hot, dry and desiccating air
as dry air returns to ITCZ
slowly picks up moisture from ocean and wet tropical regions for next cycle.
Hadley cells are continuous loops, but they are not _____ loops?
closed
Ferrel/mid-lattitude cells
flow that move towards poles initiate a 2nd pair of conveyor belt.
Ferrel cells.
- As dry air moves across earth surface toward poles, it picks up moisture
- rises creates another pair of rainy and snowy zones
- rising air reaches upper atmosphere, shoved to N and S by continuous flow form beneath.
high level flows towards the _______ close ferrel loops, flow towards _____ set up 3rd pair of circulation loops (polar cells )
1) equator
2) poles
Polar cells are the _______ and most ______ of the 3
weakest and most diffuse
Casual mechanism
theory and modelling as tools and allow predictions
Why rewind patterns critical?
redistribute heat and redistribute water (as vapour) from oceans to continent
What happens without redistribution of water?
Continents would be deserts
6-cell circulation directions:
between 0 and 30 degree N: \_\_\_\_\_\_\_\_\_ between 30 degree N and 60 degree N \_\_\_\_\_\_\_\_\_ between 60 degree North Pole \_\_\_\_\_\_\_
1) Hadley Cells (N to S)
2) Ferrel cells (S to N)
3) Polar cells (to S)
prevailing Westerlies:
wind blow from prairies
What imparts an east-west directional ten-dency to wind flows?
No actual force at work
Why does westerlies air arise?
- air being pushed straight northward by Ferrell cell is passing over the surface of a spinning sphere. Produces a twist of wind vectors
Coriolis Effect (pseudoforce)
Twist of wind vectors with resect to earth surface caused by air pushed straight north by ferrel cells
Understand how Coriolis effect happens:
1) earth spinning on axis rapidly & atmosphere near earth spins with it
2) As you proceed from equator to N pole, speed of earth rotating slows because earths diameter shrinks
Why does speed of earth rotating slow as you go form equator to N pole?
earths diameter shrinks
Wind direction in this latitudinal range acquires a _____________ component caused by coils effect
__________ comments caused by Ferrel Circulation
1) westerly
2) southerly
Air moving towards equator, air falls _______ their parent target rather than ahead. Zones subject to prevailing eaterlies
behind
prevailing winds ______. at the altitudes in the middles of the atmospheric cells
strongest
Doldrums
winless equatorial areas
- listless depression term
horsel latitude
windless areas at 30˚N and S
Roaring 40s
around 45˚S, prevailing westerlies grew fierce and known as
- winds so powerful and relentless
Why is Roaring 40s wind so powerful?
- no significant land masses in vast southern oceans
jet streams
concentrated and barrow westerlies in irregular fashion
Northern polar jet streams form between what cells?
- form at boundary between ferrel and polar cells
Long term averages:
generalizations about climate patterns in certain latitudes
biggest influences on organism place to live
temperature and precipitate
Oceans circulation pattern s
- just as air packets of diff temp rise and fall in gaseous atmosphere = directional flow, so do massive packets of water products circulation patterns (currents) in oceans
massive packets of water form circulation and what is it called in ocean?
currents
oceans influence what? 1) and 2)
- nearby land masses by producing thermal inertia
- what goes on in ocean affects neighbour land masses
Thermal inertia from ocean
land heat up = summer
land cool down = winter than water
Center of contents, bring arrives ______ in coastal area and islands, summer ______ into autumn
slowly,
longer into
Continental climates
found toward centre of bug land masses
-lack water buffering system temperature
- SUMMER = HOTTER
WINTER = FRIGID
what does ITCZ follows the equator only _____
- approximately (yes that’s correct, don’t doubt)
________ in temp zone is 1st and forest a matter of temp differences
Seasonality
in tropics, temp and ______ rainy through year
- has evergreen forest
uniform
How do continents get their rainfall?
From air that gets loaded with WV by passing over oceans
How do continents get their rainfall?
From air that gets loaded with WV by passing over oceans
- more load of water = warm water, warm water = warms air
- warmer air = get more WV
How can winds beings more potential rain?
if they being winds bowling over warm water, warm water = more WV
What happens when terrestrial topography interacts with prevailing winds?
sharp rainfall differences
air rising in ITCZ, calling causes
condensation and precipitation
Orogenic
mountain generated recitation
dry air depends eastern (leeward) slope and warms from what.
compression and friction
- now, dry air
- smilar to Hadley cells air
Rain shadow
rain served region with xeric vegetation from short grass prairie to near-desert
As dry air moves eastern, picks up moisture from what
vegetation and additional air flow from N or S
Rocky mountains creates long north south rampart , (whole NA is a rain shadow), T or F
T
Riparian vegetation or gallery forest
permanent river support narrow bands of richer, taller vegetation along banks
(cotton woods = Canada)
Additional info: for review
Yet another strong effect of topography arises from differential exposure to the sun. In the northern hemisphere, south-facing hillsides face the direct, parching rays of the sun for most of the day; north-facing slopes are mostly shaded, cooler, and more mois t. Consequently, the vegetation on slopes with different aspects usually differs sharply.
